WOODS POND DAM 2007 STRUCTURAL INTEGRITY ASSESSMENT AND INSPECTION / EVALUATION REPORT (09/12/2008 TRANSMITTAL LETTER ATTACHED)September 12, 2008
Ms. Dale C. Yaung Lead Administrative Trustee The Commonwealth of Mossachusetts ­ Executive Office of Environmentol Affairs 100 Cambridge Street Boston, MA 02114-2524
Re; Biennial Structural Integrity Assessment (August 2008) Woods Pond Dam, Housatonic River, Lee/Lenox, MA
Dear Ms. Young:
On November 14, 2007, GE's consultant MWH Americas, Inc. (MWH) conducted a structural integrity assessment of Woods Pond Dam. The results of this inspection are presented in the enclosed report "Woods Pond Dom: 2007 Structural Integrity Assessment", which was prepared by MWH.
This biennial inspection of Woods Pond Dam is part of GE's overall operation and maintenance program for the dam. This program includes monthly, quarterly and biennial inspections. GE conducts the monthly inspections and the quarterly inspections, which are more detailed than the monthly inspections. The biennial inspections are conducted by a registered professional engineer and assess the structural integrity of the dam. The next biennial inspection is scheduled for November 2009.
If you have any questions ossociated with the Biennial Structural Integrity Assessment. please contact me at (413)448-5910.
Very Truly Yours,
Kevin G. Mooney GE Project Manager
Cc: Kenneth Finkelstein, NOAA/CPRD Ken Munney, USFWS Susan Peterson, CTDEP Susan Svirsky, USEPA Susan Steenstrup, IV1ADEP Roderic Mclaren, GE* Andrew T. Silfer, GE*
* Without copies
Michael T. Carroll, GE* James Bieke, Goodwin Procter* Laurence S. Kirsch, Goodwin Procter Sam Gutter, Sidley Austin Brawn & Waod* Mario Finis, MWH* Michael R. Chelminski. Woodlot
WOODS POND DAM
State Dam ID#: 1-2-150-11
NID ID#: MA 00731
WOODS POND DAM
<m> MWH
EXECUTIVE SUMMARY
This report presents the results of the 2007 inspection and cvaluation of the Woods Pond Dam,
located on thc Housatonic River in the Towns of Lenox and Lee, in Berkshire County,
Massachusetts. Woods Pond Dam is classified as a "large" dam, having "significant" hazard
potential per Massachusetts' Dam Safety Regulations 302CMR10. The dam is owned and
operated by the General Electric Company (GE). An Operations and Maintenancc (O&M) Plan
for project operation is maintained by GE. An emergency action plan (EAP) for the dam,
updated in 2007, is on file with GE and with the Massachusetts State Office of Dam Safety.
Woods Pond Dam was found to be in Good condition overall with no major deficiencies (please
refer to Appendix D for definition of 'Good' condition). Other than the minor maintenance
items identified in this report, the dam is in excellent physical condition. Flood events up to and
including the Spillway Design Flood (SOO-year flood) are expected to be able to be passed
through the project without the failure of the project structures or uncontrolled release of the
reservoir. The minimum factors of safety for structural stability, as established by the Office of
Dam Safety, arc met or exceeded. The dam complies with Office of Dam Safety regulations.
The dam is regularly inspected and well maintained. The owner and its agents are familiar with
the O&M Plan and the EAP and their requirements.
Modifications recommended in previous inspection and assessment reports have been
satisfactorily implemented. A list of recommendations for Woods Pond Dam resulting from this
2007 inspection is provided below.
• Remove woody vegetation in vicinity of right abutment (Section 2.1.2.2).
• Identify owner of the leaning utility pole along the raceway embankment and inform
them of the pole's condition (Section 2.1.3.1).
• Monitor or remove trees on east side slope of raceway channel (Section 2.1.3.1).
• Repair! replace rip-rap on western face of raceway embankment (Section 2.1.3.1).
• Remove and replace beam in bridge over stoplog sluice structure if required for access to
operate the stoplogs. (Section 2.1.3.2).
• Remove debris from stoplog sluice structure (Section 2.1.3.2)
These are "routine maintenance" items which should be carried out over the next one to two
years. No other physical modifications or changes to operations or maintenance procedures are
recommended as a result ofthe 2007 inspection and evaluation.
Woods Pond Dam, TOll'll of Lenox/ Lee - ES-l- Date of Inspecti 011: Novemher 14, 20()7
WOODS POND DAM
EVALVA TION SUMMARY DETAIL SHEET 3. Dam Location: Berkshire 1.NID 10: MA00731 1 2. Dam Name: Woods Pond Dam
4. Inspection Date: Nov 14, 2007 5. Last Insp. Date: Nov 29,2005 6. Next Inspection: 2009
7. Inspector: Mario Finis 8. Consultant: MWH
9. Hazard Code: Significant (Class 2) 10. Insp. Frequency: Significant- 5 Yrs. 111. Insp. Condition: Good
E1. Design Methodology: 3 E7. Low-Level Discharge Capacity: 4 -­ -.. ~,,- -­
E2. Level of Maintenance: 5 E8. Low-Level Outlet Physical Condition: 4 -=­ --­ ~-,,-~-
E3. Emergency Action Plan: 5 E9. Spillway Design Flood Capacity: 5 -­ ".,,' ­ -
E4. Embankment Seepage: 5 E10. Overall Physical Condition of the Dam: 5 .. --~--'''- -
E5. Embankment Condition: 4 E11. Estimated Repair Cost (in thousand $): N/A -­ - --­ - --- ­ -"",,'---- ­ - ----- ­ E6. Concrete Condition: 4
EVALUATION DESCRIPTION El: DESIGN METHODOLOGY
I. Unknown Design - no design records available 3. Some standard design features
5. State of the art design - design records available
1£2: LEVEL OF MAINTENANCE I. No evidence of maintenance, no 0&1\-1 manual
2. Very little maintenance, no O&M manual 3. Some level of maintenance and standard procedures
4. Adequate level of maintenance and standard procedures
5. Detailed maintenance pian that is executed
E3: Ei\lEHGENCY ACTION PLAN
I. No plan or idea ofwhal to do in the event of an emergency
2. Some idea but 110 written plan
J. No fomlal plan but well thought out 4. Available written plan that needs \lpdating
5. Detailed, updated written plan avnilable and filed with tvfADCR
E4; EMBANKMENT SEEPAGE
2. Evidence of monitored piping and seepage
3. No piping but uncontrolled seepage
4. Controlled seepage 5. No seepage or piping
E5: EMBANK,\IENT CONDITION
I. Severe erosion andlor large trees
2. Significant erosion or signifie<ltlt woody vegetation 3. Bnlsh and exposed embankment soils, or moderate erosion
•-1-. Unmaintained grass, rodent activity and maintainable erosion
5, Well maintained healthy unifoOll grJs~ cover
1-:6: CONCRETE CONDITION
seepage or stability wneerns 2. Cracks with misalignment inclusive oflransverse cracks with no
r..·iisaiignmcnt 3. Significant longitudinal cracking and minor transverse cracking
4. Spalling and minor Surt~1cC cracking
5. No apparc-nt tlel1eieneies
E7: LOW LEVEL OUTLET DISCHARGE CAI)ACITY
l. No low level outlet 2. Outlet with insuil1cient dmwdown capacity
3. Inopemble gate with potentially sufficient dmwdowll capacity 4. Operable gate with sufi1eient drawdown capacity
5. Operable gate with capacity greater than necessary
E8: LOW LEVEL OUTLET PHYSICAL CONDITION
I. Outlet inoperative needs replacement, nOIl·exislent or inaccessible
2. Outlet inoperative needs repair
J. Outtet operable but needs repair 4. Outlet operable but needs maintenance
5. Outlet and operator operable and well maintained
E9: SPILLWAY DESIGN FLOOD CAPACITY
I. 0--20%oftheSDF 2,21-40%oftheSDF
3.41-60%oftheSDF
EIO: OVERALL PHYSICAL CONDITION OFTHE DAM
I. UNSAFH - Major structural, operational, and maintenance ddieiencie~
exist under normal operating conditions
2. POOR - Significant structural, operation and maintenance dcfieiencies Arc clearly rccognized Ullder normalioading conditions
3. f:4fR - Significant opemtional and maintenance deficicncies, no stmetural
dcfieiencic.~. Potential del1cieneics exist under unusual loading conditions ThaI may realistieally occur. Can be used whcn uncerlninlies exist as to .
eriticnl paramcters
Infrequent hydrologic C\'cnts would probably resull In deficiencies.
5. GOOD - No existing or potcntial defkiencies recognized. Safe pc:rfOnll,lllee is expected under all loading including SDF
Ell: ESTIMATED HEI'AIR COST
Estimation of the total cost 10 address all identil1ed stmctuml, operational,
maintenance deficiencies. Cost shaH be developed utilizing standard
cstimating guides and procedurc.'>
Changes/Deviations to Database Information since last inspection
H'oudoS Pund Dam, TOH'JI fl Lenox! Lee - ES-2- Date of Inspection: Nm'elnher 14, 2007
PREFACE
At the request of General Electric Company, an independent inspection of the Woods
Pond Dam was performed to assess the structural integrity of the dam, including
conditions and circumstances that could lead to catastrophic failure of the dam and/or
substantial release of the sediments contained in the impoundment behind the dam. This
was the fillh assessment conducted pursuant to Paragraph 123.a of a Consent Decree
executed by General Electric and various federal and state agencies, which was effective
upon approval by the com1 on October 27, 2000, conceming the GE­
Pittsfield/Housatonic River Site. The inspection was performed on 14 November 2007
by Mario Finis, P.E. and Matthew Sorrell, P.E., both ofMWH Americas, Inc. (MWI-I).
The reported condition of the dam is based on observations of field conditions made
under nOl1nal operating conditions and water levels at the time of inspection, along with
data available to the inspection team as of the date of writing.
It is critical to note that the condition of the dam depends on numerous and constantly
changing internal and extemal conditions, and is evolutionaty in nature. It would be
incorrect to assume that the present condition of the dam will continue to represent the
condition of the dam at some point in the future. Only through continued care and
inspection can there be any chance that unsafe conditions be detected.
Signed: _____________
TABLE OF CONTENTS
SECTION PAGE NO.
1.1 Geneml ............................................................................................................... 1 1.1.1 Authority ......................................................................................................... I
1.1.2 PlIlpose of Work ............................................................................................. I
1.1.3 Definitions....................................................................................................... I
1.2.5 Operations and Maintenance ........................................................................... 4
1.2.6 OCR Size Classification ................................................................................. 5
1.2.7 OCR Hazard Classification ............................................................................. 5
1.3 Pertinent Engineering Data ............................................................................... 5 1.3.1 Drainage Area ................................................................................................. 5
1.3.2 Reservoir ......................................................................................................... 6
1.3.4 General Elevations .......................................................................................... 6
1.3.5 Overflow Spillway .......................................................................................... 7
1.3.6 Outlet Stmeture ............................................................................................... 7
1.3.8 Operating Records .......................................................................................... 9
1.3.9 Previolls Inspections and Reports ................................................................... 9
Woods Pond Dam, TOII'II a/Lenox/Lee Date of Inspection: NOinnher 14. ]()07
TABLE OF CONTENTS
SECTION PAGE NO.
2.1 Field Inspection ................................................................................................ 11
2.1.1 General Findings ........................................................................................... 11
2.1.3 Appurtenant Structures ................................................................................. 14
2.1.4 Access Roads ................................................................................................ 17
2.3.1 Operational Procedures ................................................................................. 18
2.4 Emergency Wal'lling System ............................................................................ 19
2.5 Hydraulic! Hydrologic Data ............................................................................ 19
2.6 Structural Stability and Slope Stability ........................................................... 20
2.6.1 Structural Stability ........................................................................................ 20
2.6.2 Slope Stability ............................................................................................... 21
SECTION 3...................................................................................................................... 23
3.1 Assessments ...................................................................................................... 23
3.3 Yearly Reco/llllleJ1(lations ................................................................................ 24 3.4 Recommendations, illaintenaJlce, and lvlinor Repairs ................................... 25
3.5 Remedial Nleasl/res .......................................................................................... 26
3.7 Opinion ofProbable Cost ................................................................................ 26
lV(J(jd~ POlld Dam, Tvwn orLeI/ox/Lee II Date of Inspection: Novemher J4. l007
C
Exhibit I Project Location
Exhibit 2 General Plan
Exhibit 3 Typical Cross-Sections
Exhibit 4 Typical Cross-Sections
Exhibit 5 Contour Map of Riverbed Downstream of Spillway, Arcadis, 2007
APPENDICES
Previous Reports and References
F Instrumentation Data and Evaluation
Woods Pond Dum, Town (~rLemn.-lLee iii Date oflnspcction: Nm'ember 14, 20()7
SECTION 1
1.1 General
1.1.1 Authority
The General Electric Co. retained MWH Americas, Inc. to perform a visual inspection
and develop a repOlt on the condition of the dam and appurtenant structures comprising
the facility known as Woods Pond Dam, located on the Housatonic River, in the Towns
of Lenox and Lee, Massachusetts. This inspection and repoli were performed in
accordance with MGL Chapter 253, Sections 44-50 of the Massachusetts General Laws,
as amended by Chapter 330 of the Acts of 2002. This assessment was also conducted
pursuant to Paragraph 123.a of the Consent Decree executed by General Electric and
various federal and state agencies, as of October 27,2000.
1.1.2 Purpose of Work
The purpose of this investigation is to inspect and evaluate the present condition of the
dam and appurtenant structures in accordance with 302 CMRIO.07 and Paragraph 123.a
of the Consent Decree, to provide information that will assist in both prioritizing dam
repair needs and plan/conduct maintenance and operation.
1.1.3 Definitions
To provide the reader with a better understanding of this report, definitions of commonly
used terms associated with dams are provided in Appendix D. Many of these terms may
be included in this report.
1.2 Description of Project
1.2.1 Location
Woods Pond Dam is located in the towns of Lee and Lenox, in Berkshire COUllty,
Massachusetts, as shown on the Project Location Map - Exhibit I. The dam impounds
the waters of the Housatonic River, and forms what is known as Woods Pond Reservoir.
The dam may be found on the East Lee USGS Quadrangle map, at approximately 4i) 20'
50" N Latitude and 73° 14' 42" W Longitude.
WOOl/<.' PUlld Dam. TOIl'll orLe//ox! Lee • 1 • Date ofInspcction: NOl'emher}4, 20U7
The closest major road is Route 7. Access to the site frolll Route 7 is gained by exiting at
Housatonic Road (north of 1-90; south of Pittsfield, MA), and traveling east on
Housatonic Road down into the river valley. At the reservoir, the road takes a sharp right
turn to the south and changes name to Crystal Street. A short distance south on the left is
the bridge for Valley Road, downstream of the dam. The dam is accessed by crossing the
bridge and heading north on Valley Road through the mill complex to the dam site.
1.2.2 Owner/ Operator
Woods Pond Dam is owned, operated and maintained by the General Electric Company
(GE). Contact information for GE is shown below.
Table I - Owner information
159 Plastics Avenue, Bldg. 59
Pittsfield, MA 01201
1.2.3 Purpose of Dam
The original Woods Pond Dam, which was replaced by a new dam in 1989, was
constructed in about 1864 for the purpose of supplying water power for an adjacent mill.
The mill is no longer active, and the new dam currently serves to impound Woods Pond
Reservoir, which is part of the Housatonic River Valley Wildlife Management Area.
1.2.4 Description of Dam and Appurtenances
The main features of the Woods Pond Dam include:
• an overflow spillway,
• a raceway closure structure,
• a raceway channel and embankment, and
• a raceway stop log sluice structure.
Wood~ Pond Dam, 1'01\'11 o(Lcllox/ LeI.! ·2· Date of Inspeel ion: Novemhel' 14, 20()7
The present spillway and abutments were constructed in 1989 to replace the old timber
crib clam, which is now submerged upstream of the new dam. This inspection/evaluation
report focuses on the new Woods Pond Dam and its related features. The old timber crib
dam and the pOllion of raceway embankmcnt upstream of the present structures servc no
dam safety PUllJOSC and are not part of this inspection or evaluation.
The present concrete spillway is 140 feet long with an ogee-shaped crest at a crest
elevation of EI. 948.3 ft National Geodetic Vellical Datum 1929 (NGYD)I. The spillway
apron discharges at EI. 942.0 Ii. The spillway is approximately 11.9 Ii tall at its tallest
point, measured from the spillway crest (EI. 948.3 ft) to the lowest point of the
foundation bedrock at the toe (El 936.4 ft). Concrete training walls on either side of the
spillway direct flow into the downstream river channel. The walls are approximately 15
feet tall and extcnd about 20 feet downstream of the spillway section.
A concrete gravity structure forms the right (west) abutment. The crest is three feet wide
at El. 954.0 Ii. The upstream face is vellical. The downstream face is vertical down to
El. 951.0 ft, then sloped at IH: I V below the break. The downstream side of the
abutment is backfilled to about El. 947 ft. Stability analyses show that the structure does
not require this fill for structural stability. The right abutment ties into the railroad
embankment (Housatonic Railroad) that runs along thc west side of the river and
reservoir. Heavy rip-rap is provided for several hundred feet upstream of the abutment
along the railroad embankment. Riprap is also provided along the upstream face of the
abutment and on the downstream side of the abutment. Riprap was recently added on the
downstream side of the abutment along the railroad embankment.
The left abutment consists of steel sheet-pile cells with a three-foot thick concrete cap,
with top of concrete at El. 954.0 ft. The abutment ties into Valley Road, which runs
along the eastern edge of the project site. The raceway closure structure is incorporated
into the left abutment. The raceway closure structure controls flow into thc raceway
channel. The closure structure is a concrete and sheetpile structure and contains
provisions (slots, hoist, etc.) for stoplogs. Each stop log is two fect high and a total of five
stop logs may be inserted in the slot. This allows the inlet elevation of the raceway
channel to be varieel between EI. 944.0 ft and El. 954.0 ft.
I All elevations given arc referenced to NGVD unless otherwise noted.
Woods Pund Dal/l, 7tHi'll (~lLeJ/ox/ Lee - 3 - Date of Inspection: NOI'ember 14, 2007
A raceway channel runs parallel to the Housatonic River downstream of the dam along
the left side of the project. An embankment separates the raceway channel from the river
channel. Originally tlow would be diverted from the Housatonic River to thc intake for
the old mill (Mill Pond) via the raceway channel. The raceway channel now functions as
the low-level outlet for the project. The side slopes of the channel are rip-rapped and are
at a slope of 2H: IV. The embankment has a 10-foot wide crest at approximately EI.
952.0 ft. The west (river-side) of the raceway embankment is rip-rapped, and at a slope
of 2H: I V. Three open standpipe piezometers are installed within the raceway
embankment along its crest. These are the only instruments installed at the project site.
At the downstream end of the raceway channel, a stoplog sluice structure controls the
level of the water in the raceway and in the mill pond, and returns tlow from the raceway
channel to the Housatonic River. The stoplog sluice structure is a concrete structure with
stop logs, and upstream and downstream training walls. Slots within the structure allow
for the insertion of stoplogs. The stoplogs are each 14-inches high, and allow the
overtlow elevation of the outlet from the raceway channel to be varied. A bridge over the
stoplog sluice structure provides access to the raceway embankment from Valley Road.
A culvert beneath Valley Road connects the raceway channel to the mill pond. The mill
intake off of the mill pond is now closed off and the only outlet from the mill pond under
normal conditions is through the stop log sluice stl1lcture.
Chain-link fence is provided for security purposes at the entrance to the raceway
embankment and entrance to the left abutment.
A geotechnical exploration program conducted III 1988 determined that all of the
structures are founded on shallow "marbleized" bedrock, which is vel1ically bedded and
is generally fine grained, hard with variable medium to close joint spacing. Details of the
subsurface field investigation can be found in the General Design Report for Woods Pond
Dam Rehabilitation [Reference I).
1.2.5 Operations and Maintenance
An Operations and Maintenance Plan dated September 2006 is on file for the project.
Woods Pond Dam is a run-of-river project with a fixed spillway crest, and requires only
occasional adjustment of stop logs and inspection under normal opcrating conditions.
Operations under unusual and emergency conditions are described in the O&M Plan and
in the Emergency Action Plan for the project.
Woods Pond Dam, TOI\'JI olLenox/ Lee - 4 . Date of Inspection: NOI'l'mber J4. 2007
Woods Pond Dam is inspected on a monthly basis, with more thorough inspections taking
place quatterly. In addition, biennially the project is inspected by a licensed engineer,
experienced in the inspection of dams. Maintenance is performed on an as-needed basis,
based upon the observations made during the regular inspections.
GE is responsible for operation and maintenance of the project. GE at times will contract
out aspects of the work but maintains responsibility for O&M.
1.2.6 DCR Size Classification
In accordance with the Massachusetts Department of Conservation and Recreation,
Division of State Parks and Recreation (OCR) Regulations (302 CMR 10.00, November
2005), Woods Pond Dam is designated as a "large" size dam. This size classification is
based on the storage capacity that occurs during the spillway design flood (5300 acre-ft at
El. 955.8 n, during the 500-year flood).
1.2.7 DCR Hazard Classification
In accordance with Department of Conservation and Recreation classification procedures,
under Commonwealth of Massachusetts dam safety rules and regulations stated in 302
CMR 10.00 as amendcd by Chapter 330 of the Acts of 2002, Woods Pond Dam is
considered a "significant" hazard (Class 2) dam. This hazard potential classification is
based on the presumption that a failure of the dam may result in the loss of life and
significant property damage immediately downstream of the dam.
1.3 Pertinent Engineering Data
1.3.1 Drainage Area
The drainagc area of the project is approximately 170 square milcs within the Towns of
Lenox and Lee, and mainly consists of land within the Housatonic River Valley Wildlife
Management Area. There are no significant dams located within thc drainage arca of
Woods Pond Dam. The terrain in the area may be characterized as hilly with marshes
and bogs in the valleys formed by the hills.
Woods Pond Dam, TowII (~rL(!}lOxl Lee ·5- Dale of Inspection: NOI'emher 14, 2007
1.3.2 Reservoir
Table 2 - Reservoir Data
Maximum Pool (@ SDF = 500 Year 9,000 2,200 955.8 5300 12,100
Flood) *Lcnglh and Width are approxllnate and arc estnnated from aenal photographs and topographic maps.
Surface area at normal pool1evel is approximately 122 acres.
1.3.3 Discharges at the Dam Site
Woods Pond Dam operates as a l'lln-ot:river project with outflows equal to inflows on an
instantaneous basis. Water levels in the reservoir arc recorded at the time of inspections.
The USGS gaging station at Great Banington, approximately 10 miles downstream, can
be used to estimate the flow at Woods Pond Dam by prorating the flows at the gage by
the ratio of the drainage area of the clam to the drainage area of the gage.
1.3.4 General Elevations
General elevations are listed below in Table 3 in feet, referenced to NGVD 1929.
Table 3 - General Elevations
Normal Pool 948.8+/­C.
Overflow Spillway CrestD. 948.3
F. Streambed at Toe of Dam 941.9
Low Point along Toe of DamG. 936.4 -
Refer to Exhibit 5 for the survey information li'om which thc elevations for the streambed
and low point along the toe of the dam were derived.
Woods POlld DUIII, TOIm (~/Ielloxl Lee - 6- Date of Inspection: NOI'ember /4, 2007
1.3.5 Overflow Spillway
Information about the spillway is presented in thc table below.
Table 4 - Spillway Dala
140 ftB. Length of Weir
C. Crest Elevation
Upstream Channel Elevation
E. Downstream Channel Elevation* 934.5
F. Downstream Water Elevation 941.8+/­
*The lowest point of the depression just downstream of the dam was selected as the
downstream channel elevation (refer to Exhibit 5).
1.3.6 Outlet Structure
Details ofthe outlct from Woods Pond Reservoir are tabulated below.
Table 5 - Oullel Structure Data
Type of Outlet Works A. Raccway Channel
Channel Shape/ Type B. Trapezoidal/ Rip-Rap Lined
Chanel Bottom Width 20 ftC. Channel Side Slopes 2H: IVD.
Upstream Control Stoplogs EI 944 ft to EI 954 ft E.
Downstream Control Stop logs F.
1.3.7 Design and Construction Records
The original dam, no longer in operation and not the subject of this report, was reportedly
constructed in about 1864. The original structure consisted of a 9-foot high rock-filled
timber crib overflow dam with a 14-foot-high earthfill cmbankment parallel to the river
channel as its east (left) abutment. The dam had reportedly tilled with sediment up to the
crest of the spillway. No design or construction drawings for the original project
structures arc known to be available.
Woods Pond Dum, 7'01\'11 orLel/ox/ Lee - 7 - Date of Inspection: Noremher 14, 2()07
Beginning in 1979, in recognition of the deteriorated condition of the original Woods
Pond Dam, studies and investigations were performed to assess the condition of the dam
and to develop recommendations for repair and rehabilitation of the dam. In 1983, the
timber planking and heavy gage sheet mctal on the main overflow dam were replaced
with an IS-inch-thick reinforced concrete cap. After placement of the cap, a leak
developed at the east abutment masonry wall, presumably due to the cut-off of natural
seepage through the timber crib dam. The joints in the masonry wall were filled with
mOliar shortly after the 1983 construction, temporarily stopping the leakage, which
therein contributed to pressure buildup behind the wall resulting in lateral movement of
the wall.
In 1988, a plan was developed to constl11ct a new Woods Pond Dam spillway and closure
structure to provide a safer, more reliable project structure. Portions of the original
project that were to remain would be rehabilitated. Based on a geotechnical
investigation, a detailed design report for dam constl11ction and rehabilitation was
prepared in 1989 [Reference 1]. The construction and rehabilitation was cal1'ied out in
two stages. The first stage consisted of the construction of a raceway closure structure
with concrete stop logs to diveli flow away from the raceway and mill pond. The purpose
of the closure structure is to protect the raceway embankment from overtopping and
potential failure during high flows. During later (second stage) construction, this closure
structure was also used to divert water through the raceway channel while work was
performed on the new spillway and abutments.
The second stage consisted of the construction of a new replacemcnt spillway and non­
overflow gravity sections a shOlt distance downstream of the original spillway. A rockfill
berm was also constructed on the west (right) bank of the river between the original
spillway and new spillway, and the upper 2.5 feet of the original timber crib spillway
were demolished. A general plan of the rehabilitated project is shown on Exhibit 2.
Exhibits 3 anel 4 present typical cross sections of the structures.
The original stop log sluice gate structure at the downstream enel of the raceway
embankment was rehabilitated in 1991. This structure controls the water level in the Mill
Pond and raceway channel. The drawings for the dam and raceway closure structure
were provided in an Appendix to the 2000 Structural Integrity Report [Reference 6].
Several minor repairs were recommended by MWH following the biennial inspections of
the new Woods Pond Dam. All of these recommendations were implemented by GE.
The following modifications were incOlvorated into the project as a result ofMWH's last
(2005) inspection:
Woods Pond Dalll, Town of'Lellux/ Lee Date of Inspt:<.:tion: NOI'emher 14, 20(J7
I. A staff gage (reference elevation) was painted on the spillway abutment walls for
ease in estimating the reservoir water levels.
2. The deterioration along the waterline in the upstream face of the right masonry
training wall at the raceway stoplog sluice structure was repaired. Also, the
vertical crack in the upstream face of the right masonry wall located
approximately six feet 11·om the right wall edge was repaired
3. Riprap, similar to that placed along the raceway embankment, was placed along
the area just downstream of the right (west) abutment for a distance of
approximately 20 to 40 feet.
1.3.8 Operating Records
GE performs monthly, quat1erly, and formal biennial inspections of the project. Monthly
and quarterly visual inspections and piezometer readings are recorded on inspection
fonlls maintained by GE in their Pittsfield, MA facility. The formal inspections are
performed by an independent consultant and are on file with GE in its Pittsfield, MA
facility. The formal biennial inspection reports are also filed with the Massachusetts
OCR.
In addition, GE monitors flows in the Housatonic River on a daily basis through the
National Weather Service's Advanced Hydrologic Prediction Services (AHPS), a web­
based suite of forecast products that provide the magnitude and uncertainty of the
occurrence of t1oods, from hours to. days and months, in advance. These products are
displayed graphically on the AHPS website providing current t10w conditions and the
t100d forecast level to which a river will rise and when it is likely to reach its peak or
crest. GE keeps logs of the data reported on the AHPS website, and maintains those at its
Pittsfield, MA facility.
GE also provides training for inspection of the project including review of the O&M plan
and EAP, in conjunction with the formal inspection. Records of attendance at this
training are maintained by GE at its Pittsfield, MA facility.
1.3.9 Previous Inspections and Reports
Harza Engineering Company, Inc. (Harza), a predecessor to MWH, inspected the dam in
1991, sh0l11y following completion of the project rehabilitation [Reference 2]. Harza
also inspected the dam in 1998, with a report prepared in March 1999 [Reference 3].
Woods POlld Dum, TOII'J1 (?! Lenox/ Lee - 9· Date of Inspection: Novemher /4, 2007
Harza then prepared a Downstream Raccway Embankment Slope Stability Analysis III
March 2000 [Refercnce 4].
The Massachusetts Department of Environmental Management (OEM, now OCR)
perfot1ned an inspection of the dam in 1998 [Reference 5]. Harza then performed the
first Structural Integrity Assessment of Woods Pond Dam in December 2000 with a
report submitted in JanualY 2001 [Reference 6]. This was perfonned in accordance with
the Consent Decree executed by GE and various agencies. As a result of thc 2000
assessment, various modifications to the project were completed to improve the structural
integrity of the project. At the invitation of the Lead Administrative Trustee (LAT) under
the Consent Decree, a OEM staff member reviewed the modifications to the dam during a
site visit in January 2002.
MWH performed the second Structural Integrity Assessment of the Woods Pond Dam in
October 2002. As part of that work, MWH reviewed the modifications performed as a
result of recommendations made in the 2000 report and prepared rccord drawings to
reflect the work performed in 200 I. These drawings were provided in an Appendix to the
2002 Structural Integrity RepOlt [Reference 10].
MWH performed the third Structural Integrity Assessment of the projcct in November
2004 and, as part of that repOlt, made recommendations for minor repair work [Reference
II]. The work was completed in 2005.
One year later, in November of 2005, MWH performed the fourth Structural Integrity
Assessment of Woods Pond Dam. This inspection was made in response to heavy flows
experienced in October of that year. Minor repair work was recommended [Reference
12], and this work was completed in 2006. The regularly scheduled biennial inspection
program was then resumed.
Woods Pond Dalll. Towil oriel/lJx! Lee ~ I 0 ~ Dale of Inspection: Nm'elllher 14, 2007
SECTION 2
2.1 Field Inspection
The field inspection was performed on Wednesday, 14 November 2007. The temperature
was approximately 50°F with overcast skies. Weather records for Pittslield,
Massachusetts indicate a high temperature of 54°F and low temperature of 25°F for that
day with average precipitation of 0.07 inches. No ice was observed in the reservoir or
river at the time of the inspection.
The reservoir water level (upstream of the overflow spillway) was about six inches above
the spillway crest, or about El. 948.8 ft. The tailwater was at approximately El. 941.8 ft.
The inspcction was performed by Mr. Mario Finis, P.E. and Mr. Matthew SOlTell, P.E.,
both of MWH Americas Inc. The inspection included observations of the portions of the
structures visible at the time of the inspection only. No subsurface or underwater
inspections were included as part of this lield inspection. Photographs taken during the
inspection are attached to this repOli as Appendix A. A copy of the inspection checklist
is included in Appendix B.
A survey of a depression at the toe of the spillway was performed prior to the inspection,
as recommended in the 2005 Assessment Report, and is discussed in Section 2.1.2.1.
2.1.1 General Findings
Woods Pond Dam was found to be in Good condition (see Appendix D for detinition).
Recommendations of previous reports have been implemented and addressed previously­
identified concerns. A few minor deficiencies werc observed which can be addressed by
routine maintenance in the next two years. Other than the minor maintenance items
identified in this report, the dam is in excellent physical condition.
Flood events up to and including the Spillway Design Flood (500-year !lood) are
expected to be able to be passed through the project without the failure of the project
struchlres or uncontrolled relcase of the reservoir. The minimum factors of safety for
struchlral stability, as established by the Office of Dam Safety, arc met or excecded. The
dam complies with Office of Dam Safety regulations. Details of the inspection are
presented in the following sections.
Woods Pond Dalll, Tml'l1 o/Lenoxl Lee - 11 • Date of Inspection: NOI'emher 14, 2007
2.1.2 Overflow Spillway and Abutments
2.1.2.1 Overflow Spillway
Flow in the reservoir approaching the spillway was uniform III appearance, and there
were no indications of disturbances on the water surface. Two logs (Photo #2, Appendix
A) were caught upon the spillway crest, but they did not appear to be affecting the flow
over the weir. A thin sheet of water was observed passing over the weir during the
inspection. There were no apparent irregularities in the flow over the weir, other than a
continuous line that could be seen along the weir, near the downstream toe. This line
appears to be the result of a joint in the original fonnwork, and did not appear to have
changed from previous inspections.
The spillway concrete itself could not be directly observed due to the water passing over
the downstream face; however the concrete appeared to be in good condition, with no
apparent areas of spalling, deterioration, or movement. As the spillway is approaching 20
year of age, it is recommended that the water level in the reservoir be lowered to below
the spillway crest using the raceway channel, and the crest and downstream face of the
concrete weir be inspected prior to or at the time of the next biennial inspection.
A depression near the toe on the left side of the spillway was described in the 2005
Structural Integrity Assessment [Reference 12]. A survey of this area was conducted in
2007 prior to the field inspection and compared with the survey data collected in the
same area in 2002. The figure, presented as Exhibit 5, includes spot elevations and
contours developed from the spot elevations for both 2002 and 2007. The depression
docs not appear to have deepened or grown. The depression based on the 2002 survey
had a bottom elevation of approximately 934 feet with surrounding elevations of
approximately 938 feet. Similarly, the survey performed in the summer of 2007 indicates
a bottom elevation of slightly less than 935 feet with surrounding elevations of
approximately 938 feet. Some differences seen in the relief on the figure may be due to
the fact that the topographic survey was completed downstream of the dam in turbulent
water, in an area where the river bottom is rocky and uneven. The depression appears to
be stable and not growing in size and does not indicate any threat to the integrity of the
dam.
Wood« Pond Dalll, TowlI II I.CIIOX! Lee - 12- Date of Inspection: NO\'cmher 14, l007
2.1.2.2 West (Right) Abutment
The west (right) abutment and training walls (Photo #2) were found to be III good
condition. No defIciencies were visible in the concrete ..
The rip-rap along the west embankment, both upstream (Photo # I) and downstream of
the spillway, was in good condition. No scouring, undermining, or missing rip-rap was
observed.
The training wall downstream of the spillway was in good condition with no large cracks,
significant deterioration, or signs of movement noted. Rust-colored stains seen in
previous inspections were found just below the joint between the wall footing and stem
(Photo #3). The stem appeared vertical with no signs of movement or rotation. The
concrete in this area should continue to be monitored for signs of deterioration or wall
stem movement due to any possible deterioration of the rcinforcing steel that may be
indicated by the rust stains.
The concrete abutment ties into the Housatonic (formerly Boston & Maine) Railroad
tracks with riprap placed against the sheetpile driven at the end of the concrete abutment.
The railroad was walked for a distance upstream and downstream of the spillway, and no
adverse conditions, such as settlement, depressions, or sinkholes in the surtace of the
railroad bedding were noted. This area is routinely monitored for any seepage through or
around the concretc non-overflow section, or for signs of muddy or cloudy flow
downstream of the dam. Woody vegetation observed in the riprap and fill just
downstream of the abutment (Photo #4) should be removed as pmt of normal
maintenance procedures.
2.1.2.3 East (Left) Abutment and Raceway Closure Structure
Overall the structure is in good condition. Cracking and efflorescence (Photo #5 and #6)
was observed in the concrete for the left training wall; however this cracking does not
appear to have worsened since the last inspection. This concrete is a facing on the steel
sheet pile, and cracks within it do not pose a threat to the integrity of the dam.
The concrete cap for the sheetpile cells was in good condition. The steel sheetpile was in
good condition with no indication of bowing or interlock distress in any of the piles or of
loss of fill from within the sheetpile.
W(){)d~ Poud Dam, TOII'II orLeI/ox! Lee - 13- Date ofInspcction: Nm'elllher 14. 200?
The repair patch placed on the left masonry wall upstream of the entrance to the raceway
stop log closure structure had a corner spa lied oft; but has not changed since the last
inspection (Photo #7). This patch should be monitored during fuhlre inspections. The
purpose of this patch was to minimize the potential for water to seep through the bank
and around the end of the abutment under Valley Road. Inspection of the ground surface
and slope at Valley Road showed no sinkholes, depressions, erosion, or other signs of
seepage around the abutment or movement of the abutment.
The raceway closure (stoplog) structure (Photo #9) was also in good condition. A few of
the ladder rungs located on the downstream side of the stoplogs remain bent. The
concrete near the waterline, in the western wall, just downstream of the raceway closure
structure has started to erode (Photo #1 0). This erosion should be monitored during
routine inspections. These conditions do not affect the integrity or operation of the dam.
2.1.3 Appurtenant Structures
2.1.3.1 Raceway Embankment and Channel
The raccway channel was in good condition. The rip-rap on both banks was in place, and
there were no signs of sloughing, scour, movement, or undermining of the rip-rap (Photos
#12-14). A utility pole along Valley Road had started to lean towards the channel, and is
estimated to be leaning 10 to 15 degrees (Photo #13). The pole does not provide power
or telecommunications to any project features and its failure would not constitute a dam
safety problem, but could present a hazard if the wires came into contact with the water.
Some trees are prcsent on the raceway side slope toward the southern end of the channel.
The condition of these trees should he monitored such that if they dic or their condition
deteriorates and they could fall into the raceway channel and block flow, they should be
removed.
A new wingwall (Photo #15) has been installed at the downstream end of the channel to
the left of the culvert to the mill pond. The wall and culvert were in good condition.
The raceway embankment was in good condition. There was some unevenness and
minor rutting observed in the crest (Photo #14). The crest should be surveycd, and areas
that arc below the design elevation should be built up.
The west face of the raceway embankment is intended to be fully rip-rapped. An area of
exposed earth, approximately 35 ft by 5 ft, and in the vicinity of BH-2, was noted (Photo
Woods POlld Dam, TOl\'JI a/Lenox! Lee - 14 - Date oflnspcction: NOl'cmher 14, 2007
II 16). The rip-rap in this area should be repaired to protect the exposed earth from
erosion and the vegetation surrounding this area should be rcmoved.
The east face of the raceway embankment is fully-rip-rapped. This rip-rap was in good
condition. The land side (Valley Road side) of the raceway channel is partially rip­
rapped, and some erosion was noted in non-critical areas. No action is required at this
time.
Data retrieved from the three piezometers in the embankment was also reviewcd as part
of the evaluation of the project. Nothing unusual was noted in the piezometric
infotll1ation that would indicate a problcm with the embankment. The monthly program
of piezometer monitoring should continue. Piezometric information is included in this
report as Appendix F.
2.1.3.2 Raceway Stoplog Sluice Strllcture
In previous reports, the upstrcam masonry and concrete wing walls of the structure were
noted to be deteriorated, particularly at the waterline. Somc of this deterioration has been
repaired, as have most of the cracks. There was still some deterioration and erosion at
both ends of the northeast wall, near the waterline (Photo #18). This erosion should be
monitored during monthly inspections. As first noted in the 1999 inspection report
[Reference 3), the walls appear to be leaning outward slightly, but did not appear to have
worsened.
The wingwalls downstream of the stop log sluice structure are in fair condition. The
vertical cracks noted on the north and south abutment walls during the previous
inspection have been repaired as have the small holes previously observed in the south
abutment wall. The concrete near the end of the southwest wall, just above the first
horizontal joint has eroded (Photo #20). This area should be monitored during future
inspections and repaired if there is the possibility of loss of till behind the wall or
instability in the wall.
Particular attention was paid to the base of the vertical crack in the southwest wingwall
(Photo #19). Water was observed flowing from this crack during the 2005 Structural
Integrity Assessment. During this inspection, however, the crack was found to be dry.
The repairs to the upstream wing wall appeared to have stopped the leakage. The 2005
rep0l1 recommended a dye test or other investigation to detetll1ine whether the source of
leakage was deterioration in the upstream wing walls or some other sourcc. Even though
the crack appeared dry, a simple dye test was conducted during the field inspection to
Woods POlld Dam, Tml'l/ olLel1l1x/ Lee - 15 - Date of Inspection: Novell/bel' 14. 20()7
evaluate the possibility of leakage through the left upstream wing wall of this structure.
Food coloring was added to the water in the raceway channel and observed tor sevcral
minutes. The colored water allowed visualization of the flow path, which was seen to
flow over the top of the stoplogs. There was no evidence that water from the raceway
channel was seeping through the wall, causing piping, or was otherwise migrating
around, through, or under the stoplog sluice structure.
The stoplog sluice structure was in good condition. Minor debris was present in the
structure and should be cleared.
2.1.4 Access Roads
Access to the spillway and raceway closure structure is from Valley Road on the left side
of the project. Valley Road fi"Om Clystal Street to the dam, after crossing the blidge over
the river, is an asphalt-paved road that tUI11S into a dilt road just at the left abutment.
Responsibility for maintenance of this road does not lie with the Owner, but the asphalt is
well maintained and in good condition.
The crest of the raceway embankment serves as an access road to the spillway and both
the raceway closure structure and stoplog sluice structure. The crest of the raceway
embankment is accessed from the paved pottion of Valley Road. The condition of the
raceway embankment crest is described under the raceway embankment section of this
report, Section 2.1.3.1. The bridge spanning the stoplog sluice structure comprises part
of the access road along the raceway embankment crest. The eastern-most beam in the
bridge spanning the stop log sluice structure was found to be severely conoded and may
not be able to withstand heavy vehicle loads on the bridge (Photo # 17).
Access to the left abutment and to the raceway embankment crest is controlled by locked
gates in the chain-link fence. There are no additional private access roads on the site.
2.1.5 Instrumentation
There are three piezometers installed in the raceway embankment. An evaluation of this
instrumentation is discussed in Section 2.1.3.1 and Appendix F of this repoti.
Woods Pond Dalll. Tml'l1 (~I Le/lox/ Lee - 16- Date ofInspeclion: NOI'em/Ju 14, 2007
2.1.6 Downstream Area
The area downstream of the west abutment is a wetland that exhibits constant flow. The
water is believed to be surface runoff from the surrounding hilly terrain, which is
collected along the railroad embankment and channeled to a culvert under the tracks just
downstream of the abutment. The flow was observed to be relatively small, with no signs
of turbidity. Some of the larger, woody vegetation in the area should be removed.
The left bank of the river channel downstream of the spillway is the toe of the raceway
embankment, and is discussed in that section. The right side is heavily wooded. No
signs of anything unusual or concems related to dam safety were observed.
There was no evidence of any sloughing of the banks around the perimeter of the mill
pond. Steel plates were observed over the intake trashracks at the mill. The water
passage in the mill is repOltedly sealed off with concrete.
2.1.7 Reservoir Area
The impoundment formed by the dam is known as Woods Pond Reservoir, and is Palt of
the Housatonic River Valley Wildlife Management Area. The area is considered rural
with steep, wooded hills and marshy within the sUlTOllllding valleys. The Village of
Lenox is approximately two miles to the west of the reservoir.
The reservoir rim in the immediate vicinity of the dam appeared stable, with no evidence
of sloughing or distress that would be of concern to the safety of the project.
2.2 Caretaker Interview
A meeting was held on November 14, 2007 at the owner's Pittsfield offices with Mr.
Kevin Mooney and Mr. John Levesque of GE, and Mssrs. John Powers, Jim Roff, Sean
Coyle, and Joe Hamling of O'Brien and Gere, Inc., in attendance. MWH presented a
brief refresher course on dam safety and inspection procedures for the individuals
performing the monthly and quarterly inspections. A copy of the attendance list for this
training and an outline for the training session arc provided in Appendix E.
The personnel who had performed the monthly inspections of the dam during the
previous year reported nothing unusual at the site over the previous year. No high tlow
events, unusual observations, unusual piezometer readings, or other cause for concern
were repOlted by the caretakers.
Woods Pond Dalll, TCHI'II olLelll)x/ Lee - 17- Date of Inspection: No\'emher 14, 20a?
2.3 Operation and Maintenance Procedures
Operation and maintenance procedures for the Woods Pond Dam are described in detail
in the Operations and Maintenance Plan (O&M Plan) dated September 2006 [Reference
14], and summarized in this Section.
2.3.1 Operational Procedures
Operational procedures for Woods Pond Dam are described in the O&M Plan tor four
conditions:
• Extreme (Serious) Flood Conditions
• Maintenance or Emergency Drawdown
Woods Pond Dam is a run-of-river project with an ungated, overflow spillway. Under
normal conditions, no active operation is required other than normal observation and
inspection. Daily monitoring of river flows in the Housatonic River using the NWS's
AlIPC website is performed and recorded on a log. Monthly and Quarterly inspections
are conducted and recorded, including collection of piezometer data.
All five stoplogs are in the raceway closure structure, with a one-inch spacer installed
between the 2nd and 3'd stoplogs up from the bottom to keep a small amount of flow in the
raceway and Mill Pond under normal conditions. The raceway stoplog sluice structure is
normally operated with three of the seven stop logs in place.
Unusual conditions occur when a t1ood, or other event, raises the Woods Pond Reservoir
to EI. 952.0 ft, and extreme conditions are when the reservoir reaches EI. 954.0 ft. The
GE Facility Manager, as defined in the EAP, will confinn that flood conditions exist. He
will then direct a designated GE Contractor to adjust the stop logs in the raceway stoplog
sluice struchlre to prevent overtopping of the raceway embankment if required. He will
also implement the EAP in accordance with its requirements. Inspections are conducted
after all unusual and extreme events.
If necessmy for maintenance or emergency drawclown condition, stop logs could be
removed from both the raceway closure stmcture and from the stoplog sluice struchlre to
lower the reservoir or raceway water levels for maintenance, or to address an imminent
Woods Pond DOII/, TOI\'I1 olLel/ox! Lee - IS - Date of Inspection: NOI'emheJ' J4. 2007
safety concern with the dam. The stop logs at the closure structure can be operated using
a dedicated hoist while the stoplogs at the sluice structure require a small truck crane.
2.3.2 Maintenance of Dam and Operating Facilities
A program of routine inspection is in-place at the project site. Inspections are performed
by the dam owner or their agents on a monthly basis, with more thorough inspections
occulTing once per quarter. The inspections include visual inspection of thc project
features, piezometer monitoring, and collecting photographs to document changes in
project features. The Massachusetts DCR also requires that significant hazard dams be
formally inspected once evelY five years by a licensed professional engineer experienced
in the design, inspection, and construction of dams. GE has elected to have a formal
inspection of the dam performed every two years.
Maintenance is performed 'as-needed' based on the finding of the regular inspections.
2.4 Emergency Wal'11ing System
An emergency action plan (EAP) has been developed for the project and has been 111
place for a number of years. The EAP contains a dambreak analysis, inundation maps,
emergency notification flowchaJts, a description of the conditions requiring emergency
response, and a list of procedures for responding to a dam safety emergency. The EAP is
reviewed and updated annually. The GE Facility Manager, as defined in the EAr, IS
responsible for its maintenance and implementation.
2.5 Hydraulic/ Hydrologic Data
Woods Pond Dam is a large, significant hazard dam. The spillway design Hood (SDF) is
the 500 year flood.
Flood flows at the dam were assessed as part of the 1998 inspection by comparison with
Hood-frequency transposed from the USGS Housatonic River stream gage near Great
Barrington. While the gage is downstream of Wooels Ponel Dam and thus theoretically
affected by upstream regulation, USGS gage remarks indicate that upstream regulation
effect on floods is slight. Woods Pond has a small reservoir and operates as a run-of·
river project. Thus, the regulation effect was disregarded.
Flood-frequency at the gage was computed using the period of record available, 83 years
from 1914 through 1996, using the U.S. Army Corps of Engineer's HECWRC program,
IVovd~ POlld Dalll, TOH'II (lLcJlrlx/ Lee . 19· Datt;! of Inspection: Nm'emher 14, l007
following federal procedure. The resulting flood-frequency gives a 100-yr peak of
11,700 cfs and a 500-year peak of 16,400 cfs at the gage. Flood-frequency at the gage
then was transposed to the dam site by drainage-areas ratio to the 0.6 power. Area at the
gage is 282 sq. mi. and at the dam 170 sq. mi. Resulting peaks at the dam are about
8,600 cfs for the 100-yr-t100d and 12,100 for the 500-year-t100d.
During the SDF, t10w will pass over the overflow spillway with some t10w passing over
the abutments. The maximum water surface elevation reached in the reservoir for a 500­
year flood event is estimated at El. 955.8 ft, or 1.8 feet over the top of the abutments.
The total duration of overtopping is estimated at 37.5 hours. With the exception of the
overt1ow ogee section, all project elements were considered to act as a broad-crested weir
during the SDF, and were assumed to have a weir coefficient of 2.67. Additional
information on the spillway routing can be found in Reference I.
2.6 Structural Stability and Slope Stability
There was no visual evidcnce of any instability in any of thc project structures during the
field inspection. Structural stability, overturning potential and embankment slope
stability were evaluated in the 200 I Structural Integrity Assessment Report [Reference 6)
and briet1y summarized herein.
2.6.1 Structural Stability
The dam spillway and abutments are gravity sections founded on rock. Full uplift
pressures (full headwater pressure, linearly decreasing to full tailwater pressure) were
assumed to be present for all loading cases. For the seismic case, the horizontal force
coefficient used for pseudo-static earthquake design loading was 0.1. This design value
is considered equivalent to a peak ground acceleration of about 0.15g to O.2g.
In the 1999 rep0l1 [Reference 3], the factors of safety for the spillway and right abutment
stability analyses were recalculated to evaluate the sensitivity of the factors of safcty
relative to values of cohesive strength. Revised factors of safety were calculated using
values of 10 psi lor cohesive strength with a 0.75 coefficient of friction. The bedrock
encountered during construction was angular rock with some irregularities; therefore, the
values for cohesive strength and coefficient of friction are conservative for this analysis.
All factors of safety, even with this much lower value of cohesion, are acceptable and the
dam is in compliance with the required factors of safety in DCR 302 CMR to.OO.
Woods Pond Dam, Tmm vjLellox/ Lee - 20 - Date of Inspection: NOI'emher 14, 2()07
2.6.2 Slope Stability
Slope stability analyses were perfonl1ed for the raceway embankment, and are included
in the Downstream Raceway Embankment Slope Stability Analysis [Reference 4],
prepared by \-larza in March 2000. The embankment acts as a dike between the raceway
and the main channel with a hydraulic head differential of approximately 5 feet under
nOJ111al conditions. The most critical section of the raceway embankment existing at that
time was selected for analysis (a narrow section previously located approximately 100
feet downstream of the new dam which has since been widened and flattened). Soil
parameters were established using field classification of the subsurface materials,
standard penetration test N-values, grain size distribution, and water content from a
subsurface exploration program conducted in 1999 (see Ref. 4 for results of the
subsurface investigation). Cohesion was neglected in the analysis. The phreatic surfaces
within the embankment were estimated for the various analysis cases. These phreatic
surfaces correlate with the actual piezometer readings observed. The results of this
analysis indicated that the overall stability of the embankment satisfied the recommended
factors of safety for stability.
As observed during this inspection, the addition of riprap along the slopes of the raceway
embankment provides additional slope protection and stability to the embankment. The
previous narrow spot in the embankment has been filled and no longer exists. The
oversteepened slopes have been flattened, and the erosion at the toe of the embankment
has been repaired. The placement of riprap along the shOJt riverside section of the
raceway embankment just downstream of the spillway also improves the stability of the
raceway embankment. All minimum factors of safety for embankment stability, as
established by OCR, have been met or are exceeded.
2.7 Spillway Capacity and Overtopping Potential
The new spillway was designed in 1988 and constructed in 1989. The design criteria for
the spillway required that:
• There would be no change in normal Woods Pond reservoir levels; and
• There would be no change in the I DO-year flood reservoir level.
The design and construction of the dam was approved in 1989 by the OEM, under
Chapter 253 Dam Safety Permit (Waterways Application No. 89W-On, License
Woods POlld Dam, TOWII ofLenox/ Lee - 21 - Date of Inspection: Nm'cmher 14, 20m
No. 2028, August 2, 1989). The DEMlDeR regulations were subsequently revised in
December 1996, May 2004, and November 2005. Adequacy of the spillway under the
revised regulations was discussed in the March 1999 inspection report [Rderence 3].
Section 10.14 (6) of the regulations, Spillway Design, and has not changed since the
March 1999 inspection report. The discussion presented in that repOlt concluded that the
500-year flood flow can be passed without failure of the dam.
The area to the right of the west (right) abutment at the railroad bed has been previously
identified as a low spot and would be the first area to be overtopped during a major flood.
The potential for erosion and subsequent failure of this area was explored and is
summarized in the 2002 Structural Integrity Assessment Report [Reference 10], and was
reassessed in the 2005 repOlt [Reference 12].
During the 100-year flood, the peak reservoir level is estimated at El. 954.6 ft., while the
tailwater level is estimated at El. 951.5 ft. [Reference 3]. The peak reservoir level during
the 500-year flood is estimated at El. 955.8 ft. with associated tailwater estimated at
El. 952.8 ft. [Reference 3]. These flows will overtop the east and west concrete
abutments by 1.8 feet, which can be safely withstood by the stmctures. The lowest area
along the project profile other than the crest of the overflow spillway is the railroad bed
to the right of the right abutment. During the 100-year and 500-year floods, water will
flow over this low area. Evaluation of now velocities and durations for these floods
concluded that flows will oveltop the railroad bed area, but that the size of the bedding
stone and configuration of the project featurcs should not result in the failure of the
project stmctures or uncontrolled release of the reservoir for nows up to and including
the 500-year flood [Reference 12].
As an added precaution against the potential for erosion and scour to begin adjacent to
the railroad embankment behind the right abutment, GE recently placed additional riprap
in this area for a distance of approximately 20 to 40 feet (Photo #2).
Woods POlld Dom, Tml'll ofLenox/l.ee - 22- Date of Inspection: NOl'emher 14, 2007
3.1 Assessments
Woods Pond Dam was found to be in Good condition with no major deficiencies (see
Appendix 0 for definition). Other than the minor maintenance items identified in this
repoli, the dam is in excellent physical condition. No major discrepancies were
discovered during the inspection. The recommendations listed in the previous sections
can be addressed by routine maintenance. A program of regular inspection is also in
place at the project. Repairs recommended in the 2005 Structural Integrity Assessment
have been implemented. Large flood events, up to and including the spillway design
flood (SDF), a 500-year recurrence interval event, are expected to be able to be passed
through the project without the failure of the project structures or uncontrolled release of
the reservoir, though would likely result in some minor damage, such as the displacement
of riprap and some erosion The minimum factors of safety for stability of the structures
and embankments, as established by the Office of Dam Safety, are met or exceeded. The
dam complies with Office of Dam Safety regulations.
3.2 Studies and Analyses
The inspection of Woods Pond Dam did not reveal any significant dam safety
deficiencies with the project, or any indication that Woods Pond dam does not comply
with current OCR regulations. The following activities are recommended to maintain the
long-term structural integrity of project features:
• The foundation at the toe of the spillway toe should be surveyed at 10-year
intelvals to look for signs of erosion that might undermine the dam or abutment
(Section 2.1.2.1).
• During a period of low flow, lower the reservoir level to just below the spillway
crest (EI. 948.3) and inspect the crest and downstream face of the overflow
spillway to determine the condition of the concrete and joints, and detcnnine if
there has been any movement of the monoliths and if there is any damage to the
overflow structure itself (Section 2.1.2.1).
WO(Jd~ Pond Dam, TOI\'1I (?lLenox! Lee - 23 - Date of Inspection: NUI'emher 14, 2()07
• Survey the crest of the raceway embankment when low spots are visually
observed, but not less than every 10 years, to verify the minimum required crest
elevation is maintained (Section 2.1.3.1).
3.3 Yearly Recommendations
The dam owner currently has a schedule of routine inspection in place. It is
recommended that this schedule of monthly inspections be continued. The inspections
should, at minimum, consist of the following:
Monthly Inspection
• Visual inspection of structures to note obvious deficiencies
• Noting excessive debris in reservoir, raceway, or river channel that could affect
operations
• Inspection for vandalism
• Identification of other situations that could affect operation of the dam (beaver
dam, etc.)
• Visual inspection of the toe of the dam
• Thorough examination of wetland area downstream of west abutment
• Visual inspection of raceway closure structure
• Inspection of raceway embankment
• All items included in monthly inspections
During the inspections, particular attention should be paid to the following:
l. The wet areas at the west abutment (the downstream side) should be monitored
for any increase in seepage through or around the concrete non-overflow section
or for signs ofllluddy or cloudy flow (Section 2.1.4).
Woods Pond /J(lII/, Tmn/ a/Lellox/ LeI! - 24 - Date ofInspection: Noremht!l' 14. 20()7
2. The right (west) concrete training wall downstream of the spillway should be
monitored for signs of deterioration or stem movement due to rebar corrosion
(Section 2.1.2.2).
3. The raceway embankment downstream of the spillway should be monitored for
signs of erosion, piping, seepage and instability (Section 2.1.3.1).
4. The raceway channel, areas upstream and downstream of the raceway stoplog
sluice structure, and areas upstream and downstream of the raceway stop log sluice
structure should be monitored for trees that could block How in the raceway
channel (Section 2.1.3.1).
5. An inspection of riprap along the river channel side and raceway channel side of
the raceway embankment should be performed each spring as part of the quarterly
inspections to identify areas where high Hows or freeze/thaw action may have
caused damage.
6. Monitor erosion of concrete Wll1g wall at raceway sluice structure (Scction
2.1.3.2) and concrete repair upstream of raceway stoplog structure (Scction
2.1.2.3).
Any changes in site conditions identified during the inspections should be reviewed and
evaluated by a registered professional engineer with experience in dam inspection and
rehabilitation.
o Review and update the EAP.
3.4 Recommendations, Maintenance, and Minor Repairs
The following recommendations, maintenance itcms, and minor repairs are recommended
to be completed in the next two years:
• Remove woody vegetation in vicinity of right abutment (Section 2.1.2.2)
• Identify owner of the leaning utility pole along the raceway embankment and
inform thcm of the pole's condition(Section 2.1.3.1)
Wovds Pond Dam. Tml'l/ 0/ Lenox/ Lee - 25 - Date ofInspcction: NO\'('lIIher 14, 20m
• Monitor or remove trees on east side slope of raceway channel (Section 2.1.3.1)
• Repair/replace rip-rap on westcrn face of raceway embankment (Section 2.1.3.1).
• Remove and replace beam in bridge over stop log sluice structure if required for
access to operate the stoplogs. (Section 2.1.3.2)
• Remove debris from stoplog sluice structure (Section 2.1.3.2)
3.5 Remedial Measures
There are no remedial measures required for \Voods Pond Dam.
3.6 Alternatives
The recommendations consist primarily of mll10r repaIrs and measures that can be
addressed through routine maintenance. No alternatives have been dcveloped for these
recommendations.
3.7 Opinion of Probable Cost
The recommendations consist primarily of mll10r repairs and mcasures that can be
addressed through routine maintenance. No opinion as to the probable cost of
construction for these recommendations is required.
Woods Pond Dalll, Towll o/l.el/ox/ Lce ·26· Date ofInspection: Norem/}(!I' /4, 2007
EXHIBITS
SOURCE : USGS QUADRANGLE MAPS
GENERAL ELEC TRI C COMPANY P IT TSfiELD. MASSAC HU SETTS
WOODS POND DAI.1
<::::::::0 CHICAGO, ILLINOIS OWG .NO. EX H I BIT 1 ~--------------------------------~--------~~~--~~~~
:2
NOTES:
1. DETAILS OF WORK PERFORMED BY CONTRACTOR ARE SHOWN ON DRAWING 13<19$A-C2.
2. ACCESS TO SITE VIA CRYSTAL STREET FROM THE wEST
BRIDCE
BUlLDlNG L -l"--,
NORMAL TA!LWATER EL.9<12;t-
LOCKED
AND VALLEY ROAD FROM THE EAST. 3. ALL ELEVATIONS ARE BASED ON NATIONAL GEODETIC
VERTICAL DATUM (NCVO) OF 1929. 0<".-"0'" no.", ..,,.,, "'''"0<" 00<:"0.01:"" o.<:"c ..... ",. ,:to",,, t
;;wa
20'.
RIMAP LINED RACEwAY CHAN£t. NORMAL w'"TER n.. 9411t
NORUA.I. TAIU'ATER
3"0·
EL. 951.0
~5·
Z 'i TYPICAl SECTION NON-OVERFLOW GRAVITY SECTION
EL.
IS" 'I."
TYPICAL CROSS SECTIONS
~
yt CLOSURE SHHl'CTUR€:
1'-a'STQPlOG SlOT\ I
~~~-- - - ­
Section through Raceway Closure Structure
I~:'::~' I '-e~'-G' 3"'-6,' 3'·6' III FIELD (SEE PUI,lJ
H""0 b"'~ il'LI/i(i T El 'r IEXIST.....AlL ! . _,_ !' •.,' Tl'ilC": I
~i rl/SlAIl EL, o/.j<t,9 PrW.J,'/lUIlf1'tifLlN", _d
F" f,,:'CO>IC,FIl ....:; L__ ~_J¥~ __'. -~L-- - 'r~'-j3' TIlle ~ROOlEO £l qsa 5El, "lSa.0o\,o\xJ : I RlPiW" B ~ "'All
..rEL qSI,!j : ,
~tt~ J ~"""'" ~
'~ q.,~
I : STOP-lOO ..p" 4149 Slt:El;. ",('" : lSE:£ l'(P, " ," , L 44.0 '8li'AI!;;>-- " ~fu SHEeT f>'Ll7
4"3 J"l, 1\ I
C;-1p. • ", :!~ fa.10 OC.l ~I ,{ !
", , ,"" / ' i , - ,t~·'d"" .. '-'~.1."':-'-'J .
~.- .. ~ ..~,.- ~TTQM Of · L""""EO:
i Isr.ttwlNtL : U~~?~tt~J; LfiVP)! SL~.10 oc- · R1PRAP JI'- fit. Tm FMMljC : H EA. SHEET PIlEl j r.:i1'~8· IIlJ CY TOTAl , . V-"i" ,
,~.~ · Hr~B'
:· , TO R !( . ~roH ~ ·, j nVPI 1 ~~;eIOO· ·, •! - - -." - ~ - - _. ~ .. > ~ ...
I ~.~ ... "'"""""""'''~'''''--''''
Slct ? Ex/:sf. WPII
u
LIST OF PHOTOGRAPHS
Photo #I - View of railroad embankment, upstream of right abutment Photo #2 - Right Abutment and ogee crest, taken from Left Abutment Photo #3 - Close-up of rust stains above construction joint in right abutment downstream
training wall Photo #4 -- Vegetated area downstream of right abutment Photo #5 - View of left abutment and ogee crest, from right abutment Photo #6 - Close up of efflorescence on left abutment Photo #7 - Masonry training wall upstream of raceway closure structure and concrete
patch. Photo #8 - Raceway closure structure, looking upstream Photo #9 - Close up of stop logs in raceway closure structure Photo #I 0 - Eroded concrete in SW wingwall of raceway closure structure Photo # II - Sheetpile adjacent to SW wingwall of raceway closure structure Photo # 12 - Raceway channel, looking downstream form raceway closure structure Photo #13 - Leaning utility pole and trees along east bank of raceway channel Photo #14 - Raceway embankment, looking upstream toward raceway closure structure Photo #15 - New culvert and wingwall at south end of raceway channel Photo #16 - West slope of raceway embankment, looking downstream. Missing rip-rap
in area around red bushes. Photo # 17 - Raceway channel side of stop log sluice structure. Photo # 18 - Northeast wingwall of stoplog sluice structure. Deteriorated concrete just
above waterline. Photo #19 - Southwest wingwall ofstop log sluice structure. Photo #20 - Eroded concrete at end of southwest wingwall of stoplog sluice structure Photo #21 - River-side of stop log sluice structure
.... ~ .
SECTION
, . ~
RACEWAY CLO~ STRUCTURE
WOODS POND DAM /'
f12\ Location where Photo # was taken. Photo Location Map V Arrow indicates direction of view.
Woods Pond Dam. Town ofLenox/ Lee A2 Date ofInspection: November 14. 2007
Photo #I - View of railroad embankment, upstream of right abutment
Photo #2 - Right Abutment and ogee crest, taken from Left Abutment
Woods Pond Dam, TOlVn ojLenox! Lee A3 Date ojInspection: November 14, 2007
Photo #3 - Close-up of lUst stains above constlUction joint in right abutment downstream training wall
Photo #4 - Vegetated area downstream of right abutment
Woods Pond Dam, TOlVn ofLenox/ Lee A4 Date ofInspection: November 14, 2007
Photo #5 - View of left abutment and ogee crest, from right abutment
Photo #6 - Close up of efflorescence on left abutment
Woods Pond Dam, TOll'll 0.(Lenox/ Lee AS Date ofInspection: November 14, 2007
Photo #7 - Masonry training wall upstream of raceway closure structure and concrete patch.
Photo #8 - Raceway closure structure, looking upstream
Woods Pond Dalll, TOll'n a/Lenox! Lee A6 Date 0/ Inspection: Novell/bel' 14, 2007
Photo #9 - Close up of stoplogs in raceway closure structure
Photo #10- Eroded concrete in SW wingwall of raceway closure stl1lcture
1V00ds POlld Dalll, Tawil o/Lellox/ Lee A7 Dale o(llIspeclioll: NOl'elllber/4, 2007
Photo #II - Sheetpile adjacent to SW wingwall of raceway closure sttucture
Photo #12 - Raceway channel, looking downstream fonn raceway closure sttucture
Woods Pond Dam. Town ofLenox/ Lee A8 Dale ofinspeclioll: November 14. 2007
Photo # 13 - Leaning utility pole and trees along east bank of raceway channel
Photo # 14 - Raceway embankment, looking upstream toward raceway closure struchlre
Woods Pond Dall/. TOII'II 0/Lenox/ Lee A9 Date a/Inspection: Novell/ber J4. 200 7
Photo # 15 - New culvert and wingwall at south end of raceway channel
Photo #16 - West slope of raceway embankment, looking downstream. Missing rip-rap in area around red bushes.
Woods POlld Dall/, Tawil ofLenox/ Lee AID Dale o(Inspeclioll: Novell/bel' 14, 2007
Photo #17 - Raceway channel side of stoplog sluice structure.
Photo # 18 - NOltheast wingwall of stop log sluice structure. Deteriorated concrete just above waterline.
Woods Pond Dam, Town ofLenox/ Lee All Date ofInspection: November 14, 2007
Photo #19 - Southwest wingwall of stop log sluice stlUcture.
Photo #20 - Eroded concrete at end of southwest wingwall of stoplog sluice stlUcture
Woods Pond Dam. Town ojLenox/ Lee Al2 Date ojInspection: November 14. 2007
Photo #21 - River-side of stoplog sluice stmcture
Woods Pond Dam, Town ofLenox/ Lee AI3 Dale onl/speclion: November 14, 2007
APPENDIX B Dam Safety Inspection Checklist
DAM SAFETY INSPECTION CHECKLIST
REGISTERED: [;I] YES o NO NID ID#: MA 00731
STATE SIZE CLASSIFICATION: Lar~e STATE HAZARD CLASSIFICATION: Sis;nificant
LOCATION INFORMATION
DAM LOCATION: Vallev Road! Housatonic Street AKA NAME: N/A
USGS QUAD.: East Lee LAT.: N42020' 59" LONG.: W73° 14' 38"
DRAINAGE BASIN: Housatonic RIVER: Housatonic River
IMPOUNDMENT NAME(S): Woods Pond Reservoir
GENERAL DAM INFORMA TION
TYPE OF DAM: Gravi tyl Concrete OVERALL LENGTH (FT): 298 ft
PURPOSE OF DAM: Impound Woods Pond Reservoir NORMAL POOL STORAGE (ACRE-FT): 460 (cil El. 948.3 ft
YEAR BUILT: 1989 MAXIMUM POOL STORAGE (ACRE-FT): 5300 (cil El. 954.0 ft
STRUCTURAL HEIGHT (FT): 11.9 EL. NORMAL POOL (FT): 948.8+/- (NGVD 1929)
HYDRAULIC HEIGHT (FT): 11.9 EL. MAXIMUM POOL (FT): 955.8, Outflow = 12J 00 cfs (500-;(r flood)
FOR INTERNAL MADCR USE ONLY
FOLLOW-UP INSPECTION REQUIRED: DYES o NO CONDITIONAL LETTER: DYES o NO
--
NID ID#:
MA 00731
INSPECTION SUMMARY
DATE OF INSPECTION: November 14,2007 DATE OF PREVIOUS INSPECTION: November 29, 2005
TEMPERATURElWEATHER:
PREVIOUS DCR PHASE I:
GOOD "'1 DATE OF LAST REHABILITATION: 1991
EL. POOL DURING INSP.: 948.8 +/­ EL. TAILWATER DURING INSP.: 941.8+1­
PERSONS PRESENT AT INSPECTION
Mario Finis Matt Sorrell
REPRESENTING MWH MWH
~
5 .,.' 5 ...E2) LEVEL OF MAINTENANCE E9) SPILLWAY DESIGN FLOOD c:;..;..-d --""
---~
E5) EMBANKMENT CONDITION 4 ... ROADWAY OVER CREST o YES[] NO
E6) CONCRETE CONDITION 5 ...J BRlDGE NEAR DAM DYES [] NO
-;lE7) LOW-LEVEL OUTLET CAP 4 ----j
SIGNATURE OF INSPECTING ENGINEER:
Woods Pond Dam, Town of Lenox! Lee 62 Date of Inspection November 14, 2007
NAME OF DAM: Woods Pond Dam STATE ID #: 1-2-150-11
NID ID #: MA 00731
OWNER: ORGANIZATION General Electric CARETAKER: ORGANIZATION General Electric NAMEITlTLE Kevin Moonc:t NAMEITlTLE Kevin Moone~ STREET 159 Plastics A venue. Bld~. 59 STREET 159 Plastics Avenue, Bld~. 59 TOWN. STATE. ZIP Pittsfield. MA 01201 TOWN. STATE. ZIP Pittsfield. MA 01201 PHONE (413) 448-5910 PHONE (4\3) 448-59\0 FAX (413) 494-5024 FAX (413) 494-5024 EMAIL kevin mooney((i)ge_com EMAIL kevin.moonev@ge.com
OWNER TYPE Private
PRIMARY SPILL WAY TYPE Overflow - Ogee
SPILLWAY LENGTH (FT) 140 SPILLWAY CAPACITY (CFS) 12.1 00 efs (aJ El. 955.8 ft
AUXILIARY SPILLWAY TYPE N/A AUX. SPILLWAY CAPACITY (CFS) N/A
NUMBER OF OUTLETS \ OUTLET(S) CAPACITY (CFS) 850 efs (aJ El. 955.8 ft (No stoplogs installed)
TYPE OF OUTLETS Controlled Raceway TOTAL DISCHARGE CAPACITY (CFS) 12.950 efs «4 El. 955.8 ft
DRAINAGE AREQ (SQ Ml) \70 SPILLWAY DESIGN FLOOD (PERIOD/CFS) 500 ~ear flood! 12.100 efs
HAS DAM BEEN BREACHED OR OVERTOPPED 0 YES D NO IF YES. PROVIDE DATE(S) N/A
FISH LADDER (LIST TYPE IF PRESENT) N/A
DOES CREST SUPPORT PUBLIC ROAD? DYES D NO IF YES. ROAD NAME:
PUBLIC BRIDGE WITHIN 50' OF DAM? DYES D NO IF YES. ROAD/BRIDGE NAME:
Woods Pond Dam, Town of Lenox/ Lee 83 Date of Inspection: November 14, 2007
Embankment Crest
INSPECTION DATE: November 14,2007 NlD lD #: MA 00731
EMBANKMENT (Raceway)
SURFACE TYPE SURFACE CRACKING SINKHOLES, ANIMAL BURROWS VERTICAL ALIGNMENT (DEPRESSIONS) HORIZONTAL ALIGNMENT RUTS AND/OR PUDDLES VEGETATION (PRESENCE/CONDITION) ABUTMENT CONTACT
Grass/ Gravel x None observed x None observed x None observed x OK x Some uneveness in crest noted x Minor x OK x
- -----­
Woods Pond Dam. Town of Lenox/ Lee B4 Date of Inspection: November 14, 2007
Downstream Side
INSPECTION DATE: November 14,2007 NID ID#: MA0073!
EMBANKMENT (West Side)
AREA INSPECTED CONDITION OBSERVATIONS
WET AREAS (NO FLOW) None SEEPAGE None SLIDE, SLOUGH, SCARP None
D/S EMB,-ABUTMENT CONTACT OK SLOPE SINKHOLE/ANIMAL BURROWS None
EROSION Exposed Earth, area aproximately 35 ft x 5 ft UNUSUAL MOVEMENT None VEGETATION (PRESENCE/CONDITION) Shrubs/ bushes on West face
ADDITIONAL COMMENTS: Embankment entireI;t riE-raEEed Small earth eXQosure in vicini!):: of shrubs
x x x x x
x
• I ~ "
x
x
Woods Pond Dam, Town of Lenox/ Lee B5 Date of Inspection: November 14, 2007
Upstream side
INSPECTION DATE: November 14,2007 NlD lD#: MA 00731
EMBANKMENT
SUDE, SLOUGH, SCARP SLOPE PROTECTION TYPE AND CONDo SINKHOLE/ANIMAL BURROWS EMB.-ABUTMENT CONTACT EROSION UNUSUAL MOVEMENT VEGETATION (PRESENCE/CONDITION)
None x None x None x OK x
None x
None x None x
ADDITIONAL COMMENTS: River side rie-raEEed for fulllen"th Land side pal}:ially rip-rapped. Erosion alongl~~_4~i4~9~ in non-critical areas~
Woods Pond Dam, Town of Lenox! Lee B6 Date of Inspection: November 14, 2007
Instrumentation
EMBANKMENT
PIEZOMETERS OBSERVATION WELLS STAFF GAGE AND RECORDER WEIRS INCLINOMETERS SURVEY MONUMENTS DRAINS FREQUENCY OF READINGS LOCATION OF READINGS
-
x x x
ADDITIONAL COMMENTS: Three piezometers located in raceway embankment along crest continue to monitor as part of regular O&M practice
Woods Pond Dam, Town of Lenox! Lee B7 Date of Inspection: November 14, 2007
Masonry Walls
UPSTREAM ANDIOR DOWNSTREAM MASONRY WALLS
AREA INSPECTED CONDITION OBSERVATIONS
WALL TYPE Concn:tl.! WALL ALIGNMENT OK WALL CONDITION Some efflorescence inleft training wall: Minor spalling in right training wall: Open ioint in right wall
DIS HEIGHT: TOP OF WALL TO MUDLINE min: 10 ft I max: 14 ft I aV<7: 12 ft WALLS SEEPAGE OR LEAKAGE None
ABUTMENT CONTACT Good EROSION/SINKHOLES BEHIND WALL None ANIMAL BURROWS None UNUSUAL MOVEMENT None WET AREAS AT TOE OF WALL None
ADDITiONAL COMMENTS: Comments eertain to training walls on either side ofsEillway, immediately downstream of dam Stains below the ioint between the stem and the footing in the right training wall. Woody vegetation should be removed from the right abutment area There is a 3!4" gae between the concrete and the shee,!Eiles in the left abutment arca
x
x
" ~
Woods Pond Dam, Town of Lenox! Lee B8 Date of Inspection: November 14, 2007
Downstream Area
INSPECTION DATE: November 14.2007 NID ID #: MA 00731
DOWNSTREAM AREA
~
" "
ABUTMENT LEAKAGE FOUNDATION SEEPAGE SLIDE.SLOUGH.sCARP WEIRS DRAINAGE SYSTEM INSTRUMENTATION VEGETATION ACCESSIBILITY
None x None x None x n1a x nla x n1a x Yes x OK x
DOWNSTREAM HAZARD DESCRIPTION Significant
DATE OF LAST EAP UPDATE 2006
ADDITIONAL COMMENTS: Downstream of West Abutment is a wetland area with constant flow and wetland vegetation. Larger woody veo-etation to be removed.
Woods Pond Dam, Town of Lenox! Lee B9 Date of Inspection: November 14, 2007
Misc.
INSPECTION DATE: November 14.2007
RESERVOIR DEPTH (AVG) RESERVOIR SHORELINE RESERVOIR SLOPES
MISe. ACCESS ROADS SECURITY DEVICES VANDALISM OR TRESPASS A V AILABILITY OF PLANS A V AILABILITY OF DESIGN CALCS A V AILABILITY OF EAP/LAST UPDATE AVAILABILITY OF O&M MANUAL CARET AKERJOWNER A V AILABLE CONFINED SPACE ENTRY REQUIRED
ADDITIONAL COMMENTS: ------­
STATE ID#:
NID ID#:
8ft NothinO" unusual Nothina unusual PassabIe Lock present and intact
1-2-150-11
OBSERVATIONS
YES: b! NO: YES: [] NO: YES: [] NO: YES: [] NO: YES: [] NO: YES: [] NO: YES: 0 NO:
[] WHAT: 0 DATE: 1989-1991
0 DATE: 1989-1991 0 DATE: 2006 0 DATE: 2005 0 DATE: [] PURPOSE:
Woods Pond Dam. Town of Lenox! Lee 810 Date of Inspection: November 14. 2007
Primary Spillway
INSPECTION DATE: November 14.2007 NlD lD #: MA 00731
PRIMARY SPILL WAY
INSPECTED CONDITION OBSERVATIONS it "
SPILLWAY TYPE Overflow Weir x WEIR TYPE Ogee x SPILLWAY CONDITION Good x
SPILLWAY TRAINING WALLS See masonry walls x SPILLWAY CONTROLS AND CONDITION Uncontrolled x UNUSUAL MOVEMENT None x APPROACH AREA Nothing unusuaL minor debris x DISCHARGE AREA Clear. nothing unusual x DEBRIS A few larcre logs on spillway crest x WATER LEVEL AT TIME OF INSPECTION El. 948.8 ft. approximate depth of flow of6" over spillway x
ADDITIONAL COMMENTS: Lower reservoir level and inseect downstream concrete face with no flow ifeossible Monitor deeression at toe eve!): 1 0 ~ears
Woods Pond Dam, Town of Lenox! Lee 811 Date of Inspection: November 14, 2007
Auxiliary Spillway
AUXILIARY SPILLWAY
AREA INSPECTED
SPILLWAY
CONDITION
SPILLWAY TYPE WEIR TYPE SPILL WA Y CONDITION TRAINING WALLS SPILLW A Y CONTROLS AND CONDITION UNUSUAL MOVEMENT APPROACH AREA DISCHARGE AREA DEBRIS WATER LEVEL AT TIME OF INSPECTION
OBSERVATIONS
n1a
ADDITIONAL COMMENTS: