feis d-malcolm pirnie letter and leggette brashears & graham response
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Appendix D Malcolm Pirnie Letter and Leggette, Brashears, & Graham Response
JOHN NASO, JR. WILLIAM K. BECKMAN DAN C. BUZEA J. KEVIN POWERS FRANK J. GETCHELL CHARLES W. KREITLER JEFFREY B. LENNOX W. JOHN SEIFERT, JR. DAVID A. WILEY ROBERT F. GOOD, JR. TIMOTHY L. KENYON THOMAS P. CUSACK DAVID B. TERRY
MATTHEW P. PERAMAKI ____________________ R. G. SLAYBACK JOHN B. ASHWORTH
LEGGETTE, BRASHEARS & GRAHAM, INC.
PROFESSIONAL GROUND-WATER AND ENVIRONMENTAL ENGINEERING SERVICES
4 RESEARCH DRIVE, SUITE 301
SHELTON, CT 06484 203-929-8555
FAX 203-926-9140 www.lbgweb.comwww.lbgweb.com
JOHN M. BENVEGNA JOHN L. BOGNAR
KIMBERLY R. BLOMKER JORMA WEBER
JOSEPH W. STANDEN, JR. MICHAEL A. MANOLAKAS
JAMES A. BEACH WILLIAM P. PREHODA
JEFFREY M. TROMMER DAVID S. HUME
BRUCE K. DARLING KAREN B. DESTEFANIS
JEFFREY T. SCHICK KENNETH D. TAYLOR
ROBERT M. ROHLFS WILLIAM G. STEIN
JOHN W. NELSON WILLIAM H. AVERY
ROY SILBERSTEIN PAUL M. JOBMANN
BRIAN C. KIMPEL JOHN R. DIEGO
MICHAEL SUSCA KEITH J. SHORTSLEEVE
BRAD CROSS MITCHELL KANNENBERG
CONNECTICUT• LOUISIANA • OHIO • ILLINOIS • SOUTH DAKOTA • PENNSYLVANIA • FLORIDA • NEW JERSEY • MINNESOTA
TEXAS• WISCONSIN • NEW YORK • MISSOURI
June 18, 2007 Mr. Martin Lonstein, Planning Board Chair Town of Wawarsing Town Hall 108 Canal Street Ellenville, NY 12428 Dear Mr. Lonstein: Leggette, Brashears & Graham, Inc. (LBG) is providing responses to comments on the Mahamudra Buddhist Hermitage DEIS made by Malcolm Pirnie Inc. (MPI) in a March 20, 2007 letter. MPI was retained by the Town of Wawarsing Planning Board to review the hydrogeology aspects of the DEIS as a response to the concerns by the consultants for the Cragsmoor Association (CA). This letter addresses the MPI request for additional data and clarifications. Request No. 1
“a map showing the location of the discharge location of water pumped during the
drawdown tests”
Response: The discharge water from Well 1 and Well 2 was diverted through a 3-inch fire hose to a
drainage basin on the western portion of the property. The well discharge locations were
presented on figure 1 (attached) of the report entitled “Water-Supply Testing, Proposed
Mahamudra Buddhist Hermitage, Cragsmoor, New York”. Discharge for Well 2 was directed to
the northern location and discharge for Well 1 was directed to the southern location. These
locations were agreed upon by LBG and the CA’s consultant prior to the initiation of the aquifer
tests.
Request No. 2
“the dimensions and locations of the recharge area to the Hermitage wells”
Mr. Martin Lonstein -2- June 18, 2007
Response:
The Dharmakaya Water Supply Report discussed the recharge capabilities of the area,
however, a map was not provided due to the nature of bedrock aquifers. Figure 1 shows the
property boundary and the estimated upland watershed area that provides recharge to the
property. The dimensions and locations of source-water or recharge areas for bedrock wells are
greatly affected by fracture geometry, orientation and density. These factors make it impossible
to accurately delineate recharge areas even in situations where the general fracture patterns are
reasonably understood. Because of these difficulties, it is generally assumed that the recharge
area for an individual well tends to mimic the land surface topography. This is a reasonable
assumption on a regional scale or where fracture density is great enough that the system acts as a
porous-media aquifer. However, on a local scale (as in the case of the Hermitage Wells, see
figure 1 in DEIS) where fractures cross topographic divides; the assumption can produce results
that are not technically defensible. Therefore, definitive recharge areas for the Hermitage Wells
have not been delineated.
Request No. 3
“the groundwater flow direction”
Response:
The Dharmakaya Water Study contained an extensive discussion on the fractures in the
area’s bedrock and the role they play in the proposed Hermitage water supply which includes
ground-water flow process and its impact on the area. Because the ground-water flow in bedrock
aquifers is strongly influenced by fractures in the rock formation, it must be understood that a
water-level configuration map for such aquifers is, at best, only an approximation of the actual
water-level configuration, especially if the map is constructed from a network of monitor wells
tapping fractures that are not interconnected. With this in mind, LBG constructed a water-level
configuration map (figure 2) using depth-to-water and land-surface elevation information for the
wells monitored during the aquifer tests completed in 2005. Land-surface elevation data were
estimated from a USGS topographic map. Figure 2 shows that ground water in the area flows
from north to southeast (generally mimicking the surface topography).
Mr. Martin Lonstein -3- June 18, 2007
Request No. 4
“the zone of influence of the Hermitage wells”
Response:
As explained in the previous response, the bedrock nature of the aquifer strongly
influences the extent and potential impacts that may be created by the Dharmakaya project. This
is fully explained in the Dharmakaya Water Study. Therefore, because the Hermitage wells are
completed in a fracture-controlled bedrock aquifer, no clearly defined zone of influence can be
delineated. Results from the aquifer test showed that only two of the ten offsite wells (49 and
71 Old Inn Road) monitored during the aquifer tests showed discernable drawdown interference
effects from pumping of the onsite wells. Figure 1 shows that the wells monitored at 49 and
71 Old Inn Road were located approximately 840 feet and 500 feet to the north and east,
respectively, of Well 2 (the nearest onsite production well). However, because of the fractured
nature of bedrock systems, it cannot be concluded that the area of influence would be radial in
nature or that wells completed in close proximity to the impacted wells would also be impacted.
For example, no discernable interference effects were observed in the well located at 95 Old Inn
Road during the Well 2 aquifer test, even though it is located closer to Well 2 than a well (49 Old
Inn Road) impacted by pumping during the test.
It has been argued by others that aquifer parameters developed from the pumping tests
should be used to estimate the area of influence of the Cragsmoor wells. The use of aquifer
parameters to anticipate interference of the wells completed in bedrock, as proposed, is not
technically appropriate. As discussed above, ground-water flow in bedrock aquifers is strongly
influenced by fractures in the rock formation. Consequently, the conventional well-flow
equations, developed for isotropic homogeneous aquifers of infinite aerial extent, do not
adequately describe the flow in fractured rock, except in rare instances where the fracture density
is great enough that the system acts as a porous-media aquifer. This expectation is not the case
in the study area.
Another complicating factor when attempting to use aquifer parameters in this manner is
that the extent of the fracture pattern is typically unknown. This may lead to instances where
attempts are made to calculate regional aquifer parameters (so that long-term yield and well
interference effects can be estimated) from a network of monitor wells tapping fractures that are
Mr. Martin Lonstein -4- June 18, 2007
not interconnected. If the aquifer parameters calculated for the above-described monitor well
network were used to estimate long-term well yield, the results would be grossly inaccurate.
Added to this complexity is the fact that the theory of fluid flow in fractured rock is not as
established as that in porous media. Because of this, contradictory results sometimes occur when
analyzing drawdown data, even if the fracture pattern is reasonably understood (Kruseman and
Ridder, “Analysis and Evaluation of Pumping Test Data”, International Institute for Land
Reclamation and Improvement, The Netherlands, 1990). Therefore, the resulting regional
aquifer parameters would once again produce inaccurate estimates of the wells’ area of
influence.
Even if the wells proposed for testing were located in a sand and gravel aquifer
(i.e., essentially treatable as a homogeneous isotropic aquifers of infinite areal extent) rather than
a bedrock aquifer, the methodology proposed would be inappropriate to estimate potential well
interference. The analytical equations utilized to estimate aquifer parameters do not account for
impacts due to aquifer boundaries, leakage to and from surface water bodies, variations in
aquifer thickness, or the dewatering of significant shallow fractures. All of these
unaccounted-for parameters help determine the amount of replenishment available to a well.
Therefore, even under the best conditions, the use of the aquifer parameters (generated from the
analytical equations) can produce results that are not technically defensible.
Request No. 5
“a discussion of the impacts of operational pumping rates of the Heritage wells and the
area’s recharge rates on wells downhill from the Hermitage site, including potential impacts to
wells not monitored (shallow wells as well as inaccessible ones)”
Response:
The Dharmakaya Water Study did discuss the fact that there should be no impacts on
neighboring wells with the operational pumping rates for the Hermitage. One of the
downgradient wells, 19 Cragsmoor Road, was a shallow well at 22 btoc. This well did not show
any impacts during the well testing program and would be representative of others in the area.
Water-demand estimates provided by Chas. H. Sells Inc. indicated that the total potable water
demand for the project for the reduced impact layout is 8,496 gpd, or 5.9 gpm. In November
Mr. Martin Lonstein -5- June 18, 2007
2005, a 24-hour aquifer test was completed on Well 2. During the test, Well 2 was pumped at
25 gpm (or over four times the anticipated demand). Results from the aquifer test showed that
the offsite wells at 49 and 71 Old Inn Road were the only offsite wells that showed discernible
drawdown interference effects from pumping. The maximum observed drawdowns at the wells
at 49 and 71 Old Inn Road were 2.6 feet and 3.9 feet, respectively. The wells at 49 and 71 Old
Inn Road are located approximately 850 feet and 510 feet from Well 2, respectively. The
drawdown observed in these wells under normal operation of the onsite wells (12-hour daily
pumping cycles at 5.9 gpm- approximately 24 percent of the tested production) would be
considerably less. This, coupled with the fact that any potential impact would diminish with
distance and that no impact was observed in the deep bedrock wells located on Clarks Road and
Cragsmoor Road (located over 1,200 feet away), suggests that the onsite wells will not impact
shallow wells downgradient of the site. The applicant has agreed to monitor the two wells
impacted during testing for a two-year period following full build-out of the proposed project.
This additional monitoring will determine significant impacts, if any, under normal operation of
the proposed well source.
Although the locations of the well recharge areas have not been delineated, the size of the
recharge area is estimated to be approximately 16 acres (less than 18 percent of the 91-acre
parcel). The size of the recharge area under average conditions was estimated by calculating the
radius that has a volume equal to the volume of water pumped over one year and a height equal
to the annual recharge rate. The radius was then used to calculate the recharge area. The only
parameters used for this estimate are an average annual recharge and the well field pumping rate.
Therefore, this approximation does not incorporate fracture geometry, location, or density or
other variables that may influence the size of the recharge area. The estimated recharge area for
each Hermitage well at 5.9 gpm (projected average demand) with an average recharge to bedrock
of 7 inches per year (the more conservative USGS annual recharge estimate presented in the
DEIS) was calculated using the following equation:
A= (Q*268,383/R)* /43,560 Where: A = Estimated Recharge Area (in acres) Q = pumping rate (gpm) R = average annual recharge to bedrock (inches)
Note: The equation was derived using the formulas for the volume of a cylinder and the area of a circle.
Mr. Martin Lonstein -6- June 18, 2007
This analysis shows that the recharge potential to the property significantly exceeds the
estimated project demand. Based on this result, it is concluded that there would be no
discernable impact to the shallow wells downgradient of the Hermitage site resulting from
normal use and operation of the bedrock wells even if on-site recharge of wastewater is not
included in the recharge analysis. If the on-site recharge of wastewater were include in the
analysis (assuming 15 percent consumptive use), the total consumptive use (or water lost from
the ground-water system) would be approximately 0.9 gpm, resulting in a recharge area of
approximately 2.5 acres or (approximately 3 percent of the parcel).
Request No. 6
“a discussion of the effects of drought conditions on the water supply”
Response:
A discuss of drought conditions was contained in the Dharmakaya Water Study under
the “Groundwater Balance” section. In addition, the data from the two aquifer test suggests that,
in their present condition, Wells 1 and 2 can both be pumped at twice the daily demand, which
would be 12 gpm for at least 72-hours in the case of Well 1 and 12 gpm for at lest 24-hours in
the case of Well 2. To evaluate the maximum withdrawal that can be maintained by each well
during an extended dry period, the available drawdown was projected for 180 days of continuous
pumping at 50 gpm and 25 gpm for Wells 1 and 2, respectively. The projected drawdown in
Wells 1 and 2 were calculated to be approximately 55.4 feet and 33 feet, respectively. The pump
setting in each well was 350 ft btoc. Based on these figures, the estimated available drawdown
in Wells 1 and 2 after 180 days of constant pumping would be approximately 194 feet and
206 feet (discounting 100 feet above each of the pumps for a safety factor). This analysis is not
intended to imply that the test rates can be sustained for 180 consecutive days, especially
considering that the wells are completed in bedrock where fracture dewatering can occur. This
simple extrapolation, does suggest, however, that Wells 1 and 2 should be able to withdraw the
average daily demand of 5.9 gpm during drought conditions.
Mr. Martin Lonstein -7- June 18, 2007
Concerns Raised By Cragsmoor Association Consultants
The aquifer did not recover to at least 90 percent of the drawdown within 24 hours during the recovery portion the aquifer tests, as per NYSDOH regulations. Which suggest that the test rate may not be sustainable for an extended period of time.
As stated by the Planning Board’s consultant, “Taking into consideration the fact that the applicant stressed the aquifer at approximately seven times the daily demand for 72 hours and the on-site recharge greatly exceed the seven gpm demand, the loss of storage should not affect the water system’s ability to meet the seven gpm demand”. Were enough homes monitored to the north or the property to adequately protect the
homes in the area?
The NYSDOH requires an applicant to monitor 6 to 10 homes surrounding the site; ten were monitored during the tests on the Hermitage Wells. In addition, the Planning Board’s consultant concluded that the aquifer tests were conducted in accordance with the NYDOH regulations.
Concerns related to offsite pumping impacts, the water supply system’s ability to meet
system demands during and drought and the use of aquifer parameter to evaluated area of
influence have been addressed above and by the Planning Board’s consultant in the
March 25, 2007 letter.
In the summary of their recommendations, MP requested that the applicant measure the
pump setting at 49 Old Inn Road and the pump setting and depth of the well at 71 Old Inn Road.
During the well study, LBG attempted to obtain the requested data but was unable to do so
because of the well completion at each of the locations. We also attempted to obtain the
requested information from other sources (Ulster County Health Department and the individual
homeowners). In each case, the wells are so old that no records exist. Additionally, the
homeowners do not have any information on the wells, including the name of the original well
driller. Because of the type of well completion at each of the locations, it would be difficult to
obtain the requested data without potentially compromising or damaging the wells and/or pumps.
Thus, it is LBG opinion that any potential information gained by collecting this data is
outweighed by potential risk of collecting the data. Especially considering that, both of the wells
would be included in the proposed monitoring program and any potential impacts related to
withdrawals from the applicant’s water-supply system would be noted prior to adversely
impacting the homeowner.
Mr. Martin Lonstein -8- June 18, 2007
Please contact me if you have any questions or concerns at (203) 929-8555.
Very truly yours, LEGGETTE, BRASHEARS & GRAHAM, INC.
Kenneth Taylor Associate
Reviewed by: R.G. Slayback, CPG Senior Consultant KT:nv Enclosures cc: Mary Lou Christiana, Esq.-Town of Wawarsing Planning Board Attorney David Stolman – Frederick P. Clark Associates, Inc Susan Fasnacht – Chas. H. Sells, Inc. Daniel St. Germain – Malcolm Pirnie H:\Buddist Hermitage\DEIS Comment Letter - revised III.doc
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