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AD-A144 645 NATIONAL PROGaNAM FOR INSPECTION OF NON-FEDENAL DAMS 1/t

ASHLAND POND DAM (Cf..IUD CORPS OF ENDINES WALTHAM IIA

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MICROCOPY RESOLUTION TEST CHARTNATION4AL BUREA OF STMAARS -963A

to THAMES RIVER BASIN

*GRISWOLD, CONNECTICUT

ASHLAND POND DAMCT 00437

PHASE I INSPECTION REPORTNATIONAL DAM INSPECTION PROGRAM

DTICELECTE

DEPARTMUN OF THE ARMYNEW ENGLAND DIVISION, CORPS OF ENNEERS

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__________________________________________________________

SECURITY CLASSIFICATION OF THIS PAGE (When Des, Entered)

REPORT DOCUMENTATION PAGE BEFORE COMPLETING FORM

1. REPORT NUMBER 3.GOVT ACCESSION NO, 3. RECIPIENT'S CATALOG HUMMER

CT 047' i0 54, TITLE (anad S.,bliiil.) S YEO EOTAPRO

Ashland Pond DamINPCONROT

NATIONAL PROGRAM FOR INSPECTION OF NON-FEDERAL G. PERFORMING ORO. REPORT NUMBER

DAMS7. AUTHOR(*) S. CONTRACT OR GRANT NUMMER(o)

U.S. ARMY CORPS OF ENGINEERSNEW ENGLAND DIVISION

19. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT, TASKAREA A WORK UNIT WNMERS,

I~CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT OATE

DEPT. OF THE ARMY, CORPS OF ENGINEERS June 1979NEW ENGLAND DIVISION, NEDED 13. NUMBER OFPAGES424 TRAPELO ROAD, WALTHAM, MA. 02254 . 0i

14. MONITORING AGENCY NAMIE h ADORSS(If diffntf Controlingj DOUG*) IS. SECURITY CLASS. (of Ohio IePort)

UNCLASSIFIEDIfia. OIECLASSIPICATION/DOWNGRADING

SCHEDULE

16. DISTRIBUTION STATEMENT (of Ohio Aspole

APPROVAL FOR PUBLIC RELEASE: DISTRIBUTION UNLIMITED

17. DIST RIOUTION ST ATEMIENT (of the abstentereWmd in ste.s& ac. item biaten Repor)

IW SUPPLEMENTARY NOTES

Cover program reads: Phase I Inspection Report, National Dam Inspection Program;however, the official title of the program is: National Program for Inspection ofNon-Federal Dams; use cover date for date of report.

IS. KEY WORDS (Coataon, reverse aide ton...a al idntil? b ehr 4mbe)

DAMS. INSPECTION, DAM SAFETY,Thames River BasinGriswold, Connecticut

20. ABSTRACT (Constwiue re side Itieemossad Wsidatitpit biesA mmbat)

Ashland Pond Dam is an earth dam. It has a maximum height of 25 feet and is app-roximately 450 feet in length. The dam is considered to be in FAIR condition.The dam is classified as INTERMEDATE in size and a HIGH hazard structure in acc-ordance with the recommended guidelines established by the Corps of Engineers.The test flood outflow for this dam is equal to the full PMF and was estimatedto be 42,000 CFS (700 CMS).

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ASHLAND POND DAMCT 00437

PHASE I INSPECTION REPORT

NATIONAL DAM INSPECTION PROGRAM

J DTICdELECT

SAUG 2 11984

I D

D DISTITON STATEMENT AApproved for public releosel

Distribution Unlimited

' '" - ' I - I I


PHASE I - INSPECTION REPORT

Identification No.: CT 00437

Name of Dam: Ashland Pond Dam

Town: Griswold

County and State: New London County, Connecticut

Stream: Pachaug River

Date of Inspection: December 7, 8, 1978 and April 10,1979

BRIEF ASSESSMENTt'I-Ashland Pond Dam is an earth dam reportedly constructed in thelate 1700's. The dam has a maximum height of 25 feet and isapproximately 450 feet in length. The spillway is located atthe left side of the dam embankment. This stone masonryspillway has a crest length of about 110 feet and has no pro-vision for flashboards. An abandoned penstock to the adjacentmill complex and gate structure is located near the right endof the dam. An abandoned headrace and gate structure islocated at the left abutment of the dam.

Due to its age, Ashland Pond Dam was neither designed nor con-

structed by present state-of-the-art procedures. Based uponthe visual inspection at the site and the lack of engineering,operational and maintenance data, there are areas of concernwhich must be corrected to assure the long-term performance ofthis dam. The dam is considered to be in FAIR condition.Deficiencies include large trees growing on the dam embank-sent, indication of potential overtopping and limited dis-charge capacity of the spillway, inoperable outlet structuresresulting in no drawdown capability, and the minimal crosssection of the right embankment which requires strengthening.

I This dam is classified as INTERMEDIATE in size and a HIGH haz-zard structure in accordance with the recommended guidelinesestablished by the Corps of Engineers. The test flood outflowfor this dam is equal to the full PMF and was estimated to be42,000 CFS (700 CMS). This flow would overtop the dam byabout 9.7 feet, indicating the spillway capacity to be inade-quate and needing further hydrologic study. Testing the dam

[ I

using one-half the PMFlflow also results in overtopping thestructure by 6.3 feet. -The maximum spillway discharge of5,535 CFS represents only 13 percent of the test flood out-flow., Overtopping could result in the failure of this earthembankment dam.

It is recommended that the Owner engage the services of anengineer experienced in the design of dams to accomplish thefollowing: establish a procedure for removal of trees androots from the dam embankment; evaluate and develop a plan ofrehabilitation of the outlet works, conduct further hydrologicstudies of spillway adequacy; repair the masonry walls of thespillway and outlet works; evaluate and develop a plan tostrengthen the right embankment riprap erosion areas.

Recommendations and remedial measures listed above and de-tailed in Section 7 should be implemented by the Owner withinone year after receipt of this Phase I Inspection Report.

CE MAGUIRE, INC. 0 F CONAI

BY: 0RichardW.Long, P.EK.Vice President NO. 958

IIs

3A

This Phase I Inspection Report on the Ashland Pond Dam has beenreviewed by the undersigned Review Board members. In our opinion,the reported findings, conclusions, and recommendations are con-sistent with the Recommended Guidelines for Safety Inspection ofDams, and with good engineering judgment and practice, and is here-by submitted for approval.

CHARLES G. TIERSCH, ChairmanChief, Foundation and Materials BranchEngineering Division

FRED J. RAVENS, Jr., MemberChief, Design BranchEngineering Division

SAUL C. COOPER, MemberChief, Water Control BranchEngineering Division

APPROVAL RECOMMENDED:

JOE B. FRYAR Chief, Engineering Division

PREFACE

This report is prepared under guidance contained in the Recom-mended Guidelines for Safety Inspection of Dams, for Phase I Inves-tigations. Copies of these guidelines may be obtained from theOffice of Chief of Engineers, Washington, DC 20314. The purposeof a Phase I Investigation is to identify expeditiously those damswhich may pose hazards to human life or to property. The assess-ment of the general condition of the dam is based upon availabledata and visual inspections. Detailed investigation, and analysesinvolving topographic mapping, subsurface investigations, testing,and detailed computational evaluations are beyond the scope of aPhase I investigation; however, the investigation is intended toidentify any need for such studies.

In reviewing this report, it should be realized that thereported condition of the dam is based on observations of fieldconditions at the time of inspection along with data available tothe inspection team. In cases where the reserve was lowered ordrained prior to inspection, such action, while improving thestability and safety of the dam, removes the normal load on thestructure and may obscure certain conditions which might otherwisebe detectable if inspected under the normal operating environmentof the structure.

It is important to note that the condition of a dam depends onnumerous and constantly changing internal and external conditions,and is evolutionary in nature. It would be incorrect to assumethat the present condition of the dam will continue to representthe condition of the dam at some point in the future. Only throughcontinued care and inspection can there be any opportunity todetect unsafe conditions.

Phase I inspections are not intended to provide detailedhydrologic and hydraulic analyses. In accordance with the estab-lished Guidelines, the Spillway Test Flood is based on the esti-mated "Probable Maximum Flood" for the region (greatest reasonablepossible storm runoff), or fractions thereof. Because of themagnitude and rarity of such a storm event, a finding that a spill-way will not pass the test flood should not be interpreted asnecessarily posing a highly inadequate condition. The test floodprovides a measure of relative spillway capacity and serves as anaide in determining the need for more detailed hydrologic andhydraulic studies, considering the size of the dam, its generalcondition and the downstream damage potential.

i s s e |I

TABLE OF CONTENTS

Page

LETTER OF TRANSMITTAL

BRIEF ASSESSMENT

REVIEW BOARD PAGE

PREFACE

TABLE OF COINTENTS ii

OVERVIEW PHOTO vi

LOCATION MAP vii

REPORT

SECTION 1 - PROJECT INFORMATION

1.1 General

a. Authorityb. Purpose of Inspection

1.2 Description of Project

a. Locationb. Description of Dam and Appurtenancesc. Size Classificationd. Hazard Classificatione. Ownershipf. OperatorS. Purpose of Damh. Design and Construction Historyi. Normal Operating Procedures

1.3 Pertinent Data 3

a. Drainage Areab. Discharge at Dam Sitec. Elevationsd. Reservoir Lengthe. Storage

ti

Page

f. Reservoir Surfaceg. Damh. Diversion and Regulating Tunneli. Spillwayj. Regulating Outlet

SECTION 2 - ENGINEERING DATA

2.1 Design 8

2.2 Construction Data 8

2.3 Operation Data 8

2.4 Evaluation of Data 8

a. Availabilityb. Adequacyc. Validity

SECTION 3 - VISUAL INSPECTION

3.1 Findings 9

a. Generalb. Damc. Appurtenant Structuresd. Reservoir Areae. Downstream Channel

3.2 Evaluation 12

SECTION 4 - OPERATIONAL PROCEDURES

4.1 Procedures 13

4.2 Maintenance of Dam 13

4.3 Maintenance of Operating Facilities 13

4.4 Description of any Warning System inEffect 13

4.5 Evaluation 13

ill

Page

SECTION 5 - HYDRAULIC/HYDROLOGIC

5.1 Evaluation of Features 14

a. Generalb. Design Datac. Experience Datad. Visual Observatione. Test Flood Analysisf. Dam Failure Analysis

SECTION 6 - STRUCTURAL STABILITY

6.1 Evaluation of Structural Stability 18

a. Visual Observationsb. Design and Construction Datac. Operating Recordsd. Post-Construction Changese. Seismic Stability

SECTION 7 - ASSESSMENT, RECOMMENDATIONS AND REMEDIALMEASURES

7.1 Dam Assessment 19

a. Conditionb. Adequacy of Informationc. Urgencyd. Need for Additional Investigation

7.2 Recommendations 19

7.3 Remedial Measures 20

a. Operation and Maintenance Procedures

7.4 Alternatives 21

iv

APPENDICES

APPENDIX A - Inspection Check List

APPENDIX B - Engineering Data

APPENDIX C - Photographs

APPENDIX D - Hydrologic and Hydraulic Computations

APPENDIX E - Information as Contained in the National Inventoryof Dams

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PLATE 140. 1


PHASE I - INSPECTION REPORT

NAME OF DAM: ASHLAND POND DAM

SECTION 1

PROJECT INFORMATION

1.1 General

a. Authority. Public Law 92-367, August 8, 1972, authorizedthe Secretary of the Army through the Corps of Engineersto initiate a national program of dam inspection through-out the United States. The New England Division of theCorps of Engineers has been assigned the responsibilityof supervising the inspection of dams within the NewEngland Region. C E Maguire, Inc. has been retained bythe New England Division to inspect and report on se-lected dams in the State of Connecticut. Authorizationand notice to proceed was issued to C E Maguire, Inc.,under a letter from Ralph T. Garver, Colonel, Corps ofEngineers. Contract No. DACW33-79-C-O015 has been as-signed by the Corps of Engineers for this work.

b. Purpose of Inspection

1. Perform technical inspection and evaluation ofnon-Federal dams to identify conditions whichthreaten the public safety and thus permit correc-tion in a timely manner by non-Federal interests.

2. Encourage and assist the States to initiate quicklyeffective dam safety programs for non-Federal dams.

3. To update, verify and complete the National Invent-ory of Dams.

1.2 Description of the Project

a. Location. Ashland Pond Dam is located in the Town ofGriswold, New London County, Connecticut. Coordinates ofthe dam are about 410 36.3'N Latitude and 710 58.6'WLongitude. The dam is in the Village of Jewett City,which is part of Griswold, Connecticut. (See Plate 1).The dam impounds water from the Pachaug River whichdrains a 61.82 square mile water-shed of rolling terrain.I

1

The reservoir has a total surface area of 83 acres. Theimpoundment is aligned in a northeast-southwest axis,with the dam located at the southwest extremity.

b. Description of Dam and Appurtenances. The Ashland PondDam is an earth embankment approximately 450 feet inlength, 25 feet high, with a crest width of about 11feet. The main portion of the dam embankment is to theright side of the structure and has a typical slope up-stream of 2H to IV and downstream of 1.5H to IV. A stonemasonry spillway and an abandoned outlet control struc-ture are located at the left abutment of the dam. Thisabandoned outlet control structure is located to the leftof the spillway and consists of a rack and pinion verti-cal lift gate. The gate is now inoperable but was usedto control flow to a headrace for a mill complex locatedimediately downstream and to the left of the dam. Theabandoned headrace is filled with debris and small treesand effectively blocked at its downstream end. (SeePhotos C-7 through C-11 and plan on Appendix B-3).

A second abandoned control structare and penstock arealso located near the right abutment of the dam. Thegates of this control structure are also inoperable. Thepenstock supplied water for hydroelectric power genera-tion now retired for the mill complex immediately down-stream from the dam. (See Photos C-6; C-13; C-14 andplan on Appendix B-3).

An intake structure for the fire protection system of themill is located at the right abutment of the dam. Aneight-inch pipeline carries water from the intake struc-ture to a pumping station located within the mill thatprovides water for the fire protection system. (SeePhotos C-5 and C-6).

c. Size Classification. Ashland Pond Dam has an impoundmentcapacity at the top of the dam (Elev. 133.0, NationalGeodetic Vertical Datum, NGVD) of 1000 Ac-Ft. and aheight of 25.0 feet, which classifies this dam as INTER-MEDIATE in size.

d. Hazard Classification. The dam is classified as a HIGHhazard structure because it is located where its failuredischarge can cause damage due to high velocity, impactfrom debris and flooding to homes (10), commercial pro-perties (5), Ashland Street, Routes 138 and 12 and utili-ties adjacent to those roadways. The estimated waterdepth due to the possible dam failure discharge of 23,100CFS may range from 17 feet at the dam to 15 feet at a

2

distance of 4,000 feet from the dam. See Appendix D forcalculations.

e. Ownership. The Ashland Pond Dam is owned by the UnitedMerchants and Manufacturing Company.

f. Operator. Operating personnel are under the directionof:

Mr. Brian TrudellDirector of MaintenanceUnited Merchants & Manufacturing Company16 Ashland StreetJewett City, Connecticut 06351

g. Purpose of Dam. The Ashland Pond Dam impounds water fromthe Pachaug River for recreational and fire protectionuse. United Merchants and Mfg. Company and Plastic Wireand Cable company both use the reservoir as a source ofwater for their fire protection systems.

h. Design and Construction History. The dam was reportedlyconstructed in the late 1700's; however, its present con-figuration resulted from additional construction about1864. No construction records are available regardingthe history of construction, repair work or maintenance.

The mill complex immediately downstream of the dam wasconstructed in 1864 and hydroelectric generating equip-ment was installed at some later date.

i. Normal Operating Procedures

The gates of the outlet works are inoperable and thespillway is uncontrolled. There is no regulation of thewater surface levels nor is there any release of water toaugment low flows below the dam.

1.3 Pertinent Data

a. Drainage Area. Ashland Pond is located in New LondonCounty in eastern Connecticut. The basin is generallyrectangular in shape with a length of approximately 10miles, a width of 8 miles, and a total drainage area of61.82 square miles (See Drainage Basin Map in AppendixD). The topography is generally flat to rolling withelevations ranging from a high of 500 feet to 127 feet atthe spillway crest. Basin slopes are flat to moderatehaving slopes of 0.015 feet/foot to 0.045 feet/foot. Theaverage time of concentration for the entire drainagebasin is estimated to be six to ten hours.

! 3

I:

Due to the relatively large size of the watershed and theconcentration time, it is improbable that all surfacerunoff will peak at the reservoir simultaneously during ahigh intensity rainfall event. In addition, the largeupstream storage areas in the watershed tend to moder-ately dampen and delay the peak of the surface runoff.

b. Discharge at Dam Site. There are no discharge recordsavailable for this dam. Listed below are calculateddischarge data for the spillway and outlet works assumingthe outlet works to be operable:

1. Outlet Works:To Pachaug River - Two 4-ft. wide by 6-ft. high

rectangular gates.

2. Maximum Known Flood at Dam Site - Unknown.

3. Overflow spillway capacity @ Top of Dam - 5335CFS at Elevation 133.0.

4. Overflow spillway capacity at "Test Flood Level" -42,000 CFS at Elevation 142.7 with overtopping ofdam.

5. Gated outlet capacity at normal pool level - 852CFS at Elevation 127.0. (spillway crest).

6. Gated outlet capacity at maximum pool level -

1,044 CFS at Elevation 133.0.

7. Total project capacity at "Top of Dam" -6,579 CFS @ Elevation 133.0.

8. Gated outlet capacity at Test Flood Level -1,295 CFS at Elevation 142.7.

9. Total project discharge at "Test Flood Level" -43,295 CFS @ Elevation 142.7.

c. Elevations (Feet above National Geodetic Vertical Datum,

1. Streambed at centerline of dam - Upstream - notobservable; Down-stream - 108.0

2. Maximum Tailwater Unknown

/4

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3. Upstream Inlet Invert ---

4. Recreation Pool N/A

5. Full Flood Control Pool N/A

6. Spillway Crest 127.0

7. Top of Dam 133.0

8. Test Flood 142.7

d. Reservoir Length (in Feet)

1. Maximum Pool 15,000


3. Flood Control Pool N/A

e. Storage (Ac-Ft)



3. Test Flood Pool 1,805

4. Spillway Crest Pool 502

5. Top of Dam (El. 158.0) 1,000

6. Net storage between top of dam (El. 133.0) and spill-way crest is 498 Ac-Ft. and represents 0.15 inches ofrunoff from the drainage area of 61.82 square miles.

7. Each foot of surcharge storage above spillway crestto top of dam equals 0.025 inches of runoff fromthe drainage area of 61.82 square miles.

f. Reservoir Surface (Acres)

1. Top of Dam 83

2. Test Flood Pool 83


5

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5. Spillway Crest 83

g. Dam

1. Type Earth Embankment

2. Length 450 feet

3. Height (main embankment) 25 feet maximum

4. Top Width (main embankment) 11 feet

5. Side Slopes Upstream 2H:lVDownstream 1.5H:lV

6. Zoning Unknown

7. Impervious Core Unknown

8. Cutoff Unknown

9. Grout Curtain Unknown

10. Other

h. Diversion and Regulating Tunnel N/A

'i. Spillway

1. Type Overflow, sharp crest,vertical fall.

2. Length of Weir 110 feet3. Crest Elevation 127.0 (from USGS

Topographic sheet)

4. Gates None

5. U/S Channel Natural bed

6. D/S Channel Natural bed withrock and stone masonryapron

7. Design Surcharge Unknown

6

I

8. General

j. Regulating Outlet

Refer to paragraph 1.2b,"Description of Dam andAppurtenances" for descriptionof outlet works.

1. Downstream invert 112.0±

2. Size Two-4 ft. wide by6 ft. high rectangu-lar stone masonryopenings.

3. Control mechanism Manually operatedvertical lift gearmechanism, uncovered,on stone masonryplatform.

7A

Il

SECTION 2

ENGINEERING DATA

2.1 Design

No design data is available for this dam. An inspection

report has been included in Appendix B.

2.2 Construction Data

No record of construction is available for this dam.

2.3 Operation Data

No operation records of this facility are maintained.

2.4 Evaluation of Data

a. Availability. There are no plans, specifications orcomputations available from the Owner, County, State, orFederal Offices regarding the design, construction orsubsequent repairs and modifications to this dam.

b. Adequacy. The lack of in-depth engineering data did notallow for a definitive review. Therefore, the adequacyof this dam could not be assessed from the standpoint ofreviewing design and construction data, but is basedprimarily on visual inspections, past performance andsound engineering judgment.

c. Validity. The validity of the limited data must beverified.

8 I

SECTION 3

VISUAL INSPECTION

3.1 Findings

a. General. Based on visual inspection, history and generalappearance, the Ashland Pond Dam and its appurtenancesare judged to be in fair condition. The dam embankmentis overgrown with many large trees, unchecked erosionareas exist; the crest is not level, and the cross sec-tion of the right embankment is narrow and requiresstrengthening. The gate mechanism on the outlet struc-ture is inoperable resulting in no drawdown capability atthe dam.

b. Dam. The dam is an earth embankment. No constructiondrawings are available, nor are the details of design andsubsequent repair known.

1. Crest. From Sta 0+50 to 3+00, the crest of the damis generally grass-covered with numerous erosionpaths and depressions which give the surface of thecrest an irregular appearance. Average top of damelevation 133.0 varies 1.0'± at some locations. Forstation locations, see sketch Appendix B-3. Thereare trees growing on the crest in several locations,as indicated in Photos C-l, 3, and 4. The erosionon the upstream slope at Sta 1+50 has cut into theupstream edge of the crest, as shown in Photo C-15.The crest along the approximately 20-ft. sectionbetween the wing walls for the inlet gate structure(Sta 1+90) is about 18 inches lower than the crestof the adjacent embankment sections, as shown inPhoto C-4.

To the left of the spillway section the crest isgenerally covered with grjs, brush and trees, anshown in Photos C-7 and 8. A sluiceway bordered bystone masonry walls cuts through the dam at aboutSta 4+35 and joins the downstream spillway channelfurther downstream. Some water was observed flowingthrough the sluiceway and apparently seeping underthe left masonry wall of the sluiceway, as indicatedin Photos C-10 and 11. Adjacent to the right wallof the sluiceway, there is a 3 to 4-feet deep ero-sion gully. An erosion hole about 6 feet long and 4feet wide was also observed in this area.

9!

2. Upstream Slope. From Sta 0+50 to 1+80, the upstreamslope of the dam consists of a relatively steepearth slope covered with grass, tall weeds, and sometrees, as shown in Photos C-13 and 15. There is noriprap cover on the visible portion of the upstreamslope. At Sta 1+10, there is an intake system forthe fire prevention system in the factory (PhotoC-6). Extensive erosion has occurred on the up-stream slope in a 30-foot section located at aboutSta 1+50. A clump of trees up to 6 inches in dia-meter is growing on the slope in this area as indi-cated in the photos.

From Sta 1+80 to about Sta 3+00, a vertical stonemasonry wall forms the upstream face, as shown inPhoto C-13. The gate structure for the intake toplant turbines is located in this section at aboutSta 1+90 (Photos C-13 and 14). At Sta 3+00, themasonry wall makes a right angle bend downstream andforms the right training wall for the spillway anddownstream channel, as shown in Photos C-7 and 8.

The upstream slope to the left of the spillway be-tween Sta 4+12 and Sta 4+77 is also formed by avertical stone masonry wall which bends to form theleft training wall for the spillway and downstreamchannel, as shown in Photo. C-8. At about Sta 4+40,there is a gate structure, shown in Photo C-9, for asluiceway that runs through the dam to the down-stream channel. (Photo C-10).

3. Downstream Slope. As shown in Photos C-l, 3 and 4,the downstream slope of the dam from Sta 0+50 to3+00 is relatively steep and partially covered withgrass. Soil is exposed and erosion has occurred inseveral areas. There are trees up to 8 inches indiameter and large stumps on the slope at sever.&llocations. As shown in Photo C-3, at approximatelySta 2+10, there is a vehicle ramp cut in the down-stream slope. Some erosion has occurred on thisramp.

c. Appurtenant Structures. The appurtenant structures forthis dam are the overflow spillway, the abandoned outletworks structure, and the abandoned gates and penstockformerly used to supply water to generate hydroelectricpower for the mill complex.

1. Spillway and Training Walls. The spillway weir isconstructed of cut stone blocks which form a

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sharp crest as shown in Photos C-6 and 7. A smalldepression approximately three feet in diameter and8 to 12 inches deep was observed upstream of thespillway apron approximately ten feet left of theright training wall. The condition of the spillwaycrest and downstream face of the dam was not observ-able because of the depth of water overflow. Thetraining walls consist of cut stone masonry withmortared joints. Much of the mortar has been dis-lodged and repointing of the joints of the trainingwalls is necessary.

2. Outlet Works. The abandoned outlet works located atthe left abutment of the dam is in POOR condition.The hand-operated vertical lift gate mechanism isinoperable and there is considerable leakage aroundthe gate as is shown on Photos C-5 and 13. Theheadrace from this outlet works is divided into twochannels. The first channel joins the Pachaug Riverapproximately 20 feet downstream of the dam as shownin Photo C-7 and is the outlet for the outlet works;and the second channel has been plugged at its lowerend and was the headrace leading to an abandonedmill downstream. Both channels are filled withdebris as is shown on Photo C-11, 14.

3. Abandoned Penstock and Intake Works. An abandonedpenstock and intake works located at approximatelySta 1+90 is shown in Photo C-12. The gate mechan-isms have been dismantled and closed permanently asshown in Photo C-11 and water no longer flowsthrough the penstock to the turbines of the UnitedMerchants mill complex. Some leakage around thegates of the intake structure was observed but it isnot considered serious at this time.

4. Fire Protection System Intake Structure. The intakestructure for the mill's fire protection system lo-cated at Sta 1+20 is shown in Photo C-8. The fireprotection system is supplied with water by an8-inch line from this structure. The intake struc-ture was in the process of being renovated duringthe dam inspection. This structure provides nodrawdown capability for the dam.

d. Reservoir Area. No specific detrimental features in thereservoir area were observed during the visual inspec-tion. The slopes of the watershed are well-covered withgrowth to preclude sloughing of shoreline material.

( 11

e. Downstream Channel. The channel downstream of the spill-way is approximately 100 feet wide and is bordered bystone masonry walls, as shown in Photo C-12. There aretwo small drops about 1.5 and 2 feet high located ap-proximately 30 feet and 150 feet downstream from thespillway, respectively. As noted in Photo C-12, thereare a few trees growing iu the downstream channel.

3.2 Evaluation

Based on the visual inspection, the overall dam appears to bein FAIR condition. The inspection disclosed the followingitems which could affect the future performance of the dam:

a. There is no riprap protection on the earth slope portionof the upstream face of the dam and extensive erosion hasoccurred on the slope.

b. There are trees and brush on the crest, upstream slope,and downstream slopes. The root systems associated withthis vegetation can create paths for seepage if allowedto grow without limit.

c. Soil is exposed and erosion has occurred in several areasof the downstream slope, including the vehicle ramp thatis cut into the downstream slope.

d. Seepage apparently is occurring under the left trainingwall of the sluiceway of the outlet works.

e. There are trees growing in the downstream spillway chan-nel and in the sluiceway of the outlet works which couldrestrict flow in those channels.

f. There is no drawdown capability for the dam because theexisting outlet control structure is abandoned and in-operable.

g. Electric power service is carried overhead to the millcomplex by a utility pole at the toe of the right embank-ment of the dam. The electric power service to the millcould be lost in the event the dam was overtopped.

h. The cross section of the right embankment is small andshould be strengthened to provide greater stability ofthe embankment.

i. There is leakage around the gate of the abandoned outletstructure and the intake structure for the abandonedpenstock. The outlet channels from the abandoned outletstructure is filled with debris and should be cleaned.

12

SECTION 4

OPERATIONAL PROCEDURES

4.1 Procedures

Since the outlet structure for the dam is not operable, thewater level for Ashland Pond is not controlled and no formaloperational procedures are followed.

4.2 Maintenance of Dam.

Maintenance of the dam consists of the occasional cutting ofbrush and grass mowing along the crest of the earth embank-ment.

4.3 Maintenance of Operating Facilities. There are no formalmaintenance procedures followed for the operating facilities.

4.4 Description of Any Warning System in Effect.

Emergency action and/or warning would be coordinated throughthe maintenance director of United Merchants and ManufacturingCompany, Mr. Brian Trudell (203/376-4780). There are noformal emergency operation plans in effect for lowering thepond level in anticipation of severe storms. Monitoring ofthe approach of intense storm activity is normally through theU.S. Weather Service, or local weather forecasts.

4.5 Evaluation.

Regular operational maintenance procedures for this dam andits appurtenances have not been developed or implemented. Inview of the lack of drawdown capability at the dam, it isimportant that the Owner make arrangements to have the outletcontrol structure repaired and made operational.

An emergency action plan should be prepared to prevent orminimize the impact of failure. This plan should list theexpedient action to be taken and authorities to be contacted.

13

SECTION 5

HYDRAULIC/HYDROLOGIC

5.1 Evaluation of Features

a. General. The Ashland Pond Dam has a spillway length of110.0 feet and a surcharge height of 6.0 feet between thetop of the dam, at its lowest elevation, and the spillwaycrest. The total length of the dam is about 450 feet.The reservoir has a total storage capacity of 502 Ac-ft.at spillway crest elevation 127.0 and can accommodate0.15 inches of runoff from a drainage area of 61.82square miles. Every foot of depth in the reservoir abovespillway crest to top of dam can accommodate 83 Ac-ft.of volume equivalent to 0.025 inches of runoff.

The total available surcharge storage in the impoundmentis 498 Ac-Ft. which is equivalent to 0.15 inches ofrunoff. This dam is basically a low storage-high spill-age structure with outflow being 97 percent of test floodinflow. The maximum spillway capacity is 5,535 CFS,which is equivalent to 13.2 percent of the "test flood".Because the dam is an earth embankment, it should beconsidered unstable against overtopping.

b. Design Data. No specific design data is available forthis dam or its appurtenances. In lieu of existingdesign information, U.S.G.S Topographic Maps (Scale 1" =2,000') were utilized to develop hydrologic parameterssuch as drainage area, reservoir surface area, basinslopes, time of concentration and other runoff character-istics. Elevation - storage relationships for the reser-voir were approximated. Surcharge storage was computedassuming that the surface area remained constant abovethe spillway crest. Some of the pertinent hydraulicdesign data was obtained and/or confirmed by actual fieldmeasurements at the time of the field inspection.

The "Test Flood" and floods of lesser magnitude weredeveloped for comparison purposes only based on approvedand standard procedures including Corps of Engineersguidelines for Phase-1 studies. The hydrologic charac-teristics such as upstream storages, basin slopes, shapeof watershed, etc., were qualitatively assumed in adopt-ing various inflow discharge values.

Outflow values (routing procedures) and dam failureprofiles were computed in accordance with the guidelines

14

developed by the Corps of Engineers. Final values out-lined in this report are approximate and should not beconsidered a substitute for actual detailed analysis.

c. Experience Data. Certain historical data for recordeddischarges and water surface elevations are available ata U.S.G.S. gaging station (01127000) located 1.1 milesdownstream on Quinebaug River with drainage area of 715square miles. These historical data are listed below.

Discharge in W.S.E.Location Date C.F.S. (NG,VD)

i) U.S.G.S. gage Aug, 1955 40700 92.07(01127000) with gage

height of29.0 feet

ii) Ashland Pond* Aug, 1955 23100 125.0Dam Site

*Data prorated for drainage area and slope of PachangRiver.

d. Visual Observations.

1. The right embankment has a narrow crest width andsmall cross section and some erosion has takenplace. The right embankment should be strengthened.

2. The freeboard for the dam and length of spillway islimited for such a large drainage area. Provisionsshould be made to improve the spillway capacitysince overtopping can cause extensive damage down-stream.

e. Test Flood Analysis. Recommended guidelines for theSafety Inspection of Dams by the Corps of Engineers wereused for the selection of the "Test Flood". This dam isclassified as a HIGH hazard structure and INTERMEDIATE insize. Guidelines indicate that a full P.H.F. should beused as the test flood for this classification. TheAshland Pond Dam watershed has a total drainage area of61.82 square miles, of which 6.2 square miles, or 10percent, is swampy or covered by storage ponds. Theaverage basin slope is moderate and equal to 0.03 feet/feet, and for this analysis the watershed was consideredto be flat to rolling. A "test flood" equal to the fullP.M.F. was estimated to be 700 CSM, or 43,274 CFS. Theoutflow discharge developed using the Corps of Engineers

15

criteria and approximate routing techniques was 42,000CFS. Additional data developed for this investigation isincluded in the table at the end of this section.

The spillway capacity is hydraulically limited to passthe "test flood" (PMF) and overtopping of the dam wouldoccur (approximately 9.71 feet). The inflow and outflowdischarge values for this "test flood" are 43,274 CFS and42,000 CFS, respectively. The maximum outflow capacityof the spillway in a stillwater condition without over-topping of the dam is 5,535 CFS which represents 13.2percent of the test flood overflow discharge. The over-topping potential for discharges of lesser magnitude andfrequency (approximate only) are listed in the table atthe end of this section. The spillway and outlet ratingcurves are illustrated in Appendix D.

At the spillway crest elevation of 127.0, the capacity ofthe outlet structure is 852 CFS, (assuming the gate couldbe opened or removed). It will require 1.2 hours tolower the reservoir level the first foot assuming aconstant pond surface area of 83 acres.

Each foot of depth in the reservoir above spillway crestto top of dam can approximately accommodate 0.025 inchesof effective rainfall from the watershed. Consequently,it is estimated that overtopping of the dam cannot beprevented by lowering the pool level in the reservoir forthe test flood inflow.

f. Dam Failure Analysis. Assuming the reservoir is full tothe top of the dam, the calculated dam failure dischargeof 23,100 CFS will produce an approximate water surfaceelevation of 125.0 downstream from the dam. This flowwill raise the water surface 7.4 feet over the estimateddepth just prior to failure of the dam when the dischargeis 5,535 CFS. Normal uniform flow, based on Manning'sformula, will occur approximately 4,000 feet downstreamfrom the dam with a depth of flow equal to 15.0 feet.For this distance of 4,000 feet, the depth of flow willdecrease from 17.0 feet to 15.0 feet. This failuredischarge will damage approximately ten homes, fiveindustrial and commercial properties, three roads, (Ash-land Street, and State Routes 12 and 138), utilities(those adjacent to the roadways) and considerable down-stream flooding. Water surface elevations due to failureof the dam are computed and are listed in Appendix D.

16

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17

I

J SECTION 6

STRUCTURAL STABILITY

6.1 Evaluation of Structural Stability

a. Visual Observations. The visual inspection did not dis-close any immediate stability problems. The locationswhere erosion is currently occurring and where it hasoccurred in the past should be restored to avoid poten-tial future difficulties. Locations where the embankmentcross-section has been reduced by erosion or by gradingfor vehicular access should be restored to grade toassure the stability of the embankment.

b. Design and Construction Data. There is insufficientdesign and construction data to permit a formal evalua-tion of stability. There is, for example, inadequateinformation concerning zoning in the earth dam.

c. Operating Records. There is no recorded informationindicating past stability problems.

d. Post-Construction Changes. Erosion has occurred on theupstream and downstream slopes. Continued erosion willdecrease the stability of the dam.

e. Seismic Stability. Ashland Pond Dam is located in Seis-mic Zone 1 and in accordance with the recommended guide-lines of the Corps of Engineers does not warrant seismicanalysis.

II

18

SECTION 7

ASSESSMENT, RECOMMENDATIONS, AND REMEDIAL MEASURES

7.1 Dan Assessment

a. Condition. Based on the visual inspection, the damappears to be in FAIR condition. There are some featureswhich could affect the long-term performance of the damin the future if they are not corrected as recommended inSections 7.2 and 7.3.

b. Adequacy of Information. The information available and avisual inspection are not sufficient to analyze thesafety of the dam. At this time, an assessment of safetyis based solely on a visual inspection which cannotdisclose all potential problems that the dam could de-velop in the future. Downstream face and crest of spill-way could not be inspected due to overflow of water.

c. Urgency. The recommendations and remedial measurespresented below should be implemented by the Owner within1 year after receipt of this Phase I inspection report.

d. Need for Additional Investigation. No information orobservation indicates that the Ashland Pond Dam requiresa comprehensive investigation at this time. However, therecommendations and remedial measures outlined in Sec-tions 7.2 and 7.3 will require some additional engineer-ing input, analysis and design.

7.2 Recommendations

The Owner should engage the services of an engineer experi-

enced in the design of dams to accomplish the following:

1. The spillway discharge capacity is considered limited,therefore, further hydrologic studies are required to de-termine what alternative measures are necessary to signi-ficantly improve the discharge capabilities of the damand reduce the overtopping potential.

Investigate, inspect and evaluate further the conditionof the spillway crest, slopes and training walls todevelop a program for their rehabilitation if needed.This inspection to be carried out when there is no flowover the spillway.

19 )

2. Trees and brush on the upstream and downstream slopes ofthe embankment should be trimmed. The trees should beremoved only after a procedure has been developed by acompetent engineer using proper backfill and compaction.

3. The upstream slope should be repaired where it has beeneroded and suitable riprap protection should be installedin all unprotected areas.

4. Consideration should be given to strengthening the crosssection of the right embankment to provide greater stabi-lity of the dam embankment, particularly in those areasreduced in cross section.

5. The abandoned outlet structure and discharge channelshould be repaired to provide a means for lowering thereservoir level for emergency drawdown or to performmaintenance or repair of the dam.

6. The intake structure for the abandoned penstock should bepermanently sealed to prevent any leakage.

7. A topographic survey of the dam and its appurtenancesshould be made that will result in accurate drawings ofthe existing conditions to be used in a program of re-habilitation of the dam.

8. Perform more detailed hydrological studies of spillway

adequacy.

7.3 Remedial Measures

a. Operating and Maintenance Procedure.

1. Develop a system for the recording of data withregard to items such as water levels, discharges, toassist those responsible for the monitoring andoperation of the dam.

2. Existing erosion gullies should be filled and grassplanted where unprotected soil is exposed.

3. Trees, brush and debris should be removed from thedownstream spillway and sluiceway channels on aregular basis.

4. The seepage exiting under the training wall of thesluiceway should be monitored on a regular basis.

20

5. Steps should be taken to prevent trespassing on thedownstream slope and crest of the dam to reduce oreliminate further erosion.

6. Continue the technical inspections of this facilityon an annual basis.

7. Develop and post an emergency action plan includinga warning system in order to prevent or minimize theimpact of dam failure. It should include the ex-pedient action to be taken, authorities to be con-tacted, and locations of emergency equipment andmaterials.

7.4 Alternatives.

None

21

APPENDIX A'

INSPECTION CHECK LIST

VISUAL INSPECTION CHECK LISTPARTY ORGANIZATION

PROJECT Ashland Pond Dam DATE Dec. 7 and 8. 1978

TIME PM (both days)

WEATHER 500 Cloudy

W.S. ELEV. _U.S. D.S.

PARTY:

1. A. Reed - CEM 6. S. Whiteside -GEI

2. S. Khanna - CEM 7. B. Trudell - United Merchants

3. R. Brown - CEM 8. Manufacturing Co.

4. D. Sluter - CEM _.

R. Murdock -G.E.I. 0.

PROJECT FEATURE INSPECTED BY REMARKS

I.

2.

3.

4.

5.

7.

8.

9.

10.

A-1

PERIODIC INSPECTION CHECK LIST

PROJECT Asnland Pond Dam DATE December 7, 1978

INSPECTOR DISCIPLINE


AREA EVALUATED CONDITION

DAM EMBANKMENT

Crest Elevation El. 127.0

Current Pool Elevation

Maximum Impoundment to Date Unknown

Surface Cracks None observed

Pavement Condition All sections of dam unpaved

Movement or Settlement of Crest Erosion at Sta. 1+50

Lateral Movement None observed

Vertical Alignment Undulating in some areas, crest erodedat Sta. 1+50.

Horizontal Alignment Good

Condition at Abutment and at Erosion at junction of dam and stoneConcrete Structures masonry wall at Sta 1+80 & 4+39.

Indications of Movement of None observed.Structural Items on Slopes

Trespassing on Slopes Roadway cut at angle in D/S slope tocrest of dam at Sta 1+90, carstrespass on slope and crest.

Sloughing or Erosion of Slopes or Erosion evident in zones on U/S & D/SAbutments slopes and on crest.

Rock Slope Protection - Riprap No riprap on section of dam notFailures bordered w/masonry wall(from

Sta 0+00 to 1+80)

Unusual Movement or Cracking at None observed.or Near Toe

Unusual Embankment or DownstreamSeepage None observed.

Piping or Boils None observed.

Foundation Drainage Features None observed.

A-2


PROJECT Ashland Pond Dam DATE December 7. 1978

INSPECTOR ______________ DISCIPLINE_____________

INSPECTOR ______________ DISCIPLINE_____________


Toe Drains None observed

Instrumentation System None observed.

Vegetation Trees & grass on U/S slope up toSta. 1+80. Grass & trees up to 12"'on D/S slope.Trees, grass & stumps on crest.

A-3


PROJECT Ashland Pond Dam DATE




OUTLET WORKS - INTAKE CHANNEL AND (INTAKE TO MILL)

INTAKE STRUCTURE

A. Approach Channel Underwater not observable

Slope Conditions Underwater not observable

Bottom Conditions Underwater not observable

Rock Slides or Falls Underwater not observable

Log Boom None

Debris Underwater not observable

Condition of Concrete Lining Underwater not observable

Drains or Weep Holes Underwater not observable

b. Intake Structure Stone masonry, vertical lift gatesNot used (3 gates)

General Condition Poor to fair condition.Rt. side appears to have collapsedand been repaired.

Stop Logs and Slots None.

OUTLET WORKS - INTAKE CHANNEL ANDINTAKE STRUCTURE (AT SPILLWAY)

a. Approach Channel Underwater not observable.No log boom.

b. Intake Structure

General Condition Good

Stop Logs and Slots None

A-4






OUTLET WORKS - CONTROL TOWER (SPILLWAY GATE)

a. Concrete and Structural


Condition of Joints None.- Mondithic

Spalling None observed.

Visible Reinforcing None observed.

Rusting or Staining of Concrete Slight.

Any Seepage or Efflorescence None observed.

Joint Alignment None

Unsual Seepage or Leaks in Yes, leakage observed through gates.Gate Chamber

Cracks None observed.

Rusting or Corrosion of Steel Yes

b. Mechanical and Electric Vertical lift gatemechanism - rack and pinion.Inoperable due to missing teeth onrack. Gate in closed position.

A-5



I NSPECTOR DISCIPLINE



OUTLET WORKS - CONTROL TOWER INTAKE TO MILL

a. Concrete and Structural Cut stone masonry

General Condition Poor to fair; see intake structurefor mill intake.

Rusting or Corrosion of Steel Considerable

b. Mechanical and Electrical 3 vertical lift gatemechanisms - -ack and pinion - wormdrive mechanism disassembled.Appear to be inoperable;lift gate stem is missing.

A-6






OUTLET WORKS - TRANSITION AND CONDUIT (MILL INTAKE)

General Condition of Concrete Not observable (abandonedinside mill building).

Rust or Staining on Concrete

Spalling

Erosion or Cavitation

Cracking

Alignment of Monoliths

Alignment of Joints

Numbering of Monoliths

A-

A-7






OUTLET WORKS - TRANSITION AND CONDUIT (At Spillway)

General Condition Open channel stone masonry structurefilled with debris and trees.Poor conditionExtensive -leakage(seeps) into channelfrom beneath lt. wall.

A-8


PROJECT -Ashland Pond Dam. DATE

I NSPECTOR DISCIPLINE

INSPECTOR , DISCIPLINE


OUTLET WORKS - OUTLET STRUCTURE AND SPILLWAY OUTLET

OUTLET CHANNEL STONE ARCH - MORTARED

General Condition of Stone Masonry Mortared stone masonry

Rust or Staining N.A.

Spall ing None observed

Erosion or Cavitation None observed

Visible Reinforcing N.A.

Any Seepage or Efflorescence Considerable seepage observed

Condition at Joints Many open masonry joints

Drain Holes None observed

Channel Discharges to main streambed ofQuinebaug River

Loose Rock or Trees OverhangingChannel Some trees overhang channel

Condition of Discharge Channel Poor, channel is littered with

debris, trees, brush, trash, etc.

A-g




INSPECTOR DISCIPUNE


OUTLET WORKS - OUTLET STRUCTURE AND MILL OUTLETOUTLET CHANNEL Not observed. (Abandoned).

Channel Discharges into main stream ofQuinebaug River below spillway

Loose Rock or Trees Overhanging None observed at discharge.Channel

Condition of Discharge Channel Natural Riverbed.

A-l0! !

-i

Im






OUTLET WORKS - SPILLWAY WEIR, APPROACHAND DISCHARGE CHANNELS

a. Approach Channel Natural Riverbed

General "Condition Underwater not observable

Loose Rock Overhanging Channel t o "

Trees Overhanging Channel None observed.

Floor of Approach Channel Underwater not observable

Weir Weir not observable, due to volumeof flow over crest; appears to bestone masonry.

b. Training Walls

General Condition of Stone Masonr Mortared stone masonry, good conditior

Rust or Staining N.A.

Spalling None observed.

Any Visible Reinforcing N.A.

Any Seepage or Efflorescence Slight

Drain Holes None observed.

C. Discharge Channel Natural Riverbed


Loose Rock Overhanging Channel None

Trees Overhanging Channel Some trees growing on channel.

Floor of Channel 2 small drops below dam.

Other Obstructions Several bridges downstream ofS spi l lway.

A-11

APPUDIX B

ENGIMJING DATA

7I77

APPENDIX B-i

DESIGN, CONSTRUCTION AND MAINTENANCE RECORDS AND LOCATION

Victor J. Galgowski, Dam Safety EngineerDepartment of Environmental ProtectionState Office Building165 Capital AvenueHartford, Connecticut 06115

Brian Trudell, Director of MaintenanceUnited Merchants and Manufacturers, Inc.16 Ashland StreetJewett City, Connecticut 06351

- - -~

APPENDIX B-2

COPIES OF PAST INSPECTION REPORTS

- ISTATE OF CONNECTICUT 2, 71S~~ IL

t th-A

STATE BOARD OF SUPERVISION OF DAMSRoom 317. STAre OPPic oW.DIUG. madIose

.wa* mPW0 etuNOu. dw A hI, . t o~~u 1iff u om mke., byin uIh.Oct"

PLEASE REPLY TO

#114 Thayer BuildingNorwich, Connecticut

October 13, 1954

Mr. William S. WiseChairman, State Water CoumistionState Office BuildingHartford, Connecticut

Dear Sir:-

On October 7, 1952 1 reported on several dams along thePachaug River. This report covers several additional dams notpreviously covered.

(1) Stone Dam of Fisk Kill Property (United )erchants Foundation)

This dam is located on the Pachaug River a few feet Northeastof Slater Avenue in the Borough of Jewett City, Town of Griswold.This is a stone masonry dam, resting on ledge with stone masonryabutments. Some repairs were made to the dam in 1943 and it isnow in good shape. A conside'rablo length of stone wall existsboth upstream and downstre from the dam along the pond and riverbut these are in good shape and will require no work for some time,

I would say that this structure is in good condition and willrequire no major expenditures for i long time,

(2) Concrete- Dam of Fisk kill Property (United Merchants Foundation)

This is a small concrete dam located a short distance downstreamfrom number (1) described above. There are two sets of wheels in thisplant and this diverts the water through the lower set of wheels.This dam has drawoff gates and the dam itself and appurtenanceswere repaired in 1943. It is in excellent condition and in myopinion will require no work for some time.

(3) hand Dan

This dom is located on the PachauK River a short distanceNortheast of Ashland Street in-Jewett Vity, Town of. Griswold.

The spillway is a stone masonry section with stone abutmentsand au iliw7 works below it. The dom north of the spillway is N D

earth embankment for several hundred feet above the millbuilding. All of these structures are in good condition andshould require no repair work for a number of years.

(4) eachdale Dam

This dam is located at the Northerly end of Buachdale Avenuein Voluntown, Town of..Voluntown. It is a short distance West ofRoute #138.

This is an earth structure several hundred feet long withstone facings near the top. It has two spillways with woodplank foot bridges across and a wooden gate house,

All of the woodwork at these two crossings should be replacedin a short time. This is not too expensive an item but it shouldbe done. Some of the concrete on .the North spillway has washedaway by scouring and should be patched. The dam itself appearsto be in good condition. I think perhaps 43000 should be consideredas probable expense in the forseeable future.

(5) Douglas Pond

As you know, this dam Washed out several years ago andhas not been replaced. I have not made a detailed study ofthis but I would estimate it would cost at least $50,000 toput this back in shape again.

Very truly yours.

Mol/ew

OCTSTATE WIL "

MAL. TV I.

7 77

- =77

A

IL

low

_7M

Awilli

4L,. ALdFAIC

NT1zi.)li'.\I it r \iN r \i ;iF, -AV F ;,1 T I ., .

File __ Water Resources Commission Jan. 29, 1971

William H. O'Brien% III A('FNC' Water Resources Commission

r. I .v _n gi e -q._eer"

SJ sh Ashland Pond Dam, Griswold

I

I In dam folder entitled "Early Dams-Conn-New England"

item J, Page 2, there is a paragraph concerning the much greater

water usage during low flow months at this dam by the Ashland

cotton-mill due to development of reservoirs upstream pound

1865)for control of water.

Civil Engineer

WHO, ljg

II

APPENDIX B-3

IMCORD DMINZGS AN~D SICZTCHES

!A

A - -

STA 0 00TRANSFORME TAT ON

ASHLAND poND

T ANSFO RMR SPRI KLE SySTEM INTAKE

STA 1* 00~

oi~ IPEABANOOED GATES

PIPE 0 PENSTOCKO

P AICLAAGIRIV E R MIL LN Y C E '

ABANDONEDjSE O

GALL NO-AN I

RDPOAT

',J-I I F0

s1

I

i ii li 9 L

,

; I

,, %' ,r--.

I L

-II

S4. ". •

I tt

i j

0-

, • . . . .l. k :,,k .. ... * ..... ".. .

....... " ' " a - :. .. ... . ., .;,) ' '

I

APPENDIX C

PHOTOGRAPH

C-6 ASHLAVO 00#0

TRANSFORMER POLE--..0 SPRINKLER SYSTEM INTAKE

168-11IA piABANDONED GATES TO MILL

TO MILAL C-EST

MPHOT NODEI

C-2 Crest of Dam Embankment.

c-1

C-3 Downstream face of Dam.

C-4 Downstream face of Dam.

C-

F C-5 Downstream of Dam.

C-6 Kill1 Fire Protection Systm Intake Structure.

I C-3

C-7 Dam Spillway.

C-8 DM Spillway and Left-Abutment.

C-4

C-9 Abandoned outlet Control Structure.

C-10 Outlet Channiel andLeakage frcm AbandonedOutlet Control Structure.

C-!5

g C-11 Abandoned Headrace.

C-12 Downstream Channel.

[ C-13 Structure f or Abandoned Penstock intake.

C-14 Structure for Abandoned Penstock intake.

C-

C-15 Eiosion of Right Mbankment.

C-

I IIII

I iII1*1

I1 AU'!UDII D

ETD~1~OGIC AND ITDR*ULIC ~ONWZ&TIONS

I.IIII

i

I

N or0( D FUR 'E cFj 0, %AJ t I,

rP~r i'~ *Po~efl

/ 2. N

K"

a~p~ap I' \

~ f486;

O~Io ~ ~ ~ J atNtw

I~I~ )tyM~

rld "Ca - r e

ASHAN POND DA PLT0 o -____ r PIA.,a~gon

'09 16 N.. t

dO Lr'4< C- lePond N

119 Roo'

ft_4-- 1'ell

2722& "V tE~CHN ~ s hl d

Pond

'5 6.'~' \ , j

A. size Classification ASHLAND Ashland Pond Dam

Height of am - 25.0 ft.; hence Smal l

Storage capacity at top of dam (elev.133.0) - 1000 AC-F?.; hence Tntmqd .

Adopted size classification Intermediati

3. i) Hazard Potential

Dam iS loated in iirhan indiitril ; nk nf Jewett City and ig a rnmurrp nf

,standby water to its n , d Menit c hant, Manufacturer. Inc.. Failure

of dam will cause aooreciable damaae to road--Rnute I? and Rnifte 13P--

and to many houses and mills.

ii) Impact of Failure of Dam at Maui Pool (Top of Dan)It is estimated from the urle of "thimb failure hydrograph, that the follow-

inq adverse impacts are a possibility by the failure of this dam.

a) Loss of life to lives can be lost.b) Loss of homes Yes -T- to - hems can be lost.a) Loss of bligs - to * buildings can be lost.

d) Loss of hihways or roads -e roads can be damaged.e) Lose of bridges Yes o bridges can be lost.

b) Mll building can be damaged.The failure profile can affect a distance of innn feet ft= the dam. For

water surface elevation, see next page in Appendix 0.

C. Adopted Classifications

T=T FLOOD MW=E

High .... n4-- PMF

Adopted Test lood Full ... - 7on CsM

- 43274 CPS

D. oyextopiing potentialDrainag II 61.82 sq. miles

Spillway =*at elevation 127.0 V=Top of Dam Ilevation - AA n IGVD

'axim spitlwaY disch=eCapacity without overtoping of dam - ._ _ _ € .

"test flood inflow discharge US_______________________

"test flood" outflow discharge -42000I of "test flood" overflow carriedby spillway without overoing 13.2%

hoverflow over the dam 36465lb of test flood which overflows over the dam - 8 6 .0%

i illii

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"Rule of Th b Gudanace for EstinatingDown stream Dam railur* Discharge"

BASZC DATA

m of dam Ashland Pond Dam Name of town Jewett City, Conn.

Draina; e area = 61.82 sq. mi., Top of dam =3.0

spil way type - Overflow: vertical fall-, sharpCrest of spillway 127.0 N I

Surface area at cret elevation 0.13 So. Mi. (83.0 Acres)

Reservoir bottom near darnm 1 flR NGWD __________

Assumed side slope" of embankments ._2H_: _lV____

Depth of reservoir at dai site 7_N -Y-o " -n .

Mid-heiqht elevation of dan - 120.5 NGV

Length of damat crest- 40( foot

:emnqh of dam at mid-heiqht - 375 feet

22% of dam length at mid-height Wb - 84 feet

stai 1:

Elevation (1NGVD) r-st±Aote Strg in Cr

127.0 502128.0 585129.0 668130.0 751131.0 834132.0 917133.0 1000

Stag 2:a )W yo3/2 17565

Failure discharge - 17565 + 5535 - 23100 C.F.S.

NOM!: railue of dam Ise asumed to be stantaneous when pool reaches top of dam.

Failure of dam is assumed as partial width - full depth failure.l" Failure site is assumed at the side of spillway section.

II

3 Ashland Pond Dam

~~Dam Failure AnalysiLs

. Failure d.ischare with Pool at ip rf d (Olev. 133.0) = CII

2. Depth of water in reservoir at time of failure - 25.0 ft.

3. maximom depth of flow downstream of damat time of failure ) , 17.0 ft.

4. Water surface elevation just downstream)of dam at time of fallure L - 125.0 NvD

The failure discharge of 23100 CPS will enter Pachaua River and flow down-

stream 4,000 feet until the brook ,ins Ouinebauo River , Tha*e in siqni-

ficant valley storage in this 4,000 feet length of brook to reduce the

i Lscharge substantily. Also duet to rouqhnoss characteriti' cs, obstructi.ons and

fricti onal l.osses, it is very, likely th a h nsteady dam falurm.e flaw will disJsi.pate

Mani na' s fo le 4,000 feet downstream. The failure profile will have the

ifollowin hydrsuol ctoaracaerestics-s

o +. 00 133.0 Ups rem of dmo + 00 125.0 Do wse m of dtam

10 + 00 120.020 + 00 115.030 + 00 110.040 + 00 105.0 Joins Quinebaug River

Beyond a f -fot In nin.ahaua River thefailure discharge will flow in the below given channel c--- cesticst

= ,,___ __ _ law s - 0.0111

n aa05- be varies ,d 15.0 feet

Side slopes lV or 23.

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IJASHLAND POND DAM

COMPUTATIONS FORSPILLWAY RATING CURVE

Spillway width = 1O.0 feet - Spillway crest elevation 127.0 NGVD

Length of dam = 400 feet; Top of dam elevation = 133.0 NGVD

c * 3.3 for sillway and 3.0 for dam

SPILLWAY RATING CURVE COMPUTATIONS

SPILLWAYELEVATION DISCHARGE

(FT.) (CFS) REMARKS

127.00 0 Spillway crest elevation129.00 1027131.00 2904133.00 5535 Top of Dam135.00 8929137.00 15135139.00 23171141.00 32688142.70 42000 Test Flood Elevation

Notes: 1. Maximum Spillway Capacity - 5535 CFS

2. Maximum Outlet Capacity a 1044 CFS At top

of dam.

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ASHLAND POND DAM

TAILWATER DISCHARGE*RATING CURVE

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APPEZIDIX E

ITNFORMATION AS COITTAIED rIT T'HENATIONAL INVENTORY OF DAMS

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