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Fitzgerald Lake Dam Inspection Evaluation Report 6.9.2004N. a /Eva A - PREFACE The purpose of this report is to perform a preliminary assessment of the general condition of Fitzgerald Pond Dam and to identify conditions which may pose a hazard to downstream lives and property. The preliminary determination of the dam's condition is based upon historical data and an on -site visual inspection. A, more detailed analysis based upon geotechnical probes, seepage monitoring, ground surveys and detailed computational models is beyond the scope of this report. Note that the reported condition of the dam is based upon on -site observations and data made available to the inspection team at the time of the inspection. Flow into the drop inlet prevented detailed observations of the inlet. Lowering of the impoundment water surface for the inspection was not feasible. It is important to recognize that a dam's condition is in a constant state of change. External forces, such as freeze /thaw cycles, vegetation, animal burrows, vehicular traffic, flood flow overtopping, and lack of maintenance as well as internal forces, such as foundation settlement, concrete deterioration, piping and leeching of construction materials, adversely alter a dam's stability. The present condition of the dam continues to change into the future. Continued observation through ongoing inspections and routine maintenance is required to detect unsafe dams and protect the public. 7:%NWOi19%D —I.Tp do.APfef=�W.dm - _ �t 1 Project Data yr. r ! Lake Area 41 aches (0.06 sq. miles): 10 Area Drainage g 884 acres (1.38 sq. miles) VOL e &t @ids ,�1 r' ? -.. -i i. ����� } �•�,�,li dI ? I ; r / o _ d it ■ f IS - -,.` �fJ(!� %} •G�. � &PC71S; �gv _ yli 1 r, I Y(�e // I , / 7 SITE LOCATION y44 Sch LOGIC° `\ • ti EMORIAL �,+ P M �'\ r - I: 1 J !i _i '��f a fl J PARK Pit - ' / � /�j i '�, G Pavel 01 _ I ; •, J'� � i °l �5 �.��� /c i lr ��� r - 'y� Jr - .! 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J � :'S 247 S 8t�, $ rc-._ R' • �" �. •: ,�' Gem &nn rs, rp Instal te1 x/ ST ,` �4G�� -_i� •' )J �`• .+ •�•' i� ' AR]tlrrar "l� ..., %Fi r 4,S' r� yr -� �� r • +r BASED ON USGS TOPOGRAPHIC MAPS FOR SITE MAP & CONTRIBUTARY EASTHAMPTON & WILLIAMSBURG, MA DRAINAGE AREA QUADRANGLES REVISED 1979 & 1990 10 -FOOT AND 3 -METER FITZGERALD POND DAM CONTOUR INTERVALS RESPECTIVELY N CITY OF NORTHAMPTON NORTHAMPTON, MA � MASS. yj+' E , w Tighe &Band SCALE: 1:25000 MAY 2004 N0519.apr TABLE OF CONTENTS Tighe &Bond PREFACE SITE Lochs SECTION 9 PROJECT DESCRIPTION 1.1 General ................................................. ............................1 -1 1.1.1 Authority ..................................... ............................1 -1 1.1.2 Purpose of Work ..................... ............................... 1 -1 1.1.3 Definitions ............................... ............................... 1 -1 1.2 Description of Project .......................... 1.2.1 Location ...................................................... ............ 1 -1 1.2.2 Owner and Operator ............... ................................ 1-2 1.2.3 Purpose of Dam ... ............................... ................... 1-2 1.2.4 Description of Dam and Appurtenances ................. 1 -2 1.2.5 Operations and Maintenance 126 DCR Size Classification ......................................... 1-3 1.2.7 DCR Hazard Classification ...... ............................... 1 -3 1.3 Engineering Data ............................... ............................... 1 -3 SECTION 2 VISUAL INSPECTION 2.1 General Findings ................................ ............................... 2 -1 2.1.1 Dam ............................................ ............................2 -1 2.1.2 Appurtenant Structures ........... ............................... 2 -1 2.1.3 Downstream Area .................... ............................... 2 -2 2.1.4 Reservoir Area ........................ ............................... 2 -2 2.2 Caretaker Interview ............................ ............................... 2 -2 SECTION 3 OPERATION AND MAINTENANCE PROCEDURES 3.1 Operational Procedures ..................... ............................... 3 -1 3.2 Maintenance of Dam and Operating Facilities .................. 3 -1 3.3 Emergency Warning System /Emergency Action Plan ...... 3 -1 SECTION 4 HYDROLOGIC /HYDRAUL'1C DATA 4.1 Hydrologic /Hydraulic Data .................. ............................... 4 -1 SECTION 5 STRUCTURAL STABILITY /OVERTOPPING POTENTIAL 5.1 Structural Stability .............................. ............................... 5 -1 5.2 Overtopping Potential ........................ ............................... 5 -1 TABLE OF CONTENTS T1ghe&Bond SECTION 6 ASSESSMENTS AND RECOMMENDATIONS 6.1 Assessments ......................................... ............................6 -1 6.2 Recommendations ............................. ............................... 6 -1 6.3 Alternatives ........................................ ............................... 6 -1 6.4 Cost Estimates ................................... ............................... 6 -1 APPENDICIES APPENDIX A PLAN OF DAM APPENDIX B FIGURE AND PHOTOGRAPHS APPENDIX C INSPECTION CHECKLIST APPENDIX D HYDRAULIC DATA AND COMPUTATIONS APPENDIX E PREVIOUS INSPECTION REPORTS APPENDIX F DEFINITIONS APPENDIX G DAM SAFETY DATA SHEET J:1N1N05191REP0RT1Fitzgera1d LakeDamInspectionEvaluation Text.doe Fitzgerald Pond Dam - Inspection /Evaluation Report SECTION 1 PROJECT DESCRIPTION Ticghe &Bond 1.1 GENERAL 1.1.1 Authority Tighe & Bond Consulting Engineers {T &B} has been retained by the City of Northampton to perform a visual dam inspection and prepare a report detailing our findings. The inspection was carried out in accordance with Chapter 253, Section 44 through 50, amended by Chapter 330 of the Massachusetts General Laws, and with 302 CMR 10.00. 1.1.2 Purpose of Work The main purpose of this report is to evaluate the current condition of Fitzgerald Pond Dam and to identify the need for any immediate measures to avoid any threat to public safety or property damage. The report will also be used as a comparison with prior inspections to monitor the dam conditions, and to identify any progressive deterioration that will require repairs. As part of our report, we have completed the following scope of services: 1. Site reconnaissance to observe and document surficial dam conditions and any other signs of seepage, failure, or movement in the dam and related structures. 2. Reviewed available data from the City of Northampton files provided to Tighe & Bond to obtain information on the dam construction, maintenance, and operations. 3. Prepared this report summarizing our findings, conclusions, and recommendations. 1.1.3 Definitions Definitions of commonly used terms associated with dams are presented in Appendix E. 1.2 DESCRIPTION OF PROJECT 1.2.1 Location The Fitzgerald Pond Dam is located in Northampton, Hampshire County, Massachusetts, The City of Northampton owns and operates the dam. See the site locus preceding this section. Fitzgerald Pond Dam - Inspection /Evaluation Report 1 -1 SECTION 1 PROJECT DESCRIPTION I ighe &Band 1.2.2 Owner and Operator Fitzgerald Pond Dam is owned and operated by the City of Northampton. The contact information for the department is listed below: Wayne Feiden AICP Office of Planning and Development City of Northampton 210 Main Street Northampton, MA 01060 (413)- 587 -1266 1.2.3 Purpose of Dam The Fitzgerald Pond Dam provides a recreational impoundment in a conservation area within the City of Northampton. 1.2.4 Description of Dam and Appurtenances Dam The Fitzgerald Pond Dam is an earthen fill dam. The total height of the dam is 19.5 ft. with a crest width of 15 ft. A narrow footpath runs approximately down the center of the crest. The upstream and downstream slopes are vegetated, with riprap slope protection at the waterline on the upstream side. The slope of both sides is approximately 1.51-1 to 1V. Appurtenant Structures The spillway is a 66 in. diameter drop inlet with a galvanized steel debris shield. The outlet pipe is 42 in. diameter and passes through the dam from the drop inlet to a stilling pool at the toe. A concrete headwall is near the end of the outlet. Two core drains also terminate at the headwall. The emergency spillway is located at the left abutment. It is 60 ft. in length, grass lined and discharges about 150 feet downstream of the dam. Downstream Area The outlet pipe discharges to a riprap lined stilling pool. The outlet of the stilling pool is also riprap lined, then tapers to a natural stream bed. 1.2.5 Operations and Maintenance An Operations and Maintenance plan exists for this dam, but it appears that it has not been implemented. From the visual inspection, it appears that there are no regular Fitzgerald Pond Dam - Inspection /Evaluation Report 1 -2 SECTION 1 PROJECT DESCRIPTION 1 ig a &Bond maintenance procedures in place, as the dam and surrounding areas are overgrown with low brush. 1.2.6 DCR Size Classification The Fitzgerald Pond Dam has a maximum storage capacity of 420 acre -ft. and a height of 19.5 ft, The Department of Conservation and Recreation size designation for this structure is Intermediate, per the 302 CMR 10.0 Dam Safety Regulations. 1.2.7 DCR Hazard Classification In accordance with the Department of Conservation and Recreation classifications, under 302 CMR, Dam Safety Rules and Regulations, the Fitzgerald Pond Dam is classified as a Low (Class III) hazard structure. A dam failure would cause minimal damage to downstream property and loss of life is not expected. Based on the Low (Class Ill) hazard classification, the required inspection frequency for Fitzgerald Pond Dam is every 10 years under 302 CMR 10.00 Dam Safety regulations. 1.3 ENGINEERING DATA The following information was gathered from the original design plans, previous DCR Chapter 253 Permit application dated 1998 and Record Plans for dam improvements dated 1998. All documents noted are on file at the Office of Planning and Development, City of Northampton, MA and at the office of Tighe & Bond, Inc., Westfield, MA. Type of Dam: Earthfill Length: 540 feet Height: 19.5 feet Top Width: 15 feet Normal Pool Elevation (Assumed): 96.5 feet Top of Dam Elevation (Assumed): 101.5 feet Drainage Area: 1.38 square miles Reservoir: Normal Pool Surface Area: 42 acres Maximum Storage: 420 acre -feet Maximum Pool Surface Area: 50 acres Normal Spillway: Type: Drop Inlet Diameter of Drop Inlet: 66 in. Diameter of Outlet Pipe: 42 in. Emergency Spillway: Crest Elevation (Assumed): 99.00 feet Crest Length 60 feet Fitzgerald Pond Lam - Inspection /Evaluation Report 1 -3 SECTION 2 VISUAL INSPECTION Tighe &Bond 2.1 GENERAL FINDINGS Fitzgerald Pond Dam was visually inspected on October 22, 2003. A copy of the field inspection checklist is included in Appendix C. In general, the dam was very difficult to inspect due to the excessive low brush growth. It appears to be in fair condition, from the limited visual inspection. Our findings are detailed below. 2.1.1 Dam The upstream slope of the Fitzgerald Pond Dam is not maintained in its entirety (Photo 1). It was difficult to discern any areas of concern on the slope due to the excessive brush and grass growth (Photo 5). The riprap slope protection at the waterline is in good condition and covers the length of the dam. The horizontal alignment of the dam crest is good. However, the crest is very overgrown, which made it difficult to observe any erosion, sink holes, or animal burrows. A narrow footpath connecting walking trails on each side of the dam runs along the crest. The downstream slope is overgrown with excessive brush and grass growth as well (Photo 8). It was undetermined as to whether there are any animal burrows, sinkholes, or other problems with the slope. The toe of the slope was wet on both sides of the outlet. It is unclear at this time whether this is seepage or if the ground was saturated from recent rain storms. The abutment contacts on both sides of the dam appear to be in good condition. 2.1.2 Appurtenant Structures The drop inlet debris shield is in good condition (Photo 2) . The outlet pipe and headwall are also in good condition (Photo 7). The core drains located on either side of the outlet pipe are also in good condition. Some water was observed in the right drain, while the left was dry. The riprap lining the stilling pool and channel is in good condition (Photo 6). The emergency spillway is generally in good condition (Photos 3 and 4). There is excessive brush and grass growth, which made it difficult to discern any possible deficiencies. Fitzgerald Pond Dam - Inspection /Evaluation Report 2 -1 SECTION 2 VISUAL INSP €CTION Tighe &Bond 2.1.3 Downstream Area The downstream channel is in good condition. The stream channel is free of debris and is free flowing. 2.1.4 Reservoir Area The pond banks appear stable and well vegetated. 2.2 CARETAKER INTERVIEW No caretaker has been formally assigned to the Fitzgerald Pond Dam. It is unclear which Board, Department, or Commission of the City of Northampton is responsible for maintaining the dam. Previously, the Office of Planning and Development oversaw the improvements to the dam. Fitzgerald Pond Dam - Inspection /Evaluation Report 2 -2 SECTION 3 OPERATION AND MAINTENANCE PROCEDURES Tighe &Bond 3.1 OPERATIONAL PROCEDURES There are written operational procedures in place for the Fitzgerald Pond Dam but they have not been implemented. 3.2 MAINTENANCE OF DAM AND OPERATING FACILITIES The dam and areas immediately surrounding the pond do not appear to be maintained. This is apparent from the excessive overgrowth on the dam and surrounding areas. 3.3 EMERGENCY WARNING SYSTEM /EMERGENCY ACTION PLAN There is no Emergency Action Plan (EAP) or early warning system in effect for the Fitzgerald Pond Dam. According to Massachusetts General Law 253, Section 44, Chapter 302 CMR 10.00, low hazard dams are not required to have an Emergency Action Plan on file with DCR. Fitzgerald Pond Dam - Inspection /Evaluation Report 3 -1 SECTION 4 HYDROLOGICIHYDRAULIG DATA Tighe &Bond 4.1 HYDROLOGIC/HYDRAULIC DATA As part of the April 1998 DCR Chapter 253 permit application, Tighe & Bond prepared a hydraulic /hydrologic analysis for the dam. Based upon the DCR Dam Safety size and hazard classifications, the design storm event was determined to be the 100 -year storm. A rainfall intensity of 4.5 in. was used for the analysis. The percent runoff calculated was 66.8 at 2.97 in. Below are more pertinent data. Peak outflow: 250.3 cfs Maximum Flood Level Elevation: 99.4 ft. Maximum Reservoir Elevation: 99.4 ft. Maximum Depth Over Emergency Spillway: 0.39 ft. Maximum Storage: 402 acre -ft. Fitzgerald Pond Dam - Inspection /Evaluation Report 4 -1 SECTION 5 STRUCTURAL STABILITY/ OVERTOPPING POTENTIAL Tighe &Bond 5.1 STRUCTURAL STABILITY A stability analysis for Fitzgerald Pond Dam was not within the scope of this report. From observations made in the field, the conditions at the dam appear stable and do not warrant an analysis at this time. 5.2 OVERTOPPING POTENTIAL The information presented in the 1998 DCR Chapter 253 permit application shows that the 100 -year flood would result in the emergency spillway flowing 0.39 ft. deep during that event. This information indicates that the freeboard of 2.1 ft. during the design storm is approximate and that the dam will not be overtopped. Fitzgerald Pond Dam - Inspection /Evaluation Report 5 -1 SECTION 6 ASSESSMENTS AND RECOMMENDATIONS 6.1 ASSESSMENTS Tighe &Bond The overall rating for the Fitzgerald Pond Dam is fair. The major deficiency is the presence of excessive amounts of brush and grass, which made it difficult to perform a visual inspection. 6.2 RECOMMENDATIONS It is recommended that the City of Northampton carry out the following: 1. The existing Operations and Maintenance plan should be implemented for the Fitzgerald Pond Dam. This will ensure that operating and maintenance procedures remain consistent and are carried out annually. 2. Clear the brush on the upstream and downstream slopes, emergency spillway, and crest. 3. Conduct a more thorough inspection once the structure has been cleared. 4. Monitor seepage at the core drain outlet. The City should designate personnel from the Department of Public Works to monitor the seepage. 5. The saturated conditions noted at the toe of the dam should be monitored. The City should designate personnel from the Department of Public Works to monitor the saturated areas. 6.3 ALTERNATIVES No alternatives are offered for the recommendations at this site. 6.4 COST ESTIMATES The following cost estimates have been determined for the recommendations noted above. The estimates are based upon limited investigations consistent with the scope of this report. Further investigations into deficiencies listed may be necessary and may result in the scope of work being more involved, resulting in higher costs. The City of Northampton Public Works Department staff can carry out some of the tasks. Those tasks are designated as Force Account. Fitzgerald fond Dam - Inspection /Evaluation Report 6 -1 SECTION 6 ASSESSIUIENTS AND RECOMMENDATIONS Tighe &Bond Please note the information shown below, which included estimated labor and material costs, is based on limited investigations and is provided for general information only. Recommendations 1. Implement O&M plan and clear all brush and vegetation 2. Re- inspect dam after dam is cleared of brush 3. Monitor seepage at the core drain outlets and at toe of dam Total JAWN05191REPORT\Fitzgeraid LakeDaminspectionEvaluation Text.doc Total Force Account $1,000 Force Account $1,000 Fitzgerald Pond Dam - Inspection /Evaluation Report 6 -2 APPENDIX A PLAN OF DAM U) ) xVM J «as ;J 9 w m E § w § e C/) w ® Z U §[ ZE O« p? a / j) w ± q # §% 0 < °° 2 WZ °a i \ Q o dm EL N z K 2 < /§ I c m \ ® \ { O / , 2 0 \ \ � ƒ kw5-3 � . \ \ � o � O � / ® ƒ / � m � �^ MRS � 4 � � / \ L / / r r / ! r / . r r / \ APPENDIX B PHOTO LOCATIONS AND PHOTOGRAPHS U) § xd 7ZJd xJN3 J / i E < « / \ 2 3 °( ~x \ (n \ \ 0 §\ / bz °£ : / LLJ / /� \ 7 j LLj E I c u ® \ 0 ƒ Z w /w ® 2 ° \ � / © 6 \ ƒ � \ 0 (ZIA O / 0 \ E � - ¢ - � O � � r W NN O \ m Q \ / � . r r � r ! � . � ol \ Tighe & Bond Photo I - Crest - Looking Left from Right Abutment Photo 2 - Drop Inlet - From Crest Looking Upstream Fitzgerald Pond Darn Page I Tighe & Bond Photo 3 - Emergency Spillway - Looking Upstream from Middle of Spillway Photo 4 - Downstream Slope - From Emergency Spillway Looking Right Fitzgerald Pond Dam Page 2 Tighe & Bond A �1} i ,� •iJ': tom' L Photo b - Outlet Stilling Pool - Looping Downstream Fitzgerald Pond Dam Page 3 Tighe & Bond T r�y .a kk if' 4 r � -Too Photo 7 - Outlet Pipe and Headwall - Looking Upstream from Left Photo 8 - Downstream Slope - Looking Left Fitzgerald Pond Dam Page 4 APPENDIX C INSPECTION CHECKLIST �" W cd o u 0 r�o 0 � a C o p o w \ Cam-+ W o� 0� z o U C O z cn w Q o � 4.1 �4 0 C U b r�i Zi O o o a w ° cu o H. oo Ln bA "H�� �, � s�-i •on � Q con U H H, LOO U, a Qc w W H W U 0 <C Q H W UH L va LI) O W 2IIVd�2I m CD �Q nVDUSAAM N �U IMLINOW W d A z O W LO LO z O " � a o °o 7 o0 N v o cz c� c 0 a , cd w .a A b o a o o LO Uaxc�� I V)0C*,) wall ° � � � � � � C? c� m r kn �a e oo rn O C-4 W o cc mLvousaAm CD W N C.7 o Holixow A z 0 U a rr� a v L � O Ln °Q CID a Ly^ LLA O Q v V Q Q 0 Vl �� ��'wazw zzzzzzz W a A Lon W ✓ .3 Ln a a ° ° z V pv �6© p w o w o U ? Q Lo vn cn in 1 c_i a Q i ii N N N N N N N N N all m M cNn M can an d ~ a © z Lo Ca �4 OZ W lTIdda2I -T�T 7 MLVOLLSdAM m W N U HOJJNON �i F- 0 H U z O W O C W U A � w¢ U a¢, U N pQ w �uw uz O Lo O Q W Z Q U O a U VI W W � �� w H vii U U O w U A W aaqq �C O w a cn A O W A A ¢ A W WW cz U ¢ W Lo O Ol`i TM1i11 m m m O Nt -t d - � O A a p d W� L A W U Ntjw - doliAIOLH W A z U a z O N b 'd b °o a � d � Q3 f zzzz 'zzzzzz c�c� w A o o z e� rn w Q 'ONNTaLI t- co � o Ln V') kn tn vi w �o �o %a n b rn A mvm o UW W aLVOUSAAM a r, C,? '90.LIRON W Q z O E-� U a W � rn O �i a 6 U a o U O O O¢ Q D 21 O 43 O z CS w A a b O V] F � 0 � Q z W ND Q U p Ln© Q a H H o z o �x o OhI Y1i�LI N m �t �n r oa o, o o0 0o N ao 0o m CC? a Q i � o w ul�a�x N � o HOUKOW F� A O H W a Z a A as o � O� o zz z - z z z z Z, w Q w d 0 Z z Z H Z z Z Ln Z Q Ln 'OBI LI ul d o0 'n 00 oU t oD oo o0 rn Co. O Gh C7T N U cri CS U +n tT O� t rT oo T rn Ce o o U Q w Ln w z 0 H n 0 N 0 Q z 0 x v A p a r� w o Q z o x � DO Q U O CM4 PLI b c� U bA f� v Q �A 's A O U W � a W C� a t/a z W U � z o � Z U O CM4 PLI b c� U bA f� v Q �A 's APPENDIX D HYDROLOGIC DATA AND COMPUTATIONS See the DCR Chapter 253 permit application dated April 1998 prepared by Tighe & Bond, Inc., Westfield, MA on file at the Office of Dam Safety. APPENDIX E PREVIOUS INSPECTION REPORTS • No DCR Inspection /Evaluation Reports have been prepared since the implementation of improvements in 1999. DEFINITIONS Appendix F - Definitions To provide a better understanding of this report, definitions of commonly used terms associated with dams are provided below. The terms are presented under the following common categories: 1) Orientation; 2) Dam components; 3) Size classification; 4) Hazard classification; and 5) General. Orientation Upstream -- Shall mean the side of the dam that borders the impoundment. Downstream - Shall mean the high side of the dam, the side opposite the upstream side. Right - Shall mean the area to the right when looking in the downstream direction. Left - Shall mean the area to the left when looking in the downstream direction. Dam Components Dam - Shall mean any artificial barrier, including appurtenant works, which impounds or diverts water. Embankment - Shall mean the fill material, usually earth or rock, placed with sloping sides, such that it forms a barrier that impounds water. Crest - Shall mean the top of the dam, usually provides a road or path across the dam. Abutment -- Shall mean the top of the dam, usually provides a road or path across the dam. Appurtenant Works -- Shall mean any ancillary feature of a dam and shall include but not be limited to, such structures as training walls, spillways, either in the dam or separate there from and low level outlet works; also water conduits such as tunnels, channels, pipelines, or penstocks, either through the dam or its abutments. Riprap - Shall mean a loose assemblage of broken stones erected in water or soft ground as erosion protection. Toe - Shall mean the protruding base of the dam on the downstream side either natural or man -made. Weir - Shall mean the top of the spillway where the water flows to the downstream side Size Classification (as listed in Commonwealth of Massachusetts, 302 CMR Dam Safety Rules and Regulations, revised 12127/96) Large - Structure with a height greater than 40 feet and /or a storage capacity greater than 1,000 acre -feet. Intermediate - Structure with a height between 15 and 40 feet and /or a storage capacity of 50 to 1,000 acre -feet. Small - Structure with a height between 6 and 15 feet and /or a storage capacity of 15 to 50 acre -feet. Non - Jurisdictional - Structure less than 6 feet in height and having a storage capacity of less than 15 acre -feet. Hazard Classification (as listed in Commonwealth of Massachusetts, 302 CMR Dam Safety Rules and Regulations, revised 12/27/96) High Hazard (Class 1) - Shall mean dams located where failure or misoperation will likely cause loss of life and/or serious damage to homes, industrial or commercial facilities, important public utilities, or major transportation arteries. Significant Hazard (Class H) - Shall mean darns located where failure or misoperation may cause loss of life and /or damage to homes, industrial or commercial facilities, secondary highways or railroads, or cause the interruption of the use or service of important facilities. Low Hazard (Class III) - Darns located where failure or misoperation may cause minimal property damage to others and loss of life is not expected. General DCR - Department of Conservation and Recreation, formerly the Department of Environmental Management (DEM). EAP - Emergency Action Plan; shall mean a predetermined plan of action to be taken to reduce the potential for property damage and /or loss of life in an area affected by an impending dam break. O &M Manual - Operations and Maintenance Manual; document identifying routine maintenance and operational procedures under normal and storm conditions. Normal Pool - shall mean the elevation of the impoundment during normal operating conditions. Acre -foot - shall mean a volume equal to one foot of water over a one -acre area. Height of Dam - shall mean the vertical distance from the lowest portion of the natural ground, including any stream channel, along the downstream toe of the dam to the crest of the dam. Spillway Design Flood (SDF) - shall mean the flood used in the design of a dam and its appurtenant works particularly for sizing the spillway and outlet works. J:\D\Daim\DefinRions.doc APPENDIX G DAM SAFETY DETAIL SHEET 0 J N Gb A A 0 W �i b O 7g 0 td a� W b � o o � o 00 c� CD o 9:1 b ca A z 0 a 0 0 o b N m p W d � a n c � c, cli 0 �' ° .� m N m Q ai ai rA ai W of a Lv po T: a b � o o � o 00 c� CD o 9:1 b ca A z o U U u b 9 9 0 a 0 o b N m p W d � a n c � c, cli 0 �' ° .� m N m Q ai ai rA ai W of z P4 ° Q) a � Ca o ,d N Co L�41 ° P� R, w° a U N «a rl rn co W) ILI en A ++ p ai a •s.: U +� hi o U U u b 9 9 0 Commonwealth of Massachusetts Department of Environmental Management Office of Dam Safety. P.O. Box 173 Old Common Road Lancaster, MA 01523 Gentlemen: -5 -14 ary 2, 1999 Tighe &Bond Consulting Engineers Environmental Specialists Re: Fitzgerald Lake Dam Northampton, MA Dam 1 D No. 2- 8- 214 -17 On behalf of the City of Northampton, we wish to inform the Office of Dam Safety that the dam rehabilitation work in accordance with the Application For Authorization To Construct or Alter Reservoir, Reservoir Dam or Mill Dam, under M.G.L. Chapter 253, dated , March 9, 1998, has been completed in accordance with 302 CMR - Darn Safety Regulations. The construction work was carried out by Warner Brothers Construction Co., Inc of Sunderland, Massachusetts under Contract with the City of Northampton, through the Office of Planning and Development. The construction work was overseen by Tighe & Bond's full time resident engineer and all materials of construction were tested in accordance with the specifications for the project. During the progress of the work, no unusual events or conditions were encountered that would have resulted in changes to the proposed design. At the time of this writing, all punch list items are complete. Appended to this certification, please find two (2) sets of a series of photographs showing preconstruction, construction and post construction conditions of both of the dam and spillway Also, please find herewith two ( 2) sets of Record Plans for the project Please review this letter, the photographs and the record plans. Please feel free to contact the undersigned if you have any questions. Westfield Executive Park 53 Southampton Road Westfield, MA 01085 -5308 TeL 413- 562 -1600 Fax. 413- 562 -5317 Original printed on recycled paper, Tighe &Bond Consulting Engineers Environmental Specialists If you wish to carry out an inspection of the work, we will be pleased to meet you on the site and go over the work with your representative. DAVID MN'I'x �..r 'Fl E , K 1 J �?PJ AL C:1N311 Cert.doc Enclosures Copy: Office of Planning and Development Very truly yours, Ti G } & BO , David M. Lenart, P.E. Senior Project Manager -2- Uripinal printed on recycled paper. _ , r l fa' 'w R \; 0� �1 S N G b 0 U • - G 0 z 0 0 0 0 'w R \; 0� �1 S N i Pit 4. J I i i I I �r vtM ; ,. o.o i i ,r r y� i R •r1r "i ,L1 .n�j'14C. •_'4 777 cZ ,1 I Al E I 4. o 'a cV U O � � z �a� 0 o�c Wl. f)l 1 i' Y �r r`} f I i +r � J .. � ''� U J �-+ N � Y 1 i C. {, O 'ti � r, c.' 1� � „• `� o z ��,o Pr 'j - ,� o a � y I W U � ' �, I � , � 'F i �r r .� 1 � -. � �1..�� � i P � � fy �� � ` �� 'I� ..�;10;a _.� a \ yi, 1 1 yy �L � .M ��i y�T�. � \ 1F �, r Y r � { n � ��i `,Y �je `�Y 5 ��� I � J•,.� 'K ♦ 1 �T �;� '� � k4 ` +7'1p,` i �I t �� �� I, ' ,.,. ., � �' r, t a 1 ,� fV y r t ..� i�: it � 1 � � �,. ♦. Y $R„jtj(���� M � ^M �T'� � �: �� t�s- !. ' :� .. JJ v 1 I �. {`� d�. 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'- Rai sir, _A t � f.fa !ti: 1 I cz • � a A 'C rL p., Urn o .yyI �1 9 _ x_ 14 i.0 I if `�i..• `i i 1�F .� s 11 T�� /l 1 kl. fpm » ,r \� , \§ &.� , §\ {\ /\ 2\ 00 g } \j\ /J32 / \l �! r, f I Nli. 17 IN , Al, -AW,w bl u Q ol f! iii 1'4 41. , Al, -AW,w bl u Q -Oro IF 4y ti i I I II N I ^ i it I'� �l, ' '��� .Ill h� , , �y■ ,y �" �.', � o_ a �C 'C 0 1 I } 1 r� r , r � �q pp a , II � I r , t , ti n OrIA r � 1 J ,r r ^C N GJ •a' N N � � •Ct ti z o� Tighe&Bond Consulting Engineers Environmental Specialists N- 311 -1 -29 April 25, 1996 City of Northampton Office of Planning and Development City Hall 210 Main Street Northampton, MA 01060 Attn: Wayne Feiden, Principal Planner Re: Fitzgerald Pond Dam Inspection (Revised) Dear Mr. Feiden: On March 25, 1996, an inspection of the Fitzgerald Pond Dam was carried out for the purpose of identifying any deficiencies in the structure and to verify dimensions of the normal spillway and outlet conduit for design purposes. Following, are the findings from the inspection: 1) Upstream Embankment The upstream embankment has a slope of about 3 on 1 with a well established dense tall grass growth. In addition, the slope has an uncontrolled growth of hardwood saplings and brush (Photo No. 1). It appears that an attempt was made to cut the brush and saplings prior to the winter season, but efforts were terminated for some unknown reason. The tall grass, brush and saplings must be cut so that the slope surface can be maintained and can be viewed during inspections. The stumps from the saplings must be removed, the voids filled with compacted granular fill, and the disturbed areas loamed and seeded so that the slope can be maintained with conventional mowers on a regular basis. If the saplings are allowed to grow into large trees, the structural integrity of the dam could be jeopardized. For instance, in the event of a strong wind, the trees could be blown over and earth from the dam displaced, causing erosion and potential structural failure. At the location of the drop inlet spillway, there is an erosion path that has grown over with grass (Photo No. 2). This erosion appears to have been caused by persons ascending and descending the slope at the outlet works of the dam. This eroded area must be filled with compacted granular fill, graded to the contours of the slope, loam placed and seeded. Mulch and/or an erosion control geotextile fabric should be placed to prevent erosion of the newly seeded soil. Westfield Executive Park 53 Southampton Road Westfield, MA 01085 -5308 TeL 413- 562 -1600 Fax 413 -562 -5317 Original printed on recycled paper. Tighe&Bond Consulting Engineers Environmental Specralisis The tall grass, brush and saplings did not allow a close inspection of the slope, but no unusual depressions or bulges were noted on the areas that were visible. 2) Downstream Embankment The downstream slope of the dam is on a slope of 3 on 1 with a well established dense tall grass growth. In addition, the slope has an uncontrolled growth of brush and saplings (Photo Nos. 3 & 4). Here, also, it appears that an attempt was made to cut the brush and saplings prior to the winter season, but efforts were, terminated for some unknown reason. The tall grass, brush and saplings must be cut so that the slope surface can be maintained and viewed during inspections. The stumps from the trees must be removed, the voids filled with compacted granular fill, and the area loamed and seeded so that the slopes can be mowed with conventional mowers. As mentioned previously, if the saplings are allowed to grow, the structural integrity of the dam could be jeopardized. A path utilized by visitors to the site extends from the crest to the endwall at the outlet pipe (Photo No. 5). This path is not seriously eroded at this time, but if foot traffic is allowed to continue, this area will become a location for erosion. Provisions for stairs using stones could be implemented to allow the visitors to descend the slope without creating a potential erosion problem. The dense grass, - brush and saplings prevented a thorough inspection of the slope, but no unusual depressions or bulges were noted on the areas that were visible. 3) Darn Crest The dam crest has deep ruts caused by various types of motor vehicles (Photo No. 6). The vehicular traffic, over time, has eroded away the surface allowing water to pond. Continued vehicular traffic has accelerated erosion and created deep mud ruts. The crest of the dam should be filled with compacted gravel and the surface crowned down the center to allow water to run off and to prevent ponding and mud to form resulting in erosion. Consideration should be given to placing gates and fencing at each end of the dam to keep access to the crest limited to foot traffic. The crest did not show any serious horizontal or vertical grade or alignment problems. Any minor grade problems will be corrected with the filling of the crest with compacted gravel. M Original printed on recycled paper. Tighe &Bond Consulting Engineers Environmental Specialists 4) Normal Spillway The normal spillway and outlet pipe is constructed of asphalt coated corrugated metal (ACCM) pipe (Photo No. 7). Most of the asphalt coating on the pipe that is exposed to the weather and water flow has deteriorated and extensive corrosion has taken place. In addition, the debris shield at the inlet shows signs of damage due to ice action and vandalism. The top opening of the debris shield has a number of flat thin bars spaced about 6 inches apart to prevent debris and trespassers from falling into the outlet riser. The condition of the bars is poor and it is a potential hazard and liability for the City. This outlet works must be rebuilt with new and durable materials and made safe for trespassers. The ACCM pipes are structurally sound at this time, but the ACCM pipe is near the end of its expected design life and if measurers are not taken to reinforce or replace the pipes in the very near future, the integrity of the darn could be jeopardized. Failure of the ACCM pipe could result in loss of the dam and expensive repairs, not to mention the environmental damage that would result. The concrete wall at the downstream end of the outlet pipe has failed and must be replaced (Photos No. S and 9). A structure .meeting today's engineering standards should be constructed as a replacement. 5) Low Level Outlet The low level outlet does not appear to be functional. Based on the design plans, at one time there was a wharf extending from the normal outlet structure out about 40 feet to a point over the outlet gate. At the end of the wharf, a gate operator existed that operated the 24 inch gate on the outlet pipe. Over time the wharf has deteriorated and the timbers rotted away, and the stem of the gate now protrudes vertically to about 5 feet above the water and is not accessible except with a boat or over ice (Photo No. 10). If someone attempted to operate the gate and open it, it might not be possible to close it, resulting in the pond being drained. The outlet works must be repaired and made functional. In addition, the gate should be accessible to the caretaker of the dam, but not accessible to visitors using the site for recreation. Reconstruction of the wharf should not be considered, in that it would be a maintenance item and a liability. 6) Emergency Spillway The emergency spillway is located at the left abutment of the dam. The spillway, was designed to be a grass lined channel around the end of the dam. If it was to function in a flood event, it was intended to channel the BE Original printed on recycled paper. Tighe&Bond Consulting Engineers Environmental Specialists water away from the dam. If the channel did erode during an overflow event, the dam would not be jeopardized. The emergency spillway channel is overgrown with tall grass, saplings and brush adjacent to the pond (Photo No. 11). This condition creates a serious hazard in the event that the spillway was required to function. Debris could clog the channel entrance and cause the dam to be overtopped, resulting in serious damage to the dam or even complete failure. The channel of the spillway downstream of the overgrown area has an established dense grass cover, but it appears that motor vehicle traffic has eroded the channel floor forming low areas that collect water (Photo No. 12). These .wet areas will erode rapidly in the event that the spillway functions. The channel floor is very irregular due to erosion from vehicle traffic over the years (Photo No. 13). The spillway grading should be surveyed and the channel regraded to insure that there will be uniform flow across the channel and that the channel drains adequately if an overflow event occurs. 7) Core Drains The original design plans indicate that a core drainage System was provided. At the time of the inspection, a few gallons per hour of water flow was noted from beside the right side of the downstream outlet endwall (Photo No. 14). A buildup of oxidized iron was noted in the flow stream, but there was no evidence of any sand or silt being carried in the flow from the dam embankment. This flow, which can be considered not excessive for an earth darn, is most likely from the core drain system. No flow was noted on the left side of the endwall. The drainage pipe on the left side is either plugged or there is no seepage along the left side of the dam for the drain to intercept. The core drains must be located, cleared if plugged and the pipe extended through a new endwall. S) Downstream Channel The downstream channel from the stilling basin is lined with heavy brush and saplings (Photo No. 15). The brush and saplings must be cut back to keep the flow way clear. 9) Town Owned Access Road The, Town owned access road to the dam off of Hatfield Street was not passable with a two wheel drive vehicle and access was questionable with a four wheel drive vehicle due to deep ruts, muddy low points and poor drainage. In the event of an emergency at the dam, a delay in responding Original printed on recycled paper. Tighe &Bond Consulting Engineers Environmental Specialists would result. Providing proper drainage and grading is necessary to make the road passible for response to any type of emergency. Following are recommendations for improvements to the Fitzgerald Pond Darn: 1) Cut tall grass, remove all brush and saplings, including removal of stumps, from the upstream slopes, downstream slopes of the dam and the emergency spillway. The brush and sapling removal should extend to the water line on the upstream slope and to ten (10) feet beyond the toe of the dam on the downstream side. The brush and sapling removal should extend around the stilling basin -and outlet channel, about ten (10) feet from the water ][Inc. At the emergency .spillway, the tall grass, brush, saplings and stumps should be removed to at least an elevation equal to the crest of the dam upstream and the channel width at least 200 feet downstream. Any voids created by removal of the stumps and the erosion areas created by the vehicle traffic should be repaired with loam and seeded. 2) The crest of the dam should be stripped of the loam and organic matter to a depth of at least twelve (12) inches. The soil should be replaced with about twelve (12) inches of processed gravel, crowned, to allow water to drain from the surface. Gates should be placed at each end of the dam with fence to each side to restrict motor vehicle traffic on the dam. 3) The outlet works and the pond drain pipes are currently structurally sound but corrosion has and continues to tape place. The ACCM pipe has reached its expected design useful life. If measures are not taken soon to replace the pipes, the corrosion will lead to the failure of one or more of the pipes resulting in potential failure of the dam and serious environmental damage to the site. The pipes should be replaced with new and durable materials that are corrosion resistant and less of a liability for the City. Also, the pond drain system must be made accessible from the dam, easier to operate and vandal resistant. Two alternatives are available to the City. The first involves draining the pond and replacement of the pipes and riser. The second involves lining the pipes and riser with corrosion resistant materials and reinforcing the existing pipes while they are still structurally sound. This can be done with the pond maintained in an almost full condition. To preserve the pond's environment, the lining method is preferred and recommended. 4) The endwall on the outlet pipe must be replaced so that the outlet pipe is properly supported and erosion does not occur around the outlet pipe. 51 Original printed on recycled paper. Tilghe&Bond Consulting Engineers Environmental Specialists 5) The core drains must be located, cleared of any blockage and extended through the new endwall. 6) The Town owned access road to the dam site should be maintained passable at all times in the event there is an emergency condition. The ability to access the dam with a four wheel drive vehicle would be sufficient. Following are estimates of cast for the recommendations stated: The following costs are based on 1998 construction. Of the recommendations that are listed, Item No. 1 can be carried out by the City's forces. The proposed improvements to the outlet works under Item No. 3 considers maintaining a near full pond during the construction work. Costs would be somewhat lower if the pond was drained for the construction, but significant damage to fish, wildlife and plant life would result. The additional cost to preserve the pond's environment can be justified. els4N 3111LTZINS ERT BOC ril Original printed on recycled paper. Tighe &Bond Consulting Engineers Enuimmiiental Specialists Please review this letter report and call if you have any questions. Very truly yours, TiG BOND, INC. DavidG� P.E. Associate N311 \LTR \DMG.0 _7_ Orsginal printed on recycled paper Fitzgerald Pond Dam Inspection Photos Photo No. 1 - Upstream slope of dam Photo No. 2 - Erosion path upstream slope of dam J 1N3111LTRIDML.0 Photo No. 3 - Downstream slope of dam right side Photo No. 4 - Downstream slope of dam left side JAN3111LTMDML.0 Photo No. 5 - Erosion path downstream slope Photo No. 6 - Dam crest with ruts JAN311ILTRIDML.0 Photo No. 7 - Outlet works Photo No. S - Failed endwall JAN31 IkLTRNDML.0 woo- OWN �f y re v t� rr, Photo No. 7 - Outlet works Photo No. S - Failed endwall JAN31 IkLTRNDML.0 Photo No. 9 - Failed endwall Photo No. 10 - Low level outlet valve operator JAN3111LTR\DNM.0 Photo No. 11 - Brush and saplings at emergency spillway Photo No. 12 - Low areas in emergency spillway channel 7:IN3111LTRIDML.0 r � Photo No. 13 - Emergency spillway channel Photo No. 14 - Core drain outlet ]:W3111LTMDML.0 Photo No. 15 - Outlet channel J;\N311\LTR\DNM.0