r -, r b -rtl4 · r -, r -, r . l ~-ltf'~ b 07 -p~ €"" -rtl4 . hampton water works...

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r -, r -, r l B 07 - €"" -rtL4 . HAMPTON WATER WORKS CO. 1 .,_,. 1.) A AUG 0 6 \99\ HAND DELIVERED Department of Environmental Service.! August 5, 1991 !dvard J. Schaidt , P.E., Ph.D. Director, Dapart•ant of Environmental Sarvicaa 6 Hazan Dr 1 va concord, NH 03302-0095 RE: BALI.!ST!RO REPORT - HAMPTON WATER WORKS CO. HOBBS WELL tl5 Dear Doctor Schaidt: 0 Attached ia a raviav or tha June 27 , 1991 Thoaaa p, Ballaataro "Aaaaaaaant" Rapo.,.-t, Thia review waa partoraad by the hydroqaoloqiat ataff of o. L. Mahar company for tha Coapany. Aa indicatad. in thia raviav , tha Ballaataro MODFLOW •odal and aubaaquant concluaiona dravn baaed on tha aodal ara aarioualy tlavad and randar tha antira report to ba auapact in tara• of ita credibility. The coapany and D. L. Mahar are available to you and tha o.!. s. Staff tor quaationa or further aaaiatanca that we can otter with regard to any and all data andjor apprabala o! the data on Ha•pton' Well Sincerely, Manager (}' I• Attachment Su... PO Boo 11•1 • H• mi)IIOn. NH036<'2 t6031iH· lllt -..J

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Page 1: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

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07 - euro -rtL4 HAMPTON WATER WORKS CO 1_ 1 ) A

AUG 0 6 99

HAND DELIVERED Department of Environmental Service

August 5 1991

dvard J Schaidt PE PhD Director Dapartbullant of Environmental Sarvicaa 6 Hazan Dr 1 va concord NH 03302-0095

RE BALISTRO REPORT - HAMPTON WATER WORKS CO HOBBS WELL tl5

Dear Doctor Schaidt

0 Attached ia a raviav or tha June 27 1991 Thoaaa p Ballaataro Aaaaaaaant Rapo-t Thia review waa partoraad by the hydroqaoloqiat ataff of o L Mahar company for tha Coapany Aa indicatad in thia raviav tha Ballaataro MODFLOW bullodal and aubaaquant concluaiona dravn baaed on tha aodal ara aarioualy tlavad and randar tha antira report to ba auapact in tarabull of ita credibility

The coapany and D L Mahar are available to you and tha o s Staff tor quaationa or further aaaiatanca that we can otter with regard to any and all data andjor apprabala o the data on Habullpton bull Well fl~l

Sincerely

~~~~Manager ~unq (

I bull Attachment

~21+9 Su bull PO Boo 11bull1 bull Hbull mi)IIOn NH036lt2 t6031iHmiddot lllt

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DL MAHER CO ~~~~t=AUG0699t

Department of Auquot s lUI[nvlronmental Strvicll

Mr Keith Boaeung Hampton Water Works 52 High Street Hampton NH 03842

REI Review of Balleatero Report

Dear Mr Boaaung1

We have completed a review o f the report titled Aaaeantent of the Potential Interaction Between the Aquifer Contamination Prom the Coakley Landfill and the Hampton Water Works Propoaed Hobba Well by Thomabull P Balleatero June 27 1991 The Balle1tero report h r e ferenced in t hh letter by the inltlah TB D L MAHER Report a D LH and the Remedial Inveatiqation Coakley Landfill report u RICL The following conta pertain to the aforementioned reporta1

1 Page 1 - T B report aaya inorganic and organic paruatera

indicative of landfill leachate have been detected abull tar

bullouth and webullt aa North Road However on paqe 7-30

(RLC L ) bulltatea However bullbulltimatea of qroundwater bull- shy

~9bull velocitiebull within the Little River Wetlandbull of only

003 to 0 3 teetday indicate that advective tranaport of

VOC contaminantbull from the Coakley Landfill aoutherly toward

monitorinq vella GZ-127 and GZ-129 may not have occurred in

the approximate ly lS yean aince the landfill dhpoaal

activitiebull beqan Therefore an additional undefined 10urce

h conaidered a pouibilitymiddot

2 Page 7- Eucutive Summary (R IC L ) - Although water

quality data suggest c ontaminant migration aa far aa North

Road within the Li ttle Ri ver wate r s hed hydrogeo l ogic da t a

71 CONCORD Sl REET NORlH READING MASSACHUSETlS 01864 6171933middot3210 FAX 508166 middot3299

co

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indicate that thh 1a improbable bull The T B report doea not

qualify ita statement through recognition of the RICL

raporta uncerta inty on contamination migration to North Road

or ita aourca

3 Paqa J - (TB ) - The Litt e River as preaented in the TB

report did not and could not have depoaited the bullavathbull of

low permeability material which holatea the Hobba Site from

Coakley The Little River h of recent origin reaultinq

from runoff on top of the underlying low permeable marine

depoe ita The low permeable material ia a product of aanda

aUt and claya depodtad in a glacioeatuarine marine

enviroNMnt during deglaciation approximately 8000-11000

B P The Little River ie too IMell of dynampJIIic erosional

-chanhbull to have reworked the aandgravel depoeitbull A

caplata undantandinq of the bulltudy are qeoloqic

depobullitional processes h a very important part in

conbulltructinq an accurate model

4 Paqa 3 (TB) - 0 L MAHER Te8t Well loq 9-90 bullhowbull

pradoinantly dlt and clay are found throuqhout the

bulltratabullbull indicative of marine deposita of vary low

hydraulic c onductivity The T B report states - there h

atronq evidence that t he sand and qravel deposits o f the

Hobba Site ia connec ted to t he sand and gravel of the

Coakley Site - Howe ver TB does not preaent any evidenc e

other than speculation

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5 Page S (T B) etatee ~ bedrock fracturebull to the weet of

Coakley exte nd towarde t he Hobba Site The TB report

doea not eubetantiate tha statement with d11ta in thie

portion of tha report

6 Paqe 6 (TB) - middot 60 o f the average annual rainfall

recharqea the aanda and gravele bull the OLM report utilized

50 not 60 of the average annual rainfall On page 11 of

T B report 21 inchesyearbull h used which equah 50

Apparent lack of cone latency in data uee

7 Paqe 8 (TBJ- a apecific yield of 005 falh within

publbhed water table valuea particularly for ailty eand _

aedimenta auch aa thoae edatinq within the Hobba aquifer

8 Pa9a 8-9 (T B ) - The logic of a direct ratio chanqa ~tween

groundwater level and change in total precipitation ia

incorrect Thle logic anwnee the aquifer ia a cloaed

ayater11 without horhontal dhcharge The Hobba aquifer h

reactinq in reality aa a mound with horhontal diacharqe

continually occurring through the fine qrain aedJnenta

aurroundinq the aquifer Aa precipitation entera the

aquifer qroundwater dilchar9t1 11 o ngo in9 draining the

aquifer A direc t rat io relationehip between precipitation

and groundwa ter levale h flawed

A rain induc ed rea ponee o f t he water tabla in a fi neshy

grained (allty) unc onfined aquHar 11 related to the eoil

moiature c o nt e nt air e ntrainmen t and the tillable porosi ty

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in the uneaturated zona Dry material can ftbaorb

eubltantially more water than can wet material because in

the latter c aae part o f t he atoraqe apace ie alre ady

occupied Therefore in reality the TB value o f bull 16 of

precipitation 18 e hown t o result in r echar9e bull la not a

reliable nor accurate number Alec the Hobba aquifer doea

not have uniform aquifer characterletice Run off on the

marine aUtclay cap overlying parte of the aquifer affect

the rate of recharge often imparting a delayed reaponae to

water lavale The recharqe area a actually quite amorphous

in ahape not suitable to the application of a circulac

andylie utilhinq linear radiua logic Derivinq an area of

radiua of 3210 feet and any concluliona from thh area are

not valid

t Pa~ 9 (T B ) - An 80 ratio of water level chanqe to total

precipitation ill u11ad in the T B report to indicate water

leveh at the end of the pWIIpinq test should be 0 1 feat

hiqher In contra lit a 16 ratio 111 used on paqe 9 (T B)

to e11tiJiate the recharqe area to the well The T B report

loqic 18 contradictory and euqqe11ts t hat the valubullbull selected

for a particular analyais are baBed on whichever value will

produce the most severe r e 11ult not on ac tual field

conditionbull The 11tre n9 th o f the conclusions r e ac hed by this

analyllill ill wea k

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10 Paqa 10 (TB J - The effect of hydrogeologic boundaziee such

aa lov permeable sediments and a ehallow depth to bedrock in

the vicinity of Well 6-90 Wood Knoll Drive serving aa a

hydrogeologic boundary between U SGS 69 waa not mentioned

in the T B report Test Well H- 2 is located in low

permeable sediments with shallow depth to bedrock The

pumping effects would take a much longer period of time to

be felt withJn the low permeable eedimente surrounding M-2

than in higher permeable sandbull and gravel

11 Page 10 (TB) - It appeare that a 3420 foot radius of

influence after 20 days of pumpinq at 260 GPM ia calculated

by the Theis equation The Theis equation assumes the

J aquifer ia hOiftOgeneoua hotroplc of uniform thickneaa of

infinite areal extent horizontal piezometric surface the

vell 1bull fully ~netratinq and tranerniuivity ie conbulltant

The ubulle of the Theie equation in thia report qrobullbullly

violatebull thbullbullbull aabullumptionbull when applied to loncr dbtancebull

(qreater than 700 feet) from the well The Hobbbull aquifer h

hiqhly heterocrenaoua of variable thicknenhydraulic

conductivity and areal extent A eloping water table

exbtbull Bedrock barrier boundaries axht within 700 feet of

the pwnped well near Wood rnoll and 1200 feet to the north

near North Road The depth to bedrock shallows to 30 feet

at M-2 Co nc luding t hat uniform radius o f 3420 feet h111

achieved after 20 days pumping h er r oneoue

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12 Paqe 10 (TB) - There 18 little evidence that Mtainted

river waterbull exists at RIC L aampling location S-2 along

the North River which contains cherllical parameters capable

of migrating through the marine aedimentll to the Hobbe Well

Site

13 Paqe 10-11 (TB) - The logic of 58 GPH appears to be basad

on the use of the Thaie equation To reach a aubatantial

concluaion and precision of 58 GPM utilizing the Theia

equation h incorrect

14 Paqe 10 (TB) - The 3420 foot radius appears to incorporate

the apecUic yield value of 0 05 yet on page 8 the T B

report states middoto2 is moat likely a very reasonable value

for sand and gravel bull There does not appear to be

condatency in the T B reporU logic

lS Paqe 12 (TB) - The DL M report flow path model equations

do not utilize storage coefficient valuebull in bullteady bulltate

analybullh Porosity is only utilized in the reverbullbull particle

tracking portion of the model for time of travel capture

ampone delineation not hydraulic head calculationa It would

be ubulleful for the TB author to read the flow path manual

to better understand the model

16 (DL M ) report flow path wae utilized o nly in a conceptual

format (DLM paqe 30) abull a precunor to r unning MODFLOW

Thie procedure is utlhe quite o ften i n many states to

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efficiently and economically determine where additionall field data needs to be collected in order to increase the

predicative accuracy of the HODFLOW model

17 Page 13 (TB)- a porosity of 02 not specific yield of

0 2 wae utilized in the 180-day particle tracking zoe of

the DLM report

18 Page 13 (TB) report states there was an annual rainfall

rate of 78 inchesyear during the seven days of pumping

Thh statement ia confusing and should be clarified Ie the

equivalent amount of rainfall experienced during the pump

teat extrapolated out an annual baaia

0 19 Page lJ (TB ) - The 180-day ZOC determined i n the OL M

report h derived from reverse particle tracking which

deterwinea how lonq it would take a conaervative aolute euch

aa chloride to reach the wbullll The time of travbulll to

TOT-ZOC dbulllineation method haa been an accepted method by

the EPA The particle tracking zoe method ia D2t intended

to mimic the area of influence of the well It is incorrect

tor the TB report to auume the particle tr~ckinq zoe of

thbull vall is the aame as its area of influence

20 Page 17 (TB ) report states Corneliua Brook has an

elevation of 59 feet HSL However Cor nelius Brook when it

haa water in it has a signific ant gradient and not just one

elevation of 59 feet Cornellua Brook is not a po nd but

_ -7 shy

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rather hu multiple elevations depending on where i t l8

lftllaaured (Henry Fuller property or near I-95) Teet Nella

3middot84 and 4-84 which are located in c loae proximity to

Cornelius Brook have groundwater elevationa of 6724 and

65 75 feet reapectlvely The Little River has variable

elevations betwee n 6744 and 652 feet at RIC L staff

qauga SN-9 The TB report aqain eeema to aelect values

for a particular analyah baaed upon whichever value will

produce the desired outcome Therefore it la lncorract for

the TB report to aaaume ~that the Little River would be

aarving aa aOIMI portion of the recharge to the Hobbs Well~

baaed upon thh logic

21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta

aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull

Site b anhotropic hiqhly etratified with variable

hydraulic conductivitlee and traneminivltlee thereby

viohtinq the majority of the Theia auumptionbull and

conclubullione derived thereof

22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the

y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct

a atraiqht line encompaebullinq small dhtancee and drawing

bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect

Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat

ie covered yet the T B report extrapolatebull t he line out to

10 000 feet

-middotshy

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The T B Figure 1 plot clearly shows the drawdown ie

variable and not uniform in all directions thereby

violating a major aaaumption of Thela theory Teat Well

5-84 ahowa greater drawdown than Teet Well 11-90 in TB

Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from

the pumping well than 11-90 ( 97) It is reasonable to

conclude that low permeable boundarlea muet e xist in the

directio n of 5-84 If a radial line la constructed

connec ting 2-84 to 11-90 leas drawdown la s hown towards

11-90 indicative of more permeable material existing in

thia directio n The aquifer permeability variations are

clearly ahovn on DLH report Figure P4

A conparison of OLM teat well logs 5-84 and 11-90

ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84

Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while

11-90 pumped 20 GPM DL H cro section 8-8 shows leu

permeable eilty eand and gravel (not highly permeability

zones as stated in the TB report) surrounds the highly

permeable und and gravel in which the e ight inch pumped

well h located As an example on Tab l e J o f the RICL

report low hydraulic conductivity (lq values a r e shown for

six out of seven overburden wel ls even though t he strata

descriptions would imply a high~ value TB Figure 1 and

D L H P- 4 confirm the exhtence of l ow permeable barrier

boundaries to the north and northeast o f the pumped well

eite It ia incorrect t o c alc ulate and apply a radius o f

- 9 shy

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l influence projecting (10000 feat in TB report) in the

direction of and beyond the barrier boundarlee

I 23 Page 18 - TB Figure 1 plot doea not include all t he

observation well data points thereby biasing the

conclusions

24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the

principal recharge direction to the well is from the

northwat and weat Thil recharge direction interpretation

bullbullkbullbull aenae aa it is in the direction of the center of the

aquifer

25 Page 18 (TB) - The last aentence in paragraph one

beginning with Both wells ~ and the first sentence in

paragraph two beginning with ~Another interpretation bull

contradict one another

2 Paqe 18 - T B atatee One curious point but does not aay

what that point is

27 Paqbull 18 - TB report doea not aubatanthte what data in the

drawdown level ill revealing vertical flow from the

underlying bedrock

28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J

fracture tracea underlying the aite The O LM report

atatea bulla potential north - northeaat trending fault atructure

may underlie the we ll sitebull The D L M r epo r t sta t ement

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l vabull baaed upon cron-section interpretation ll2t from remote

1enaln9 and geophysical methods Frecture tracea are

obtained from rerre eeneing imagery analysis not croae

I aactlon i nterpretation The TB r epor t impllea that the

D L H report is s aying the structure 1a fact where the

DLM words poten t ioll and may are ignored

29 Page 20 - T B report Theae fractures presumably continue

directly towards the Ho bbs Site The major frequency

concentration of lineamentamp i dentified in the R IC L study

rlqure 5 doea rurt ehow the prominent lineaments 1111

continuing towards the Hobbs Site The TB report and

IIOdal have incorrectly extrapolated the photolineament swarm

0 aa ahown in the RICL report RI CL bedrock

110nltorin9 well GZ-128 wu drille d in the prominent

UneiUMtnt ewarm waet of the Coakley Landfill to a depth of

184 feet and produced only 0 25 GPH Tabla 4 (R IC L)

ehowe packer pressure taetad hydraulic conduc tivities

ranqinq frobull 014 to 682 feetday GZ-128 was not packer

teetad because o f the nonfractured and l ow water bearing

characterhtics o f the bedrock GZ-105 (bedrock corehola)

only had a hydraulic conductivity o f 2 0 fee tday Basad

upon the field technic al drill dat4 presented in the

R I cL report i t can Jl2t be concluded tha t the prominent

lineament s warm ae identified o n Figure 5 has a high

hydraulic conductivity Remote sensing analy8111 only

identlfie11 linear photo feature11 These f e a t ures may also

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be attributed to nonhydraulically significant geologic

1tructure1 Remote aenaing is an ~art- and drawing far

reachim~ concluaiona without drilling data ill incorrec t

However thh letter recognizee that due to the limitations

of remota saneincJ other signi ficant water bearing fracturea

may exbt in the bedrock not identified in the R ICL

JO Page 20 - TB states ~ bedrock groundwater generally flowa

in the direction of the Little River - However the T B

report oaita that bedrock groundwater aho generally flowbull

aoutheabullt to North Brook as ahovn on Fiqure 13 of the

R ICL report Bedrock groundwater flowbull radially in bullany

directionbull from the Coakley Landfill and the TB report

should not uae the word bullqenerally bull as it impli one major

direction only when in fact there are many flow pathe

R IC L total volatile organic compounds in

Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127

128 129 and 130 were either nondetected or leu than 5 ppb

Theee leveh are very low concentrations Only GZ-105

ehowed eignificant volatile organic compounds weet of the

Coakley Landfill The VOC levels at GZ-129 and GZ-130 may

b attributed t o additional small transient lind undefined

bullourcea in this area The R I C L r epo r t conc ludes o n paqe

8 - Exec utive Summary bullAt t his t lme however five years

of qrou ndwater contam i na t i o n e x ist away from the l andfill

per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill

- 12shy

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a likely consequence of the diepereive radial flow and

reaultant contaminant dilution ae well abull othe r operative

attenuation mechaniems diacueaed herein Beaed on the

available data it is anticipated that these olttenuatlon

mechanismbull would be a significant llrniting factor in the

diatance contaminants are able to migrate from the landfill

in detectable conc entrations

31 Pa9e 20 (TB) -The OLM and RICL reporta do not

auqqeat that the bedrock and overburden groundwater are

atrictly aeparated from each other

32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa

the Hobbs Site will create flow of groundwater fro11 beneath

and po ibly east of the Little River durinq amplltended low

rainfall recharge periods bull h very weak and baaed upon

faulty auwnptiona and data No creditable field data or

analyaia were brought forth to support the conclusionbull

JJ Fax Page J (TB) - Placing much emphasis upon the

conclusions derived from the application of Theis theory to

large distances beyond the pumping well is not valid due to

the qaologic conditione grouly violate Theta uawnptione

34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods

It is unclear aa to which time period conclus i o ns are

derived for It i s hiqhly unlikely pumpinq effects c an

deleteriously propaqate in 20 days thro uqh t he l ow permeable

- 13 shy

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11atariale located east of the Hobbs Site

35 Paqe llA (T B ) concludes that the safe yield from the

Hobbs Site is in the ranqe of 14 to 58 GPW If this yield

h true than the combined pumpage o f all the residential

wellbull in the study area will exceed the safe yie ld and

potentially impact the Coakley Landfill

36 Paqa 22 - TB reports etatea (1) a nything th11t wu not

sand and gravel laterally or vertically) was impermeable

and (2) streams to the northwest (Cornelius Brook) was

repreaented aa havinq a constant water level (basically an

infinite supply of water) bull In the D L MAHER report Paqe

Jl only the bedrock waa treated aa impermeable The llarine

aedlaentbull vera treated aa a constant head boundary allovinq

for flow into the aquifer Cornelius Brook waa not modeled

bullbull havinq a constant water level in the D L MAHER report

37 Paqe 22 (TB) -Some of the streams modeled as drains are

actually perched above the aquifer11 groundwater table upon

very low permeable marine sedmenta The drainbull are not

JnOdeled correctly Cornelius Brook dries up naturally from

June throuqh September and a significant portion h perched

above the aquifers water table Cornelius Brook receives

ita intermittent recharqe from runoff o n top o f the marine

aediment c ap overlying the northern portion of the Hobba

aquife r Some of t he Little River drain c ella are not

located properly Drain file conductance values appear very

-1 4 shy

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high for etreama flowing upon silts and claye

38 Page 27 (T B) model wa11 run b) atar tng at ateady state

conditione 2 of nonnal rechnrge for 180 day a and pumping

250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead

Protection area delineation requires the contributing area

to ~ delineated for a period of 180 daye pumpin with no

net rainfall recharge upon the ~~ regional

piezometric surface map This method of Wellhead

delineation wae stated by Paul Currier Administrator

Groundwater Protection Bureau during the July 25 1991

bullbullUnq at D E S offices in Concord The TB report

apparently did not model the zoe under thie criteria

39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling

effort it h etated that the model should uee hydraulic

coefficients which were measured in the field~ but fails to

follow through with this premise in the model The

tranbullmhbulllvity values selected for both fractured and

unfractured bedrock are neither explained nor supported by

field data If the va lues were taken from publlahed ranges

they are at t he upper ende of t heee rangee and not

reflective of typical conditio ne in New Enqland Based on

Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of

4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x

10middot1 to 1 2 x 10 feet day for unfractured roc k are more

realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy

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U S GS Water Supply Paper 2220 page 13 ehowa hydraulic

conductivity rangee for igneoua lind metamorphic rocks of

10middot7 feat day unfractured to 15 feet day fracture d

40 Page 218 (T B) - The r e port no tee t hat a ~three-layer

ayetam waa modeled however the model used wae a twt middotmiddot layer

110del It appears that the VCONT variable wae ueed to

repreaent the eiltclayfine eand layer with layer

thickneea eat to o ne foot Thera h no eupportive data of

the one foot thic knen value other than being arbitrarily

aeaiqnad Thia ie not an accurate rapraaantation of actual

conditiona nor ie it the beat way to fully and accurately

-adal thh ayatem

41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy

layer RIOdal and the eimpUfying aWDption of horhontal

layerl re1ult in a model which doee not reflect the actual

qeoloqy at thia alta The variable bedrock topography and

aquifer hydraulic conductivitiebull muet be accounte d for in

the lftOdal if an accurate delineation of the rona of

contribution 1a to be made

42 (T B ) - Thera h no me ntion in the text of either a

aanaitiv ity anal yeh being made or o f a water budget being

c alc ula t ed The s e efforts are both important compone nts of

a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the

acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d

they ehould ha ve been no t ed i n t he report I f e ither o f

- 16 shy

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these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

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area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

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n Q = = Ul

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the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

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49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

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conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

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habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

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C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 2: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

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bull EltCltllWIDl I

DL MAHER CO ~~~~t=AUG0699t

Department of Auquot s lUI[nvlronmental Strvicll

Mr Keith Boaeung Hampton Water Works 52 High Street Hampton NH 03842

REI Review of Balleatero Report

Dear Mr Boaaung1

We have completed a review o f the report titled Aaaeantent of the Potential Interaction Between the Aquifer Contamination Prom the Coakley Landfill and the Hampton Water Works Propoaed Hobba Well by Thomabull P Balleatero June 27 1991 The Balle1tero report h r e ferenced in t hh letter by the inltlah TB D L MAHER Report a D LH and the Remedial Inveatiqation Coakley Landfill report u RICL The following conta pertain to the aforementioned reporta1

1 Page 1 - T B report aaya inorganic and organic paruatera

indicative of landfill leachate have been detected abull tar

bullouth and webullt aa North Road However on paqe 7-30

(RLC L ) bulltatea However bullbulltimatea of qroundwater bull- shy

~9bull velocitiebull within the Little River Wetlandbull of only

003 to 0 3 teetday indicate that advective tranaport of

VOC contaminantbull from the Coakley Landfill aoutherly toward

monitorinq vella GZ-127 and GZ-129 may not have occurred in

the approximate ly lS yean aince the landfill dhpoaal

activitiebull beqan Therefore an additional undefined 10urce

h conaidered a pouibilitymiddot

2 Page 7- Eucutive Summary (R IC L ) - Although water

quality data suggest c ontaminant migration aa far aa North

Road within the Li ttle Ri ver wate r s hed hydrogeo l ogic da t a

71 CONCORD Sl REET NORlH READING MASSACHUSETlS 01864 6171933middot3210 FAX 508166 middot3299

co

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indicate that thh 1a improbable bull The T B report doea not

qualify ita statement through recognition of the RICL

raporta uncerta inty on contamination migration to North Road

or ita aourca

3 Paqa J - (TB ) - The Litt e River as preaented in the TB

report did not and could not have depoaited the bullavathbull of

low permeability material which holatea the Hobba Site from

Coakley The Little River h of recent origin reaultinq

from runoff on top of the underlying low permeable marine

depoe ita The low permeable material ia a product of aanda

aUt and claya depodtad in a glacioeatuarine marine

enviroNMnt during deglaciation approximately 8000-11000

B P The Little River ie too IMell of dynampJIIic erosional

-chanhbull to have reworked the aandgravel depoeitbull A

caplata undantandinq of the bulltudy are qeoloqic

depobullitional processes h a very important part in

conbulltructinq an accurate model

4 Paqa 3 (TB) - 0 L MAHER Te8t Well loq 9-90 bullhowbull

pradoinantly dlt and clay are found throuqhout the

bulltratabullbull indicative of marine deposita of vary low

hydraulic c onductivity The T B report states - there h

atronq evidence that t he sand and qravel deposits o f the

Hobba Site ia connec ted to t he sand and gravel of the

Coakley Site - Howe ver TB does not preaent any evidenc e

other than speculation

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5 Page S (T B) etatee ~ bedrock fracturebull to the weet of

Coakley exte nd towarde t he Hobba Site The TB report

doea not eubetantiate tha statement with d11ta in thie

portion of tha report

6 Paqe 6 (TB) - middot 60 o f the average annual rainfall

recharqea the aanda and gravele bull the OLM report utilized

50 not 60 of the average annual rainfall On page 11 of

T B report 21 inchesyearbull h used which equah 50

Apparent lack of cone latency in data uee

7 Paqe 8 (TBJ- a apecific yield of 005 falh within

publbhed water table valuea particularly for ailty eand _

aedimenta auch aa thoae edatinq within the Hobba aquifer

8 Pa9a 8-9 (T B ) - The logic of a direct ratio chanqa ~tween

groundwater level and change in total precipitation ia

incorrect Thle logic anwnee the aquifer ia a cloaed

ayater11 without horhontal dhcharge The Hobba aquifer h

reactinq in reality aa a mound with horhontal diacharqe

continually occurring through the fine qrain aedJnenta

aurroundinq the aquifer Aa precipitation entera the

aquifer qroundwater dilchar9t1 11 o ngo in9 draining the

aquifer A direc t rat io relationehip between precipitation

and groundwa ter levale h flawed

A rain induc ed rea ponee o f t he water tabla in a fi neshy

grained (allty) unc onfined aquHar 11 related to the eoil

moiature c o nt e nt air e ntrainmen t and the tillable porosi ty

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in the uneaturated zona Dry material can ftbaorb

eubltantially more water than can wet material because in

the latter c aae part o f t he atoraqe apace ie alre ady

occupied Therefore in reality the TB value o f bull 16 of

precipitation 18 e hown t o result in r echar9e bull la not a

reliable nor accurate number Alec the Hobba aquifer doea

not have uniform aquifer characterletice Run off on the

marine aUtclay cap overlying parte of the aquifer affect

the rate of recharge often imparting a delayed reaponae to

water lavale The recharqe area a actually quite amorphous

in ahape not suitable to the application of a circulac

andylie utilhinq linear radiua logic Derivinq an area of

radiua of 3210 feet and any concluliona from thh area are

not valid

t Pa~ 9 (T B ) - An 80 ratio of water level chanqe to total

precipitation ill u11ad in the T B report to indicate water

leveh at the end of the pWIIpinq test should be 0 1 feat

hiqher In contra lit a 16 ratio 111 used on paqe 9 (T B)

to e11tiJiate the recharqe area to the well The T B report

loqic 18 contradictory and euqqe11ts t hat the valubullbull selected

for a particular analyais are baBed on whichever value will

produce the most severe r e 11ult not on ac tual field

conditionbull The 11tre n9 th o f the conclusions r e ac hed by this

analyllill ill wea k

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10 Paqa 10 (TB J - The effect of hydrogeologic boundaziee such

aa lov permeable sediments and a ehallow depth to bedrock in

the vicinity of Well 6-90 Wood Knoll Drive serving aa a

hydrogeologic boundary between U SGS 69 waa not mentioned

in the T B report Test Well H- 2 is located in low

permeable sediments with shallow depth to bedrock The

pumping effects would take a much longer period of time to

be felt withJn the low permeable eedimente surrounding M-2

than in higher permeable sandbull and gravel

11 Page 10 (TB) - It appeare that a 3420 foot radius of

influence after 20 days of pumpinq at 260 GPM ia calculated

by the Theis equation The Theis equation assumes the

J aquifer ia hOiftOgeneoua hotroplc of uniform thickneaa of

infinite areal extent horizontal piezometric surface the

vell 1bull fully ~netratinq and tranerniuivity ie conbulltant

The ubulle of the Theie equation in thia report qrobullbullly

violatebull thbullbullbull aabullumptionbull when applied to loncr dbtancebull

(qreater than 700 feet) from the well The Hobbbull aquifer h

hiqhly heterocrenaoua of variable thicknenhydraulic

conductivity and areal extent A eloping water table

exbtbull Bedrock barrier boundaries axht within 700 feet of

the pwnped well near Wood rnoll and 1200 feet to the north

near North Road The depth to bedrock shallows to 30 feet

at M-2 Co nc luding t hat uniform radius o f 3420 feet h111

achieved after 20 days pumping h er r oneoue

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12 Paqe 10 (TB) - There 18 little evidence that Mtainted

river waterbull exists at RIC L aampling location S-2 along

the North River which contains cherllical parameters capable

of migrating through the marine aedimentll to the Hobbe Well

Site

13 Paqe 10-11 (TB) - The logic of 58 GPH appears to be basad

on the use of the Thaie equation To reach a aubatantial

concluaion and precision of 58 GPM utilizing the Theia

equation h incorrect

14 Paqe 10 (TB) - The 3420 foot radius appears to incorporate

the apecUic yield value of 0 05 yet on page 8 the T B

report states middoto2 is moat likely a very reasonable value

for sand and gravel bull There does not appear to be

condatency in the T B reporU logic

lS Paqe 12 (TB) - The DL M report flow path model equations

do not utilize storage coefficient valuebull in bullteady bulltate

analybullh Porosity is only utilized in the reverbullbull particle

tracking portion of the model for time of travel capture

ampone delineation not hydraulic head calculationa It would

be ubulleful for the TB author to read the flow path manual

to better understand the model

16 (DL M ) report flow path wae utilized o nly in a conceptual

format (DLM paqe 30) abull a precunor to r unning MODFLOW

Thie procedure is utlhe quite o ften i n many states to

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efficiently and economically determine where additionall field data needs to be collected in order to increase the

predicative accuracy of the HODFLOW model

17 Page 13 (TB)- a porosity of 02 not specific yield of

0 2 wae utilized in the 180-day particle tracking zoe of

the DLM report

18 Page 13 (TB) report states there was an annual rainfall

rate of 78 inchesyear during the seven days of pumping

Thh statement ia confusing and should be clarified Ie the

equivalent amount of rainfall experienced during the pump

teat extrapolated out an annual baaia

0 19 Page lJ (TB ) - The 180-day ZOC determined i n the OL M

report h derived from reverse particle tracking which

deterwinea how lonq it would take a conaervative aolute euch

aa chloride to reach the wbullll The time of travbulll to

TOT-ZOC dbulllineation method haa been an accepted method by

the EPA The particle tracking zoe method ia D2t intended

to mimic the area of influence of the well It is incorrect

tor the TB report to auume the particle tr~ckinq zoe of

thbull vall is the aame as its area of influence

20 Page 17 (TB ) report states Corneliua Brook has an

elevation of 59 feet HSL However Cor nelius Brook when it

haa water in it has a signific ant gradient and not just one

elevation of 59 feet Cornellua Brook is not a po nd but

_ -7 shy

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rather hu multiple elevations depending on where i t l8

lftllaaured (Henry Fuller property or near I-95) Teet Nella

3middot84 and 4-84 which are located in c loae proximity to

Cornelius Brook have groundwater elevationa of 6724 and

65 75 feet reapectlvely The Little River has variable

elevations betwee n 6744 and 652 feet at RIC L staff

qauga SN-9 The TB report aqain eeema to aelect values

for a particular analyah baaed upon whichever value will

produce the desired outcome Therefore it la lncorract for

the TB report to aaaume ~that the Little River would be

aarving aa aOIMI portion of the recharge to the Hobbs Well~

baaed upon thh logic

21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta

aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull

Site b anhotropic hiqhly etratified with variable

hydraulic conductivitlee and traneminivltlee thereby

viohtinq the majority of the Theia auumptionbull and

conclubullione derived thereof

22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the

y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct

a atraiqht line encompaebullinq small dhtancee and drawing

bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect

Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat

ie covered yet the T B report extrapolatebull t he line out to

10 000 feet

-middotshy

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The T B Figure 1 plot clearly shows the drawdown ie

variable and not uniform in all directions thereby

violating a major aaaumption of Thela theory Teat Well

5-84 ahowa greater drawdown than Teet Well 11-90 in TB

Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from

the pumping well than 11-90 ( 97) It is reasonable to

conclude that low permeable boundarlea muet e xist in the

directio n of 5-84 If a radial line la constructed

connec ting 2-84 to 11-90 leas drawdown la s hown towards

11-90 indicative of more permeable material existing in

thia directio n The aquifer permeability variations are

clearly ahovn on DLH report Figure P4

A conparison of OLM teat well logs 5-84 and 11-90

ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84

Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while

11-90 pumped 20 GPM DL H cro section 8-8 shows leu

permeable eilty eand and gravel (not highly permeability

zones as stated in the TB report) surrounds the highly

permeable und and gravel in which the e ight inch pumped

well h located As an example on Tab l e J o f the RICL

report low hydraulic conductivity (lq values a r e shown for

six out of seven overburden wel ls even though t he strata

descriptions would imply a high~ value TB Figure 1 and

D L H P- 4 confirm the exhtence of l ow permeable barrier

boundaries to the north and northeast o f the pumped well

eite It ia incorrect t o c alc ulate and apply a radius o f

- 9 shy

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l influence projecting (10000 feat in TB report) in the

direction of and beyond the barrier boundarlee

I 23 Page 18 - TB Figure 1 plot doea not include all t he

observation well data points thereby biasing the

conclusions

24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the

principal recharge direction to the well is from the

northwat and weat Thil recharge direction interpretation

bullbullkbullbull aenae aa it is in the direction of the center of the

aquifer

25 Page 18 (TB) - The last aentence in paragraph one

beginning with Both wells ~ and the first sentence in

paragraph two beginning with ~Another interpretation bull

contradict one another

2 Paqe 18 - T B atatee One curious point but does not aay

what that point is

27 Paqbull 18 - TB report doea not aubatanthte what data in the

drawdown level ill revealing vertical flow from the

underlying bedrock

28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J

fracture tracea underlying the aite The O LM report

atatea bulla potential north - northeaat trending fault atructure

may underlie the we ll sitebull The D L M r epo r t sta t ement

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l vabull baaed upon cron-section interpretation ll2t from remote

1enaln9 and geophysical methods Frecture tracea are

obtained from rerre eeneing imagery analysis not croae

I aactlon i nterpretation The TB r epor t impllea that the

D L H report is s aying the structure 1a fact where the

DLM words poten t ioll and may are ignored

29 Page 20 - T B report Theae fractures presumably continue

directly towards the Ho bbs Site The major frequency

concentration of lineamentamp i dentified in the R IC L study

rlqure 5 doea rurt ehow the prominent lineaments 1111

continuing towards the Hobbs Site The TB report and

IIOdal have incorrectly extrapolated the photolineament swarm

0 aa ahown in the RICL report RI CL bedrock

110nltorin9 well GZ-128 wu drille d in the prominent

UneiUMtnt ewarm waet of the Coakley Landfill to a depth of

184 feet and produced only 0 25 GPH Tabla 4 (R IC L)

ehowe packer pressure taetad hydraulic conduc tivities

ranqinq frobull 014 to 682 feetday GZ-128 was not packer

teetad because o f the nonfractured and l ow water bearing

characterhtics o f the bedrock GZ-105 (bedrock corehola)

only had a hydraulic conductivity o f 2 0 fee tday Basad

upon the field technic al drill dat4 presented in the

R I cL report i t can Jl2t be concluded tha t the prominent

lineament s warm ae identified o n Figure 5 has a high

hydraulic conductivity Remote sensing analy8111 only

identlfie11 linear photo feature11 These f e a t ures may also

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be attributed to nonhydraulically significant geologic

1tructure1 Remote aenaing is an ~art- and drawing far

reachim~ concluaiona without drilling data ill incorrec t

However thh letter recognizee that due to the limitations

of remota saneincJ other signi ficant water bearing fracturea

may exbt in the bedrock not identified in the R ICL

JO Page 20 - TB states ~ bedrock groundwater generally flowa

in the direction of the Little River - However the T B

report oaita that bedrock groundwater aho generally flowbull

aoutheabullt to North Brook as ahovn on Fiqure 13 of the

R ICL report Bedrock groundwater flowbull radially in bullany

directionbull from the Coakley Landfill and the TB report

should not uae the word bullqenerally bull as it impli one major

direction only when in fact there are many flow pathe

R IC L total volatile organic compounds in

Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127

128 129 and 130 were either nondetected or leu than 5 ppb

Theee leveh are very low concentrations Only GZ-105

ehowed eignificant volatile organic compounds weet of the

Coakley Landfill The VOC levels at GZ-129 and GZ-130 may

b attributed t o additional small transient lind undefined

bullourcea in this area The R I C L r epo r t conc ludes o n paqe

8 - Exec utive Summary bullAt t his t lme however five years

of qrou ndwater contam i na t i o n e x ist away from the l andfill

per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill

- 12shy

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a likely consequence of the diepereive radial flow and

reaultant contaminant dilution ae well abull othe r operative

attenuation mechaniems diacueaed herein Beaed on the

available data it is anticipated that these olttenuatlon

mechanismbull would be a significant llrniting factor in the

diatance contaminants are able to migrate from the landfill

in detectable conc entrations

31 Pa9e 20 (TB) -The OLM and RICL reporta do not

auqqeat that the bedrock and overburden groundwater are

atrictly aeparated from each other

32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa

the Hobbs Site will create flow of groundwater fro11 beneath

and po ibly east of the Little River durinq amplltended low

rainfall recharge periods bull h very weak and baaed upon

faulty auwnptiona and data No creditable field data or

analyaia were brought forth to support the conclusionbull

JJ Fax Page J (TB) - Placing much emphasis upon the

conclusions derived from the application of Theis theory to

large distances beyond the pumping well is not valid due to

the qaologic conditione grouly violate Theta uawnptione

34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods

It is unclear aa to which time period conclus i o ns are

derived for It i s hiqhly unlikely pumpinq effects c an

deleteriously propaqate in 20 days thro uqh t he l ow permeable

- 13 shy

~ n = = =Ul

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11atariale located east of the Hobbs Site

35 Paqe llA (T B ) concludes that the safe yield from the

Hobbs Site is in the ranqe of 14 to 58 GPW If this yield

h true than the combined pumpage o f all the residential

wellbull in the study area will exceed the safe yie ld and

potentially impact the Coakley Landfill

36 Paqa 22 - TB reports etatea (1) a nything th11t wu not

sand and gravel laterally or vertically) was impermeable

and (2) streams to the northwest (Cornelius Brook) was

repreaented aa havinq a constant water level (basically an

infinite supply of water) bull In the D L MAHER report Paqe

Jl only the bedrock waa treated aa impermeable The llarine

aedlaentbull vera treated aa a constant head boundary allovinq

for flow into the aquifer Cornelius Brook waa not modeled

bullbull havinq a constant water level in the D L MAHER report

37 Paqe 22 (TB) -Some of the streams modeled as drains are

actually perched above the aquifer11 groundwater table upon

very low permeable marine sedmenta The drainbull are not

JnOdeled correctly Cornelius Brook dries up naturally from

June throuqh September and a significant portion h perched

above the aquifers water table Cornelius Brook receives

ita intermittent recharqe from runoff o n top o f the marine

aediment c ap overlying the northern portion of the Hobba

aquife r Some of t he Little River drain c ella are not

located properly Drain file conductance values appear very

-1 4 shy

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high for etreama flowing upon silts and claye

38 Page 27 (T B) model wa11 run b) atar tng at ateady state

conditione 2 of nonnal rechnrge for 180 day a and pumping

250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead

Protection area delineation requires the contributing area

to ~ delineated for a period of 180 daye pumpin with no

net rainfall recharge upon the ~~ regional

piezometric surface map This method of Wellhead

delineation wae stated by Paul Currier Administrator

Groundwater Protection Bureau during the July 25 1991

bullbullUnq at D E S offices in Concord The TB report

apparently did not model the zoe under thie criteria

39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling

effort it h etated that the model should uee hydraulic

coefficients which were measured in the field~ but fails to

follow through with this premise in the model The

tranbullmhbulllvity values selected for both fractured and

unfractured bedrock are neither explained nor supported by

field data If the va lues were taken from publlahed ranges

they are at t he upper ende of t heee rangee and not

reflective of typical conditio ne in New Enqland Based on

Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of

4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x

10middot1 to 1 2 x 10 feet day for unfractured roc k are more

realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy

- 15shy

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U S GS Water Supply Paper 2220 page 13 ehowa hydraulic

conductivity rangee for igneoua lind metamorphic rocks of

10middot7 feat day unfractured to 15 feet day fracture d

40 Page 218 (T B) - The r e port no tee t hat a ~three-layer

ayetam waa modeled however the model used wae a twt middotmiddot layer

110del It appears that the VCONT variable wae ueed to

repreaent the eiltclayfine eand layer with layer

thickneea eat to o ne foot Thera h no eupportive data of

the one foot thic knen value other than being arbitrarily

aeaiqnad Thia ie not an accurate rapraaantation of actual

conditiona nor ie it the beat way to fully and accurately

-adal thh ayatem

41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy

layer RIOdal and the eimpUfying aWDption of horhontal

layerl re1ult in a model which doee not reflect the actual

qeoloqy at thia alta The variable bedrock topography and

aquifer hydraulic conductivitiebull muet be accounte d for in

the lftOdal if an accurate delineation of the rona of

contribution 1a to be made

42 (T B ) - Thera h no me ntion in the text of either a

aanaitiv ity anal yeh being made or o f a water budget being

c alc ula t ed The s e efforts are both important compone nts of

a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the

acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d

they ehould ha ve been no t ed i n t he report I f e ither o f

- 16 shy

I r -r I

these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

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area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

- 19shy

n Q = = Ul

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the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

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49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

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conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

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habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

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C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

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  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 3: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

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indicate that thh 1a improbable bull The T B report doea not

qualify ita statement through recognition of the RICL

raporta uncerta inty on contamination migration to North Road

or ita aourca

3 Paqa J - (TB ) - The Litt e River as preaented in the TB

report did not and could not have depoaited the bullavathbull of

low permeability material which holatea the Hobba Site from

Coakley The Little River h of recent origin reaultinq

from runoff on top of the underlying low permeable marine

depoe ita The low permeable material ia a product of aanda

aUt and claya depodtad in a glacioeatuarine marine

enviroNMnt during deglaciation approximately 8000-11000

B P The Little River ie too IMell of dynampJIIic erosional

-chanhbull to have reworked the aandgravel depoeitbull A

caplata undantandinq of the bulltudy are qeoloqic

depobullitional processes h a very important part in

conbulltructinq an accurate model

4 Paqa 3 (TB) - 0 L MAHER Te8t Well loq 9-90 bullhowbull

pradoinantly dlt and clay are found throuqhout the

bulltratabullbull indicative of marine deposita of vary low

hydraulic c onductivity The T B report states - there h

atronq evidence that t he sand and qravel deposits o f the

Hobba Site ia connec ted to t he sand and gravel of the

Coakley Site - Howe ver TB does not preaent any evidenc e

other than speculation

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5 Page S (T B) etatee ~ bedrock fracturebull to the weet of

Coakley exte nd towarde t he Hobba Site The TB report

doea not eubetantiate tha statement with d11ta in thie

portion of tha report

6 Paqe 6 (TB) - middot 60 o f the average annual rainfall

recharqea the aanda and gravele bull the OLM report utilized

50 not 60 of the average annual rainfall On page 11 of

T B report 21 inchesyearbull h used which equah 50

Apparent lack of cone latency in data uee

7 Paqe 8 (TBJ- a apecific yield of 005 falh within

publbhed water table valuea particularly for ailty eand _

aedimenta auch aa thoae edatinq within the Hobba aquifer

8 Pa9a 8-9 (T B ) - The logic of a direct ratio chanqa ~tween

groundwater level and change in total precipitation ia

incorrect Thle logic anwnee the aquifer ia a cloaed

ayater11 without horhontal dhcharge The Hobba aquifer h

reactinq in reality aa a mound with horhontal diacharqe

continually occurring through the fine qrain aedJnenta

aurroundinq the aquifer Aa precipitation entera the

aquifer qroundwater dilchar9t1 11 o ngo in9 draining the

aquifer A direc t rat io relationehip between precipitation

and groundwa ter levale h flawed

A rain induc ed rea ponee o f t he water tabla in a fi neshy

grained (allty) unc onfined aquHar 11 related to the eoil

moiature c o nt e nt air e ntrainmen t and the tillable porosi ty

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in the uneaturated zona Dry material can ftbaorb

eubltantially more water than can wet material because in

the latter c aae part o f t he atoraqe apace ie alre ady

occupied Therefore in reality the TB value o f bull 16 of

precipitation 18 e hown t o result in r echar9e bull la not a

reliable nor accurate number Alec the Hobba aquifer doea

not have uniform aquifer characterletice Run off on the

marine aUtclay cap overlying parte of the aquifer affect

the rate of recharge often imparting a delayed reaponae to

water lavale The recharqe area a actually quite amorphous

in ahape not suitable to the application of a circulac

andylie utilhinq linear radiua logic Derivinq an area of

radiua of 3210 feet and any concluliona from thh area are

not valid

t Pa~ 9 (T B ) - An 80 ratio of water level chanqe to total

precipitation ill u11ad in the T B report to indicate water

leveh at the end of the pWIIpinq test should be 0 1 feat

hiqher In contra lit a 16 ratio 111 used on paqe 9 (T B)

to e11tiJiate the recharqe area to the well The T B report

loqic 18 contradictory and euqqe11ts t hat the valubullbull selected

for a particular analyais are baBed on whichever value will

produce the most severe r e 11ult not on ac tual field

conditionbull The 11tre n9 th o f the conclusions r e ac hed by this

analyllill ill wea k

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10 Paqa 10 (TB J - The effect of hydrogeologic boundaziee such

aa lov permeable sediments and a ehallow depth to bedrock in

the vicinity of Well 6-90 Wood Knoll Drive serving aa a

hydrogeologic boundary between U SGS 69 waa not mentioned

in the T B report Test Well H- 2 is located in low

permeable sediments with shallow depth to bedrock The

pumping effects would take a much longer period of time to

be felt withJn the low permeable eedimente surrounding M-2

than in higher permeable sandbull and gravel

11 Page 10 (TB) - It appeare that a 3420 foot radius of

influence after 20 days of pumpinq at 260 GPM ia calculated

by the Theis equation The Theis equation assumes the

J aquifer ia hOiftOgeneoua hotroplc of uniform thickneaa of

infinite areal extent horizontal piezometric surface the

vell 1bull fully ~netratinq and tranerniuivity ie conbulltant

The ubulle of the Theie equation in thia report qrobullbullly

violatebull thbullbullbull aabullumptionbull when applied to loncr dbtancebull

(qreater than 700 feet) from the well The Hobbbull aquifer h

hiqhly heterocrenaoua of variable thicknenhydraulic

conductivity and areal extent A eloping water table

exbtbull Bedrock barrier boundaries axht within 700 feet of

the pwnped well near Wood rnoll and 1200 feet to the north

near North Road The depth to bedrock shallows to 30 feet

at M-2 Co nc luding t hat uniform radius o f 3420 feet h111

achieved after 20 days pumping h er r oneoue

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12 Paqe 10 (TB) - There 18 little evidence that Mtainted

river waterbull exists at RIC L aampling location S-2 along

the North River which contains cherllical parameters capable

of migrating through the marine aedimentll to the Hobbe Well

Site

13 Paqe 10-11 (TB) - The logic of 58 GPH appears to be basad

on the use of the Thaie equation To reach a aubatantial

concluaion and precision of 58 GPM utilizing the Theia

equation h incorrect

14 Paqe 10 (TB) - The 3420 foot radius appears to incorporate

the apecUic yield value of 0 05 yet on page 8 the T B

report states middoto2 is moat likely a very reasonable value

for sand and gravel bull There does not appear to be

condatency in the T B reporU logic

lS Paqe 12 (TB) - The DL M report flow path model equations

do not utilize storage coefficient valuebull in bullteady bulltate

analybullh Porosity is only utilized in the reverbullbull particle

tracking portion of the model for time of travel capture

ampone delineation not hydraulic head calculationa It would

be ubulleful for the TB author to read the flow path manual

to better understand the model

16 (DL M ) report flow path wae utilized o nly in a conceptual

format (DLM paqe 30) abull a precunor to r unning MODFLOW

Thie procedure is utlhe quite o ften i n many states to

- 6shy

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efficiently and economically determine where additionall field data needs to be collected in order to increase the

predicative accuracy of the HODFLOW model

17 Page 13 (TB)- a porosity of 02 not specific yield of

0 2 wae utilized in the 180-day particle tracking zoe of

the DLM report

18 Page 13 (TB) report states there was an annual rainfall

rate of 78 inchesyear during the seven days of pumping

Thh statement ia confusing and should be clarified Ie the

equivalent amount of rainfall experienced during the pump

teat extrapolated out an annual baaia

0 19 Page lJ (TB ) - The 180-day ZOC determined i n the OL M

report h derived from reverse particle tracking which

deterwinea how lonq it would take a conaervative aolute euch

aa chloride to reach the wbullll The time of travbulll to

TOT-ZOC dbulllineation method haa been an accepted method by

the EPA The particle tracking zoe method ia D2t intended

to mimic the area of influence of the well It is incorrect

tor the TB report to auume the particle tr~ckinq zoe of

thbull vall is the aame as its area of influence

20 Page 17 (TB ) report states Corneliua Brook has an

elevation of 59 feet HSL However Cor nelius Brook when it

haa water in it has a signific ant gradient and not just one

elevation of 59 feet Cornellua Brook is not a po nd but

_ -7 shy

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rather hu multiple elevations depending on where i t l8

lftllaaured (Henry Fuller property or near I-95) Teet Nella

3middot84 and 4-84 which are located in c loae proximity to

Cornelius Brook have groundwater elevationa of 6724 and

65 75 feet reapectlvely The Little River has variable

elevations betwee n 6744 and 652 feet at RIC L staff

qauga SN-9 The TB report aqain eeema to aelect values

for a particular analyah baaed upon whichever value will

produce the desired outcome Therefore it la lncorract for

the TB report to aaaume ~that the Little River would be

aarving aa aOIMI portion of the recharge to the Hobbs Well~

baaed upon thh logic

21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta

aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull

Site b anhotropic hiqhly etratified with variable

hydraulic conductivitlee and traneminivltlee thereby

viohtinq the majority of the Theia auumptionbull and

conclubullione derived thereof

22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the

y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct

a atraiqht line encompaebullinq small dhtancee and drawing

bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect

Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat

ie covered yet the T B report extrapolatebull t he line out to

10 000 feet

-middotshy

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The T B Figure 1 plot clearly shows the drawdown ie

variable and not uniform in all directions thereby

violating a major aaaumption of Thela theory Teat Well

5-84 ahowa greater drawdown than Teet Well 11-90 in TB

Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from

the pumping well than 11-90 ( 97) It is reasonable to

conclude that low permeable boundarlea muet e xist in the

directio n of 5-84 If a radial line la constructed

connec ting 2-84 to 11-90 leas drawdown la s hown towards

11-90 indicative of more permeable material existing in

thia directio n The aquifer permeability variations are

clearly ahovn on DLH report Figure P4

A conparison of OLM teat well logs 5-84 and 11-90

ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84

Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while

11-90 pumped 20 GPM DL H cro section 8-8 shows leu

permeable eilty eand and gravel (not highly permeability

zones as stated in the TB report) surrounds the highly

permeable und and gravel in which the e ight inch pumped

well h located As an example on Tab l e J o f the RICL

report low hydraulic conductivity (lq values a r e shown for

six out of seven overburden wel ls even though t he strata

descriptions would imply a high~ value TB Figure 1 and

D L H P- 4 confirm the exhtence of l ow permeable barrier

boundaries to the north and northeast o f the pumped well

eite It ia incorrect t o c alc ulate and apply a radius o f

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l influence projecting (10000 feat in TB report) in the

direction of and beyond the barrier boundarlee

I 23 Page 18 - TB Figure 1 plot doea not include all t he

observation well data points thereby biasing the

conclusions

24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the

principal recharge direction to the well is from the

northwat and weat Thil recharge direction interpretation

bullbullkbullbull aenae aa it is in the direction of the center of the

aquifer

25 Page 18 (TB) - The last aentence in paragraph one

beginning with Both wells ~ and the first sentence in

paragraph two beginning with ~Another interpretation bull

contradict one another

2 Paqe 18 - T B atatee One curious point but does not aay

what that point is

27 Paqbull 18 - TB report doea not aubatanthte what data in the

drawdown level ill revealing vertical flow from the

underlying bedrock

28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J

fracture tracea underlying the aite The O LM report

atatea bulla potential north - northeaat trending fault atructure

may underlie the we ll sitebull The D L M r epo r t sta t ement

- 10shy

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I r -r -

l vabull baaed upon cron-section interpretation ll2t from remote

1enaln9 and geophysical methods Frecture tracea are

obtained from rerre eeneing imagery analysis not croae

I aactlon i nterpretation The TB r epor t impllea that the

D L H report is s aying the structure 1a fact where the

DLM words poten t ioll and may are ignored

29 Page 20 - T B report Theae fractures presumably continue

directly towards the Ho bbs Site The major frequency

concentration of lineamentamp i dentified in the R IC L study

rlqure 5 doea rurt ehow the prominent lineaments 1111

continuing towards the Hobbs Site The TB report and

IIOdal have incorrectly extrapolated the photolineament swarm

0 aa ahown in the RICL report RI CL bedrock

110nltorin9 well GZ-128 wu drille d in the prominent

UneiUMtnt ewarm waet of the Coakley Landfill to a depth of

184 feet and produced only 0 25 GPH Tabla 4 (R IC L)

ehowe packer pressure taetad hydraulic conduc tivities

ranqinq frobull 014 to 682 feetday GZ-128 was not packer

teetad because o f the nonfractured and l ow water bearing

characterhtics o f the bedrock GZ-105 (bedrock corehola)

only had a hydraulic conductivity o f 2 0 fee tday Basad

upon the field technic al drill dat4 presented in the

R I cL report i t can Jl2t be concluded tha t the prominent

lineament s warm ae identified o n Figure 5 has a high

hydraulic conductivity Remote sensing analy8111 only

identlfie11 linear photo feature11 These f e a t ures may also

-11shy

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be attributed to nonhydraulically significant geologic

1tructure1 Remote aenaing is an ~art- and drawing far

reachim~ concluaiona without drilling data ill incorrec t

However thh letter recognizee that due to the limitations

of remota saneincJ other signi ficant water bearing fracturea

may exbt in the bedrock not identified in the R ICL

JO Page 20 - TB states ~ bedrock groundwater generally flowa

in the direction of the Little River - However the T B

report oaita that bedrock groundwater aho generally flowbull

aoutheabullt to North Brook as ahovn on Fiqure 13 of the

R ICL report Bedrock groundwater flowbull radially in bullany

directionbull from the Coakley Landfill and the TB report

should not uae the word bullqenerally bull as it impli one major

direction only when in fact there are many flow pathe

R IC L total volatile organic compounds in

Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127

128 129 and 130 were either nondetected or leu than 5 ppb

Theee leveh are very low concentrations Only GZ-105

ehowed eignificant volatile organic compounds weet of the

Coakley Landfill The VOC levels at GZ-129 and GZ-130 may

b attributed t o additional small transient lind undefined

bullourcea in this area The R I C L r epo r t conc ludes o n paqe

8 - Exec utive Summary bullAt t his t lme however five years

of qrou ndwater contam i na t i o n e x ist away from the l andfill

per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill

- 12shy

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a likely consequence of the diepereive radial flow and

reaultant contaminant dilution ae well abull othe r operative

attenuation mechaniems diacueaed herein Beaed on the

available data it is anticipated that these olttenuatlon

mechanismbull would be a significant llrniting factor in the

diatance contaminants are able to migrate from the landfill

in detectable conc entrations

31 Pa9e 20 (TB) -The OLM and RICL reporta do not

auqqeat that the bedrock and overburden groundwater are

atrictly aeparated from each other

32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa

the Hobbs Site will create flow of groundwater fro11 beneath

and po ibly east of the Little River durinq amplltended low

rainfall recharge periods bull h very weak and baaed upon

faulty auwnptiona and data No creditable field data or

analyaia were brought forth to support the conclusionbull

JJ Fax Page J (TB) - Placing much emphasis upon the

conclusions derived from the application of Theis theory to

large distances beyond the pumping well is not valid due to

the qaologic conditione grouly violate Theta uawnptione

34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods

It is unclear aa to which time period conclus i o ns are

derived for It i s hiqhly unlikely pumpinq effects c an

deleteriously propaqate in 20 days thro uqh t he l ow permeable

- 13 shy

~ n = = =Ul

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11atariale located east of the Hobbs Site

35 Paqe llA (T B ) concludes that the safe yield from the

Hobbs Site is in the ranqe of 14 to 58 GPW If this yield

h true than the combined pumpage o f all the residential

wellbull in the study area will exceed the safe yie ld and

potentially impact the Coakley Landfill

36 Paqa 22 - TB reports etatea (1) a nything th11t wu not

sand and gravel laterally or vertically) was impermeable

and (2) streams to the northwest (Cornelius Brook) was

repreaented aa havinq a constant water level (basically an

infinite supply of water) bull In the D L MAHER report Paqe

Jl only the bedrock waa treated aa impermeable The llarine

aedlaentbull vera treated aa a constant head boundary allovinq

for flow into the aquifer Cornelius Brook waa not modeled

bullbull havinq a constant water level in the D L MAHER report

37 Paqe 22 (TB) -Some of the streams modeled as drains are

actually perched above the aquifer11 groundwater table upon

very low permeable marine sedmenta The drainbull are not

JnOdeled correctly Cornelius Brook dries up naturally from

June throuqh September and a significant portion h perched

above the aquifers water table Cornelius Brook receives

ita intermittent recharqe from runoff o n top o f the marine

aediment c ap overlying the northern portion of the Hobba

aquife r Some of t he Little River drain c ella are not

located properly Drain file conductance values appear very

-1 4 shy

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high for etreama flowing upon silts and claye

38 Page 27 (T B) model wa11 run b) atar tng at ateady state

conditione 2 of nonnal rechnrge for 180 day a and pumping

250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead

Protection area delineation requires the contributing area

to ~ delineated for a period of 180 daye pumpin with no

net rainfall recharge upon the ~~ regional

piezometric surface map This method of Wellhead

delineation wae stated by Paul Currier Administrator

Groundwater Protection Bureau during the July 25 1991

bullbullUnq at D E S offices in Concord The TB report

apparently did not model the zoe under thie criteria

39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling

effort it h etated that the model should uee hydraulic

coefficients which were measured in the field~ but fails to

follow through with this premise in the model The

tranbullmhbulllvity values selected for both fractured and

unfractured bedrock are neither explained nor supported by

field data If the va lues were taken from publlahed ranges

they are at t he upper ende of t heee rangee and not

reflective of typical conditio ne in New Enqland Based on

Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of

4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x

10middot1 to 1 2 x 10 feet day for unfractured roc k are more

realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy

- 15shy

r -r I

U S GS Water Supply Paper 2220 page 13 ehowa hydraulic

conductivity rangee for igneoua lind metamorphic rocks of

10middot7 feat day unfractured to 15 feet day fracture d

40 Page 218 (T B) - The r e port no tee t hat a ~three-layer

ayetam waa modeled however the model used wae a twt middotmiddot layer

110del It appears that the VCONT variable wae ueed to

repreaent the eiltclayfine eand layer with layer

thickneea eat to o ne foot Thera h no eupportive data of

the one foot thic knen value other than being arbitrarily

aeaiqnad Thia ie not an accurate rapraaantation of actual

conditiona nor ie it the beat way to fully and accurately

-adal thh ayatem

41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy

layer RIOdal and the eimpUfying aWDption of horhontal

layerl re1ult in a model which doee not reflect the actual

qeoloqy at thia alta The variable bedrock topography and

aquifer hydraulic conductivitiebull muet be accounte d for in

the lftOdal if an accurate delineation of the rona of

contribution 1a to be made

42 (T B ) - Thera h no me ntion in the text of either a

aanaitiv ity anal yeh being made or o f a water budget being

c alc ula t ed The s e efforts are both important compone nts of

a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the

acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d

they ehould ha ve been no t ed i n t he report I f e ither o f

- 16 shy

I r -r I

these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

r -r -

area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

- 19shy

n Q = = Ul

r -r I

the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

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49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

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conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

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habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

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C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 4: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

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5 Page S (T B) etatee ~ bedrock fracturebull to the weet of

Coakley exte nd towarde t he Hobba Site The TB report

doea not eubetantiate tha statement with d11ta in thie

portion of tha report

6 Paqe 6 (TB) - middot 60 o f the average annual rainfall

recharqea the aanda and gravele bull the OLM report utilized

50 not 60 of the average annual rainfall On page 11 of

T B report 21 inchesyearbull h used which equah 50

Apparent lack of cone latency in data uee

7 Paqe 8 (TBJ- a apecific yield of 005 falh within

publbhed water table valuea particularly for ailty eand _

aedimenta auch aa thoae edatinq within the Hobba aquifer

8 Pa9a 8-9 (T B ) - The logic of a direct ratio chanqa ~tween

groundwater level and change in total precipitation ia

incorrect Thle logic anwnee the aquifer ia a cloaed

ayater11 without horhontal dhcharge The Hobba aquifer h

reactinq in reality aa a mound with horhontal diacharqe

continually occurring through the fine qrain aedJnenta

aurroundinq the aquifer Aa precipitation entera the

aquifer qroundwater dilchar9t1 11 o ngo in9 draining the

aquifer A direc t rat io relationehip between precipitation

and groundwa ter levale h flawed

A rain induc ed rea ponee o f t he water tabla in a fi neshy

grained (allty) unc onfined aquHar 11 related to the eoil

moiature c o nt e nt air e ntrainmen t and the tillable porosi ty

-3shy

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in the uneaturated zona Dry material can ftbaorb

eubltantially more water than can wet material because in

the latter c aae part o f t he atoraqe apace ie alre ady

occupied Therefore in reality the TB value o f bull 16 of

precipitation 18 e hown t o result in r echar9e bull la not a

reliable nor accurate number Alec the Hobba aquifer doea

not have uniform aquifer characterletice Run off on the

marine aUtclay cap overlying parte of the aquifer affect

the rate of recharge often imparting a delayed reaponae to

water lavale The recharqe area a actually quite amorphous

in ahape not suitable to the application of a circulac

andylie utilhinq linear radiua logic Derivinq an area of

radiua of 3210 feet and any concluliona from thh area are

not valid

t Pa~ 9 (T B ) - An 80 ratio of water level chanqe to total

precipitation ill u11ad in the T B report to indicate water

leveh at the end of the pWIIpinq test should be 0 1 feat

hiqher In contra lit a 16 ratio 111 used on paqe 9 (T B)

to e11tiJiate the recharqe area to the well The T B report

loqic 18 contradictory and euqqe11ts t hat the valubullbull selected

for a particular analyais are baBed on whichever value will

produce the most severe r e 11ult not on ac tual field

conditionbull The 11tre n9 th o f the conclusions r e ac hed by this

analyllill ill wea k

-middotshy

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I

10 Paqa 10 (TB J - The effect of hydrogeologic boundaziee such

aa lov permeable sediments and a ehallow depth to bedrock in

the vicinity of Well 6-90 Wood Knoll Drive serving aa a

hydrogeologic boundary between U SGS 69 waa not mentioned

in the T B report Test Well H- 2 is located in low

permeable sediments with shallow depth to bedrock The

pumping effects would take a much longer period of time to

be felt withJn the low permeable eedimente surrounding M-2

than in higher permeable sandbull and gravel

11 Page 10 (TB) - It appeare that a 3420 foot radius of

influence after 20 days of pumpinq at 260 GPM ia calculated

by the Theis equation The Theis equation assumes the

J aquifer ia hOiftOgeneoua hotroplc of uniform thickneaa of

infinite areal extent horizontal piezometric surface the

vell 1bull fully ~netratinq and tranerniuivity ie conbulltant

The ubulle of the Theie equation in thia report qrobullbullly

violatebull thbullbullbull aabullumptionbull when applied to loncr dbtancebull

(qreater than 700 feet) from the well The Hobbbull aquifer h

hiqhly heterocrenaoua of variable thicknenhydraulic

conductivity and areal extent A eloping water table

exbtbull Bedrock barrier boundaries axht within 700 feet of

the pwnped well near Wood rnoll and 1200 feet to the north

near North Road The depth to bedrock shallows to 30 feet

at M-2 Co nc luding t hat uniform radius o f 3420 feet h111

achieved after 20 days pumping h er r oneoue

-5shy

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12 Paqe 10 (TB) - There 18 little evidence that Mtainted

river waterbull exists at RIC L aampling location S-2 along

the North River which contains cherllical parameters capable

of migrating through the marine aedimentll to the Hobbe Well

Site

13 Paqe 10-11 (TB) - The logic of 58 GPH appears to be basad

on the use of the Thaie equation To reach a aubatantial

concluaion and precision of 58 GPM utilizing the Theia

equation h incorrect

14 Paqe 10 (TB) - The 3420 foot radius appears to incorporate

the apecUic yield value of 0 05 yet on page 8 the T B

report states middoto2 is moat likely a very reasonable value

for sand and gravel bull There does not appear to be

condatency in the T B reporU logic

lS Paqe 12 (TB) - The DL M report flow path model equations

do not utilize storage coefficient valuebull in bullteady bulltate

analybullh Porosity is only utilized in the reverbullbull particle

tracking portion of the model for time of travel capture

ampone delineation not hydraulic head calculationa It would

be ubulleful for the TB author to read the flow path manual

to better understand the model

16 (DL M ) report flow path wae utilized o nly in a conceptual

format (DLM paqe 30) abull a precunor to r unning MODFLOW

Thie procedure is utlhe quite o ften i n many states to

- 6shy

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efficiently and economically determine where additionall field data needs to be collected in order to increase the

predicative accuracy of the HODFLOW model

17 Page 13 (TB)- a porosity of 02 not specific yield of

0 2 wae utilized in the 180-day particle tracking zoe of

the DLM report

18 Page 13 (TB) report states there was an annual rainfall

rate of 78 inchesyear during the seven days of pumping

Thh statement ia confusing and should be clarified Ie the

equivalent amount of rainfall experienced during the pump

teat extrapolated out an annual baaia

0 19 Page lJ (TB ) - The 180-day ZOC determined i n the OL M

report h derived from reverse particle tracking which

deterwinea how lonq it would take a conaervative aolute euch

aa chloride to reach the wbullll The time of travbulll to

TOT-ZOC dbulllineation method haa been an accepted method by

the EPA The particle tracking zoe method ia D2t intended

to mimic the area of influence of the well It is incorrect

tor the TB report to auume the particle tr~ckinq zoe of

thbull vall is the aame as its area of influence

20 Page 17 (TB ) report states Corneliua Brook has an

elevation of 59 feet HSL However Cor nelius Brook when it

haa water in it has a signific ant gradient and not just one

elevation of 59 feet Cornellua Brook is not a po nd but

_ -7 shy

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r r

rather hu multiple elevations depending on where i t l8

lftllaaured (Henry Fuller property or near I-95) Teet Nella

3middot84 and 4-84 which are located in c loae proximity to

Cornelius Brook have groundwater elevationa of 6724 and

65 75 feet reapectlvely The Little River has variable

elevations betwee n 6744 and 652 feet at RIC L staff

qauga SN-9 The TB report aqain eeema to aelect values

for a particular analyah baaed upon whichever value will

produce the desired outcome Therefore it la lncorract for

the TB report to aaaume ~that the Little River would be

aarving aa aOIMI portion of the recharge to the Hobbs Well~

baaed upon thh logic

21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta

aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull

Site b anhotropic hiqhly etratified with variable

hydraulic conductivitlee and traneminivltlee thereby

viohtinq the majority of the Theia auumptionbull and

conclubullione derived thereof

22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the

y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct

a atraiqht line encompaebullinq small dhtancee and drawing

bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect

Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat

ie covered yet the T B report extrapolatebull t he line out to

10 000 feet

-middotshy

r r I

The T B Figure 1 plot clearly shows the drawdown ie

variable and not uniform in all directions thereby

violating a major aaaumption of Thela theory Teat Well

5-84 ahowa greater drawdown than Teet Well 11-90 in TB

Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from

the pumping well than 11-90 ( 97) It is reasonable to

conclude that low permeable boundarlea muet e xist in the

directio n of 5-84 If a radial line la constructed

connec ting 2-84 to 11-90 leas drawdown la s hown towards

11-90 indicative of more permeable material existing in

thia directio n The aquifer permeability variations are

clearly ahovn on DLH report Figure P4

A conparison of OLM teat well logs 5-84 and 11-90

ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84

Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while

11-90 pumped 20 GPM DL H cro section 8-8 shows leu

permeable eilty eand and gravel (not highly permeability

zones as stated in the TB report) surrounds the highly

permeable und and gravel in which the e ight inch pumped

well h located As an example on Tab l e J o f the RICL

report low hydraulic conductivity (lq values a r e shown for

six out of seven overburden wel ls even though t he strata

descriptions would imply a high~ value TB Figure 1 and

D L H P- 4 confirm the exhtence of l ow permeable barrier

boundaries to the north and northeast o f the pumped well

eite It ia incorrect t o c alc ulate and apply a radius o f

- 9 shy

-shy

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- r -r I

l influence projecting (10000 feat in TB report) in the

direction of and beyond the barrier boundarlee

I 23 Page 18 - TB Figure 1 plot doea not include all t he

observation well data points thereby biasing the

conclusions

24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the

principal recharge direction to the well is from the

northwat and weat Thil recharge direction interpretation

bullbullkbullbull aenae aa it is in the direction of the center of the

aquifer

25 Page 18 (TB) - The last aentence in paragraph one

beginning with Both wells ~ and the first sentence in

paragraph two beginning with ~Another interpretation bull

contradict one another

2 Paqe 18 - T B atatee One curious point but does not aay

what that point is

27 Paqbull 18 - TB report doea not aubatanthte what data in the

drawdown level ill revealing vertical flow from the

underlying bedrock

28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J

fracture tracea underlying the aite The O LM report

atatea bulla potential north - northeaat trending fault atructure

may underlie the we ll sitebull The D L M r epo r t sta t ement

- 10shy

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I r -r -

l vabull baaed upon cron-section interpretation ll2t from remote

1enaln9 and geophysical methods Frecture tracea are

obtained from rerre eeneing imagery analysis not croae

I aactlon i nterpretation The TB r epor t impllea that the

D L H report is s aying the structure 1a fact where the

DLM words poten t ioll and may are ignored

29 Page 20 - T B report Theae fractures presumably continue

directly towards the Ho bbs Site The major frequency

concentration of lineamentamp i dentified in the R IC L study

rlqure 5 doea rurt ehow the prominent lineaments 1111

continuing towards the Hobbs Site The TB report and

IIOdal have incorrectly extrapolated the photolineament swarm

0 aa ahown in the RICL report RI CL bedrock

110nltorin9 well GZ-128 wu drille d in the prominent

UneiUMtnt ewarm waet of the Coakley Landfill to a depth of

184 feet and produced only 0 25 GPH Tabla 4 (R IC L)

ehowe packer pressure taetad hydraulic conduc tivities

ranqinq frobull 014 to 682 feetday GZ-128 was not packer

teetad because o f the nonfractured and l ow water bearing

characterhtics o f the bedrock GZ-105 (bedrock corehola)

only had a hydraulic conductivity o f 2 0 fee tday Basad

upon the field technic al drill dat4 presented in the

R I cL report i t can Jl2t be concluded tha t the prominent

lineament s warm ae identified o n Figure 5 has a high

hydraulic conductivity Remote sensing analy8111 only

identlfie11 linear photo feature11 These f e a t ures may also

-11shy

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be attributed to nonhydraulically significant geologic

1tructure1 Remote aenaing is an ~art- and drawing far

reachim~ concluaiona without drilling data ill incorrec t

However thh letter recognizee that due to the limitations

of remota saneincJ other signi ficant water bearing fracturea

may exbt in the bedrock not identified in the R ICL

JO Page 20 - TB states ~ bedrock groundwater generally flowa

in the direction of the Little River - However the T B

report oaita that bedrock groundwater aho generally flowbull

aoutheabullt to North Brook as ahovn on Fiqure 13 of the

R ICL report Bedrock groundwater flowbull radially in bullany

directionbull from the Coakley Landfill and the TB report

should not uae the word bullqenerally bull as it impli one major

direction only when in fact there are many flow pathe

R IC L total volatile organic compounds in

Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127

128 129 and 130 were either nondetected or leu than 5 ppb

Theee leveh are very low concentrations Only GZ-105

ehowed eignificant volatile organic compounds weet of the

Coakley Landfill The VOC levels at GZ-129 and GZ-130 may

b attributed t o additional small transient lind undefined

bullourcea in this area The R I C L r epo r t conc ludes o n paqe

8 - Exec utive Summary bullAt t his t lme however five years

of qrou ndwater contam i na t i o n e x ist away from the l andfill

per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill

- 12shy

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a likely consequence of the diepereive radial flow and

reaultant contaminant dilution ae well abull othe r operative

attenuation mechaniems diacueaed herein Beaed on the

available data it is anticipated that these olttenuatlon

mechanismbull would be a significant llrniting factor in the

diatance contaminants are able to migrate from the landfill

in detectable conc entrations

31 Pa9e 20 (TB) -The OLM and RICL reporta do not

auqqeat that the bedrock and overburden groundwater are

atrictly aeparated from each other

32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa

the Hobbs Site will create flow of groundwater fro11 beneath

and po ibly east of the Little River durinq amplltended low

rainfall recharge periods bull h very weak and baaed upon

faulty auwnptiona and data No creditable field data or

analyaia were brought forth to support the conclusionbull

JJ Fax Page J (TB) - Placing much emphasis upon the

conclusions derived from the application of Theis theory to

large distances beyond the pumping well is not valid due to

the qaologic conditione grouly violate Theta uawnptione

34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods

It is unclear aa to which time period conclus i o ns are

derived for It i s hiqhly unlikely pumpinq effects c an

deleteriously propaqate in 20 days thro uqh t he l ow permeable

- 13 shy

~ n = = =Ul

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r -r -

11atariale located east of the Hobbs Site

35 Paqe llA (T B ) concludes that the safe yield from the

Hobbs Site is in the ranqe of 14 to 58 GPW If this yield

h true than the combined pumpage o f all the residential

wellbull in the study area will exceed the safe yie ld and

potentially impact the Coakley Landfill

36 Paqa 22 - TB reports etatea (1) a nything th11t wu not

sand and gravel laterally or vertically) was impermeable

and (2) streams to the northwest (Cornelius Brook) was

repreaented aa havinq a constant water level (basically an

infinite supply of water) bull In the D L MAHER report Paqe

Jl only the bedrock waa treated aa impermeable The llarine

aedlaentbull vera treated aa a constant head boundary allovinq

for flow into the aquifer Cornelius Brook waa not modeled

bullbull havinq a constant water level in the D L MAHER report

37 Paqe 22 (TB) -Some of the streams modeled as drains are

actually perched above the aquifer11 groundwater table upon

very low permeable marine sedmenta The drainbull are not

JnOdeled correctly Cornelius Brook dries up naturally from

June throuqh September and a significant portion h perched

above the aquifers water table Cornelius Brook receives

ita intermittent recharqe from runoff o n top o f the marine

aediment c ap overlying the northern portion of the Hobba

aquife r Some of t he Little River drain c ella are not

located properly Drain file conductance values appear very

-1 4 shy

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high for etreama flowing upon silts and claye

38 Page 27 (T B) model wa11 run b) atar tng at ateady state

conditione 2 of nonnal rechnrge for 180 day a and pumping

250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead

Protection area delineation requires the contributing area

to ~ delineated for a period of 180 daye pumpin with no

net rainfall recharge upon the ~~ regional

piezometric surface map This method of Wellhead

delineation wae stated by Paul Currier Administrator

Groundwater Protection Bureau during the July 25 1991

bullbullUnq at D E S offices in Concord The TB report

apparently did not model the zoe under thie criteria

39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling

effort it h etated that the model should uee hydraulic

coefficients which were measured in the field~ but fails to

follow through with this premise in the model The

tranbullmhbulllvity values selected for both fractured and

unfractured bedrock are neither explained nor supported by

field data If the va lues were taken from publlahed ranges

they are at t he upper ende of t heee rangee and not

reflective of typical conditio ne in New Enqland Based on

Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of

4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x

10middot1 to 1 2 x 10 feet day for unfractured roc k are more

realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy

- 15shy

r -r I

U S GS Water Supply Paper 2220 page 13 ehowa hydraulic

conductivity rangee for igneoua lind metamorphic rocks of

10middot7 feat day unfractured to 15 feet day fracture d

40 Page 218 (T B) - The r e port no tee t hat a ~three-layer

ayetam waa modeled however the model used wae a twt middotmiddot layer

110del It appears that the VCONT variable wae ueed to

repreaent the eiltclayfine eand layer with layer

thickneea eat to o ne foot Thera h no eupportive data of

the one foot thic knen value other than being arbitrarily

aeaiqnad Thia ie not an accurate rapraaantation of actual

conditiona nor ie it the beat way to fully and accurately

-adal thh ayatem

41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy

layer RIOdal and the eimpUfying aWDption of horhontal

layerl re1ult in a model which doee not reflect the actual

qeoloqy at thia alta The variable bedrock topography and

aquifer hydraulic conductivitiebull muet be accounte d for in

the lftOdal if an accurate delineation of the rona of

contribution 1a to be made

42 (T B ) - Thera h no me ntion in the text of either a

aanaitiv ity anal yeh being made or o f a water budget being

c alc ula t ed The s e efforts are both important compone nts of

a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the

acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d

they ehould ha ve been no t ed i n t he report I f e ither o f

- 16 shy

I r -r I

these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

r -r -

area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

- 19shy

n Q = = Ul

r -r I

the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

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49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

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conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

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habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

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C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

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  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 5: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

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in the uneaturated zona Dry material can ftbaorb

eubltantially more water than can wet material because in

the latter c aae part o f t he atoraqe apace ie alre ady

occupied Therefore in reality the TB value o f bull 16 of

precipitation 18 e hown t o result in r echar9e bull la not a

reliable nor accurate number Alec the Hobba aquifer doea

not have uniform aquifer characterletice Run off on the

marine aUtclay cap overlying parte of the aquifer affect

the rate of recharge often imparting a delayed reaponae to

water lavale The recharqe area a actually quite amorphous

in ahape not suitable to the application of a circulac

andylie utilhinq linear radiua logic Derivinq an area of

radiua of 3210 feet and any concluliona from thh area are

not valid

t Pa~ 9 (T B ) - An 80 ratio of water level chanqe to total

precipitation ill u11ad in the T B report to indicate water

leveh at the end of the pWIIpinq test should be 0 1 feat

hiqher In contra lit a 16 ratio 111 used on paqe 9 (T B)

to e11tiJiate the recharqe area to the well The T B report

loqic 18 contradictory and euqqe11ts t hat the valubullbull selected

for a particular analyais are baBed on whichever value will

produce the most severe r e 11ult not on ac tual field

conditionbull The 11tre n9 th o f the conclusions r e ac hed by this

analyllill ill wea k

-middotshy

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I

10 Paqa 10 (TB J - The effect of hydrogeologic boundaziee such

aa lov permeable sediments and a ehallow depth to bedrock in

the vicinity of Well 6-90 Wood Knoll Drive serving aa a

hydrogeologic boundary between U SGS 69 waa not mentioned

in the T B report Test Well H- 2 is located in low

permeable sediments with shallow depth to bedrock The

pumping effects would take a much longer period of time to

be felt withJn the low permeable eedimente surrounding M-2

than in higher permeable sandbull and gravel

11 Page 10 (TB) - It appeare that a 3420 foot radius of

influence after 20 days of pumpinq at 260 GPM ia calculated

by the Theis equation The Theis equation assumes the

J aquifer ia hOiftOgeneoua hotroplc of uniform thickneaa of

infinite areal extent horizontal piezometric surface the

vell 1bull fully ~netratinq and tranerniuivity ie conbulltant

The ubulle of the Theie equation in thia report qrobullbullly

violatebull thbullbullbull aabullumptionbull when applied to loncr dbtancebull

(qreater than 700 feet) from the well The Hobbbull aquifer h

hiqhly heterocrenaoua of variable thicknenhydraulic

conductivity and areal extent A eloping water table

exbtbull Bedrock barrier boundaries axht within 700 feet of

the pwnped well near Wood rnoll and 1200 feet to the north

near North Road The depth to bedrock shallows to 30 feet

at M-2 Co nc luding t hat uniform radius o f 3420 feet h111

achieved after 20 days pumping h er r oneoue

-5shy

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12 Paqe 10 (TB) - There 18 little evidence that Mtainted

river waterbull exists at RIC L aampling location S-2 along

the North River which contains cherllical parameters capable

of migrating through the marine aedimentll to the Hobbe Well

Site

13 Paqe 10-11 (TB) - The logic of 58 GPH appears to be basad

on the use of the Thaie equation To reach a aubatantial

concluaion and precision of 58 GPM utilizing the Theia

equation h incorrect

14 Paqe 10 (TB) - The 3420 foot radius appears to incorporate

the apecUic yield value of 0 05 yet on page 8 the T B

report states middoto2 is moat likely a very reasonable value

for sand and gravel bull There does not appear to be

condatency in the T B reporU logic

lS Paqe 12 (TB) - The DL M report flow path model equations

do not utilize storage coefficient valuebull in bullteady bulltate

analybullh Porosity is only utilized in the reverbullbull particle

tracking portion of the model for time of travel capture

ampone delineation not hydraulic head calculationa It would

be ubulleful for the TB author to read the flow path manual

to better understand the model

16 (DL M ) report flow path wae utilized o nly in a conceptual

format (DLM paqe 30) abull a precunor to r unning MODFLOW

Thie procedure is utlhe quite o ften i n many states to

- 6shy

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efficiently and economically determine where additionall field data needs to be collected in order to increase the

predicative accuracy of the HODFLOW model

17 Page 13 (TB)- a porosity of 02 not specific yield of

0 2 wae utilized in the 180-day particle tracking zoe of

the DLM report

18 Page 13 (TB) report states there was an annual rainfall

rate of 78 inchesyear during the seven days of pumping

Thh statement ia confusing and should be clarified Ie the

equivalent amount of rainfall experienced during the pump

teat extrapolated out an annual baaia

0 19 Page lJ (TB ) - The 180-day ZOC determined i n the OL M

report h derived from reverse particle tracking which

deterwinea how lonq it would take a conaervative aolute euch

aa chloride to reach the wbullll The time of travbulll to

TOT-ZOC dbulllineation method haa been an accepted method by

the EPA The particle tracking zoe method ia D2t intended

to mimic the area of influence of the well It is incorrect

tor the TB report to auume the particle tr~ckinq zoe of

thbull vall is the aame as its area of influence

20 Page 17 (TB ) report states Corneliua Brook has an

elevation of 59 feet HSL However Cor nelius Brook when it

haa water in it has a signific ant gradient and not just one

elevation of 59 feet Cornellua Brook is not a po nd but

_ -7 shy

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rather hu multiple elevations depending on where i t l8

lftllaaured (Henry Fuller property or near I-95) Teet Nella

3middot84 and 4-84 which are located in c loae proximity to

Cornelius Brook have groundwater elevationa of 6724 and

65 75 feet reapectlvely The Little River has variable

elevations betwee n 6744 and 652 feet at RIC L staff

qauga SN-9 The TB report aqain eeema to aelect values

for a particular analyah baaed upon whichever value will

produce the desired outcome Therefore it la lncorract for

the TB report to aaaume ~that the Little River would be

aarving aa aOIMI portion of the recharge to the Hobbs Well~

baaed upon thh logic

21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta

aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull

Site b anhotropic hiqhly etratified with variable

hydraulic conductivitlee and traneminivltlee thereby

viohtinq the majority of the Theia auumptionbull and

conclubullione derived thereof

22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the

y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct

a atraiqht line encompaebullinq small dhtancee and drawing

bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect

Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat

ie covered yet the T B report extrapolatebull t he line out to

10 000 feet

-middotshy

r r I

The T B Figure 1 plot clearly shows the drawdown ie

variable and not uniform in all directions thereby

violating a major aaaumption of Thela theory Teat Well

5-84 ahowa greater drawdown than Teet Well 11-90 in TB

Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from

the pumping well than 11-90 ( 97) It is reasonable to

conclude that low permeable boundarlea muet e xist in the

directio n of 5-84 If a radial line la constructed

connec ting 2-84 to 11-90 leas drawdown la s hown towards

11-90 indicative of more permeable material existing in

thia directio n The aquifer permeability variations are

clearly ahovn on DLH report Figure P4

A conparison of OLM teat well logs 5-84 and 11-90

ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84

Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while

11-90 pumped 20 GPM DL H cro section 8-8 shows leu

permeable eilty eand and gravel (not highly permeability

zones as stated in the TB report) surrounds the highly

permeable und and gravel in which the e ight inch pumped

well h located As an example on Tab l e J o f the RICL

report low hydraulic conductivity (lq values a r e shown for

six out of seven overburden wel ls even though t he strata

descriptions would imply a high~ value TB Figure 1 and

D L H P- 4 confirm the exhtence of l ow permeable barrier

boundaries to the north and northeast o f the pumped well

eite It ia incorrect t o c alc ulate and apply a radius o f

- 9 shy

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l influence projecting (10000 feat in TB report) in the

direction of and beyond the barrier boundarlee

I 23 Page 18 - TB Figure 1 plot doea not include all t he

observation well data points thereby biasing the

conclusions

24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the

principal recharge direction to the well is from the

northwat and weat Thil recharge direction interpretation

bullbullkbullbull aenae aa it is in the direction of the center of the

aquifer

25 Page 18 (TB) - The last aentence in paragraph one

beginning with Both wells ~ and the first sentence in

paragraph two beginning with ~Another interpretation bull

contradict one another

2 Paqe 18 - T B atatee One curious point but does not aay

what that point is

27 Paqbull 18 - TB report doea not aubatanthte what data in the

drawdown level ill revealing vertical flow from the

underlying bedrock

28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J

fracture tracea underlying the aite The O LM report

atatea bulla potential north - northeaat trending fault atructure

may underlie the we ll sitebull The D L M r epo r t sta t ement

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l vabull baaed upon cron-section interpretation ll2t from remote

1enaln9 and geophysical methods Frecture tracea are

obtained from rerre eeneing imagery analysis not croae

I aactlon i nterpretation The TB r epor t impllea that the

D L H report is s aying the structure 1a fact where the

DLM words poten t ioll and may are ignored

29 Page 20 - T B report Theae fractures presumably continue

directly towards the Ho bbs Site The major frequency

concentration of lineamentamp i dentified in the R IC L study

rlqure 5 doea rurt ehow the prominent lineaments 1111

continuing towards the Hobbs Site The TB report and

IIOdal have incorrectly extrapolated the photolineament swarm

0 aa ahown in the RICL report RI CL bedrock

110nltorin9 well GZ-128 wu drille d in the prominent

UneiUMtnt ewarm waet of the Coakley Landfill to a depth of

184 feet and produced only 0 25 GPH Tabla 4 (R IC L)

ehowe packer pressure taetad hydraulic conduc tivities

ranqinq frobull 014 to 682 feetday GZ-128 was not packer

teetad because o f the nonfractured and l ow water bearing

characterhtics o f the bedrock GZ-105 (bedrock corehola)

only had a hydraulic conductivity o f 2 0 fee tday Basad

upon the field technic al drill dat4 presented in the

R I cL report i t can Jl2t be concluded tha t the prominent

lineament s warm ae identified o n Figure 5 has a high

hydraulic conductivity Remote sensing analy8111 only

identlfie11 linear photo feature11 These f e a t ures may also

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be attributed to nonhydraulically significant geologic

1tructure1 Remote aenaing is an ~art- and drawing far

reachim~ concluaiona without drilling data ill incorrec t

However thh letter recognizee that due to the limitations

of remota saneincJ other signi ficant water bearing fracturea

may exbt in the bedrock not identified in the R ICL

JO Page 20 - TB states ~ bedrock groundwater generally flowa

in the direction of the Little River - However the T B

report oaita that bedrock groundwater aho generally flowbull

aoutheabullt to North Brook as ahovn on Fiqure 13 of the

R ICL report Bedrock groundwater flowbull radially in bullany

directionbull from the Coakley Landfill and the TB report

should not uae the word bullqenerally bull as it impli one major

direction only when in fact there are many flow pathe

R IC L total volatile organic compounds in

Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127

128 129 and 130 were either nondetected or leu than 5 ppb

Theee leveh are very low concentrations Only GZ-105

ehowed eignificant volatile organic compounds weet of the

Coakley Landfill The VOC levels at GZ-129 and GZ-130 may

b attributed t o additional small transient lind undefined

bullourcea in this area The R I C L r epo r t conc ludes o n paqe

8 - Exec utive Summary bullAt t his t lme however five years

of qrou ndwater contam i na t i o n e x ist away from the l andfill

per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill

- 12shy

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a likely consequence of the diepereive radial flow and

reaultant contaminant dilution ae well abull othe r operative

attenuation mechaniems diacueaed herein Beaed on the

available data it is anticipated that these olttenuatlon

mechanismbull would be a significant llrniting factor in the

diatance contaminants are able to migrate from the landfill

in detectable conc entrations

31 Pa9e 20 (TB) -The OLM and RICL reporta do not

auqqeat that the bedrock and overburden groundwater are

atrictly aeparated from each other

32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa

the Hobbs Site will create flow of groundwater fro11 beneath

and po ibly east of the Little River durinq amplltended low

rainfall recharge periods bull h very weak and baaed upon

faulty auwnptiona and data No creditable field data or

analyaia were brought forth to support the conclusionbull

JJ Fax Page J (TB) - Placing much emphasis upon the

conclusions derived from the application of Theis theory to

large distances beyond the pumping well is not valid due to

the qaologic conditione grouly violate Theta uawnptione

34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods

It is unclear aa to which time period conclus i o ns are

derived for It i s hiqhly unlikely pumpinq effects c an

deleteriously propaqate in 20 days thro uqh t he l ow permeable

- 13 shy

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11atariale located east of the Hobbs Site

35 Paqe llA (T B ) concludes that the safe yield from the

Hobbs Site is in the ranqe of 14 to 58 GPW If this yield

h true than the combined pumpage o f all the residential

wellbull in the study area will exceed the safe yie ld and

potentially impact the Coakley Landfill

36 Paqa 22 - TB reports etatea (1) a nything th11t wu not

sand and gravel laterally or vertically) was impermeable

and (2) streams to the northwest (Cornelius Brook) was

repreaented aa havinq a constant water level (basically an

infinite supply of water) bull In the D L MAHER report Paqe

Jl only the bedrock waa treated aa impermeable The llarine

aedlaentbull vera treated aa a constant head boundary allovinq

for flow into the aquifer Cornelius Brook waa not modeled

bullbull havinq a constant water level in the D L MAHER report

37 Paqe 22 (TB) -Some of the streams modeled as drains are

actually perched above the aquifer11 groundwater table upon

very low permeable marine sedmenta The drainbull are not

JnOdeled correctly Cornelius Brook dries up naturally from

June throuqh September and a significant portion h perched

above the aquifers water table Cornelius Brook receives

ita intermittent recharqe from runoff o n top o f the marine

aediment c ap overlying the northern portion of the Hobba

aquife r Some of t he Little River drain c ella are not

located properly Drain file conductance values appear very

-1 4 shy

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high for etreama flowing upon silts and claye

38 Page 27 (T B) model wa11 run b) atar tng at ateady state

conditione 2 of nonnal rechnrge for 180 day a and pumping

250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead

Protection area delineation requires the contributing area

to ~ delineated for a period of 180 daye pumpin with no

net rainfall recharge upon the ~~ regional

piezometric surface map This method of Wellhead

delineation wae stated by Paul Currier Administrator

Groundwater Protection Bureau during the July 25 1991

bullbullUnq at D E S offices in Concord The TB report

apparently did not model the zoe under thie criteria

39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling

effort it h etated that the model should uee hydraulic

coefficients which were measured in the field~ but fails to

follow through with this premise in the model The

tranbullmhbulllvity values selected for both fractured and

unfractured bedrock are neither explained nor supported by

field data If the va lues were taken from publlahed ranges

they are at t he upper ende of t heee rangee and not

reflective of typical conditio ne in New Enqland Based on

Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of

4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x

10middot1 to 1 2 x 10 feet day for unfractured roc k are more

realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy

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U S GS Water Supply Paper 2220 page 13 ehowa hydraulic

conductivity rangee for igneoua lind metamorphic rocks of

10middot7 feat day unfractured to 15 feet day fracture d

40 Page 218 (T B) - The r e port no tee t hat a ~three-layer

ayetam waa modeled however the model used wae a twt middotmiddot layer

110del It appears that the VCONT variable wae ueed to

repreaent the eiltclayfine eand layer with layer

thickneea eat to o ne foot Thera h no eupportive data of

the one foot thic knen value other than being arbitrarily

aeaiqnad Thia ie not an accurate rapraaantation of actual

conditiona nor ie it the beat way to fully and accurately

-adal thh ayatem

41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy

layer RIOdal and the eimpUfying aWDption of horhontal

layerl re1ult in a model which doee not reflect the actual

qeoloqy at thia alta The variable bedrock topography and

aquifer hydraulic conductivitiebull muet be accounte d for in

the lftOdal if an accurate delineation of the rona of

contribution 1a to be made

42 (T B ) - Thera h no me ntion in the text of either a

aanaitiv ity anal yeh being made or o f a water budget being

c alc ula t ed The s e efforts are both important compone nts of

a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the

acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d

they ehould ha ve been no t ed i n t he report I f e ither o f

- 16 shy

I r -r I

these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

r -r -

area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

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n Q = = Ul

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the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

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49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

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conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

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habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

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C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

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  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 6: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

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10 Paqa 10 (TB J - The effect of hydrogeologic boundaziee such

aa lov permeable sediments and a ehallow depth to bedrock in

the vicinity of Well 6-90 Wood Knoll Drive serving aa a

hydrogeologic boundary between U SGS 69 waa not mentioned

in the T B report Test Well H- 2 is located in low

permeable sediments with shallow depth to bedrock The

pumping effects would take a much longer period of time to

be felt withJn the low permeable eedimente surrounding M-2

than in higher permeable sandbull and gravel

11 Page 10 (TB) - It appeare that a 3420 foot radius of

influence after 20 days of pumpinq at 260 GPM ia calculated

by the Theis equation The Theis equation assumes the

J aquifer ia hOiftOgeneoua hotroplc of uniform thickneaa of

infinite areal extent horizontal piezometric surface the

vell 1bull fully ~netratinq and tranerniuivity ie conbulltant

The ubulle of the Theie equation in thia report qrobullbullly

violatebull thbullbullbull aabullumptionbull when applied to loncr dbtancebull

(qreater than 700 feet) from the well The Hobbbull aquifer h

hiqhly heterocrenaoua of variable thicknenhydraulic

conductivity and areal extent A eloping water table

exbtbull Bedrock barrier boundaries axht within 700 feet of

the pwnped well near Wood rnoll and 1200 feet to the north

near North Road The depth to bedrock shallows to 30 feet

at M-2 Co nc luding t hat uniform radius o f 3420 feet h111

achieved after 20 days pumping h er r oneoue

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12 Paqe 10 (TB) - There 18 little evidence that Mtainted

river waterbull exists at RIC L aampling location S-2 along

the North River which contains cherllical parameters capable

of migrating through the marine aedimentll to the Hobbe Well

Site

13 Paqe 10-11 (TB) - The logic of 58 GPH appears to be basad

on the use of the Thaie equation To reach a aubatantial

concluaion and precision of 58 GPM utilizing the Theia

equation h incorrect

14 Paqe 10 (TB) - The 3420 foot radius appears to incorporate

the apecUic yield value of 0 05 yet on page 8 the T B

report states middoto2 is moat likely a very reasonable value

for sand and gravel bull There does not appear to be

condatency in the T B reporU logic

lS Paqe 12 (TB) - The DL M report flow path model equations

do not utilize storage coefficient valuebull in bullteady bulltate

analybullh Porosity is only utilized in the reverbullbull particle

tracking portion of the model for time of travel capture

ampone delineation not hydraulic head calculationa It would

be ubulleful for the TB author to read the flow path manual

to better understand the model

16 (DL M ) report flow path wae utilized o nly in a conceptual

format (DLM paqe 30) abull a precunor to r unning MODFLOW

Thie procedure is utlhe quite o ften i n many states to

- 6shy

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efficiently and economically determine where additionall field data needs to be collected in order to increase the

predicative accuracy of the HODFLOW model

17 Page 13 (TB)- a porosity of 02 not specific yield of

0 2 wae utilized in the 180-day particle tracking zoe of

the DLM report

18 Page 13 (TB) report states there was an annual rainfall

rate of 78 inchesyear during the seven days of pumping

Thh statement ia confusing and should be clarified Ie the

equivalent amount of rainfall experienced during the pump

teat extrapolated out an annual baaia

0 19 Page lJ (TB ) - The 180-day ZOC determined i n the OL M

report h derived from reverse particle tracking which

deterwinea how lonq it would take a conaervative aolute euch

aa chloride to reach the wbullll The time of travbulll to

TOT-ZOC dbulllineation method haa been an accepted method by

the EPA The particle tracking zoe method ia D2t intended

to mimic the area of influence of the well It is incorrect

tor the TB report to auume the particle tr~ckinq zoe of

thbull vall is the aame as its area of influence

20 Page 17 (TB ) report states Corneliua Brook has an

elevation of 59 feet HSL However Cor nelius Brook when it

haa water in it has a signific ant gradient and not just one

elevation of 59 feet Cornellua Brook is not a po nd but

_ -7 shy

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rather hu multiple elevations depending on where i t l8

lftllaaured (Henry Fuller property or near I-95) Teet Nella

3middot84 and 4-84 which are located in c loae proximity to

Cornelius Brook have groundwater elevationa of 6724 and

65 75 feet reapectlvely The Little River has variable

elevations betwee n 6744 and 652 feet at RIC L staff

qauga SN-9 The TB report aqain eeema to aelect values

for a particular analyah baaed upon whichever value will

produce the desired outcome Therefore it la lncorract for

the TB report to aaaume ~that the Little River would be

aarving aa aOIMI portion of the recharge to the Hobbs Well~

baaed upon thh logic

21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta

aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull

Site b anhotropic hiqhly etratified with variable

hydraulic conductivitlee and traneminivltlee thereby

viohtinq the majority of the Theia auumptionbull and

conclubullione derived thereof

22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the

y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct

a atraiqht line encompaebullinq small dhtancee and drawing

bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect

Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat

ie covered yet the T B report extrapolatebull t he line out to

10 000 feet

-middotshy

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The T B Figure 1 plot clearly shows the drawdown ie

variable and not uniform in all directions thereby

violating a major aaaumption of Thela theory Teat Well

5-84 ahowa greater drawdown than Teet Well 11-90 in TB

Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from

the pumping well than 11-90 ( 97) It is reasonable to

conclude that low permeable boundarlea muet e xist in the

directio n of 5-84 If a radial line la constructed

connec ting 2-84 to 11-90 leas drawdown la s hown towards

11-90 indicative of more permeable material existing in

thia directio n The aquifer permeability variations are

clearly ahovn on DLH report Figure P4

A conparison of OLM teat well logs 5-84 and 11-90

ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84

Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while

11-90 pumped 20 GPM DL H cro section 8-8 shows leu

permeable eilty eand and gravel (not highly permeability

zones as stated in the TB report) surrounds the highly

permeable und and gravel in which the e ight inch pumped

well h located As an example on Tab l e J o f the RICL

report low hydraulic conductivity (lq values a r e shown for

six out of seven overburden wel ls even though t he strata

descriptions would imply a high~ value TB Figure 1 and

D L H P- 4 confirm the exhtence of l ow permeable barrier

boundaries to the north and northeast o f the pumped well

eite It ia incorrect t o c alc ulate and apply a radius o f

- 9 shy

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l influence projecting (10000 feat in TB report) in the

direction of and beyond the barrier boundarlee

I 23 Page 18 - TB Figure 1 plot doea not include all t he

observation well data points thereby biasing the

conclusions

24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the

principal recharge direction to the well is from the

northwat and weat Thil recharge direction interpretation

bullbullkbullbull aenae aa it is in the direction of the center of the

aquifer

25 Page 18 (TB) - The last aentence in paragraph one

beginning with Both wells ~ and the first sentence in

paragraph two beginning with ~Another interpretation bull

contradict one another

2 Paqe 18 - T B atatee One curious point but does not aay

what that point is

27 Paqbull 18 - TB report doea not aubatanthte what data in the

drawdown level ill revealing vertical flow from the

underlying bedrock

28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J

fracture tracea underlying the aite The O LM report

atatea bulla potential north - northeaat trending fault atructure

may underlie the we ll sitebull The D L M r epo r t sta t ement

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l vabull baaed upon cron-section interpretation ll2t from remote

1enaln9 and geophysical methods Frecture tracea are

obtained from rerre eeneing imagery analysis not croae

I aactlon i nterpretation The TB r epor t impllea that the

D L H report is s aying the structure 1a fact where the

DLM words poten t ioll and may are ignored

29 Page 20 - T B report Theae fractures presumably continue

directly towards the Ho bbs Site The major frequency

concentration of lineamentamp i dentified in the R IC L study

rlqure 5 doea rurt ehow the prominent lineaments 1111

continuing towards the Hobbs Site The TB report and

IIOdal have incorrectly extrapolated the photolineament swarm

0 aa ahown in the RICL report RI CL bedrock

110nltorin9 well GZ-128 wu drille d in the prominent

UneiUMtnt ewarm waet of the Coakley Landfill to a depth of

184 feet and produced only 0 25 GPH Tabla 4 (R IC L)

ehowe packer pressure taetad hydraulic conduc tivities

ranqinq frobull 014 to 682 feetday GZ-128 was not packer

teetad because o f the nonfractured and l ow water bearing

characterhtics o f the bedrock GZ-105 (bedrock corehola)

only had a hydraulic conductivity o f 2 0 fee tday Basad

upon the field technic al drill dat4 presented in the

R I cL report i t can Jl2t be concluded tha t the prominent

lineament s warm ae identified o n Figure 5 has a high

hydraulic conductivity Remote sensing analy8111 only

identlfie11 linear photo feature11 These f e a t ures may also

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be attributed to nonhydraulically significant geologic

1tructure1 Remote aenaing is an ~art- and drawing far

reachim~ concluaiona without drilling data ill incorrec t

However thh letter recognizee that due to the limitations

of remota saneincJ other signi ficant water bearing fracturea

may exbt in the bedrock not identified in the R ICL

JO Page 20 - TB states ~ bedrock groundwater generally flowa

in the direction of the Little River - However the T B

report oaita that bedrock groundwater aho generally flowbull

aoutheabullt to North Brook as ahovn on Fiqure 13 of the

R ICL report Bedrock groundwater flowbull radially in bullany

directionbull from the Coakley Landfill and the TB report

should not uae the word bullqenerally bull as it impli one major

direction only when in fact there are many flow pathe

R IC L total volatile organic compounds in

Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127

128 129 and 130 were either nondetected or leu than 5 ppb

Theee leveh are very low concentrations Only GZ-105

ehowed eignificant volatile organic compounds weet of the

Coakley Landfill The VOC levels at GZ-129 and GZ-130 may

b attributed t o additional small transient lind undefined

bullourcea in this area The R I C L r epo r t conc ludes o n paqe

8 - Exec utive Summary bullAt t his t lme however five years

of qrou ndwater contam i na t i o n e x ist away from the l andfill

per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill

- 12shy

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a likely consequence of the diepereive radial flow and

reaultant contaminant dilution ae well abull othe r operative

attenuation mechaniems diacueaed herein Beaed on the

available data it is anticipated that these olttenuatlon

mechanismbull would be a significant llrniting factor in the

diatance contaminants are able to migrate from the landfill

in detectable conc entrations

31 Pa9e 20 (TB) -The OLM and RICL reporta do not

auqqeat that the bedrock and overburden groundwater are

atrictly aeparated from each other

32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa

the Hobbs Site will create flow of groundwater fro11 beneath

and po ibly east of the Little River durinq amplltended low

rainfall recharge periods bull h very weak and baaed upon

faulty auwnptiona and data No creditable field data or

analyaia were brought forth to support the conclusionbull

JJ Fax Page J (TB) - Placing much emphasis upon the

conclusions derived from the application of Theis theory to

large distances beyond the pumping well is not valid due to

the qaologic conditione grouly violate Theta uawnptione

34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods

It is unclear aa to which time period conclus i o ns are

derived for It i s hiqhly unlikely pumpinq effects c an

deleteriously propaqate in 20 days thro uqh t he l ow permeable

- 13 shy

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11atariale located east of the Hobbs Site

35 Paqe llA (T B ) concludes that the safe yield from the

Hobbs Site is in the ranqe of 14 to 58 GPW If this yield

h true than the combined pumpage o f all the residential

wellbull in the study area will exceed the safe yie ld and

potentially impact the Coakley Landfill

36 Paqa 22 - TB reports etatea (1) a nything th11t wu not

sand and gravel laterally or vertically) was impermeable

and (2) streams to the northwest (Cornelius Brook) was

repreaented aa havinq a constant water level (basically an

infinite supply of water) bull In the D L MAHER report Paqe

Jl only the bedrock waa treated aa impermeable The llarine

aedlaentbull vera treated aa a constant head boundary allovinq

for flow into the aquifer Cornelius Brook waa not modeled

bullbull havinq a constant water level in the D L MAHER report

37 Paqe 22 (TB) -Some of the streams modeled as drains are

actually perched above the aquifer11 groundwater table upon

very low permeable marine sedmenta The drainbull are not

JnOdeled correctly Cornelius Brook dries up naturally from

June throuqh September and a significant portion h perched

above the aquifers water table Cornelius Brook receives

ita intermittent recharqe from runoff o n top o f the marine

aediment c ap overlying the northern portion of the Hobba

aquife r Some of t he Little River drain c ella are not

located properly Drain file conductance values appear very

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high for etreama flowing upon silts and claye

38 Page 27 (T B) model wa11 run b) atar tng at ateady state

conditione 2 of nonnal rechnrge for 180 day a and pumping

250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead

Protection area delineation requires the contributing area

to ~ delineated for a period of 180 daye pumpin with no

net rainfall recharge upon the ~~ regional

piezometric surface map This method of Wellhead

delineation wae stated by Paul Currier Administrator

Groundwater Protection Bureau during the July 25 1991

bullbullUnq at D E S offices in Concord The TB report

apparently did not model the zoe under thie criteria

39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling

effort it h etated that the model should uee hydraulic

coefficients which were measured in the field~ but fails to

follow through with this premise in the model The

tranbullmhbulllvity values selected for both fractured and

unfractured bedrock are neither explained nor supported by

field data If the va lues were taken from publlahed ranges

they are at t he upper ende of t heee rangee and not

reflective of typical conditio ne in New Enqland Based on

Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of

4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x

10middot1 to 1 2 x 10 feet day for unfractured roc k are more

realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy

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U S GS Water Supply Paper 2220 page 13 ehowa hydraulic

conductivity rangee for igneoua lind metamorphic rocks of

10middot7 feat day unfractured to 15 feet day fracture d

40 Page 218 (T B) - The r e port no tee t hat a ~three-layer

ayetam waa modeled however the model used wae a twt middotmiddot layer

110del It appears that the VCONT variable wae ueed to

repreaent the eiltclayfine eand layer with layer

thickneea eat to o ne foot Thera h no eupportive data of

the one foot thic knen value other than being arbitrarily

aeaiqnad Thia ie not an accurate rapraaantation of actual

conditiona nor ie it the beat way to fully and accurately

-adal thh ayatem

41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy

layer RIOdal and the eimpUfying aWDption of horhontal

layerl re1ult in a model which doee not reflect the actual

qeoloqy at thia alta The variable bedrock topography and

aquifer hydraulic conductivitiebull muet be accounte d for in

the lftOdal if an accurate delineation of the rona of

contribution 1a to be made

42 (T B ) - Thera h no me ntion in the text of either a

aanaitiv ity anal yeh being made or o f a water budget being

c alc ula t ed The s e efforts are both important compone nts of

a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the

acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d

they ehould ha ve been no t ed i n t he report I f e ither o f

- 16 shy

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these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

r -r -

area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

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the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

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49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

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conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

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habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

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C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

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  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 7: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

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12 Paqe 10 (TB) - There 18 little evidence that Mtainted

river waterbull exists at RIC L aampling location S-2 along

the North River which contains cherllical parameters capable

of migrating through the marine aedimentll to the Hobbe Well

Site

13 Paqe 10-11 (TB) - The logic of 58 GPH appears to be basad

on the use of the Thaie equation To reach a aubatantial

concluaion and precision of 58 GPM utilizing the Theia

equation h incorrect

14 Paqe 10 (TB) - The 3420 foot radius appears to incorporate

the apecUic yield value of 0 05 yet on page 8 the T B

report states middoto2 is moat likely a very reasonable value

for sand and gravel bull There does not appear to be

condatency in the T B reporU logic

lS Paqe 12 (TB) - The DL M report flow path model equations

do not utilize storage coefficient valuebull in bullteady bulltate

analybullh Porosity is only utilized in the reverbullbull particle

tracking portion of the model for time of travel capture

ampone delineation not hydraulic head calculationa It would

be ubulleful for the TB author to read the flow path manual

to better understand the model

16 (DL M ) report flow path wae utilized o nly in a conceptual

format (DLM paqe 30) abull a precunor to r unning MODFLOW

Thie procedure is utlhe quite o ften i n many states to

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efficiently and economically determine where additionall field data needs to be collected in order to increase the

predicative accuracy of the HODFLOW model

17 Page 13 (TB)- a porosity of 02 not specific yield of

0 2 wae utilized in the 180-day particle tracking zoe of

the DLM report

18 Page 13 (TB) report states there was an annual rainfall

rate of 78 inchesyear during the seven days of pumping

Thh statement ia confusing and should be clarified Ie the

equivalent amount of rainfall experienced during the pump

teat extrapolated out an annual baaia

0 19 Page lJ (TB ) - The 180-day ZOC determined i n the OL M

report h derived from reverse particle tracking which

deterwinea how lonq it would take a conaervative aolute euch

aa chloride to reach the wbullll The time of travbulll to

TOT-ZOC dbulllineation method haa been an accepted method by

the EPA The particle tracking zoe method ia D2t intended

to mimic the area of influence of the well It is incorrect

tor the TB report to auume the particle tr~ckinq zoe of

thbull vall is the aame as its area of influence

20 Page 17 (TB ) report states Corneliua Brook has an

elevation of 59 feet HSL However Cor nelius Brook when it

haa water in it has a signific ant gradient and not just one

elevation of 59 feet Cornellua Brook is not a po nd but

_ -7 shy

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r r

rather hu multiple elevations depending on where i t l8

lftllaaured (Henry Fuller property or near I-95) Teet Nella

3middot84 and 4-84 which are located in c loae proximity to

Cornelius Brook have groundwater elevationa of 6724 and

65 75 feet reapectlvely The Little River has variable

elevations betwee n 6744 and 652 feet at RIC L staff

qauga SN-9 The TB report aqain eeema to aelect values

for a particular analyah baaed upon whichever value will

produce the desired outcome Therefore it la lncorract for

the TB report to aaaume ~that the Little River would be

aarving aa aOIMI portion of the recharge to the Hobbs Well~

baaed upon thh logic

21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta

aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull

Site b anhotropic hiqhly etratified with variable

hydraulic conductivitlee and traneminivltlee thereby

viohtinq the majority of the Theia auumptionbull and

conclubullione derived thereof

22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the

y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct

a atraiqht line encompaebullinq small dhtancee and drawing

bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect

Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat

ie covered yet the T B report extrapolatebull t he line out to

10 000 feet

-middotshy

r r I

The T B Figure 1 plot clearly shows the drawdown ie

variable and not uniform in all directions thereby

violating a major aaaumption of Thela theory Teat Well

5-84 ahowa greater drawdown than Teet Well 11-90 in TB

Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from

the pumping well than 11-90 ( 97) It is reasonable to

conclude that low permeable boundarlea muet e xist in the

directio n of 5-84 If a radial line la constructed

connec ting 2-84 to 11-90 leas drawdown la s hown towards

11-90 indicative of more permeable material existing in

thia directio n The aquifer permeability variations are

clearly ahovn on DLH report Figure P4

A conparison of OLM teat well logs 5-84 and 11-90

ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84

Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while

11-90 pumped 20 GPM DL H cro section 8-8 shows leu

permeable eilty eand and gravel (not highly permeability

zones as stated in the TB report) surrounds the highly

permeable und and gravel in which the e ight inch pumped

well h located As an example on Tab l e J o f the RICL

report low hydraulic conductivity (lq values a r e shown for

six out of seven overburden wel ls even though t he strata

descriptions would imply a high~ value TB Figure 1 and

D L H P- 4 confirm the exhtence of l ow permeable barrier

boundaries to the north and northeast o f the pumped well

eite It ia incorrect t o c alc ulate and apply a radius o f

- 9 shy

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- r -r I

l influence projecting (10000 feat in TB report) in the

direction of and beyond the barrier boundarlee

I 23 Page 18 - TB Figure 1 plot doea not include all t he

observation well data points thereby biasing the

conclusions

24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the

principal recharge direction to the well is from the

northwat and weat Thil recharge direction interpretation

bullbullkbullbull aenae aa it is in the direction of the center of the

aquifer

25 Page 18 (TB) - The last aentence in paragraph one

beginning with Both wells ~ and the first sentence in

paragraph two beginning with ~Another interpretation bull

contradict one another

2 Paqe 18 - T B atatee One curious point but does not aay

what that point is

27 Paqbull 18 - TB report doea not aubatanthte what data in the

drawdown level ill revealing vertical flow from the

underlying bedrock

28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J

fracture tracea underlying the aite The O LM report

atatea bulla potential north - northeaat trending fault atructure

may underlie the we ll sitebull The D L M r epo r t sta t ement

- 10shy

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I r -r -

l vabull baaed upon cron-section interpretation ll2t from remote

1enaln9 and geophysical methods Frecture tracea are

obtained from rerre eeneing imagery analysis not croae

I aactlon i nterpretation The TB r epor t impllea that the

D L H report is s aying the structure 1a fact where the

DLM words poten t ioll and may are ignored

29 Page 20 - T B report Theae fractures presumably continue

directly towards the Ho bbs Site The major frequency

concentration of lineamentamp i dentified in the R IC L study

rlqure 5 doea rurt ehow the prominent lineaments 1111

continuing towards the Hobbs Site The TB report and

IIOdal have incorrectly extrapolated the photolineament swarm

0 aa ahown in the RICL report RI CL bedrock

110nltorin9 well GZ-128 wu drille d in the prominent

UneiUMtnt ewarm waet of the Coakley Landfill to a depth of

184 feet and produced only 0 25 GPH Tabla 4 (R IC L)

ehowe packer pressure taetad hydraulic conduc tivities

ranqinq frobull 014 to 682 feetday GZ-128 was not packer

teetad because o f the nonfractured and l ow water bearing

characterhtics o f the bedrock GZ-105 (bedrock corehola)

only had a hydraulic conductivity o f 2 0 fee tday Basad

upon the field technic al drill dat4 presented in the

R I cL report i t can Jl2t be concluded tha t the prominent

lineament s warm ae identified o n Figure 5 has a high

hydraulic conductivity Remote sensing analy8111 only

identlfie11 linear photo feature11 These f e a t ures may also

-11shy

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be attributed to nonhydraulically significant geologic

1tructure1 Remote aenaing is an ~art- and drawing far

reachim~ concluaiona without drilling data ill incorrec t

However thh letter recognizee that due to the limitations

of remota saneincJ other signi ficant water bearing fracturea

may exbt in the bedrock not identified in the R ICL

JO Page 20 - TB states ~ bedrock groundwater generally flowa

in the direction of the Little River - However the T B

report oaita that bedrock groundwater aho generally flowbull

aoutheabullt to North Brook as ahovn on Fiqure 13 of the

R ICL report Bedrock groundwater flowbull radially in bullany

directionbull from the Coakley Landfill and the TB report

should not uae the word bullqenerally bull as it impli one major

direction only when in fact there are many flow pathe

R IC L total volatile organic compounds in

Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127

128 129 and 130 were either nondetected or leu than 5 ppb

Theee leveh are very low concentrations Only GZ-105

ehowed eignificant volatile organic compounds weet of the

Coakley Landfill The VOC levels at GZ-129 and GZ-130 may

b attributed t o additional small transient lind undefined

bullourcea in this area The R I C L r epo r t conc ludes o n paqe

8 - Exec utive Summary bullAt t his t lme however five years

of qrou ndwater contam i na t i o n e x ist away from the l andfill

per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill

- 12shy

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a likely consequence of the diepereive radial flow and

reaultant contaminant dilution ae well abull othe r operative

attenuation mechaniems diacueaed herein Beaed on the

available data it is anticipated that these olttenuatlon

mechanismbull would be a significant llrniting factor in the

diatance contaminants are able to migrate from the landfill

in detectable conc entrations

31 Pa9e 20 (TB) -The OLM and RICL reporta do not

auqqeat that the bedrock and overburden groundwater are

atrictly aeparated from each other

32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa

the Hobbs Site will create flow of groundwater fro11 beneath

and po ibly east of the Little River durinq amplltended low

rainfall recharge periods bull h very weak and baaed upon

faulty auwnptiona and data No creditable field data or

analyaia were brought forth to support the conclusionbull

JJ Fax Page J (TB) - Placing much emphasis upon the

conclusions derived from the application of Theis theory to

large distances beyond the pumping well is not valid due to

the qaologic conditione grouly violate Theta uawnptione

34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods

It is unclear aa to which time period conclus i o ns are

derived for It i s hiqhly unlikely pumpinq effects c an

deleteriously propaqate in 20 days thro uqh t he l ow permeable

- 13 shy

~ n = = =Ul

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r -r -

11atariale located east of the Hobbs Site

35 Paqe llA (T B ) concludes that the safe yield from the

Hobbs Site is in the ranqe of 14 to 58 GPW If this yield

h true than the combined pumpage o f all the residential

wellbull in the study area will exceed the safe yie ld and

potentially impact the Coakley Landfill

36 Paqa 22 - TB reports etatea (1) a nything th11t wu not

sand and gravel laterally or vertically) was impermeable

and (2) streams to the northwest (Cornelius Brook) was

repreaented aa havinq a constant water level (basically an

infinite supply of water) bull In the D L MAHER report Paqe

Jl only the bedrock waa treated aa impermeable The llarine

aedlaentbull vera treated aa a constant head boundary allovinq

for flow into the aquifer Cornelius Brook waa not modeled

bullbull havinq a constant water level in the D L MAHER report

37 Paqe 22 (TB) -Some of the streams modeled as drains are

actually perched above the aquifer11 groundwater table upon

very low permeable marine sedmenta The drainbull are not

JnOdeled correctly Cornelius Brook dries up naturally from

June throuqh September and a significant portion h perched

above the aquifers water table Cornelius Brook receives

ita intermittent recharqe from runoff o n top o f the marine

aediment c ap overlying the northern portion of the Hobba

aquife r Some of t he Little River drain c ella are not

located properly Drain file conductance values appear very

-1 4 shy

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high for etreama flowing upon silts and claye

38 Page 27 (T B) model wa11 run b) atar tng at ateady state

conditione 2 of nonnal rechnrge for 180 day a and pumping

250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead

Protection area delineation requires the contributing area

to ~ delineated for a period of 180 daye pumpin with no

net rainfall recharge upon the ~~ regional

piezometric surface map This method of Wellhead

delineation wae stated by Paul Currier Administrator

Groundwater Protection Bureau during the July 25 1991

bullbullUnq at D E S offices in Concord The TB report

apparently did not model the zoe under thie criteria

39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling

effort it h etated that the model should uee hydraulic

coefficients which were measured in the field~ but fails to

follow through with this premise in the model The

tranbullmhbulllvity values selected for both fractured and

unfractured bedrock are neither explained nor supported by

field data If the va lues were taken from publlahed ranges

they are at t he upper ende of t heee rangee and not

reflective of typical conditio ne in New Enqland Based on

Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of

4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x

10middot1 to 1 2 x 10 feet day for unfractured roc k are more

realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy

- 15shy

r -r I

U S GS Water Supply Paper 2220 page 13 ehowa hydraulic

conductivity rangee for igneoua lind metamorphic rocks of

10middot7 feat day unfractured to 15 feet day fracture d

40 Page 218 (T B) - The r e port no tee t hat a ~three-layer

ayetam waa modeled however the model used wae a twt middotmiddot layer

110del It appears that the VCONT variable wae ueed to

repreaent the eiltclayfine eand layer with layer

thickneea eat to o ne foot Thera h no eupportive data of

the one foot thic knen value other than being arbitrarily

aeaiqnad Thia ie not an accurate rapraaantation of actual

conditiona nor ie it the beat way to fully and accurately

-adal thh ayatem

41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy

layer RIOdal and the eimpUfying aWDption of horhontal

layerl re1ult in a model which doee not reflect the actual

qeoloqy at thia alta The variable bedrock topography and

aquifer hydraulic conductivitiebull muet be accounte d for in

the lftOdal if an accurate delineation of the rona of

contribution 1a to be made

42 (T B ) - Thera h no me ntion in the text of either a

aanaitiv ity anal yeh being made or o f a water budget being

c alc ula t ed The s e efforts are both important compone nts of

a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the

acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d

they ehould ha ve been no t ed i n t he report I f e ither o f

- 16 shy

I r -r I

these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

r -r -

area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

- 19shy

n Q = = Ul

r -r I

the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

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49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

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conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

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habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

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C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

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  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 8: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

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efficiently and economically determine where additionall field data needs to be collected in order to increase the

predicative accuracy of the HODFLOW model

17 Page 13 (TB)- a porosity of 02 not specific yield of

0 2 wae utilized in the 180-day particle tracking zoe of

the DLM report

18 Page 13 (TB) report states there was an annual rainfall

rate of 78 inchesyear during the seven days of pumping

Thh statement ia confusing and should be clarified Ie the

equivalent amount of rainfall experienced during the pump

teat extrapolated out an annual baaia

0 19 Page lJ (TB ) - The 180-day ZOC determined i n the OL M

report h derived from reverse particle tracking which

deterwinea how lonq it would take a conaervative aolute euch

aa chloride to reach the wbullll The time of travbulll to

TOT-ZOC dbulllineation method haa been an accepted method by

the EPA The particle tracking zoe method ia D2t intended

to mimic the area of influence of the well It is incorrect

tor the TB report to auume the particle tr~ckinq zoe of

thbull vall is the aame as its area of influence

20 Page 17 (TB ) report states Corneliua Brook has an

elevation of 59 feet HSL However Cor nelius Brook when it

haa water in it has a signific ant gradient and not just one

elevation of 59 feet Cornellua Brook is not a po nd but

_ -7 shy

--

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rather hu multiple elevations depending on where i t l8

lftllaaured (Henry Fuller property or near I-95) Teet Nella

3middot84 and 4-84 which are located in c loae proximity to

Cornelius Brook have groundwater elevationa of 6724 and

65 75 feet reapectlvely The Little River has variable

elevations betwee n 6744 and 652 feet at RIC L staff

qauga SN-9 The TB report aqain eeema to aelect values

for a particular analyah baaed upon whichever value will

produce the desired outcome Therefore it la lncorract for

the TB report to aaaume ~that the Little River would be

aarving aa aOIMI portion of the recharge to the Hobbs Well~

baaed upon thh logic

21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta

aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull

Site b anhotropic hiqhly etratified with variable

hydraulic conductivitlee and traneminivltlee thereby

viohtinq the majority of the Theia auumptionbull and

conclubullione derived thereof

22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the

y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct

a atraiqht line encompaebullinq small dhtancee and drawing

bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect

Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat

ie covered yet the T B report extrapolatebull t he line out to

10 000 feet

-middotshy

r r I

The T B Figure 1 plot clearly shows the drawdown ie

variable and not uniform in all directions thereby

violating a major aaaumption of Thela theory Teat Well

5-84 ahowa greater drawdown than Teet Well 11-90 in TB

Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from

the pumping well than 11-90 ( 97) It is reasonable to

conclude that low permeable boundarlea muet e xist in the

directio n of 5-84 If a radial line la constructed

connec ting 2-84 to 11-90 leas drawdown la s hown towards

11-90 indicative of more permeable material existing in

thia directio n The aquifer permeability variations are

clearly ahovn on DLH report Figure P4

A conparison of OLM teat well logs 5-84 and 11-90

ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84

Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while

11-90 pumped 20 GPM DL H cro section 8-8 shows leu

permeable eilty eand and gravel (not highly permeability

zones as stated in the TB report) surrounds the highly

permeable und and gravel in which the e ight inch pumped

well h located As an example on Tab l e J o f the RICL

report low hydraulic conductivity (lq values a r e shown for

six out of seven overburden wel ls even though t he strata

descriptions would imply a high~ value TB Figure 1 and

D L H P- 4 confirm the exhtence of l ow permeable barrier

boundaries to the north and northeast o f the pumped well

eite It ia incorrect t o c alc ulate and apply a radius o f

- 9 shy

-shy

--

- r -r I

l influence projecting (10000 feat in TB report) in the

direction of and beyond the barrier boundarlee

I 23 Page 18 - TB Figure 1 plot doea not include all t he

observation well data points thereby biasing the

conclusions

24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the

principal recharge direction to the well is from the

northwat and weat Thil recharge direction interpretation

bullbullkbullbull aenae aa it is in the direction of the center of the

aquifer

25 Page 18 (TB) - The last aentence in paragraph one

beginning with Both wells ~ and the first sentence in

paragraph two beginning with ~Another interpretation bull

contradict one another

2 Paqe 18 - T B atatee One curious point but does not aay

what that point is

27 Paqbull 18 - TB report doea not aubatanthte what data in the

drawdown level ill revealing vertical flow from the

underlying bedrock

28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J

fracture tracea underlying the aite The O LM report

atatea bulla potential north - northeaat trending fault atructure

may underlie the we ll sitebull The D L M r epo r t sta t ement

- 10shy

--

I r -r -

l vabull baaed upon cron-section interpretation ll2t from remote

1enaln9 and geophysical methods Frecture tracea are

obtained from rerre eeneing imagery analysis not croae

I aactlon i nterpretation The TB r epor t impllea that the

D L H report is s aying the structure 1a fact where the

DLM words poten t ioll and may are ignored

29 Page 20 - T B report Theae fractures presumably continue

directly towards the Ho bbs Site The major frequency

concentration of lineamentamp i dentified in the R IC L study

rlqure 5 doea rurt ehow the prominent lineaments 1111

continuing towards the Hobbs Site The TB report and

IIOdal have incorrectly extrapolated the photolineament swarm

0 aa ahown in the RICL report RI CL bedrock

110nltorin9 well GZ-128 wu drille d in the prominent

UneiUMtnt ewarm waet of the Coakley Landfill to a depth of

184 feet and produced only 0 25 GPH Tabla 4 (R IC L)

ehowe packer pressure taetad hydraulic conduc tivities

ranqinq frobull 014 to 682 feetday GZ-128 was not packer

teetad because o f the nonfractured and l ow water bearing

characterhtics o f the bedrock GZ-105 (bedrock corehola)

only had a hydraulic conductivity o f 2 0 fee tday Basad

upon the field technic al drill dat4 presented in the

R I cL report i t can Jl2t be concluded tha t the prominent

lineament s warm ae identified o n Figure 5 has a high

hydraulic conductivity Remote sensing analy8111 only

identlfie11 linear photo feature11 These f e a t ures may also

-11shy

--

r -r -

be attributed to nonhydraulically significant geologic

1tructure1 Remote aenaing is an ~art- and drawing far

reachim~ concluaiona without drilling data ill incorrec t

However thh letter recognizee that due to the limitations

of remota saneincJ other signi ficant water bearing fracturea

may exbt in the bedrock not identified in the R ICL

JO Page 20 - TB states ~ bedrock groundwater generally flowa

in the direction of the Little River - However the T B

report oaita that bedrock groundwater aho generally flowbull

aoutheabullt to North Brook as ahovn on Fiqure 13 of the

R ICL report Bedrock groundwater flowbull radially in bullany

directionbull from the Coakley Landfill and the TB report

should not uae the word bullqenerally bull as it impli one major

direction only when in fact there are many flow pathe

R IC L total volatile organic compounds in

Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127

128 129 and 130 were either nondetected or leu than 5 ppb

Theee leveh are very low concentrations Only GZ-105

ehowed eignificant volatile organic compounds weet of the

Coakley Landfill The VOC levels at GZ-129 and GZ-130 may

b attributed t o additional small transient lind undefined

bullourcea in this area The R I C L r epo r t conc ludes o n paqe

8 - Exec utive Summary bullAt t his t lme however five years

of qrou ndwater contam i na t i o n e x ist away from the l andfill

per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill

- 12shy

- r -r -

a likely consequence of the diepereive radial flow and

reaultant contaminant dilution ae well abull othe r operative

attenuation mechaniems diacueaed herein Beaed on the

available data it is anticipated that these olttenuatlon

mechanismbull would be a significant llrniting factor in the

diatance contaminants are able to migrate from the landfill

in detectable conc entrations

31 Pa9e 20 (TB) -The OLM and RICL reporta do not

auqqeat that the bedrock and overburden groundwater are

atrictly aeparated from each other

32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa

the Hobbs Site will create flow of groundwater fro11 beneath

and po ibly east of the Little River durinq amplltended low

rainfall recharge periods bull h very weak and baaed upon

faulty auwnptiona and data No creditable field data or

analyaia were brought forth to support the conclusionbull

JJ Fax Page J (TB) - Placing much emphasis upon the

conclusions derived from the application of Theis theory to

large distances beyond the pumping well is not valid due to

the qaologic conditione grouly violate Theta uawnptione

34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods

It is unclear aa to which time period conclus i o ns are

derived for It i s hiqhly unlikely pumpinq effects c an

deleteriously propaqate in 20 days thro uqh t he l ow permeable

- 13 shy

~ n = = =Ul

--

r -r -

11atariale located east of the Hobbs Site

35 Paqe llA (T B ) concludes that the safe yield from the

Hobbs Site is in the ranqe of 14 to 58 GPW If this yield

h true than the combined pumpage o f all the residential

wellbull in the study area will exceed the safe yie ld and

potentially impact the Coakley Landfill

36 Paqa 22 - TB reports etatea (1) a nything th11t wu not

sand and gravel laterally or vertically) was impermeable

and (2) streams to the northwest (Cornelius Brook) was

repreaented aa havinq a constant water level (basically an

infinite supply of water) bull In the D L MAHER report Paqe

Jl only the bedrock waa treated aa impermeable The llarine

aedlaentbull vera treated aa a constant head boundary allovinq

for flow into the aquifer Cornelius Brook waa not modeled

bullbull havinq a constant water level in the D L MAHER report

37 Paqe 22 (TB) -Some of the streams modeled as drains are

actually perched above the aquifer11 groundwater table upon

very low permeable marine sedmenta The drainbull are not

JnOdeled correctly Cornelius Brook dries up naturally from

June throuqh September and a significant portion h perched

above the aquifers water table Cornelius Brook receives

ita intermittent recharqe from runoff o n top o f the marine

aediment c ap overlying the northern portion of the Hobba

aquife r Some of t he Little River drain c ella are not

located properly Drain file conductance values appear very

-1 4 shy

r -r -

high for etreama flowing upon silts and claye

38 Page 27 (T B) model wa11 run b) atar tng at ateady state

conditione 2 of nonnal rechnrge for 180 day a and pumping

250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead

Protection area delineation requires the contributing area

to ~ delineated for a period of 180 daye pumpin with no

net rainfall recharge upon the ~~ regional

piezometric surface map This method of Wellhead

delineation wae stated by Paul Currier Administrator

Groundwater Protection Bureau during the July 25 1991

bullbullUnq at D E S offices in Concord The TB report

apparently did not model the zoe under thie criteria

39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling

effort it h etated that the model should uee hydraulic

coefficients which were measured in the field~ but fails to

follow through with this premise in the model The

tranbullmhbulllvity values selected for both fractured and

unfractured bedrock are neither explained nor supported by

field data If the va lues were taken from publlahed ranges

they are at t he upper ende of t heee rangee and not

reflective of typical conditio ne in New Enqland Based on

Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of

4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x

10middot1 to 1 2 x 10 feet day for unfractured roc k are more

realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy

- 15shy

r -r I

U S GS Water Supply Paper 2220 page 13 ehowa hydraulic

conductivity rangee for igneoua lind metamorphic rocks of

10middot7 feat day unfractured to 15 feet day fracture d

40 Page 218 (T B) - The r e port no tee t hat a ~three-layer

ayetam waa modeled however the model used wae a twt middotmiddot layer

110del It appears that the VCONT variable wae ueed to

repreaent the eiltclayfine eand layer with layer

thickneea eat to o ne foot Thera h no eupportive data of

the one foot thic knen value other than being arbitrarily

aeaiqnad Thia ie not an accurate rapraaantation of actual

conditiona nor ie it the beat way to fully and accurately

-adal thh ayatem

41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy

layer RIOdal and the eimpUfying aWDption of horhontal

layerl re1ult in a model which doee not reflect the actual

qeoloqy at thia alta The variable bedrock topography and

aquifer hydraulic conductivitiebull muet be accounte d for in

the lftOdal if an accurate delineation of the rona of

contribution 1a to be made

42 (T B ) - Thera h no me ntion in the text of either a

aanaitiv ity anal yeh being made or o f a water budget being

c alc ula t ed The s e efforts are both important compone nts of

a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the

acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d

they ehould ha ve been no t ed i n t he report I f e ither o f

- 16 shy

I r -r I

these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

r -r -

area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

- 19shy

n Q = = Ul

r -r I

the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

r -r I

49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

r -r -

conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

r -r I

habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

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C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 9: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

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rather hu multiple elevations depending on where i t l8

lftllaaured (Henry Fuller property or near I-95) Teet Nella

3middot84 and 4-84 which are located in c loae proximity to

Cornelius Brook have groundwater elevationa of 6724 and

65 75 feet reapectlvely The Little River has variable

elevations betwee n 6744 and 652 feet at RIC L staff

qauga SN-9 The TB report aqain eeema to aelect values

for a particular analyah baaed upon whichever value will

produce the desired outcome Therefore it la lncorract for

the TB report to aaaume ~that the Little River would be

aarving aa aOIMI portion of the recharge to the Hobbs Well~

baaed upon thh logic

21 Paqe 17 (T B ) - Uae of the Thais theory at the Hobbs alta

aaauin9 the aquifer b h01110ganaoua ill incorrect The Hobbbull

Site b anhotropic hiqhly etratified with variable

hydraulic conductivitlee and traneminivltlee thereby

viohtinq the majority of the Theia auumptionbull and

conclubullione derived thereof

22 Paqe 19 (TB) - Drawdown in feet are not ahovn on the

y-axis in Fiqure 1 Usinq o nly two data pointe to conetruct

a atraiqht line encompaebullinq small dhtancee and drawing

bulliqni flc ant c onclueiona from suc h a plot ie i ncorrect

Between 2- 84 and 5- 84 an aquifer dhtance o f only 150 feat

ie covered yet the T B report extrapolatebull t he line out to

10 000 feet

-middotshy

r r I

The T B Figure 1 plot clearly shows the drawdown ie

variable and not uniform in all directions thereby

violating a major aaaumption of Thela theory Teat Well

5-84 ahowa greater drawdown than Teet Well 11-90 in TB

Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from

the pumping well than 11-90 ( 97) It is reasonable to

conclude that low permeable boundarlea muet e xist in the

directio n of 5-84 If a radial line la constructed

connec ting 2-84 to 11-90 leas drawdown la s hown towards

11-90 indicative of more permeable material existing in

thia directio n The aquifer permeability variations are

clearly ahovn on DLH report Figure P4

A conparison of OLM teat well logs 5-84 and 11-90

ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84

Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while

11-90 pumped 20 GPM DL H cro section 8-8 shows leu

permeable eilty eand and gravel (not highly permeability

zones as stated in the TB report) surrounds the highly

permeable und and gravel in which the e ight inch pumped

well h located As an example on Tab l e J o f the RICL

report low hydraulic conductivity (lq values a r e shown for

six out of seven overburden wel ls even though t he strata

descriptions would imply a high~ value TB Figure 1 and

D L H P- 4 confirm the exhtence of l ow permeable barrier

boundaries to the north and northeast o f the pumped well

eite It ia incorrect t o c alc ulate and apply a radius o f

- 9 shy

-shy

--

- r -r I

l influence projecting (10000 feat in TB report) in the

direction of and beyond the barrier boundarlee

I 23 Page 18 - TB Figure 1 plot doea not include all t he

observation well data points thereby biasing the

conclusions

24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the

principal recharge direction to the well is from the

northwat and weat Thil recharge direction interpretation

bullbullkbullbull aenae aa it is in the direction of the center of the

aquifer

25 Page 18 (TB) - The last aentence in paragraph one

beginning with Both wells ~ and the first sentence in

paragraph two beginning with ~Another interpretation bull

contradict one another

2 Paqe 18 - T B atatee One curious point but does not aay

what that point is

27 Paqbull 18 - TB report doea not aubatanthte what data in the

drawdown level ill revealing vertical flow from the

underlying bedrock

28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J

fracture tracea underlying the aite The O LM report

atatea bulla potential north - northeaat trending fault atructure

may underlie the we ll sitebull The D L M r epo r t sta t ement

- 10shy

--

I r -r -

l vabull baaed upon cron-section interpretation ll2t from remote

1enaln9 and geophysical methods Frecture tracea are

obtained from rerre eeneing imagery analysis not croae

I aactlon i nterpretation The TB r epor t impllea that the

D L H report is s aying the structure 1a fact where the

DLM words poten t ioll and may are ignored

29 Page 20 - T B report Theae fractures presumably continue

directly towards the Ho bbs Site The major frequency

concentration of lineamentamp i dentified in the R IC L study

rlqure 5 doea rurt ehow the prominent lineaments 1111

continuing towards the Hobbs Site The TB report and

IIOdal have incorrectly extrapolated the photolineament swarm

0 aa ahown in the RICL report RI CL bedrock

110nltorin9 well GZ-128 wu drille d in the prominent

UneiUMtnt ewarm waet of the Coakley Landfill to a depth of

184 feet and produced only 0 25 GPH Tabla 4 (R IC L)

ehowe packer pressure taetad hydraulic conduc tivities

ranqinq frobull 014 to 682 feetday GZ-128 was not packer

teetad because o f the nonfractured and l ow water bearing

characterhtics o f the bedrock GZ-105 (bedrock corehola)

only had a hydraulic conductivity o f 2 0 fee tday Basad

upon the field technic al drill dat4 presented in the

R I cL report i t can Jl2t be concluded tha t the prominent

lineament s warm ae identified o n Figure 5 has a high

hydraulic conductivity Remote sensing analy8111 only

identlfie11 linear photo feature11 These f e a t ures may also

-11shy

--

r -r -

be attributed to nonhydraulically significant geologic

1tructure1 Remote aenaing is an ~art- and drawing far

reachim~ concluaiona without drilling data ill incorrec t

However thh letter recognizee that due to the limitations

of remota saneincJ other signi ficant water bearing fracturea

may exbt in the bedrock not identified in the R ICL

JO Page 20 - TB states ~ bedrock groundwater generally flowa

in the direction of the Little River - However the T B

report oaita that bedrock groundwater aho generally flowbull

aoutheabullt to North Brook as ahovn on Fiqure 13 of the

R ICL report Bedrock groundwater flowbull radially in bullany

directionbull from the Coakley Landfill and the TB report

should not uae the word bullqenerally bull as it impli one major

direction only when in fact there are many flow pathe

R IC L total volatile organic compounds in

Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127

128 129 and 130 were either nondetected or leu than 5 ppb

Theee leveh are very low concentrations Only GZ-105

ehowed eignificant volatile organic compounds weet of the

Coakley Landfill The VOC levels at GZ-129 and GZ-130 may

b attributed t o additional small transient lind undefined

bullourcea in this area The R I C L r epo r t conc ludes o n paqe

8 - Exec utive Summary bullAt t his t lme however five years

of qrou ndwater contam i na t i o n e x ist away from the l andfill

per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill

- 12shy

- r -r -

a likely consequence of the diepereive radial flow and

reaultant contaminant dilution ae well abull othe r operative

attenuation mechaniems diacueaed herein Beaed on the

available data it is anticipated that these olttenuatlon

mechanismbull would be a significant llrniting factor in the

diatance contaminants are able to migrate from the landfill

in detectable conc entrations

31 Pa9e 20 (TB) -The OLM and RICL reporta do not

auqqeat that the bedrock and overburden groundwater are

atrictly aeparated from each other

32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa

the Hobbs Site will create flow of groundwater fro11 beneath

and po ibly east of the Little River durinq amplltended low

rainfall recharge periods bull h very weak and baaed upon

faulty auwnptiona and data No creditable field data or

analyaia were brought forth to support the conclusionbull

JJ Fax Page J (TB) - Placing much emphasis upon the

conclusions derived from the application of Theis theory to

large distances beyond the pumping well is not valid due to

the qaologic conditione grouly violate Theta uawnptione

34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods

It is unclear aa to which time period conclus i o ns are

derived for It i s hiqhly unlikely pumpinq effects c an

deleteriously propaqate in 20 days thro uqh t he l ow permeable

- 13 shy

~ n = = =Ul

--

r -r -

11atariale located east of the Hobbs Site

35 Paqe llA (T B ) concludes that the safe yield from the

Hobbs Site is in the ranqe of 14 to 58 GPW If this yield

h true than the combined pumpage o f all the residential

wellbull in the study area will exceed the safe yie ld and

potentially impact the Coakley Landfill

36 Paqa 22 - TB reports etatea (1) a nything th11t wu not

sand and gravel laterally or vertically) was impermeable

and (2) streams to the northwest (Cornelius Brook) was

repreaented aa havinq a constant water level (basically an

infinite supply of water) bull In the D L MAHER report Paqe

Jl only the bedrock waa treated aa impermeable The llarine

aedlaentbull vera treated aa a constant head boundary allovinq

for flow into the aquifer Cornelius Brook waa not modeled

bullbull havinq a constant water level in the D L MAHER report

37 Paqe 22 (TB) -Some of the streams modeled as drains are

actually perched above the aquifer11 groundwater table upon

very low permeable marine sedmenta The drainbull are not

JnOdeled correctly Cornelius Brook dries up naturally from

June throuqh September and a significant portion h perched

above the aquifers water table Cornelius Brook receives

ita intermittent recharqe from runoff o n top o f the marine

aediment c ap overlying the northern portion of the Hobba

aquife r Some of t he Little River drain c ella are not

located properly Drain file conductance values appear very

-1 4 shy

r -r -

high for etreama flowing upon silts and claye

38 Page 27 (T B) model wa11 run b) atar tng at ateady state

conditione 2 of nonnal rechnrge for 180 day a and pumping

250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead

Protection area delineation requires the contributing area

to ~ delineated for a period of 180 daye pumpin with no

net rainfall recharge upon the ~~ regional

piezometric surface map This method of Wellhead

delineation wae stated by Paul Currier Administrator

Groundwater Protection Bureau during the July 25 1991

bullbullUnq at D E S offices in Concord The TB report

apparently did not model the zoe under thie criteria

39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling

effort it h etated that the model should uee hydraulic

coefficients which were measured in the field~ but fails to

follow through with this premise in the model The

tranbullmhbulllvity values selected for both fractured and

unfractured bedrock are neither explained nor supported by

field data If the va lues were taken from publlahed ranges

they are at t he upper ende of t heee rangee and not

reflective of typical conditio ne in New Enqland Based on

Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of

4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x

10middot1 to 1 2 x 10 feet day for unfractured roc k are more

realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy

- 15shy

r -r I

U S GS Water Supply Paper 2220 page 13 ehowa hydraulic

conductivity rangee for igneoua lind metamorphic rocks of

10middot7 feat day unfractured to 15 feet day fracture d

40 Page 218 (T B) - The r e port no tee t hat a ~three-layer

ayetam waa modeled however the model used wae a twt middotmiddot layer

110del It appears that the VCONT variable wae ueed to

repreaent the eiltclayfine eand layer with layer

thickneea eat to o ne foot Thera h no eupportive data of

the one foot thic knen value other than being arbitrarily

aeaiqnad Thia ie not an accurate rapraaantation of actual

conditiona nor ie it the beat way to fully and accurately

-adal thh ayatem

41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy

layer RIOdal and the eimpUfying aWDption of horhontal

layerl re1ult in a model which doee not reflect the actual

qeoloqy at thia alta The variable bedrock topography and

aquifer hydraulic conductivitiebull muet be accounte d for in

the lftOdal if an accurate delineation of the rona of

contribution 1a to be made

42 (T B ) - Thera h no me ntion in the text of either a

aanaitiv ity anal yeh being made or o f a water budget being

c alc ula t ed The s e efforts are both important compone nts of

a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the

acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d

they ehould ha ve been no t ed i n t he report I f e ither o f

- 16 shy

I r -r I

these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

r -r -

area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

- 19shy

n Q = = Ul

r -r I

the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

r -r I

49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

r -r -

conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

r -r I

habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

--

r -r --

C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 10: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

r r I

The T B Figure 1 plot clearly shows the drawdown ie

variable and not uniform in all directions thereby

violating a major aaaumption of Thela theory Teat Well

5-84 ahowa greater drawdown than Teet Well 11-90 in TB

Figure 1 Yet Teat Well 5-84 is farther away ( 150 ) from

the pumping well than 11-90 ( 97) It is reasonable to

conclude that low permeable boundarlea muet e xist in the

directio n of 5-84 If a radial line la constructed

connec ting 2-84 to 11-90 leas drawdown la s hown towards

11-90 indicative of more permeable material existing in

thia directio n The aquifer permeability variations are

clearly ahovn on DLH report Figure P4

A conparison of OLM teat well logs 5-84 and 11-90

ahow more permeable aedlmanta exiata at 11 - 90 than at 5-84

Teat Well 5-84 pumped 8 GPM 2-90 S GPM H-2 0 S GPH while

11-90 pumped 20 GPM DL H cro section 8-8 shows leu

permeable eilty eand and gravel (not highly permeability

zones as stated in the TB report) surrounds the highly

permeable und and gravel in which the e ight inch pumped

well h located As an example on Tab l e J o f the RICL

report low hydraulic conductivity (lq values a r e shown for

six out of seven overburden wel ls even though t he strata

descriptions would imply a high~ value TB Figure 1 and

D L H P- 4 confirm the exhtence of l ow permeable barrier

boundaries to the north and northeast o f the pumped well

eite It ia incorrect t o c alc ulate and apply a radius o f

- 9 shy

-shy

--

- r -r I

l influence projecting (10000 feat in TB report) in the

direction of and beyond the barrier boundarlee

I 23 Page 18 - TB Figure 1 plot doea not include all t he

observation well data points thereby biasing the

conclusions

24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the

principal recharge direction to the well is from the

northwat and weat Thil recharge direction interpretation

bullbullkbullbull aenae aa it is in the direction of the center of the

aquifer

25 Page 18 (TB) - The last aentence in paragraph one

beginning with Both wells ~ and the first sentence in

paragraph two beginning with ~Another interpretation bull

contradict one another

2 Paqe 18 - T B atatee One curious point but does not aay

what that point is

27 Paqbull 18 - TB report doea not aubatanthte what data in the

drawdown level ill revealing vertical flow from the

underlying bedrock

28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J

fracture tracea underlying the aite The O LM report

atatea bulla potential north - northeaat trending fault atructure

may underlie the we ll sitebull The D L M r epo r t sta t ement

- 10shy

--

I r -r -

l vabull baaed upon cron-section interpretation ll2t from remote

1enaln9 and geophysical methods Frecture tracea are

obtained from rerre eeneing imagery analysis not croae

I aactlon i nterpretation The TB r epor t impllea that the

D L H report is s aying the structure 1a fact where the

DLM words poten t ioll and may are ignored

29 Page 20 - T B report Theae fractures presumably continue

directly towards the Ho bbs Site The major frequency

concentration of lineamentamp i dentified in the R IC L study

rlqure 5 doea rurt ehow the prominent lineaments 1111

continuing towards the Hobbs Site The TB report and

IIOdal have incorrectly extrapolated the photolineament swarm

0 aa ahown in the RICL report RI CL bedrock

110nltorin9 well GZ-128 wu drille d in the prominent

UneiUMtnt ewarm waet of the Coakley Landfill to a depth of

184 feet and produced only 0 25 GPH Tabla 4 (R IC L)

ehowe packer pressure taetad hydraulic conduc tivities

ranqinq frobull 014 to 682 feetday GZ-128 was not packer

teetad because o f the nonfractured and l ow water bearing

characterhtics o f the bedrock GZ-105 (bedrock corehola)

only had a hydraulic conductivity o f 2 0 fee tday Basad

upon the field technic al drill dat4 presented in the

R I cL report i t can Jl2t be concluded tha t the prominent

lineament s warm ae identified o n Figure 5 has a high

hydraulic conductivity Remote sensing analy8111 only

identlfie11 linear photo feature11 These f e a t ures may also

-11shy

--

r -r -

be attributed to nonhydraulically significant geologic

1tructure1 Remote aenaing is an ~art- and drawing far

reachim~ concluaiona without drilling data ill incorrec t

However thh letter recognizee that due to the limitations

of remota saneincJ other signi ficant water bearing fracturea

may exbt in the bedrock not identified in the R ICL

JO Page 20 - TB states ~ bedrock groundwater generally flowa

in the direction of the Little River - However the T B

report oaita that bedrock groundwater aho generally flowbull

aoutheabullt to North Brook as ahovn on Fiqure 13 of the

R ICL report Bedrock groundwater flowbull radially in bullany

directionbull from the Coakley Landfill and the TB report

should not uae the word bullqenerally bull as it impli one major

direction only when in fact there are many flow pathe

R IC L total volatile organic compounds in

Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127

128 129 and 130 were either nondetected or leu than 5 ppb

Theee leveh are very low concentrations Only GZ-105

ehowed eignificant volatile organic compounds weet of the

Coakley Landfill The VOC levels at GZ-129 and GZ-130 may

b attributed t o additional small transient lind undefined

bullourcea in this area The R I C L r epo r t conc ludes o n paqe

8 - Exec utive Summary bullAt t his t lme however five years

of qrou ndwater contam i na t i o n e x ist away from the l andfill

per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill

- 12shy

- r -r -

a likely consequence of the diepereive radial flow and

reaultant contaminant dilution ae well abull othe r operative

attenuation mechaniems diacueaed herein Beaed on the

available data it is anticipated that these olttenuatlon

mechanismbull would be a significant llrniting factor in the

diatance contaminants are able to migrate from the landfill

in detectable conc entrations

31 Pa9e 20 (TB) -The OLM and RICL reporta do not

auqqeat that the bedrock and overburden groundwater are

atrictly aeparated from each other

32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa

the Hobbs Site will create flow of groundwater fro11 beneath

and po ibly east of the Little River durinq amplltended low

rainfall recharge periods bull h very weak and baaed upon

faulty auwnptiona and data No creditable field data or

analyaia were brought forth to support the conclusionbull

JJ Fax Page J (TB) - Placing much emphasis upon the

conclusions derived from the application of Theis theory to

large distances beyond the pumping well is not valid due to

the qaologic conditione grouly violate Theta uawnptione

34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods

It is unclear aa to which time period conclus i o ns are

derived for It i s hiqhly unlikely pumpinq effects c an

deleteriously propaqate in 20 days thro uqh t he l ow permeable

- 13 shy

~ n = = =Ul

--

r -r -

11atariale located east of the Hobbs Site

35 Paqe llA (T B ) concludes that the safe yield from the

Hobbs Site is in the ranqe of 14 to 58 GPW If this yield

h true than the combined pumpage o f all the residential

wellbull in the study area will exceed the safe yie ld and

potentially impact the Coakley Landfill

36 Paqa 22 - TB reports etatea (1) a nything th11t wu not

sand and gravel laterally or vertically) was impermeable

and (2) streams to the northwest (Cornelius Brook) was

repreaented aa havinq a constant water level (basically an

infinite supply of water) bull In the D L MAHER report Paqe

Jl only the bedrock waa treated aa impermeable The llarine

aedlaentbull vera treated aa a constant head boundary allovinq

for flow into the aquifer Cornelius Brook waa not modeled

bullbull havinq a constant water level in the D L MAHER report

37 Paqe 22 (TB) -Some of the streams modeled as drains are

actually perched above the aquifer11 groundwater table upon

very low permeable marine sedmenta The drainbull are not

JnOdeled correctly Cornelius Brook dries up naturally from

June throuqh September and a significant portion h perched

above the aquifers water table Cornelius Brook receives

ita intermittent recharqe from runoff o n top o f the marine

aediment c ap overlying the northern portion of the Hobba

aquife r Some of t he Little River drain c ella are not

located properly Drain file conductance values appear very

-1 4 shy

r -r -

high for etreama flowing upon silts and claye

38 Page 27 (T B) model wa11 run b) atar tng at ateady state

conditione 2 of nonnal rechnrge for 180 day a and pumping

250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead

Protection area delineation requires the contributing area

to ~ delineated for a period of 180 daye pumpin with no

net rainfall recharge upon the ~~ regional

piezometric surface map This method of Wellhead

delineation wae stated by Paul Currier Administrator

Groundwater Protection Bureau during the July 25 1991

bullbullUnq at D E S offices in Concord The TB report

apparently did not model the zoe under thie criteria

39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling

effort it h etated that the model should uee hydraulic

coefficients which were measured in the field~ but fails to

follow through with this premise in the model The

tranbullmhbulllvity values selected for both fractured and

unfractured bedrock are neither explained nor supported by

field data If the va lues were taken from publlahed ranges

they are at t he upper ende of t heee rangee and not

reflective of typical conditio ne in New Enqland Based on

Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of

4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x

10middot1 to 1 2 x 10 feet day for unfractured roc k are more

realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy

- 15shy

r -r I

U S GS Water Supply Paper 2220 page 13 ehowa hydraulic

conductivity rangee for igneoua lind metamorphic rocks of

10middot7 feat day unfractured to 15 feet day fracture d

40 Page 218 (T B) - The r e port no tee t hat a ~three-layer

ayetam waa modeled however the model used wae a twt middotmiddot layer

110del It appears that the VCONT variable wae ueed to

repreaent the eiltclayfine eand layer with layer

thickneea eat to o ne foot Thera h no eupportive data of

the one foot thic knen value other than being arbitrarily

aeaiqnad Thia ie not an accurate rapraaantation of actual

conditiona nor ie it the beat way to fully and accurately

-adal thh ayatem

41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy

layer RIOdal and the eimpUfying aWDption of horhontal

layerl re1ult in a model which doee not reflect the actual

qeoloqy at thia alta The variable bedrock topography and

aquifer hydraulic conductivitiebull muet be accounte d for in

the lftOdal if an accurate delineation of the rona of

contribution 1a to be made

42 (T B ) - Thera h no me ntion in the text of either a

aanaitiv ity anal yeh being made or o f a water budget being

c alc ula t ed The s e efforts are both important compone nts of

a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the

acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d

they ehould ha ve been no t ed i n t he report I f e ither o f

- 16 shy

I r -r I

these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

r -r -

area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

- 19shy

n Q = = Ul

r -r I

the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

r -r I

49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

r -r -

conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

r -r I

habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

--

r -r --

C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 11: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

--

- r -r I

l influence projecting (10000 feat in TB report) in the

direction of and beyond the barrier boundarlee

I 23 Page 18 - TB Figure 1 plot doea not include all t he

observation well data points thereby biasing the

conclusions

24 Page 18 - TB Figures 1 and 6 and DLM P-4 plots show the

principal recharge direction to the well is from the

northwat and weat Thil recharge direction interpretation

bullbullkbullbull aenae aa it is in the direction of the center of the

aquifer

25 Page 18 (TB) - The last aentence in paragraph one

beginning with Both wells ~ and the first sentence in

paragraph two beginning with ~Another interpretation bull

contradict one another

2 Paqe 18 - T B atatee One curious point but does not aay

what that point is

27 Paqbull 18 - TB report doea not aubatanthte what data in the

drawdown level ill revealing vertical flow from the

underlying bedrock

28 Paqe 20 - TB report atate8 middoto L KAHER report aa havlnq -J

fracture tracea underlying the aite The O LM report

atatea bulla potential north - northeaat trending fault atructure

may underlie the we ll sitebull The D L M r epo r t sta t ement

- 10shy

--

I r -r -

l vabull baaed upon cron-section interpretation ll2t from remote

1enaln9 and geophysical methods Frecture tracea are

obtained from rerre eeneing imagery analysis not croae

I aactlon i nterpretation The TB r epor t impllea that the

D L H report is s aying the structure 1a fact where the

DLM words poten t ioll and may are ignored

29 Page 20 - T B report Theae fractures presumably continue

directly towards the Ho bbs Site The major frequency

concentration of lineamentamp i dentified in the R IC L study

rlqure 5 doea rurt ehow the prominent lineaments 1111

continuing towards the Hobbs Site The TB report and

IIOdal have incorrectly extrapolated the photolineament swarm

0 aa ahown in the RICL report RI CL bedrock

110nltorin9 well GZ-128 wu drille d in the prominent

UneiUMtnt ewarm waet of the Coakley Landfill to a depth of

184 feet and produced only 0 25 GPH Tabla 4 (R IC L)

ehowe packer pressure taetad hydraulic conduc tivities

ranqinq frobull 014 to 682 feetday GZ-128 was not packer

teetad because o f the nonfractured and l ow water bearing

characterhtics o f the bedrock GZ-105 (bedrock corehola)

only had a hydraulic conductivity o f 2 0 fee tday Basad

upon the field technic al drill dat4 presented in the

R I cL report i t can Jl2t be concluded tha t the prominent

lineament s warm ae identified o n Figure 5 has a high

hydraulic conductivity Remote sensing analy8111 only

identlfie11 linear photo feature11 These f e a t ures may also

-11shy

--

r -r -

be attributed to nonhydraulically significant geologic

1tructure1 Remote aenaing is an ~art- and drawing far

reachim~ concluaiona without drilling data ill incorrec t

However thh letter recognizee that due to the limitations

of remota saneincJ other signi ficant water bearing fracturea

may exbt in the bedrock not identified in the R ICL

JO Page 20 - TB states ~ bedrock groundwater generally flowa

in the direction of the Little River - However the T B

report oaita that bedrock groundwater aho generally flowbull

aoutheabullt to North Brook as ahovn on Fiqure 13 of the

R ICL report Bedrock groundwater flowbull radially in bullany

directionbull from the Coakley Landfill and the TB report

should not uae the word bullqenerally bull as it impli one major

direction only when in fact there are many flow pathe

R IC L total volatile organic compounds in

Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127

128 129 and 130 were either nondetected or leu than 5 ppb

Theee leveh are very low concentrations Only GZ-105

ehowed eignificant volatile organic compounds weet of the

Coakley Landfill The VOC levels at GZ-129 and GZ-130 may

b attributed t o additional small transient lind undefined

bullourcea in this area The R I C L r epo r t conc ludes o n paqe

8 - Exec utive Summary bullAt t his t lme however five years

of qrou ndwater contam i na t i o n e x ist away from the l andfill

per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill

- 12shy

- r -r -

a likely consequence of the diepereive radial flow and

reaultant contaminant dilution ae well abull othe r operative

attenuation mechaniems diacueaed herein Beaed on the

available data it is anticipated that these olttenuatlon

mechanismbull would be a significant llrniting factor in the

diatance contaminants are able to migrate from the landfill

in detectable conc entrations

31 Pa9e 20 (TB) -The OLM and RICL reporta do not

auqqeat that the bedrock and overburden groundwater are

atrictly aeparated from each other

32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa

the Hobbs Site will create flow of groundwater fro11 beneath

and po ibly east of the Little River durinq amplltended low

rainfall recharge periods bull h very weak and baaed upon

faulty auwnptiona and data No creditable field data or

analyaia were brought forth to support the conclusionbull

JJ Fax Page J (TB) - Placing much emphasis upon the

conclusions derived from the application of Theis theory to

large distances beyond the pumping well is not valid due to

the qaologic conditione grouly violate Theta uawnptione

34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods

It is unclear aa to which time period conclus i o ns are

derived for It i s hiqhly unlikely pumpinq effects c an

deleteriously propaqate in 20 days thro uqh t he l ow permeable

- 13 shy

~ n = = =Ul

--

r -r -

11atariale located east of the Hobbs Site

35 Paqe llA (T B ) concludes that the safe yield from the

Hobbs Site is in the ranqe of 14 to 58 GPW If this yield

h true than the combined pumpage o f all the residential

wellbull in the study area will exceed the safe yie ld and

potentially impact the Coakley Landfill

36 Paqa 22 - TB reports etatea (1) a nything th11t wu not

sand and gravel laterally or vertically) was impermeable

and (2) streams to the northwest (Cornelius Brook) was

repreaented aa havinq a constant water level (basically an

infinite supply of water) bull In the D L MAHER report Paqe

Jl only the bedrock waa treated aa impermeable The llarine

aedlaentbull vera treated aa a constant head boundary allovinq

for flow into the aquifer Cornelius Brook waa not modeled

bullbull havinq a constant water level in the D L MAHER report

37 Paqe 22 (TB) -Some of the streams modeled as drains are

actually perched above the aquifer11 groundwater table upon

very low permeable marine sedmenta The drainbull are not

JnOdeled correctly Cornelius Brook dries up naturally from

June throuqh September and a significant portion h perched

above the aquifers water table Cornelius Brook receives

ita intermittent recharqe from runoff o n top o f the marine

aediment c ap overlying the northern portion of the Hobba

aquife r Some of t he Little River drain c ella are not

located properly Drain file conductance values appear very

-1 4 shy

r -r -

high for etreama flowing upon silts and claye

38 Page 27 (T B) model wa11 run b) atar tng at ateady state

conditione 2 of nonnal rechnrge for 180 day a and pumping

250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead

Protection area delineation requires the contributing area

to ~ delineated for a period of 180 daye pumpin with no

net rainfall recharge upon the ~~ regional

piezometric surface map This method of Wellhead

delineation wae stated by Paul Currier Administrator

Groundwater Protection Bureau during the July 25 1991

bullbullUnq at D E S offices in Concord The TB report

apparently did not model the zoe under thie criteria

39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling

effort it h etated that the model should uee hydraulic

coefficients which were measured in the field~ but fails to

follow through with this premise in the model The

tranbullmhbulllvity values selected for both fractured and

unfractured bedrock are neither explained nor supported by

field data If the va lues were taken from publlahed ranges

they are at t he upper ende of t heee rangee and not

reflective of typical conditio ne in New Enqland Based on

Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of

4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x

10middot1 to 1 2 x 10 feet day for unfractured roc k are more

realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy

- 15shy

r -r I

U S GS Water Supply Paper 2220 page 13 ehowa hydraulic

conductivity rangee for igneoua lind metamorphic rocks of

10middot7 feat day unfractured to 15 feet day fracture d

40 Page 218 (T B) - The r e port no tee t hat a ~three-layer

ayetam waa modeled however the model used wae a twt middotmiddot layer

110del It appears that the VCONT variable wae ueed to

repreaent the eiltclayfine eand layer with layer

thickneea eat to o ne foot Thera h no eupportive data of

the one foot thic knen value other than being arbitrarily

aeaiqnad Thia ie not an accurate rapraaantation of actual

conditiona nor ie it the beat way to fully and accurately

-adal thh ayatem

41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy

layer RIOdal and the eimpUfying aWDption of horhontal

layerl re1ult in a model which doee not reflect the actual

qeoloqy at thia alta The variable bedrock topography and

aquifer hydraulic conductivitiebull muet be accounte d for in

the lftOdal if an accurate delineation of the rona of

contribution 1a to be made

42 (T B ) - Thera h no me ntion in the text of either a

aanaitiv ity anal yeh being made or o f a water budget being

c alc ula t ed The s e efforts are both important compone nts of

a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the

acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d

they ehould ha ve been no t ed i n t he report I f e ither o f

- 16 shy

I r -r I

these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

r -r -

area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

- 19shy

n Q = = Ul

r -r I

the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

r -r I

49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

r -r -

conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

r -r I

habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

--

r -r --

C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 12: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

--

I r -r -

l vabull baaed upon cron-section interpretation ll2t from remote

1enaln9 and geophysical methods Frecture tracea are

obtained from rerre eeneing imagery analysis not croae

I aactlon i nterpretation The TB r epor t impllea that the

D L H report is s aying the structure 1a fact where the

DLM words poten t ioll and may are ignored

29 Page 20 - T B report Theae fractures presumably continue

directly towards the Ho bbs Site The major frequency

concentration of lineamentamp i dentified in the R IC L study

rlqure 5 doea rurt ehow the prominent lineaments 1111

continuing towards the Hobbs Site The TB report and

IIOdal have incorrectly extrapolated the photolineament swarm

0 aa ahown in the RICL report RI CL bedrock

110nltorin9 well GZ-128 wu drille d in the prominent

UneiUMtnt ewarm waet of the Coakley Landfill to a depth of

184 feet and produced only 0 25 GPH Tabla 4 (R IC L)

ehowe packer pressure taetad hydraulic conduc tivities

ranqinq frobull 014 to 682 feetday GZ-128 was not packer

teetad because o f the nonfractured and l ow water bearing

characterhtics o f the bedrock GZ-105 (bedrock corehola)

only had a hydraulic conductivity o f 2 0 fee tday Basad

upon the field technic al drill dat4 presented in the

R I cL report i t can Jl2t be concluded tha t the prominent

lineament s warm ae identified o n Figure 5 has a high

hydraulic conductivity Remote sensing analy8111 only

identlfie11 linear photo feature11 These f e a t ures may also

-11shy

--

r -r -

be attributed to nonhydraulically significant geologic

1tructure1 Remote aenaing is an ~art- and drawing far

reachim~ concluaiona without drilling data ill incorrec t

However thh letter recognizee that due to the limitations

of remota saneincJ other signi ficant water bearing fracturea

may exbt in the bedrock not identified in the R ICL

JO Page 20 - TB states ~ bedrock groundwater generally flowa

in the direction of the Little River - However the T B

report oaita that bedrock groundwater aho generally flowbull

aoutheabullt to North Brook as ahovn on Fiqure 13 of the

R ICL report Bedrock groundwater flowbull radially in bullany

directionbull from the Coakley Landfill and the TB report

should not uae the word bullqenerally bull as it impli one major

direction only when in fact there are many flow pathe

R IC L total volatile organic compounds in

Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127

128 129 and 130 were either nondetected or leu than 5 ppb

Theee leveh are very low concentrations Only GZ-105

ehowed eignificant volatile organic compounds weet of the

Coakley Landfill The VOC levels at GZ-129 and GZ-130 may

b attributed t o additional small transient lind undefined

bullourcea in this area The R I C L r epo r t conc ludes o n paqe

8 - Exec utive Summary bullAt t his t lme however five years

of qrou ndwater contam i na t i o n e x ist away from the l andfill

per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill

- 12shy

- r -r -

a likely consequence of the diepereive radial flow and

reaultant contaminant dilution ae well abull othe r operative

attenuation mechaniems diacueaed herein Beaed on the

available data it is anticipated that these olttenuatlon

mechanismbull would be a significant llrniting factor in the

diatance contaminants are able to migrate from the landfill

in detectable conc entrations

31 Pa9e 20 (TB) -The OLM and RICL reporta do not

auqqeat that the bedrock and overburden groundwater are

atrictly aeparated from each other

32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa

the Hobbs Site will create flow of groundwater fro11 beneath

and po ibly east of the Little River durinq amplltended low

rainfall recharge periods bull h very weak and baaed upon

faulty auwnptiona and data No creditable field data or

analyaia were brought forth to support the conclusionbull

JJ Fax Page J (TB) - Placing much emphasis upon the

conclusions derived from the application of Theis theory to

large distances beyond the pumping well is not valid due to

the qaologic conditione grouly violate Theta uawnptione

34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods

It is unclear aa to which time period conclus i o ns are

derived for It i s hiqhly unlikely pumpinq effects c an

deleteriously propaqate in 20 days thro uqh t he l ow permeable

- 13 shy

~ n = = =Ul

--

r -r -

11atariale located east of the Hobbs Site

35 Paqe llA (T B ) concludes that the safe yield from the

Hobbs Site is in the ranqe of 14 to 58 GPW If this yield

h true than the combined pumpage o f all the residential

wellbull in the study area will exceed the safe yie ld and

potentially impact the Coakley Landfill

36 Paqa 22 - TB reports etatea (1) a nything th11t wu not

sand and gravel laterally or vertically) was impermeable

and (2) streams to the northwest (Cornelius Brook) was

repreaented aa havinq a constant water level (basically an

infinite supply of water) bull In the D L MAHER report Paqe

Jl only the bedrock waa treated aa impermeable The llarine

aedlaentbull vera treated aa a constant head boundary allovinq

for flow into the aquifer Cornelius Brook waa not modeled

bullbull havinq a constant water level in the D L MAHER report

37 Paqe 22 (TB) -Some of the streams modeled as drains are

actually perched above the aquifer11 groundwater table upon

very low permeable marine sedmenta The drainbull are not

JnOdeled correctly Cornelius Brook dries up naturally from

June throuqh September and a significant portion h perched

above the aquifers water table Cornelius Brook receives

ita intermittent recharqe from runoff o n top o f the marine

aediment c ap overlying the northern portion of the Hobba

aquife r Some of t he Little River drain c ella are not

located properly Drain file conductance values appear very

-1 4 shy

r -r -

high for etreama flowing upon silts and claye

38 Page 27 (T B) model wa11 run b) atar tng at ateady state

conditione 2 of nonnal rechnrge for 180 day a and pumping

250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead

Protection area delineation requires the contributing area

to ~ delineated for a period of 180 daye pumpin with no

net rainfall recharge upon the ~~ regional

piezometric surface map This method of Wellhead

delineation wae stated by Paul Currier Administrator

Groundwater Protection Bureau during the July 25 1991

bullbullUnq at D E S offices in Concord The TB report

apparently did not model the zoe under thie criteria

39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling

effort it h etated that the model should uee hydraulic

coefficients which were measured in the field~ but fails to

follow through with this premise in the model The

tranbullmhbulllvity values selected for both fractured and

unfractured bedrock are neither explained nor supported by

field data If the va lues were taken from publlahed ranges

they are at t he upper ende of t heee rangee and not

reflective of typical conditio ne in New Enqland Based on

Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of

4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x

10middot1 to 1 2 x 10 feet day for unfractured roc k are more

realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy

- 15shy

r -r I

U S GS Water Supply Paper 2220 page 13 ehowa hydraulic

conductivity rangee for igneoua lind metamorphic rocks of

10middot7 feat day unfractured to 15 feet day fracture d

40 Page 218 (T B) - The r e port no tee t hat a ~three-layer

ayetam waa modeled however the model used wae a twt middotmiddot layer

110del It appears that the VCONT variable wae ueed to

repreaent the eiltclayfine eand layer with layer

thickneea eat to o ne foot Thera h no eupportive data of

the one foot thic knen value other than being arbitrarily

aeaiqnad Thia ie not an accurate rapraaantation of actual

conditiona nor ie it the beat way to fully and accurately

-adal thh ayatem

41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy

layer RIOdal and the eimpUfying aWDption of horhontal

layerl re1ult in a model which doee not reflect the actual

qeoloqy at thia alta The variable bedrock topography and

aquifer hydraulic conductivitiebull muet be accounte d for in

the lftOdal if an accurate delineation of the rona of

contribution 1a to be made

42 (T B ) - Thera h no me ntion in the text of either a

aanaitiv ity anal yeh being made or o f a water budget being

c alc ula t ed The s e efforts are both important compone nts of

a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the

acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d

they ehould ha ve been no t ed i n t he report I f e ither o f

- 16 shy

I r -r I

these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

r -r -

area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

- 19shy

n Q = = Ul

r -r I

the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

r -r I

49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

r -r -

conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

r -r I

habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

--

r -r --

C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 13: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

--

r -r -

be attributed to nonhydraulically significant geologic

1tructure1 Remote aenaing is an ~art- and drawing far

reachim~ concluaiona without drilling data ill incorrec t

However thh letter recognizee that due to the limitations

of remota saneincJ other signi ficant water bearing fracturea

may exbt in the bedrock not identified in the R ICL

JO Page 20 - TB states ~ bedrock groundwater generally flowa

in the direction of the Little River - However the T B

report oaita that bedrock groundwater aho generally flowbull

aoutheabullt to North Brook as ahovn on Fiqure 13 of the

R ICL report Bedrock groundwater flowbull radially in bullany

directionbull from the Coakley Landfill and the TB report

should not uae the word bullqenerally bull as it impli one major

direction only when in fact there are many flow pathe

R IC L total volatile organic compounds in

Qroundwater overburden (Figurabull 14 and 17) at GZ-123 127

128 129 and 130 were either nondetected or leu than 5 ppb

Theee leveh are very low concentrations Only GZ-105

ehowed eignificant volatile organic compounds weet of the

Coakley Landfill The VOC levels at GZ-129 and GZ-130 may

b attributed t o additional small transient lind undefined

bullourcea in this area The R I C L r epo r t conc ludes o n paqe

8 - Exec utive Summary bullAt t his t lme however five years

of qrou ndwater contam i na t i o n e x ist away from the l andfill

per i me t er and the wetl andbull i mmedia te l y we s t o f t he landfill

- 12shy

- r -r -

a likely consequence of the diepereive radial flow and

reaultant contaminant dilution ae well abull othe r operative

attenuation mechaniems diacueaed herein Beaed on the

available data it is anticipated that these olttenuatlon

mechanismbull would be a significant llrniting factor in the

diatance contaminants are able to migrate from the landfill

in detectable conc entrations

31 Pa9e 20 (TB) -The OLM and RICL reporta do not

auqqeat that the bedrock and overburden groundwater are

atrictly aeparated from each other

32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa

the Hobbs Site will create flow of groundwater fro11 beneath

and po ibly east of the Little River durinq amplltended low

rainfall recharge periods bull h very weak and baaed upon

faulty auwnptiona and data No creditable field data or

analyaia were brought forth to support the conclusionbull

JJ Fax Page J (TB) - Placing much emphasis upon the

conclusions derived from the application of Theis theory to

large distances beyond the pumping well is not valid due to

the qaologic conditione grouly violate Theta uawnptione

34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods

It is unclear aa to which time period conclus i o ns are

derived for It i s hiqhly unlikely pumpinq effects c an

deleteriously propaqate in 20 days thro uqh t he l ow permeable

- 13 shy

~ n = = =Ul

--

r -r -

11atariale located east of the Hobbs Site

35 Paqe llA (T B ) concludes that the safe yield from the

Hobbs Site is in the ranqe of 14 to 58 GPW If this yield

h true than the combined pumpage o f all the residential

wellbull in the study area will exceed the safe yie ld and

potentially impact the Coakley Landfill

36 Paqa 22 - TB reports etatea (1) a nything th11t wu not

sand and gravel laterally or vertically) was impermeable

and (2) streams to the northwest (Cornelius Brook) was

repreaented aa havinq a constant water level (basically an

infinite supply of water) bull In the D L MAHER report Paqe

Jl only the bedrock waa treated aa impermeable The llarine

aedlaentbull vera treated aa a constant head boundary allovinq

for flow into the aquifer Cornelius Brook waa not modeled

bullbull havinq a constant water level in the D L MAHER report

37 Paqe 22 (TB) -Some of the streams modeled as drains are

actually perched above the aquifer11 groundwater table upon

very low permeable marine sedmenta The drainbull are not

JnOdeled correctly Cornelius Brook dries up naturally from

June throuqh September and a significant portion h perched

above the aquifers water table Cornelius Brook receives

ita intermittent recharqe from runoff o n top o f the marine

aediment c ap overlying the northern portion of the Hobba

aquife r Some of t he Little River drain c ella are not

located properly Drain file conductance values appear very

-1 4 shy

r -r -

high for etreama flowing upon silts and claye

38 Page 27 (T B) model wa11 run b) atar tng at ateady state

conditione 2 of nonnal rechnrge for 180 day a and pumping

250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead

Protection area delineation requires the contributing area

to ~ delineated for a period of 180 daye pumpin with no

net rainfall recharge upon the ~~ regional

piezometric surface map This method of Wellhead

delineation wae stated by Paul Currier Administrator

Groundwater Protection Bureau during the July 25 1991

bullbullUnq at D E S offices in Concord The TB report

apparently did not model the zoe under thie criteria

39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling

effort it h etated that the model should uee hydraulic

coefficients which were measured in the field~ but fails to

follow through with this premise in the model The

tranbullmhbulllvity values selected for both fractured and

unfractured bedrock are neither explained nor supported by

field data If the va lues were taken from publlahed ranges

they are at t he upper ende of t heee rangee and not

reflective of typical conditio ne in New Enqland Based on

Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of

4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x

10middot1 to 1 2 x 10 feet day for unfractured roc k are more

realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy

- 15shy

r -r I

U S GS Water Supply Paper 2220 page 13 ehowa hydraulic

conductivity rangee for igneoua lind metamorphic rocks of

10middot7 feat day unfractured to 15 feet day fracture d

40 Page 218 (T B) - The r e port no tee t hat a ~three-layer

ayetam waa modeled however the model used wae a twt middotmiddot layer

110del It appears that the VCONT variable wae ueed to

repreaent the eiltclayfine eand layer with layer

thickneea eat to o ne foot Thera h no eupportive data of

the one foot thic knen value other than being arbitrarily

aeaiqnad Thia ie not an accurate rapraaantation of actual

conditiona nor ie it the beat way to fully and accurately

-adal thh ayatem

41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy

layer RIOdal and the eimpUfying aWDption of horhontal

layerl re1ult in a model which doee not reflect the actual

qeoloqy at thia alta The variable bedrock topography and

aquifer hydraulic conductivitiebull muet be accounte d for in

the lftOdal if an accurate delineation of the rona of

contribution 1a to be made

42 (T B ) - Thera h no me ntion in the text of either a

aanaitiv ity anal yeh being made or o f a water budget being

c alc ula t ed The s e efforts are both important compone nts of

a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the

acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d

they ehould ha ve been no t ed i n t he report I f e ither o f

- 16 shy

I r -r I

these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

r -r -

area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

- 19shy

n Q = = Ul

r -r I

the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

r -r I

49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

r -r -

conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

r -r I

habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

--

r -r --

C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 14: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

- r -r -

a likely consequence of the diepereive radial flow and

reaultant contaminant dilution ae well abull othe r operative

attenuation mechaniems diacueaed herein Beaed on the

available data it is anticipated that these olttenuatlon

mechanismbull would be a significant llrniting factor in the

diatance contaminants are able to migrate from the landfill

in detectable conc entrations

31 Pa9e 20 (TB) -The OLM and RICL reporta do not

auqqeat that the bedrock and overburden groundwater are

atrictly aeparated from each other

32 Paqe 20 (TB) - The conclueion -that pumping 260 GPM froa

the Hobbs Site will create flow of groundwater fro11 beneath

and po ibly east of the Little River durinq amplltended low

rainfall recharge periods bull h very weak and baaed upon

faulty auwnptiona and data No creditable field data or

analyaia were brought forth to support the conclusionbull

JJ Fax Page J (TB) - Placing much emphasis upon the

conclusions derived from the application of Theis theory to

large distances beyond the pumping well is not valid due to

the qaologic conditione grouly violate Theta uawnptione

34 Fax Page 3 (TB) -Usee 20-day and 180-day tlrne periods

It is unclear aa to which time period conclus i o ns are

derived for It i s hiqhly unlikely pumpinq effects c an

deleteriously propaqate in 20 days thro uqh t he l ow permeable

- 13 shy

~ n = = =Ul

--

r -r -

11atariale located east of the Hobbs Site

35 Paqe llA (T B ) concludes that the safe yield from the

Hobbs Site is in the ranqe of 14 to 58 GPW If this yield

h true than the combined pumpage o f all the residential

wellbull in the study area will exceed the safe yie ld and

potentially impact the Coakley Landfill

36 Paqa 22 - TB reports etatea (1) a nything th11t wu not

sand and gravel laterally or vertically) was impermeable

and (2) streams to the northwest (Cornelius Brook) was

repreaented aa havinq a constant water level (basically an

infinite supply of water) bull In the D L MAHER report Paqe

Jl only the bedrock waa treated aa impermeable The llarine

aedlaentbull vera treated aa a constant head boundary allovinq

for flow into the aquifer Cornelius Brook waa not modeled

bullbull havinq a constant water level in the D L MAHER report

37 Paqe 22 (TB) -Some of the streams modeled as drains are

actually perched above the aquifer11 groundwater table upon

very low permeable marine sedmenta The drainbull are not

JnOdeled correctly Cornelius Brook dries up naturally from

June throuqh September and a significant portion h perched

above the aquifers water table Cornelius Brook receives

ita intermittent recharqe from runoff o n top o f the marine

aediment c ap overlying the northern portion of the Hobba

aquife r Some of t he Little River drain c ella are not

located properly Drain file conductance values appear very

-1 4 shy

r -r -

high for etreama flowing upon silts and claye

38 Page 27 (T B) model wa11 run b) atar tng at ateady state

conditione 2 of nonnal rechnrge for 180 day a and pumping

250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead

Protection area delineation requires the contributing area

to ~ delineated for a period of 180 daye pumpin with no

net rainfall recharge upon the ~~ regional

piezometric surface map This method of Wellhead

delineation wae stated by Paul Currier Administrator

Groundwater Protection Bureau during the July 25 1991

bullbullUnq at D E S offices in Concord The TB report

apparently did not model the zoe under thie criteria

39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling

effort it h etated that the model should uee hydraulic

coefficients which were measured in the field~ but fails to

follow through with this premise in the model The

tranbullmhbulllvity values selected for both fractured and

unfractured bedrock are neither explained nor supported by

field data If the va lues were taken from publlahed ranges

they are at t he upper ende of t heee rangee and not

reflective of typical conditio ne in New Enqland Based on

Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of

4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x

10middot1 to 1 2 x 10 feet day for unfractured roc k are more

realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy

- 15shy

r -r I

U S GS Water Supply Paper 2220 page 13 ehowa hydraulic

conductivity rangee for igneoua lind metamorphic rocks of

10middot7 feat day unfractured to 15 feet day fracture d

40 Page 218 (T B) - The r e port no tee t hat a ~three-layer

ayetam waa modeled however the model used wae a twt middotmiddot layer

110del It appears that the VCONT variable wae ueed to

repreaent the eiltclayfine eand layer with layer

thickneea eat to o ne foot Thera h no eupportive data of

the one foot thic knen value other than being arbitrarily

aeaiqnad Thia ie not an accurate rapraaantation of actual

conditiona nor ie it the beat way to fully and accurately

-adal thh ayatem

41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy

layer RIOdal and the eimpUfying aWDption of horhontal

layerl re1ult in a model which doee not reflect the actual

qeoloqy at thia alta The variable bedrock topography and

aquifer hydraulic conductivitiebull muet be accounte d for in

the lftOdal if an accurate delineation of the rona of

contribution 1a to be made

42 (T B ) - Thera h no me ntion in the text of either a

aanaitiv ity anal yeh being made or o f a water budget being

c alc ula t ed The s e efforts are both important compone nts of

a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the

acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d

they ehould ha ve been no t ed i n t he report I f e ither o f

- 16 shy

I r -r I

these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

r -r -

area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

- 19shy

n Q = = Ul

r -r I

the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

r -r I

49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

r -r -

conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

r -r I

habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

--

r -r --

C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 15: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

--

r -r -

11atariale located east of the Hobbs Site

35 Paqe llA (T B ) concludes that the safe yield from the

Hobbs Site is in the ranqe of 14 to 58 GPW If this yield

h true than the combined pumpage o f all the residential

wellbull in the study area will exceed the safe yie ld and

potentially impact the Coakley Landfill

36 Paqa 22 - TB reports etatea (1) a nything th11t wu not

sand and gravel laterally or vertically) was impermeable

and (2) streams to the northwest (Cornelius Brook) was

repreaented aa havinq a constant water level (basically an

infinite supply of water) bull In the D L MAHER report Paqe

Jl only the bedrock waa treated aa impermeable The llarine

aedlaentbull vera treated aa a constant head boundary allovinq

for flow into the aquifer Cornelius Brook waa not modeled

bullbull havinq a constant water level in the D L MAHER report

37 Paqe 22 (TB) -Some of the streams modeled as drains are

actually perched above the aquifer11 groundwater table upon

very low permeable marine sedmenta The drainbull are not

JnOdeled correctly Cornelius Brook dries up naturally from

June throuqh September and a significant portion h perched

above the aquifers water table Cornelius Brook receives

ita intermittent recharqe from runoff o n top o f the marine

aediment c ap overlying the northern portion of the Hobba

aquife r Some of t he Little River drain c ella are not

located properly Drain file conductance values appear very

-1 4 shy

r -r -

high for etreama flowing upon silts and claye

38 Page 27 (T B) model wa11 run b) atar tng at ateady state

conditione 2 of nonnal rechnrge for 180 day a and pumping

250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead

Protection area delineation requires the contributing area

to ~ delineated for a period of 180 daye pumpin with no

net rainfall recharge upon the ~~ regional

piezometric surface map This method of Wellhead

delineation wae stated by Paul Currier Administrator

Groundwater Protection Bureau during the July 25 1991

bullbullUnq at D E S offices in Concord The TB report

apparently did not model the zoe under thie criteria

39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling

effort it h etated that the model should uee hydraulic

coefficients which were measured in the field~ but fails to

follow through with this premise in the model The

tranbullmhbulllvity values selected for both fractured and

unfractured bedrock are neither explained nor supported by

field data If the va lues were taken from publlahed ranges

they are at t he upper ende of t heee rangee and not

reflective of typical conditio ne in New Enqland Based on

Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of

4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x

10middot1 to 1 2 x 10 feet day for unfractured roc k are more

realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy

- 15shy

r -r I

U S GS Water Supply Paper 2220 page 13 ehowa hydraulic

conductivity rangee for igneoua lind metamorphic rocks of

10middot7 feat day unfractured to 15 feet day fracture d

40 Page 218 (T B) - The r e port no tee t hat a ~three-layer

ayetam waa modeled however the model used wae a twt middotmiddot layer

110del It appears that the VCONT variable wae ueed to

repreaent the eiltclayfine eand layer with layer

thickneea eat to o ne foot Thera h no eupportive data of

the one foot thic knen value other than being arbitrarily

aeaiqnad Thia ie not an accurate rapraaantation of actual

conditiona nor ie it the beat way to fully and accurately

-adal thh ayatem

41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy

layer RIOdal and the eimpUfying aWDption of horhontal

layerl re1ult in a model which doee not reflect the actual

qeoloqy at thia alta The variable bedrock topography and

aquifer hydraulic conductivitiebull muet be accounte d for in

the lftOdal if an accurate delineation of the rona of

contribution 1a to be made

42 (T B ) - Thera h no me ntion in the text of either a

aanaitiv ity anal yeh being made or o f a water budget being

c alc ula t ed The s e efforts are both important compone nts of

a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the

acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d

they ehould ha ve been no t ed i n t he report I f e ither o f

- 16 shy

I r -r I

these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

r -r -

area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

- 19shy

n Q = = Ul

r -r I

the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

r -r I

49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

r -r -

conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

r -r I

habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

--

r -r --

C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 16: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

r -r -

high for etreama flowing upon silts and claye

38 Page 27 (T B) model wa11 run b) atar tng at ateady state

conditione 2 of nonnal rechnrge for 180 day a and pumping

250 GPK bull Draft rules of May 9 1990 WS31S08C Wellhead

Protection area delineation requires the contributing area

to ~ delineated for a period of 180 daye pumpin with no

net rainfall recharge upon the ~~ regional

piezometric surface map This method of Wellhead

delineation wae stated by Paul Currier Administrator

Groundwater Protection Bureau during the July 25 1991

bullbullUnq at D E S offices in Concord The TB report

apparently did not model the zoe under thie criteria

39 P8tJ8 21A (TB ) - In the introduction to the fiiOdeling

effort it h etated that the model should uee hydraulic

coefficients which were measured in the field~ but fails to

follow through with this premise in the model The

tranbullmhbulllvity values selected for both fractured and

unfractured bedrock are neither explained nor supported by

field data If the va lues were taken from publlahed ranges

they are at t he upper ende of t heee rangee and not

reflective of typical conditio ne in New Enqland Based on

Freeze and Cherry ( 1979) hydraulic condu c tivity ranqee of

4 0 x 10 middot1 to 120 feet day for fractured roc k and 1 34 x

10middot1 to 1 2 x 10 feet day for unfractured roc k are more

realistic Heath ( 198 3) i n Basic Ground- Water Hydroloqy

- 15shy

r -r I

U S GS Water Supply Paper 2220 page 13 ehowa hydraulic

conductivity rangee for igneoua lind metamorphic rocks of

10middot7 feat day unfractured to 15 feet day fracture d

40 Page 218 (T B) - The r e port no tee t hat a ~three-layer

ayetam waa modeled however the model used wae a twt middotmiddot layer

110del It appears that the VCONT variable wae ueed to

repreaent the eiltclayfine eand layer with layer

thickneea eat to o ne foot Thera h no eupportive data of

the one foot thic knen value other than being arbitrarily

aeaiqnad Thia ie not an accurate rapraaantation of actual

conditiona nor ie it the beat way to fully and accurately

-adal thh ayatem

41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy

layer RIOdal and the eimpUfying aWDption of horhontal

layerl re1ult in a model which doee not reflect the actual

qeoloqy at thia alta The variable bedrock topography and

aquifer hydraulic conductivitiebull muet be accounte d for in

the lftOdal if an accurate delineation of the rona of

contribution 1a to be made

42 (T B ) - Thera h no me ntion in the text of either a

aanaitiv ity anal yeh being made or o f a water budget being

c alc ula t ed The s e efforts are both important compone nts of

a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the

acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d

they ehould ha ve been no t ed i n t he report I f e ither o f

- 16 shy

I r -r I

these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

r -r -

area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

- 19shy

n Q = = Ul

r -r I

the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

r -r I

49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

r -r -

conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

r -r I

habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

--

r -r --

C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 17: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

r -r I

U S GS Water Supply Paper 2220 page 13 ehowa hydraulic

conductivity rangee for igneoua lind metamorphic rocks of

10middot7 feat day unfractured to 15 feet day fracture d

40 Page 218 (T B) - The r e port no tee t hat a ~three-layer

ayetam waa modeled however the model used wae a twt middotmiddot layer

110del It appears that the VCONT variable wae ueed to

repreaent the eiltclayfine eand layer with layer

thickneea eat to o ne foot Thera h no eupportive data of

the one foot thic knen value other than being arbitrarily

aeaiqnad Thia ie not an accurate rapraaantation of actual

conditiona nor ie it the beat way to fully and accurately

-adal thh ayatem

41 9bull 22 (T B ) - The uaa of a two-layer rather than threeshy

layer RIOdal and the eimpUfying aWDption of horhontal

layerl re1ult in a model which doee not reflect the actual

qeoloqy at thia alta The variable bedrock topography and

aquifer hydraulic conductivitiebull muet be accounte d for in

the lftOdal if an accurate delineation of the rona of

contribution 1a to be made

42 (T B ) - Thera h no me ntion in the text of either a

aanaitiv ity anal yeh being made or o f a water budget being

c alc ula t ed The s e efforts are both important compone nts of

a modalinq p r oqram with siq n i fl c an t implicationbull bullbull to the

acc u r a c y and integrity o f t he mo del o utpu t If conlide r e d

they ehould ha ve been no t ed i n t he report I f e ither o f

- 16 shy

I r -r I

these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

r -r -

area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

- 19shy

n Q = = Ul

r -r I

the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

r -r I

49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

r -r -

conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

r -r I

habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

--

r -r --

C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 18: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

I r -r I

these was omitted the model results should be viewed as

potentially inacc urate

43 (TB ) - The use of porous media approximation to model flow

in fractured bedrock c an be accomplished ulling HOOFLOW

However reeet~rch done by the Waconein Geologic Survey has

shown that for thie approximation to be valid the model

scale should be two ardara of magnitude greater than the

magnitude of the fracture eyatem This 18 clearly not the

case in the Ballestero model caating doubt on the validity

of the model and accuracy of the model output A larger

JIOdel must be used to model the fracture zone if a porous

dia approdmatlon il to be used

The model area is too small and fails to include

aquifer area extending northwest and southwest of the

proposed well Ae a result model boundary conditionbull

interfere with the model aolution The T B report

recognizebull this need on Page 12 ~ the modeler hopes that the

boundaries are far enough away from the area o f intereat in

order not to influence the aolution at the area of

interest ~ but falls to follow it in the model

On Page 22 it ia noted that ~ groundwater elevationbull

could not be ma tc hed in the locatio n of the Coakley

Landfill because of t he contraat between t he actual s ite

conditione and t he eimplUying anumptione used in t he

development o f the mode l Coneiderlnq the slqnlfic ance o f

the Coakley Site a nd t he need to accurately model thh

- 17shy

n 0 gt = =Ul

r -r -

area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

- 19shy

n Q = = Ul

r -r I

the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

r -r I

49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

r -r -

conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

r -r I

habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

--

r -r --

C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 19: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

r -r -

area a model more reflective o f actua l co nditione ehould

have been run At the least the model boundary 8hould have

been eKtanded paat t he vicinity of the landfill to ina ure

that an accur ate repre a e ntat ion of gro undwater flow in this

area waa made The T B report recogn izee t his ne ceaaity on

Page 12 however does not adhere to i t i n the T B model

44 Paqe 218- TS hydraulic conductivitiea i n the R IC L

Tabla three s how i n -flitu hydraulic conducti v itlee r anging

from 006 feet day to 25 feetday for the overburden

GJ-101 It values ( 510 feet day) h highly auepect ae the top

two feet of the well acraan h installed above the water

tabla in unsaturated coarse aand and gravel (aea Wall Loq

Gl-101 and eubeurface profile A-A Figure 9 R ICL) The

r-ainder of the screen 1bull lnbulltslled i n t ill The saturated

thicknebullbull of the sand gravel at GZ-101 is at beat three fee t

and not repre aentativa of the average t ransmha ivlty for the

overburden at the Coakley Landfill

Bedrock borehole pac ker pressure t e ats calculated

hydraulic conduc tivity valuaa ranging between 014 to 6 82

feetday GZ-109 and GZ-125 were not teeted due t o the

bedrock being unfrac tured and nonwater bea ring GZ - 105

(bedrock coreho le) had a hydraulic conducti vity o f only two

feet day and 1a des c ribed ae moderately f rac tured GZ- 10 5

and 128 are l oca ted i n t he h i gh transmhs ivity bedr ock zone

o f t he TB r eport Theref o r e t he bedrock tranamlaaivi ty

v a l ue o f 11 000 f eet2 day s hown on t he HOOFLOW BCF f ile h

-18 shy

i n = = = U

c

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

- 19shy

n Q = = Ul

r -r I

the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

r -r I

49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

r -r -

conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

r -r I

habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

--

r -r --

C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 20: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

~middot r -r I

unrealiatically high The unfractured bedrock

tranemiuivity value of 100 foot2day utilhed outaide the

fracture zone ia very high for typical New England bedrock

Table 4 of the RICL report ehowe a hydraulic

conductivity value o f 0018 feet day for bedrock well

Gl-125 Thie well produced three GPH whic h la

rapreeent ative of typical Nev Hampshire metamorphic bedrock

45 (TB ) - report model does not calibrate correctly at the

Coakley Landfill for no pumping normal recharge in the

bedrock or overburden head mapa The model haa severe

problema in the calculated overburden steady state - head

p1 pup 260 GPM in the vicinity of the Coakley Landfill

The elevationbull under 260 GPM pumpinq c onditione are hiqher

(aa lftuch ae 8 9 feet) than the no pumping normal recharge

overburde n head map An a ccurate rnodel over the Coakley

Landfill bullhould a how either no drawdown or drawdown under

pwnping conditions The pumping 260 GPH normal recharge

overburden eteady a tate head map a leo shows 9999 elevatione

in the southeast and southwest corners where the c alculated

overburden headmap1 c alibration - no pump ing normal

recharge ahowa e levationbull in the 69 to 75 feet range in the

aoutheaet and 65 to 70 feet in the aout hweat Figures 12

a nd 13 page 34 (TB ) ahow regio ns affec ted by drawdown

e xc eedi ng 0 5 feet in overburden and bedrock At nodee Cl7

18 19 20 21 2 2 R8 o f the c alc ulated over burden and

bedrock maps pumping 260 GPH show elevatio ns higher t han

- 19shy

n Q = = Ul

r -r I

the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

r -r I

49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

r -r -

conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

r -r I

habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

--

r -r --

C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 21: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

r -r I

the no pWipinq head mapa Thea a bullbullrioua model flawe

underecore the waakneaa of the model accuracy and the

reportbull concluaiona

46 Page 37 38 - TB report mapa show Coak ley contaminan t

movement in overburden and bedrock ae not edeting in the

reQion around North Road (GZ-127 128 129 130 well a) Yet

T B report (page 1) aaye Inorganic and organic parameters

indicative of landfill leachate have been detected ae far

eouth and west aa North Road and the Little Riven bull Alec

the TB report on page 50 atatee Ae welh 127128 may

already be raceivinq Coakhy Leachate Figure 23 (page 46)

of the TB report ahowe only three cells affected by

contination when c ompared to Figure 14 (page 37) Fiqure

24 (page 47) bedrock ahowe only tvo cella affected by

contaalnation in bedrock when compared to Fiqure 15 (paqe

Jl)

47 Pe~ 49 (TB) report atatea bull the eJtact nature of bedrock

fracturebull and the eJttent of the ailt c lay layer between

overburden and bedrock are unknown~ Thia atatement

undencorea the queat1on1 If the reliability of the T B

odel input data la questionable how accurate are the

conclubulliona7

-J48 Paqe 49 (T B) Under recommendatio na t he report oppea ra to

aqree with t he OL M r eport

-2 0 shy

r -r I

49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

r -r -

conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

r -r I

habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

--

r -r --

C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 22: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

r -r I

49 Page 50 (TB ) report atataa bullsuch a scenario rahgatea the

monitorlnq wells as ineffective~ yet in the naJtt paragraph

the report statee bullmonitoring wells H2 127 128 9-90 and

10-90 are in good poaitlona for monitoring any long-term

effecta due to Co11kley contaminants bull This section of the

report ia confusing and contradictory

50 Page 51 (T B) - Wetland areas are incorrectly modeled in

the TB report many of the watlanda are naturally parched

aa much as five feet above the aquifer groundwater tabla

0

51 Paqa 53 (TB) - The report auqqeating the town of North

Hopton to tu or lmpoaa a fee schedule on each qallon of

water puped from the well h counter productive towarda the

auccaaa of the New Hampahlre Wellhead Protection Prograa and

would be precedent settinq Also the tu would only be

pbullbullbullbulld on to the coneumer

52 Paqe 55 (T B ) - Movinq the well to a location about 1000

feet to the south would place the well on Stanley Knowles

property Prior to the Hobbs bullbullvan day pump test HampJnpton

Water Works ne gotiationbull with Kr II nowlee to locate a well

on his property were unsucceeeful Aho u sGS 69 well

water quality indicates manganese l evelll at 0 13 mg1 which

il well above the Safe Drinking Water Standard of 005 mg1

A atrong hydrogen sulfide odo r was detec ted in Tebullt

Well 5 - 90 during pump t esting Majo r wetlands exht in

cloee proximity t o t he pro posed l ocatio n which are in

- 21 shy

r -r -

conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

r -r I

habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

--

r -r --

C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 23: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

r -r -

conflict to groundwater pumpage according to the log

presented in the TB report

53 Paqe 55 (TB) - The concept of withdrawing surface water to

artificially recharge the Hobbs aquifer eeema contradictory

to the surface water conclueione ie wetlanda atreame

presented in thie report It a surface water existed with a

suitable safe yield and quality a water treatment plant

would btl constructed

54 Page 55 (T B) - The Dalton Well doea not pwnp two million

qallone ~r day aa it hu a aate yield of approd111ately

100-125 GPM

55 The T B report nun concludea that contaJilinanta from

Coakley will reach the Hobbe Well Site under dry weather

periods ThiB h an important concluaion and aupporta the

D L MAHER aeven day pump teat report

56 The T B report never defines the definition of eafe yield

51 Monitoring Welle 9-90 and GZ-127 have btten removed by 11

private land owner without perlftheion from Hampton Water

Workll or the State of New Hampehire

58 (T B) - In the overburden head map at 180 daye with no

recharge only 13 feet o f drawdown oc c urre d at the Ho bbe

Well node C9Rll resulting in 43 feet o f aquife r saturate d

thlcknen rema i ning The T B report conUrme the wall site

- 22 shy

r -r I

habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

--

r -r --

C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 24: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

r -r I

habull a 180-day eafe yield of 260 GPM starting at steady etate

conditione

RICQMKENDATIONS 1

In order to move forward on the Hobba wall project it

h rec01111nended that Hampton Water Worka conduct the

following1

A Inatall bedrock and overburden observation walla at

bullelected locations between the Hobba Well Site and

Coakley Landfill The purpoee of the walla h to

obtain additional hydrogeoloqic information on the

0 overburden and bedrock Alao the observation vella

ahould be conatructed in a manner to monitor water

lavale over time

B Perfona a fully three-dimensional model utilhing

MODFLOW and MOOPATH computer programs The model

ahould have a variable-aha horizontal grid with

aufficient are a to include the entire aquifer extent

and avoid boundary interference Variable layer

thicknesaebull and elevationbull should ba hued upon field

veoloqic data and hydraulic parameters The model

ahould foll o w the Hay 1990 draft Wellhead Protection

are a delineatio n rules 1991 AugustSeptember ambient

water leve ls shou ld be incorporated i n the model

-2]shy

--

r -r --

C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672
Page 25: r -, r B -rtL4 · r -, r -, r . l ~-ltf'~ B 07 -p~ €"" -rtL4 . HAMPTON WATER WORKS CO. 1.,_,. 1 . ) A . AUG 0 6 \99\ HAND DELIVERED . Department of Environmental Service.!

--

r -r --

C Lonq term actual pWipinq over many yn will provide

the meet accurate repreaentation of the Hobbe Aquifer

~rformance

Very truly youre

O L MAHER Co

jJ-wJkJYI~ C-t J Theodore Ho~fn~

~ vlea Preedent Senior Hydroqeoloqbt

J f~ ~- Saith Project Manaqar

- 24shy

  1. barcode 571672
  2. barcodetext SDMS Doc ID 571672