BASIS OF DESIGN REPORT - DURHAM WATERLINE REMEDIAL DESIGN …

Prepared by:AECOMRocky Hill, CT60445033May, 2018

Basis of Design Report – DurhamWaterline Remedial DesignDurham Meadows Superfund SiteDurham, Connecticut

EPA Contract No. EP-S1-06-01EPA Task Order No. 0072-TA-TA-01D5EPA Project Officer: Heidi HorahanEPA Task Order Project Manager: Ed Hathaway

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Contents

1.0 Introduction ............................................................................................................... 1-11.1 Background .......................................................................................................................... 1-1

1.2 Site Description and History ................................................................................................ 1-1

1.3 Purpose ................................................................................................................................ 1-4

2.0 Hydraulic Analysis .................................................................................................... 2-12.1 Purpose ................................................................................................................................ 2-1

2.2 Existing System.................................................................................................................... 2-1

2.3 Recommended Water System Expansion .......................................................................... 2-1

2.4 Model Development ............................................................................................................. 2-3

2.5 Talcott Ridge Drive Boosted Pressure Zone .................................................................... 2-21

2.6 Recommendations ............................................................................................................. 2-23

3.0 Regulatory Coordination and Permits ...................................................................... 3-13.1 Summary of Permit Requirements ...................................................................................... 3-1

3.2 Identified Resources and Mitigation during Construction ................................................... 3-4

4.0 Subsurface Investigation Program ........................................................................... 4-14.1 Cherry Hill Water Storage Tank .......................................................................................... 4-1

4.2 Pipeline Foundation (from connection to Middletown line through and including Area Aand a portion of Area I) ........................................................................................................ 4-2

4.3 Pipeline Foundation (extension to a portion of Area F including the RSD #13 schoolsystem) ................................................................................................................................. 4-3

4.4 Water Meter Vault and Talcott Ridge Booster Station ........................................................ 4-4

5.0 Design Criteria .......................................................................................................... 5-15.1 Reference Standards ........................................................................................................... 5-1

5.2 Elevated Storage Tank ........................................................................................................ 5-1

5.3 Water Distribution Pipe and Support Services.................................................................... 5-2

5.4 Site Civil Works .................................................................................................................... 5-4

5.5 Hydrants and Valves ............................................................................................................ 5-4

5.6 Operation and Control Strategy ........................................................................................... 5-5

5.7 Water Quality Modeling ....................................................................................................... 5-6

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5.8 Water Supply Well Abandonment ..................................................................................... 5-10

5.9 Water Supply Well Conversion to Monitoring Well ........................................................... 5-10

6.0 Contract Packaging................................................................................................... 6-16.1 Contract Packaging.............................................................................................................. 6-1

List of AppendicesAppendix A 100% Design Drawings – Provided under separate cover

Appendix B 100% Specifications – Provided under separate cover

Appendix C Wetland Delineation Memorandum (July 2017)

Appendix D1. Geotechnical Design Memorandum: Cherry Hill Water Storage Tank (on CD in backpocket of report)

Appendix D2. Geotechnical Design Memoranda: Durham Meadows Waterline RD, RevisedOctober 27, 2014 (on CD in back pocket of report)

Appendix D3. Geotechnical Design Memoranda: Durham Meadows Waterline RD, RevisedFebruary 5, 2016 (on CD in back pocket of report)

Appendix D4. Geotechnical Design Memoranda: Durham Meadows Waterline RD, October 2017(on CD in back pocket of report)

Appendix E Agency Correspondence and Permit Documents

Appendix F Purchasing Standards for Waterworks Material, Connecticut Water Company andMaine Water Company (Rev. October 2016)

Appendix G General Requirements, Water Main and Service Installation, City of MiddletownWater and Sewer Department, (January 2017)

Appendix H Value Engineering Screening of the Remedial Design Memorandum (Rev. January30, 2015)

Appendix I Durham Water Quality Modeling Memorandum dated October 20, 2015 regardingAECOM Protocol for Durham Water TTHM Testing.

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List of TablesTable 1. Tank Volume Alternative Analysis ..................................................................................... 2-4

Table 2. Demands used in Model .................................................................................................... 2-8

Table 3. Needed Fire Flow Analysis .............................................................................................. 2-10

Table 4. System Analysis with Cherry Hill Tank Off-Line .............................................................. 2-19

Table 5. Domestic Water Supply Flow Requirements ................................................................... 2-22

Table 6. Estimated Talcott Ridge Pump Station Service Area Pressures .................................... 2-24

Table 7. Summary of Results of Baseline Sampling ....................................................................... 5-7

Table 8. Summary of Chorine Decay and TTHM Formation .......................................................... 5-9

List of FiguresFigure 1. Proposed Water System Expansion .................................................................................. 1-3

Figure 2. Recommended Infrastructure Improvements for RD Project............................................ 1-5

Figure 3. Critical Elevations for Cherry Hill Tank .............................................................................. 2-2

Figure 4. Proposed PRV Location ..................................................................................................... 2-6

Figure 5. Boosted Pressure Zone Options........................................................................................ 2-7

Figure 6. Location of Existing Middletown Demands........................................................................ 2-9

Figure 7. Maximum Day Extended Period Results – Cherry Hill Tank .......................................... 2-16

Figure 8. Pump Operation with Cherry Hill Tank Off-line ............................................................... 2-21

Figure 9. Talcott Ridge Drive Pressure Zone Boundary ................................................................. 2-22

Figure 10. Critical Volumes for Cherry Hill Tanks ............................................................................. 2-25

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1.0 Introduction

1.1 BackgroundThis Basis of Design Report (BODR) for the Durham Meadows Waterline task order was prepared todefine the technical parameters used to design the remedy. The rationale for the selected remedy ispresented in the Record of Decision (ROD) for the Durham Meadows Superfund Site (EPA, 2005).

The BODR was prepared by AECOM under the EPA Response Action Contract 2 (RAC 2), EP-S1-06-01, Task Order #0060-RDRD-01D5 and revised under RAC2 Task Order #0072-TA-TA-01D5.Pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act of 1980(CERCLA), 42 U.S.C. § 9601 et seq., a Remedial Investigation (RI) and Feasibility Study (FS) wereoriginally prepared for the Site in 2005. EPA issued a Record of Decision (ROD) in September 2005(USEPA, 2005) that selected remedial actions for all areas of the Site, based on the results of the2005 RI and FS. Three study areas were included; the Durham Manufacturing Area (DMC), theMerriam Manufacturing Area (MMC), and the Site-wide Groundwater Study Area, each described inbelow. This BODR addresses the Alternate Water Supply for the Site-wide Groundwater Study Areawhich includes a buffer zone of residences located near the contaminated area.

1.2 Site Description and HistoryThe Durham Meadows Superfund Site is located in the town of Durham, Connecticut, and includes anarea of groundwater contamination generally centered on Main Street. The Site includes historic MainStreet in Durham center, and contains industrial and residential properties. It is generally bounded byTalcott Lane to the north; Brick Lane, Ball Brook and Allyn Brook to the East; wetlands west of MapleAvenue to the west; and, based on recent sampling, the intersections of Maple Avenue and FowlerAvenue with Main Street to the south.

The Site is centered around the Durham Manufacturing Company (DMC), a currently operatingmanufacturing facility located at 201 Main Street (the “DMC Study Area”), and the former location ofMerriam Manufacturing Company, Inc. (MMC) at 281 Main Street. The Merriam ManufacturingCompany Study Area, or “MMC Study Area,” includes the property on which the MMC plant wasformerly located at 281 Main Street, and the abutting residential property at 275 Main Street.

Both companies manufactured metal cabinets, boxes, and other items. The companies’ past disposalof wastewater in lagoons or sludge drying beds, spills at both facilities, and inadequate drum storagepractices at MMC, among other things, contributed to the contamination at each facility and in theoverall area of groundwater surrounding both facilities (the “Site-wide Groundwater Study Area”).Contamination from volatile organic compounds (VOCs) has been detected in soil and groundwateron both industrial properties, as well as in residential drinking water wells surrounding the MMC andDMC facilities. As of September 2017, there are 54 locations where GAC filtration units and/or bottledwater are necessary due to groundwater contamination. Regular monitoring occurs at 28 additionallocations, where filtration and/or bottled water are not yet needed.

The Record of Decision for the Site was issued on September 30, 2005. For the Site-wideGroundwater Study Area, the remedy includes a connection to the city of Middletown’s WaterDistribution System to distribute an alternative source of public water to all residences currentlyaffected by groundwater contamination and a buffer zone of residences located near thecontaminated area. The city of Middletown is located north of the town of Durham. This alternativeaddresses current and future risk to human health from ingestion of contaminated groundwater.

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Under this alternative, the existing Middletown Water Distribution System will be extended from thecity of Middletown south along Route 17 to residences within the Study Area providing potable waterto all impacted residents and reducing current and future risk to human health from ingestion ofgroundwater. This alternative will provide a permanent source of drinking water to all residencescurrently affected by groundwater contamination and a buffer zone of residences located near thecontaminated area. This alternative, combined with institutional controls on existing groundwater use,will prevent exposure to contaminated groundwater.

Since the ROD was issued, EPA has been working with a large number of entities to address thewater system extension, including the Connecticut Department of Energy & Environmental Protection(CT DEEP), the Connecticut Department of Public Health (CT DPH), the city of Middletown’s Water &Sewer Department, and the town of Durham. The parties identified a number of contaminated areaswithin the town of Durham that could be provided with a public water supply at some point in thefuture, with the main focus being the Superfund Site area. EPA fully considered the long-termplanning input from the state and local communities when developing the design for the water line tobe provided to the Durham Meadows Superfund Site.

Through a contract with the town of Durham, Fuss & O’Neill, Inc. (F&O) developed the “Durham WaterSystem Extension Feasibility Study Update” (F&O, 2012; herein referred to as the F&O Report) andan “Environmental Impact Evaluation of the Durham Water System Extension” (F&O 2012a). Thesereports were originally prepared in 2010 and revised in November 2012. The F&O Report identifiednine (9) areas with the town of Durham with documented well contamination problems. The SuperfundSite-Wide Groundwater Study Area, as defined in the 2005 ROD, is identified as “Area A”.

The F&O report includes provisions and costs for development of additional sources of water withinthe city of Middletown to provide potable water to the affected areas in Durham. Although the 2012F&O Report states that Middletown has little excess capacity, the CT DPH has informed the EPA thatMiddletown has updated its water supply plan and that CT DPH has agreed that Middletown now hasenough capacity and safe yield to supply water (including fire protection) to all identified areas withinthe town of Durham. (A copy of the updated plan has not been provided to EPA or to AECOM.)

In late 2013, sampling results indicated that contaminated groundwater had migrated to potable wellsbeyond Area A, into a portion of the Durham Center Area, defined as “Area I” in the F&O report, southof Allyn Brook. Based on these findings, a decision was made to extend the Superfund Site boundarysouth of Allyn Brook to the intersection of Maple Avenue and Main Street, to incorporate areas ofknown contamination and a buffer zone of residences located near the contaminated area.

EPA identified the need to eliminate the pumping well on the property of school district RSD 13 toprevent future migration of the contamination. As a result, the design was revised to include the RSD13 schools adjacent to the DMC facility location. The RSD schools were identified as “Area E” in theF&O report, and include the Coginchaug High School, the Korn Elementary School, and the StrongMiddle School (RSD13) located on Pickett Lane along with additional residents along Maiden Lane.

The Superfund Site, identified as “Area A”, the Durham Center Area (Area I), the Schools Area (AreaE), and each of the other areas (B through H), as well as the new piping, the proposed Cherry HillStorage Tank, and the Long Hill Pump Station (to be upgraded) are shown on Figure 1.

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Figure 1. Proposed Water System Expansion

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PROPOSED WATER SYSTEM EXPANSION 8

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1.3 PurposeThe overall project objective is to provide potable water to all properties located within the Site-wideGroundwater Study Area. This includes the abandonment of existing drilled and dug wells on privateproperty and connection to a new municipal water supply.

AECOM has been tasked to design a system to meet the identified needs of the areas within theSuperfund site and to also not restrict the opportunity for the state and community to serve other areasin the future. Based on the F&O report and AECOM’s scope of work under contract to EPA, thedesign includes the following:

· For the Site-wide Groundwater Study Area, a new water transmission line, connecting theMiddletown Water Distribution System to distribute public water to all residences located inArea A;

· Sizing of the main trunk line (from Middletown into Durham), storage tanks, and pumpingstations such that all study areas could be served in the future;

· Fire protection capacity for all study areas, including greater capacity piping, as needed, andfire hydrants along the transmission main to and on distribution mains within the SuperfundSite Area;

· Secondary piping beyond the main trunk and all connections to residential homes andbusinesses within “Area A,” the Superfund Site area, and the portion of the Durham CenterWater System service area (Area I) that is impacted, and a portion of “Area E,” the Schoolsarea;

· For all other areas outside of the Superfund Site, including study areas B through I (except asidentified), stub line connections along the main trunk as needed in order to serve these areasin the future;

· New potable water storage tank (Cherry Hill Storage Tank);

· Pressure Reducing Vault;

· Meter Vault at the Middletown/Durham line;

· Booster Station to provide domestic water service to 23 single family homes located onTalcott Ridge Drive and Watch Hill Drive; and

· Abandonment of wells located within designated areas (Area A,a portion of Area I on MapleAvenue and Main Street between Maple Avenue and Allyn Brook, and a portion of Area E onPickett Lane and Maiden Lane).

· Connection to the existing Durham Center Water System service area at Mill Pond LaneNorth of Allyn Brook

· Connection to the existing Durham Center Water System service area at the capped end inMaple Avenue South of Allyn Brook, and

· Disconnection of the Durham Center Water System from the Fairground Wells boosterstation.

The scope of the new infrastructure proposed for the Durham Meadows Waterline RD expansionproject piping is highlighted yellow in Figure 2 on the following page.

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Figure 2. Recommended Infrastructure Improvements for RD Project

MIDDLEFIELD

RECOMMENDED INFRASTRUCTURE IMPROVEMENT FOR RD PROJECT

Durham property lines are based oo Tovm of Durham Assessa- Maps Middletown property lines from CT DEEP

5()0 1,000 2,000 --=::::::11---•Feet

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As an initial task during the preliminary design phase, AECOM reviewed the F&O report to verify thewater demand requirements for the Study Areas. After verification of the water demands, the existingMiddletown Hydraulic Model of its Water Distribution System was utilized to simulate various demandconditions: average day, maximum day, maximum day plus fire flow, and peak hour demands for theproposed water system improvements. The results of these analyses were used to verify water maindiameter sizes, establish the required hydraulic grade line and capacity required for the proposedwater storage tank, establish pump capacities needed to boost system pressures during high demandperiods, and to identify required pressure regulating valve settings. A summary of this analysis (asrevised for the extended service area requirements) is contained in the following Section 2 – HydraulicAnalysis.

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2.0 Hydraulic Analysis

2.1 PurposeThe purpose of the Hydraulic Analysis is to evaluate the proposed expansion of the Durham Watersystem and connection to the Middletown water system. The analysis included the recommendedexpansion as well as potential future build out of the water system in Durham. Modifications to theMiddletown system will include construction of a new water storage tank and construction of a newwater main from the tank to the Durham municipal boundary. The water infrastructure in Durham willinclude water mains and appurtenances to serve the areas indicated. Design of the modifications tothe Middletown system and the new infrastructure in Durham will be based on the planned full build-out of the system in Durham as indicated in Figures 1 and 2 in Section 1.0.

2.2 Existing SystemMiddletown. As previously noted, the City of Middletown and the CT Department of Health (DPH)have stated there will be sufficient capacity to supply the additional flows projected for the Durhamsystem from the existing Long Hill pumping station. Planned increases in water supplies inMiddletown are also assumed to have been implemented prior to connection to the expanded systemin Durham.

The Long Hill pump station has two 750 gpm fire duty pumps and a jockey pump with ahydropneumatic tank to serve existing customers in Middletown. The pumps draw from the existingLong Hill tank which operates with a water level between elevations 336 to 346 feet as indicated byMiddletown Water Department. The ability of these pumps to serve the existing customers and thenew customers in Durham is evaluated in this report. The assumed elevation in the Long Hill tank is336 feet for all evaluations herein.

Durham. There are several small public water supply systems serving parts of Durham (e.g., DurhamCenter System, Durham Elderly Housing Division, several systems serving condominiums andschools, etc.). These systems’ supplies are restricted for various reasons and are not sufficient toserve the entire proposed service area in Durham. There is limited water distribution infrastructure insome of these systems with the most extensive in the Durham Center system.

2.3 Recommended Water System ExpansionThe F&O report recommended development of the water system in Durham to include the Core Areaconsisting of the Superfund site and other areas. The expanded water distribution system wouldinclude water mains from the intersection of Main Street at Higganum Road in Durham, north to theDurham/Middletown town line. In Middletown the water distribution system would be expanded fromthe Durham/Middletown town line north to the Cherry Hill Tank. The future build-out of the waterdistribution system, which was included in the model, is expected to include all areas shown inFigures 1 and 2 as described in Section 1.0

The Hydraulic Grade Line for the proposed system will be set by the water level in the proposedCherry Hill Storage Tank. Ground elevations within the Durham service areas range from 150 to 480feet. Section 19-13-B102(f)(1) of the Regulations of Connecticut State Agencies (RCSA) requires thatall service connections have a minimum water pressure at the main of 25 psi under normal operatingconditions which in these guidelines includes normal peak demands but excludes fire flow demands.Whenever feasible, it is recommended that the minimum water pressure be 35 psi. Positive pressure(20 psi minimum recommended) should be maintained under all flow conditions, including fire flows if

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fire protection is provided, within the distribution system as measured in the street. Pressure reducingdevices should be installed where static pressures will exceed 100 psi. The F&O Reportrecommended that this tank's ground elevation would be 430 feet with an overflow elevation of 505feet. Further evaluation of the service area by AECOM found that there is an existing water serviceon Talcott Ridge Road in Middletown that is at elevation 406 feet. This is the controlling elevation fortank levels to maintain adequate system pressures. Figure 3 shows the critical elevations in theCherry Hill tank to maintain adequate minimum pressures.

Figure 3. Critical Elevations for Cherry Hill Tank

There are other high elevations along Acorn Drive in Durham that will require additional boosterpumping when this area is connected to the system to maintain adequate pressures. Lowerelevations occur in the Durham Center area will require installation of a pressure reducing valve. Thefollowing additional infrastructure is necessary in areas to account for elevations and systempressures expected:

1. A pressure reducing valve (PRV) in an underground vault chamber is recommended along MainStreet just north of Middlefield Road to reduce static pressures along Main Street, Maiden Laneand Maple Avenue to a range of 50 to 80 psi regardless of whether fire protection is provided.

Minimum Level for Normal Pressure

406+ 35 psi x 2.31 ft/psi

487' MSL

Minimum Fire Flow Level 406+ 20 psi x 2.31 ft/psi+ 5.8

feet Head Loss Allowance

Highest Water Main Elevation at Customer

Connection

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2. If the water supply is expanded to Area H in the future, a future booster pump station will berequired along Main Street just north of Acorn Drive for Area "H". The ground elevation rangesfrom approximately 400 feet to 480 feet. This matches or is higher than the ground elevation ofthe Cherry Hill Storage Tank (440 feet). Pressures in this area would be less than acceptablegiven the expected range of water levels in the Cherry Hill tank.

3. A meter station at the town line.

4. A booster pump station on South Main Street in Middletown on the northern portion of the CTDOT property across from the intersection of Talcott Ridge Road to provide domestic waterservice to 23 single residential homes location on Talcott Ridge Drive and Watch Hill Drive. Theproposed Talcott Ridge water booster station and pressure zone will be supplied by the CherryHill Tank. The Cherry Hill tank will have a normal operating water range of between 508 and 498feet. The bottom of the domestic storage in the water tank will be at elevation 487. Without thebooster station the water pressure at the Talcott Ridge Drive cul-de-sac (elevation 410), which isthe highest location in the proposed Talcott Ridge pressure zone, would range between 44 and39.8 psi. However, the expected water pressure at the second floor of 199 Talcott Ridge Drive,which is approximately 43 feet higher than the cul-de-sac, would range between 25 and 21.2 psi.The hydraulic analysis for the booster station was not conducted using the model, but wasinterpolated based on model results, and therefore is not discussed in Section 2.4.

2.4 Model DevelopmentThe water distribution model of the Proposed Durham water system was developed in the Bentleysoftware WaterGEMS version 8.i. using the model provided by the Middletown Water Department toincorporate existing infrastructure. Pipe alignments in the model were developed to match thoseshown on Figure 2 as preliminarily developed by Fuss & O’Neil. The pipe sizes in the distributionmodel were initially based on the pipe sizes presented in Table 5-2 of the F&O report with somechanges made during design which are described herein.

A. Preliminary Design Modeling Components

The Cherry Hill tank will supply flows to the Durham system for peak demand equalization, firefightingand emergency storage.

The results of an analysis of potential tank volumes to meet these storage requirements are presentedin Table 1. Green highlighting indicates that sufficient storage is provided for that category.

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Table 1. Tank Volume Alternative Analysis

Tank Diameter, ft. 40 42.5 45 47.5 50 52.5 55

Unit Volume, gal/ft. 9,399.6 10,611.3 11,896.4 13,255.0 14,686.9 16,192.4 17,771.2

Elev., Ft. MSL

Base 441 Available Volumes, Gal

Min Level for Fire 458 Emergency Storage 159,793 180,392 202239 225,335 249,677 275,271 302,110

Days of Emergency Storage 0.7 0.8 0.9 1.0 1.1 1.2 1.3

Min Level for 35 psi 487 Fire Storage 272,588 307,728 345,728 384,395 425,920 469,580 515,365

Max Level 508 Equalization Storage 197,392 222,837 249,824 278,355 308,425 340,040 373,195

Required Pumping Time @750 gpm, Hours 5.5 4.9 4.3 3.7 3.0 2.3 1.6

Total Tank Volume, Gallons 629,773 710,957 797,791 888,085 984,022 1,084,891 1,190,670

Recommended TankDiameter

-----:::;;...-----

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AECOM’s model indicated that the PRV location will be along Main Street between the MiddlefieldRoad and Haddam Quarter Road as shown on Figure 4. The modeled pressure setting was 55 psi todetermine the extended period simulation (EPS) of tank level variation over a 24-hour (or longer)period of time.

Due to the elevations within the service area, a boosted pressure zone would be required to maintainpressures and fire flows in the future if water supply is extended to Area H. This area would includeeither of the following options, as shown in Figure 5:

1. Area H encompassing Acorn Drive, Holly Lane, Blackwater Drive and Ironwood Lane (Option 1).Option 1 incorporates the minimum area boosted pressure zone needed as indicated by thehydraulic model.

2. Evergreen Terrace may need to be included which would also include the addition of Royal OakDrive (Option 2). The pressures in the additional area included in Option 2 would be marginal, asindicated in the hydraulic model, if Option 2 is not implemented. If implemented, additional costwould be incurred from the need to increase the capacity of the proposed booster pump station(domestic pumps only) and additional water main construction to loop the system.

The sizing of the proposed water transmission and distribution expansion includes the demands fromthe area encompassed by Options 1 and 2. However, future connection of this area would alsorequire the construction of a new booster pump station in order to meet minimum flow and pressurerequirements. Therefore, the selection of Option 1 versus Option 2 would be based on a cost-benefitanalysis of the options and the available funding at the time of the improvements. The design of thisbooster pump station is not included in this design.

B. Demands

Potential demands to be served in Durham were presented in the Fuss &O’Neil report andsubsequently modified by AECOM based on information provided by the City of Middletown.Projected demands for the Durham system are based on the estimated unit demands as summarizedbelow:

· Single family 300 gpd

· Two family 450 gpd

· Multi-family 675 gpd

· Commercial/Industrial – Connecticut Public Health Code (PHC Table 4) was used fordemands

Demands for various model scenarios that were evaluated were as presented in the Fuss & O’Neilreport:

· Maximum Day Demand – Average Day Demand (gpm) x 1.5 multiplier

· Peak Hourly Demand – Average Day Demand (gpd) x 1/3 ¸ 60 min/hr.

The average day demand included an allowance of 10% unaccounted for water. The average dayand maximum day demands (gpm calculations) were based on 24 hours per day of operation.

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Figure 4. Proposed PRV Location

Proposed PRV

Location

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Figure 5. Boosted Pressure Zone Options

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Middletown provided information on the historical flows from the Long Hill pump station that representthe existing demands in Middletown served by the Long Hill pump station. In addition, the DurhamCenter Water System provided information on historical water usage for the Durham Fairgrounds.The fairgrounds’ demands are seasonal and are included only with the maximum day and peak hourdemands. Table 2 lists the projected demands for each area. Figure 6 shows the location of theexisting Middletown demands.

Table 2. Demands used in Model

AreaAverageDay, gpm

MaximumDay, gpm

Peak Hour,gpm

Existing Middletown Demands 6.0 9.0 48

A 40.0 60.0 320.0

B 12.2 18.3 97.7

C 6.0 8.9 47.7

D 14.9 22.3 119.2

E 8.0 12.0 64.0

F 21.9 32.8 175.1

G 12.6 18.9 100.8

H 25.7 38.5 205.3

I (existing) 9.1 14.6 77.7

I (future) 4.16 6.25 33.3

Durham Fair 0 66.84 384.72

Initial Demands

Total, Durham Only 57.10 153.44 846.42

Total w/Existing Middletown Demands 63.10 162.44 894.42

Build-Out Demands

Total, Durham Only 153.68 299.07 1,625.52

Total w/Existing Middletown Demands 159.68 308.07 1,673.52

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Figure 6. Location of Existing Middletown Demands

Existing Demands in Middletown

Br sh Hill Rd

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AECOM conducted a needed fire flow analysis of commercial properties within the service area whichare listed in Table 3.

Table 3. Needed Fire Flow Analysis

Address NameBuildingArea (ft2)

FireProtection

ApproximateNeeded FireFlow (gpm)

Fire FlowDuration

(hr)

Tank Storage ToSupport Fire Flow

(gallons)

Municipal and Commercial Properties of Concern in Durham

203R Main Street DurhamManufacturing 66,997 Not Sprinklered 5,500 4hr 1,320,000

27 Parsons Lane Parsons LaneAssociates 38,784 Not Sprinklered 3,500 3hr 630,000

FairgroundsDurhamFairgrounds(largest building)

30,000 Not Sprinklered 3,500 3hr 630,000

350 Main StreetAdams Commons(2 story woodframe)


35 WinsomeRoad

ClaremontCorporation 29,220 Not Sprinklered 2,500 2hr 300,000

201 Main StreetDurhamManufacturingWarehouse


337 Main StreetAdams CountryBarn (Partial 2ndstory)


144 Pickett Lane Korn ElementarySchool 29,826 Part.

Sprinklered 2,250 2hr 270,000

30 TownhouseRd

Durham TownHall 5,961 Not Sprinklered 2,000 2hr 240,000

7 Maple Avenue Durham Library 11,754 Not Sprinklered 2,000 2hr 240,000

360 Main Street Office / Retail 8,800 Not Sprinklered 1,250 2hr 150,000

18 Middlefield Rd Dean’sAutomotive 6,072 Not Sprinklered 1,250 2hr 150,000

236 Main Street First Church ofChrist 4,076 Not Sprinklered 1,000 2hr 120,000

422 Main Street Automotive Sales 5,228 Not Sprinklered 1,000 2hr 120,000

13 Middlefield Rd AutomotiveRepair 4,440 Not Sprinklered 1,000 2hr 120,000

280 Main Street Notre DameChurch 3,758 Not Sprinklered 750 2hr 90,000

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Address NameBuildingArea (ft2)

FireProtection

ApproximateNeeded FireFlow (gpm)

Fire FlowDuration

(hr)

Tank Storage ToSupport Fire Flow

(gallons)

135 Pickett LaneCoginchaugRegional HighSchool

N/A Sprinklered 750 2hr 90,000

191 Main Street Strong MiddleSchool N/A Sprinklered 750 2hr 90,000

Commercial Properties of Concern in Middletown

2055 South MainStreet Tisbury LLC 36,885 Sprinklered Unknown

2081 South MainStreet Oaks LLC 59,557 Sprinklered Unknown

2303 South MainStreet

Jem WireProducts 33,670 Not Sprinklered 3,000 3 hr 540,000

60 Trigo Drive Trigo Realty 13,950 Sprinklered Unknown

Based on discussion with EPA and municipal officials in Durham and Middletown, it was agreed that afire flow of 2,500 gpm would be the largest fire flow that could be provided within the system. Theduration of this event would be 2 hours. As indicated in Table 3, there would be some structures forwhich the needed fire flows would be provided by other means available to the Durham FireDepartment. For modeling purposes, these fire flows were simulated at the intersection of Main Streetand Higganum Road, the furthest location from a tank within the entire system including areas beyondthe Superfund site.

C. Model Scenarios Evaluated

To facilitate the design of the storage tank and pump station, the system was evaluated under fullbuild-out conditions to ensure the piping from the pump station to the tank and the transmission mainon Main Street (Rte 17) are large enough to convey future demands. These facilities must bedesigned for the following operating and demand conditions:

· Normal Operations

- Steady State Analyses

- Maximum Day Demands

§ Full Build-Out - 0.44 MGD

- Maximum Day Demands plus fire flow

§ Full Build-Out - 0.44 MGD plus 2,500 gpm fire flow

- Peak Hour Demands

- Full Build-Out 2.40 MGD

- Available Fire Flow

- Full Build-Out 0.44 MGD

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· Extended Period Analyses

- 72 hours for hydraulic analysis



- Maximum Day Demands plus Fire Flow

§ Full Build-Out - 0.36 MGD plus 2,500 gpm fire flow, for a duration of 2 hours

- 1800 hours (75 days) for water quality analysis

- Average Day Demands

§ Initial - 0.09 MGD


D. Evaluation Criteria

The results of each scenario were evaluated using criteria appropriate for the type of simulationconducted. These are listed below:

· Normal Operations:


- Maximum Day Demands - System pressures between 35 psi and 100 psi

- Maximum Day Demands plus fire flow - System pressures greater than 20 psi

- Peak Hour Demands - System pressures between 30 psi and 100 psi

- Available Fire Flow Analysis – available flow at junctions and hydrants with a residualpressure of 20 psi

- Extended Period Hydraulic Analyses

- Maximum Day Demands - Minimum system pressures greater than 30 psi andmaximum system pressures less than 100 psi. Tank level at end of analysis is within+/- 1 foot of starting tank level

- Maximum Day Demands plus Fire Flow - Minimum system pressures greater than 20psi. Minimum tank level such that system pressures are maintained.

- Extended Period Water Quality Analyses

- Determine water age in storage tank and within the system to assess the need forbooster chlorination

E. Modeling Results

The results of each scenario are presented below along with discussion of the findings and designparameters determined in these scenarios:

· Normal Operations:



§ Initial Tank elevation set at 491 feet

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§ Long Hill pump 1 on with discharge pressure set point at 75 psi

§ Pressures

§ Served directly from Long Hill PS:

§ Minimum 35.1 psi at 214 Talcott Ridge Dr.

§ Maximum 96.9 psi at Main St. and Winsome Road

§ Downstream of PRV:

§ Minimum 52.2 psi at Oak Terrace and Woodland Road

§ Maximum 93.4 psi at Talcott Avenue and Middlefield Road.

§ PRV located on Main Street just north of intersection of Haddam Quarter Road,with a pressure setting of 55 psi

§ Flow of 198 gpm and a head loss of 124.2 feet, shown in Figure 4

§ Long Hill Pump(s)

§ Flow 741.3 gpm at 161.2 feet

§ Cherry Hill Tank

§ Flow 914.75 gpm ( Filling)

§ Locations (represented by model nodes) that would need to be serviced by aBooster Pump Station to meet minimum pressures, as shown in the attachedmodel schematic in Figure 5:

§ J-1336 through J-1339

§ J-1343 through J-1347

§ Pressure at booster station suction on Main St. 68.4 psi

- Maximum Day Demands plus fire flow -



§ Fire flow of 2,500 gpm at Main St. and Higganum Rd.

§ Pressures


§ Minimum 21.4 psi at 214 Talcott Ridge Road

§ Maximum 84.6 psi at South Main St. and Long Hill Rd. (Middletown).


§ Minimum 37.1 psi at Main St. and Higganum Rd.

§ Maximum 88.8 psi at Wallingford Rd. at Maple Ave.


§ Flow of 2,698 gpm and a head loss of 115 feet and a head loss of 63.7 feet,shown in Figure 4


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§ Flow 1,048 gpm at 141.1 feet

§ Cherry Hill Tank

§ Flow 1,756.9 gpm (Draining)

§ Closed pipe along Oak Terrace (P-6085 in the model) to facilitate the installationof the PRV on the main line


§ J-1336 through J-1339

§ J-1343 through J-1347


- Peak Hour Demands –



§ Pressures


§ Minimum 34.7 psi at 214 Talcott Ridge Road.

§ Maximum 95.5 psi at South Main St. and Long Hill Rd. (Middletown)


§ Minimum 52.0 psi at Haddam Quarter Road at Oak Terrace

§ Maximum 92.3 psi at Wallingford Rd. at Maple Ave.


§ Flow of 1,085 gpm and a head loss of 115 feet, shown in Figure 4


§ Flow 741.3 gpm at 161.2 feet

§ Cherry Hill Tank

§ Flow 914.8 gpm (Filling)


§ J-1336 through J-1339

§ J-1343 through J-1347


- Available Fire Flow


§ Long Hill pumps off

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§ Available fire flows evaluated for all areas served by Long Hill Booster Pumpstation except for boosted zone off Acorn Drive.

§ Minimum acceptable pressure = 20 psi for area evaluated

§ Minimum available fire flows:


§ Minimum 959 gpm at Edwards Rd. and Partridge Ln.

§ Maximum 3,500 gpm at several locations


§ 1,086 gpm at Haddam Quarter Road east of Olde Yankee Way

§ Maximum 3,500 gpm at most locations in zone

- Extended Period Analyses

§ Maximum Day Demands –

§ Initial Tank elevation set at 495 feet and at the end of the 24-hour simulation,tank elevation is 503.9 feet

§ The minimum tank level was 491 feet and the maximum tank level was 507.6feet during the 24-hour simulation. Tank level variation illustrated in Figure 7.

§ Pressures


§ Minimum 35.0 psi at 214 Talcott Ridge Road.

§ Maximum 104.1 psi at Main Street and Winsome Road.


§ Minimum 52.1 psi at Haddam Quarter Road east of Olde YankeeWay.

§ Maximum 92.8 psi at Wallingford Rd. west of Maple Ave.

§ Long Hill Pumps

§ Long Hill Pump 1 runs from 12:00 am to 5:00 am when it shuts off asscheduled.

§ Long Hill Pump 2 runs from 3:50 pm when the Cherry Hill tank leveldrops to 491 feet and continues to run until 12:00 am

§ Only one pump running at a time.

§ Max Flow of 805.1 gpm with an average of 641.5 gpm when apump is running.

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Figure 7. Maximum Day Extended Period Results – Cherry Hill Tank

Cherry Hill Tank - MaxDay-EPS -Hydraulic Grade (ft)

; 500 +-------------------------~

~ 5~ +------/-- ~ ------------------------6 "j 504

~ 502 +--- ~--------",---=-------------- ~ ~

-~ 500 +--,__-------~- ------------ ~--.; l 498 +---1------------__...,_ _________ ___,,~--/; -~ 496 -++----------------"~ -----~,,C.----'S ~ 4~ -i-----------------~--------=7"------> :::c 492 +------------------_, ________ _

4~ +--------------------------0 12

Time, hours

15 18

Cherry Hill Tank - MaxDay-EPS -Volume (gallons)

21 24

~ 400,000 .J,,,£---------------"" ..... ,---------------,~-""=-----.!! 'ii .. ~- 300,000 +------------------------E ~

~ 200,000 +------------------------

400

200

E 0

"' 3 .. ~-1; -200 0:

~ 0 ;.:

-400

-600

-800

6 9 12

Time, hours

15 18

Cherry Hill Tank - MaxDay-EPS -Flow (In - negative, out - positive)

6 9 12 15

Time, hours

21 24

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§ PRV located on Main Street just north of intersection of Haddam QuarterRoad, with a pressure setting of 55 psi,

§ Flow through valve ranged from a minimum of 63.1 gpm up to amaximum of 559.8 gpm with an average of 120 gpm.

§ Head loss through the valve ranged from a minimum of 123.9 feet upto a maximum of 141.1 feet with an average of 134.2 feet

- Maximum Day Demands plus Fire Flow –


§ The minimum tank level was 453.9 feet and the maximum tank level was 508.7feet during the 24-hour simulation

§ Fire flow of 2,500 gpm for two hours at node 1332 (Main Street at HigganumRoad), with a residual node pressure of 37.9 psi

§ Pressures


§ Minimum 20.0 psi at 214 Talcott Ridge Road

§ Maximum 104.6 psi at Main St. and Winsome Road


§ Minimum 37.9 psi at Cherry Lane and Higganum Rd.

§ Maximum 92.8 psi at Wallingford Rd. west of Maple Ave.

§ Long Hill Pumps

§ Long Hill Pump 1 runs from 12:00 am to 5:00 am when it shuts off asscheduled.

§ Long Hill Pump 2 runs from 3:50 pm when the Cherry Hill tank level drops to491 feet and continues to run until 12:00 am

§ Only one pump running at a time.

§ Max Flow of 805.1 gpm with an average of 641.5 gpm when a pump isrunning.

§ PRV located on Main Street just north of intersection of Haddam Quarter Road,with a pressure setting of 55 psi, shown in Figure 4

§ Flow through valve ranged from a minimum of 40.4 gpm up to a maximum of2609.8 gpm with an average of 136.6 gpm.

§ Head loss through the valve ranged from a minimum of 73.0 feet up to amaximum of 142.1 feet with an average of 133.9 feet

F. Additional Modeling and Results

Subsequent to the 90% Design additional modeling was conducted to consider the effects ofconnecting to the Durham Center system without including the recommended improvements at thistime. The modeling also considered the elimination of the 8-inch water main to loop across OldCemetery Road between Maple Avenue and Main Street and the addition of the 12-inch main atWallingford Road and Main Street along Maple Avenue to the Durham Center system connection.

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The hydraulic analyses concluded that even without the implementing the recommended pipingimprovements in Durham Center, water can be supplied at adequate pressures under all normaldemand conditions. The analysis did find that for steady state conditions the fire flow scenariosindicate the greatest impact from the modified piping configuration to connect to the Durham TownCenter system. Fire flows of 2,000 gpm in Durham Center (which were recommended in the Fuss &O’Neill Report) would cause reduced pressures at certain locations. However, the available steadystate fire flow would be about 1,360 gpm at either of the two evaluated fire flow locations in DurhamCenter; at the end of the 8-inch water main on Cherry Lane, and at Main Street and Higganum Roadwhich would be considered adequate at an increased level of risk.

The design does not include the 8-inch water main to loop across Old Cemetery Road between MapleAvenue and Main Street and the addition of the 12-inch main at Wallingford Road and Main Streetalong Maple Avenue to the Durham Center system connection. These are recommendedimprovements to be made in the future by others.

Operation with Cherry Hill Tank Off-Line

Analyses were conducted to assess the system pressures with the Cherry Hill tank off-line (such asfor maintenance). Also evaluated is the performance of the pumps at the Long Hill pump station.The results of this analysis are presented in Table 4. The results in this table indicate that pressureswill remain above 40 psi for all non-fire scenarios up to maximum day demand conditions and above20 psi for all fire flow scenarios. A maximum non-fire demand of 1523 gpm could be supplied which is91 percent of the full peak demand of 1673 gpm. The pump results indicate that a single pump wouldbe running for average day and maximum day demand conditions and that two pumps would berunning for maximum day demand, peak hour demand and fire flow scenarios. The pump controlswould need to be set so the pump speed is varied to maintain a constant pressure at the Long Hillpump station. Figure 8 illustrates the operating points of the pump for these scenarios with the pumpcurve shown for reference.

Water Quality Analyses

The water delivered to the Durham system through the Long Hill pump station will have traveled aconsiderable distance from the WTP in Middletown. Middletown officials estimated that the travel timeis about 3 days. As the water flows from the WTP to the pump station, the residual chlorinedisinfectant will have decayed from its initial levels. Water age analysis using the WaterGEMS modelwas used to assess the travel time in the Durham system from the Long Hill pump station. Water ageanalysis can be used as a surrogate method for estimating the extent to which chlorine will furtherdecay.

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Table 4. System Analysis with Cherry Hill Tank Off-Line

Model Label Elevation

InitialConditions- AverageDemands

Full-Build Out -AverageDemands

InitialConditions -

MaximumDemands

Full-BuildOut -

MaximumDemands

Full-Build Out- Peak Hour

Initial Conditions- Maximum + FF

Demands

Full-Build Out -Maximum + FF

Demands

System Demands ® 63.1 162.85 187.79 310.12 1523.25187.79 + 1,330

gpm FF310.12 + 1,215

gpm FFJunction Results

Pressure (psi)984 (Talcott RidgeRoad near tank) 410 45.74 45.51 45.41 44.81 20.42 20.02 20.00

J-1306 325.51 58.21 58.21 58.18 58.17 57.27 52.93 71.60

PRV-12 (Upstream) 239.39 119.55 119.28 119.16 118.47 91.26 89.98 90.10

PRV-12 (Downstream) 239.39 55.02 55.02 55.02 55.02 55.02 55.02 55.02

J-1332 (DurhamFairgrounds) 232 82.33 82.29 82.27 82.13 71.76 71.60 52.80

Pump ResultsFlow (gpm)

Pump 1 - Lead 330 61.99 156.48 91.46 152.17 753.24 756.63 757.81

Pump 2 - Lag 330 0.00 0.00 92.35 153.00 753.79 757.18 758.36

Pump 3 - Standby 330 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Head (ft)

Pump 1 - Lead 175.83 175.72 175.81 175.73 159.37 159.13 159.05

Pump 2 - Lag 0.00 0.00 175.81 175.73 159.33 159.09 159.01

Pump 3 - Standby 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Speed (rpm)

Pump 1 - Lead 1780.00 1780.00 1780.00 1780.00 1780.00 1780.00 1780.00

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Model Label Elevation

InitialConditions- AverageDemands

Full-Build Out -AverageDemands

InitialConditions -

MaximumDemands

Full-BuildOut -

MaximumDemands

Full-Build Out- Peak Hour

Initial Conditions- Maximum + FF

Demands

Full-Build Out -Maximum + FF

Demands

Pump 2 - Lag 0.00 0.00 1780.00 1780.00 1780.00 1780.00 1780.00

Pump 3 - Standby 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Pipe ResultsFlow (gpm)

Long Hill PS Discharge P-6013 61.99 156.48 183.81 305.17 1507.03 1513.81 1516.17

16-inch Main in MainStreet P-6058 57.08 152.88 177.76 296.16 1463.31 1507.76 1507.16

16-inch Main in TalcottRidge Dr P-6119 25.55 68.21 79.35 132.18 653.07 672.00 671.80

Velocity (ft/s)

Long Hill PS Discharge P-6013 0.18 0.44 0.52 0.87 4.28 4.29 4.30

16-inch Main in MainStreet P-6058 0.09 0.24 0.28 0.47 2.33 2.41 2.40

16-inch Main in TalcottRidge Dr P-6119 0.04 0.11 0.13 0.21 1.04 1.07 1.07

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Figure 8. Pump Operation with Cherry Hill Tank Off-line

Several analyses were conducted related to water age in the system under both initial conditions andfull build-out conditions. The analyses indicated that the average water age in the Cherry Hill tankswould be on the order of 4-6 days under full build-out conditions and on the order of 6-8 days underinitial conditions. This may be too long of a duration for the chlorine residual added at the MiddletownWTP to remain above levels required by Connecticut DPH (0.2 mg/l). Furthermore, the water age inthe Durham Center area would be on the order of 8 days under full build-out conditions and on theorder of 10-11 days under initial conditions.

In addition to the water age analysis conducted using the WaterGEMS hydraulic model, a separateanalysis of chlorine decay and trihalomethane formation was conducted that confirmed that thechlorine decay under some conditions would drop residuals lower than 0.2 mg/l within the water agesindicated by the model. Furthermore, the THM formation analyses indicated that with boosterchlorination, there is a potential for approaching or exceeding maximum contaminant levels for THM.As a result, booster chlorination will be included at the Long Hill pump station and aeration will beadded with a tank mixing system at the Cherry Hill tank to lower THM levels.

2.5 Talcott Ridge Drive Boosted Pressure ZoneThe Talcott Ridge Drive Water Booster Station is intended to provide only domestic water service to23 single family homes located on Talcott Ridge Drive and Watch Hill Drive in Middletown Connecticutas indicated in Figure 9.

Long Hill Pump Station Operation Without Cherry Hill Tank

250 Ini t ial Condi t ions -Average Demands

200

'; 150 ~ Ini t ial Condi t ions --g- Maximum Demands

~ 100

50

0 0 ....

0 0

N 0 0

Full-Build Out -

Full-Build Out -Average Demands

w 0 0

.,::. 0 0

V, 0 0

Full-Build Out -Maximum+FF

Full-Build Out - Peak

Maximum+FF Demands

er, -..J 00 I!) 0 0 0 0 0 0 0 0

Flow, gpm

.... 0 0 0

.... ""' 0 0

.... 1.,., 0 0

...... V, 0 0

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Figure 9. Talcott Ridge Drive Pressure Zone Boundary

Fire protection for this area will be provided by the new water mains and water storage tank proposedto serve the Town of Durham. Available fire protection flows are expected to be in excess of 2,500gallons per minute (GPM).

Service Area Flow Requirements

The required domestic flows for the proposed booster station service area are included in Table 5 andare based upon the domestic flows provided in the Section 2.4.

Table 5. Domestic Water Supply Flow Requirements

Criteria Gallons Per Day (gpd) Gallons Per Minute (gpm)Average Daily Demand (ADD)(23 single family homes @300 gpd+ 10% unaccounted water)

7,590 5.27

Maximum Day Demand(ADD x 1.5 Peaking Factor)

11,385 7.91

Peak Hour Demand(ADD / 3 / 60 min./hr.)

60,720 42.17

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Service Area Pressure Requirements

The existing water distribution system is supplied from the Long Hill water storage tank and the LongHill water booster station. The Long Hill booster station controls maintain the pressure at the stationbetween 80 and 110 psi or between a hydraulic grade line of 509 and 578 feet. Table 6 provides alisting of the system pressures at the residences connected to the existing water distribution systemwithin the proposed Talcott Ridge pressure zone.

The proposed Talcott Ridge water booster station and pressure zone will be supplied by the CherryHill Tank. The Cherry Hill tank will have a normal operating water range of between 508 and 498 feet.The bottom of the domestic storage in the water tank will be at elevation 487. Without the boosterstation the water pressure at the Talcott Ridge Drive cul-de-sac (elevation 410), which is the highestlocation in the proposed Talcott Ridge pressure zone, would range between 44 and 39.8 psi.However, the expected water pressure at the second floor of 199 Talcott Ridge Drive, which isapproximately 43 feet higher than the cul-de-sac, would range between 25 and 21.2 psi.

The proposed Talcott Ridge booster station will be designed to operate between a hydraulic grade lineof 592 to 546 feet or within a 20 psi operating range. The booster station will be provided with variablespeed pumps that will allow the station to maintain a constant discharge pressure over a variable flowrange except for very low or very high flow periods and to compensate for varying operating waterlevels in the Cherry Hill Tank. The design hydraulic grade line set-point will be at the middle of theproposed operating range or at 570 feet. Table 6 below contains a listing of the expected high, lowand set-point pressures for the lowest and highest properties in the proposed pressure zone.

2.6 RecommendationsThe following are the recommended system design parameters for the system based on the modelingresults and further interpolation:

Cherry Hill Water Storage Tank

· Base 441 ft

· Diameter 45 feet

· Overflow 509 ft (Maximum level of 508 ft plus 1 foot)

· Min .level for Max Day 487 ft

· Min Level for EPS Fire 458 ft

· Tank Volumes:

- Overflow level = 0.81 MGal

- Maximum water level = 0.80 MGal

- Minimum Water level on Maximum Day = 0.55 MGal

- Minimum Water Level on Maximum Day after 2-hour, 2,500 gpm fire = 0.20 MGal

- Available volume below minimum tank level would be available in emergency = 0.9 xAverage Day Demand

· Booster chlorination at Long Hill pump station

· Mechanical mixing system to keep tank contents completely mixed

· Spray aeration system with blower to remove THMs

Address

Approx.Street

Elevation

WaterMain

Elevation

Approx.First FloorElevation

Approx.SecondFloor

ShowerElevation

(feet) (feet) (feet) (feet) Minimum Normal Maximum Minimum Normal Maximum Minimum Normal Maximum

9 Talcott Ridge Drive 358 353.5 369 384 83 94 103 77 87 97 70 81 9018 Talcott Ridge Drive 360 355.5 358 373 82 93 102 81 92 101 75 85 9533 Talcott Ridge Drive 364 359.5 371 386 81 91 101 76 86 96 69 80 8948 Talcott Ridge Drive 367 362.5 363 378 79 90 99 79 90 99 73 83 9368 Talcott Ridge Drive 370 365.5 363 378 78 89 98 79 90 99 73 83 9383 Talcott Ridge Drive 370 365.5 382 397 78 89 98 71 81 91 65 75 8488 Talcott Ridge Drive 370 365.5 360 375 78 89 98 81 91 100 74 84 94105 Talcott Ridge Drive 370 365.5 382 397 78 89 98 71 81 91 65 75 84108 Talcott Ridge Drive 370 365.5 358 373 78 89 98 81 92 101 75 85 95124 Talcott Ridge Drive 370 365.5 369 384 78 89 98 77 87 97 70 81 90142 Talcott Ridge Drive 379 374.5 372 387 74 85 94 75 86 95 69 79 89164 Talcott Ridge Drive 387 382.5 374 389 71 81 91 74 85 94 68 78 88182 Talcott Ridge Drive 396 391.5 388 403 67 77 87 68 79 88 62 72 82199 Talcott Ridge Drive 410 405.5 438 453 61 71 81 47 57 67 40 51 60204 Talcott Ridge Drive 405 400.5 388 403 63 73 83 68 79 88 62 72 82

8 Watch Hill Drive 370 365.5 382 397 78 89 98 71 81 91 65 75 8417 Watch Hill Drive 384 379.5 401 416 72 82 92 63 73 83 56 67 7634 Watch Hill Drive 392 387.5 404 419 69 79 89 61 72 81 55 65 7537 Watch Hill Drive 394 389.5 417 432 68 78 88 56 66 76 49 60 6960 Watch Hill Drive 406 401.5 405 420 63 73 82 61 71 81 55 65 7467 Watch Hill Drive 406 401.5 414 429 63 73 82 57 68 77 51 61 7182 Watch Hill Drive 402 397.5 403 418 64 75 84 62 72 82 55 66 7587 Watch Hill Drive 400 395.5 413 428 65 76 85 58 68 77 51 61 71

Notes19 Connected customers in pressure zone.* - Not currently connected to water system.Street and first floor elevations based upon City of Middletown GIS contour data.Water main elevation is 4.5' below street elevation.Second floor shower head estimated to be 15' above first floor elevation.

TABLE 6. ESTIMATED TALCOTT RIDGE PUMP STATION SERVICE AREA PRESSURES

Water Pressure At Water Main (psi) Water Pressure At First Floor (psi)Water Pressure At Second Floor

Shower (psi)

Proposed Talcott Ridge Pump Station Service Area

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Final storage tank elevations are depicted in Figure 10.

Figure 10. Critical Volumes for Cherry Hill Tanks

509' MSL

508' MSL

487'

MSL

458' MSL

Equalization Storage

Fire Storage

Emergency Storage

Minimum Level on Maximum Day (System

Pressures >= 35 psi)

Minimum Level After Fire (System Pressures

>= 20 psi)

Tank Base

Equalization Storage -Amount withdrawn from tank on a maximum demand day during period less

supply from Long Hill pumps. Maximum Day demand 308.07 gpm x 1,440 min/day= 443. 7 K gal

Pump Options (Assume 1 pump running at 750 gpm) 4 hours - Pump Volume 180 K gal, Equalization Volume= 263.6 K gal 5 hours - Pump Volume 225 K gal, Equalization Volume= 218.6 K Gal 6 hours - Pump Volume 270 K gal, Equalization Volume= 173.6 K gal

Fire Storage - Required fire flow rate times duration of fire= 2,500 gpm x 2 hours= 300 K gal

Emergency Storage - Volume available for use but would require emergency pumping or pressures in some locations less than 20 psi. Must be at least equal to 24 hours of average use or 230K gal Total Storage Requirement: - Equalization (Variable)+ Fire (300 K gal)+ Emergency Storage (Variable)

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PRV

· Located at on Main Street between intersections with Middlefield Road and Haddam QuarterRoad.

· Pressure setting 55 psi.

Talcott Ridge Drive Boosted Pressure Zone

· Located on South Main Street on the northern portion of property owned by the CT DOT,across from the intersection of Talcott Ridge Drive in Middletown, CT.

· Boosted pressure zone will maintain flow and pressure for domestic water supply to 23residences on Talcott Ridge Drive and Watch Hill Drive. Fire flow will be provided by the newwater mains and water storage tank.

· Flow range capacity

- Two (redundant) vertical multistage centrifugal pump: 8 to 45 gpm

· Booster Station discharge setting 90 psi.

Future Boosted Pressure Zone

· Due to the elevations within the service area, a boosted pressure zone would be required tomaintain pressures and fire flows in the future if water supply is extended to Area H. Thisarea would include either of the following options, as shown in Figure 5.

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3.0 Regulatory Coordination and Permits

3.1 Summary of Permit RequirementsAccording to Superfund NCP Section 300.400(e)(1), CERCLA Section 121 (e) (1), and per the Officeof Solid Waste Emergency Response (OSWER) Directive 9355.7-03, no federal, state or local permitsare required for a Superfund remediation for the work done entirely on-site; however, the work still hasto meet the substantive requirements of any applicable or relevant and appropriate permits.

Section 300.400(e)(1) of the NCP clarifies that this rule applies to all of the work conducted within theareal extent of contamination and all suitable areas in very close proximity to the contaminationnecessary for implementation of the response action. EPA has determined that all work performed inDurham is considered “on-site” with respect to permits.

All relevant permits outside of the Durham Service Area will need to be secured for this project. Forexample, a Connecticut Department of Transportation (CT DOT) encroachment permit is requiredalong all state roads (see details below). A number of permits for work outside of the service areahave already been secured, as discussed below.

The following is a summary of the permits that have been obtained for the project or shall be requiredprior to or during construction:

A. City of Middletown:

The work located in Middletown is located outside the on-site area of the Superfund “Site” so anyapplicable permits and reviews will still be required. Generally, the permitting process requires closecoordination with City of Middletown Officials and, depending on the type of permit, public hearingsmay be required. Permit requirements and status of permits obtained during the design are identifiedbelow. A pre-planning meeting with the City’s Environmental Planner was conducted to facilitate thereview process. An initial meeting was held in December 2014, and subsequent meetings were heldas needed. Requirements of the City of Middletown are identified below:

· Middletown Site Plan Review for tank site: The Middletown Planning, Conservation andDevelopment Department must conduct a site plan review for new structures, including thewater storage tank site, the booster station site, and the meter vault site. The ‘MiddletownInitial Application for Land Use’ form, which must be completed in advance of the Site PlanReview, was submitted on September 26, 2016 to identify the project. The Site Plan Reviewwas approved on January 12, 2018. A copy of the approval is included in Appendix E.

· Zoning Variances and Special Exceptions. The Middletown Zoning Board of Appeals (ZBA)approved two variances for setbacks in support of the project on November 2, 2017: avariance to construct the booster station on the on the CT DOT property (Map 32/Lot 0008)and a variance to install the meter vault on a City-owned parcel of land (Map 32/Lot 0048). ASpecial Exception was granted by the Middletown Planning and Zoning Commission onJanuary 10, 2018 for to each of the following project areas: Special Exception for the TankParcel on Talcott Ridge Road to facilitate bringing water to the Town of Durham; to constructthe Booster/Pump Station at South Main Street (Map 32/Lot 0008); and to construct the metervault at South Main Street and Acorn Drive (Map 32/Lot 0048). The project was alsoapproved by the Planning and Zoning Commission pursuant to an 8-24 review and

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subsequently endorsed by the City of Middletown Common Council. Copies of the variancesand Special Exceptions are included in Appendix E.

· Middletown Inland Wetlands & Watercourses Permit: An application for Inland Wetlands andWatercourses Activity must be submitted to the Middletown Inland Wetland andWatercourses Agency (IWWA) for any work that is to be conducted within 100 feet of awetland or watercourse. The wetland permit process may require attendance at one or morepublic hearings, abutter notification, and placement of signage informing the public of thetime, date, and location of the public hearing. Once approved, the permit is valid for a periodof five years from approval by the Agency. Wetlands in Middletown were delineated in threeareas: the area near the access drive to the Cherry Hill Tank Site was delineated in July2013, a small detention pond wetland near the location of the meter vault (parcel 32-0048)and a wetland on the Connecticut Department of Transportation property (CT DOT) for theBooster Station in July 2017, (parcel 32-0008) . The results of the wetland investigations arepresented in wetland delineation reports in Appendix C. An application to address the work inthe vicinity of wetlands adjacent to the tank site access drive was submitted on October 21,2016 and approved on January 4, 2017. Attendance at two public hearings was requiredbefore approval was granted. This permit will remain in effect until January 4, 2022. Anapplication to address work on the booster station and meter vault locations was submitted onSeptember 22, 2017 and approved on November 1, 2017. Attendance at one public hearingwas required for this permit. This permit will remain in effect until November 1, 2022. A copyof both Middletown applications and permits for Inland Wetland and Watercourses Activity arepresented in Appendix E.

· Conservation Commission Review: According to the Environmental Planner in Middletown,because the tank site is near the Guida Conservation property, the Conservation Commissionwill require a review of the plans. Plans were provided as part of the permitting process.

B. Town of Middlefield

Work at the Meter Vault site on Route 17 in Middletown is within 100 feet of two intermittentwatercourses in the town of Middlefield. However these intermittent watercourses are created only byoutfalls from roadway drainage systems, are on the other side of the roadway from most of the work,and the project will not affect their function with the proper Best Management Practices (BMPs) inplace. The Middlefield Inland Wetlands and Watercourses Agency was notified, and a meeting washeld on-site in August 2017. After meeting with project staff, the Inland Wetlands Enforcement Officerfrom Middlefield did not require a permit application and was satisfied that proper procedures will befollowed to protect the watercourses.

C. Connecticut Department of Transportation:

For the portion of the water main constructed on state highways, a CT DOT encroachment permit isrequired, and all work must comply with the requirements of the CT DOT.

· CT DOT Encroachment Permit District 1: This permit allows the use of a State highway forsomething other than travel (in this case, a water main). The encroachment permit will beissued to the Contractor, however, the DOT will do an informal review of the plans prior to theContractor applying for the permit. The plans must show erosion and sedimentation (E&S)controls and mitigation measures on plans. A copy of the application is included in AppendixE.

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D. Town of Durham:

The inland wetlands near a crossing of Allyn Brook at Maple Avenue were delineated in July 2013 forthe original project scope this was extended to include three other crossings that were delineated inSeptember 2014, and July 2015. At the Maple Ave crossing the proposed water main will extendunder the brook on the west side of the bridge to connect to the existing Town Center water system atMaple Avenue. The three other crossings are in an area near schools. There will be a crossing atPickett Lane Bridge, where Allyn Brook will be traversed in a similar fashion to the Maple AvenueBridge. Two other crossings in the school area will be constructed within the roadway, these watermains will be constructed under the existing culverts within the bridges and will not alter thestreambed. The results of the wetland investigations are presented in wetland delineation reportspresented in Appendix C. This portion of the project is within the on-site area of the Superfund “Site”or expanded potential impact areas, therefore an inland wetland review and application for permit isnot required. However, the spirit of the regulations will be observed and erosion control measuresand implementation of best management practices will be required of the Contractor duringconstruction to minimize any impacts to wetland areas.

E. Connecticut Department of Energy and Environmental Protection:

Two permits are required from the CT DEEP; a permit for discharge of hydrostatic pressure testingwater, and a permit for diversion of water for consumptive use. These permits are described in moredetail below.

· General Permit for the Discharge of Hydrostatic Pressure Testing Wastewater: This generalpermit applies to all discharges of waters used to test the structural integrity of new tanks andpipelines and tanks and pipelines which have been used to hold or transfer drinking water,sewage, or natural gas. Registration is required to be submitted to the CT DEEP in order forthe discharges to be authorized by this general permit. A copy of the application is included inAppendix E.

· General Permit for the Diversion of Water for Consumptive Use: This general permit allowsthe transfer of water from Middletown to Durham. A reauthorization of an earlier approval ofthis permit was granted by CT DEEP in March 2017. The current authorization will expire onJanuary 27, 2027. A copy of the permit reauthorization, which includes the conditions of theGeneral Permit, is included in Appendix E.

F. Connecticut Department of Public Health:

A review of the design by CT DPH was completed, and the following permits have been completedand submitted to the CT DPH:

· Water Main Application:

http://www.ct.gov/dph/LIB/dph/drinking_water/pdf/watermain_app.pdf

· Storage Tank Application:

http://www.ct.gov/dph/lib/dph/drinking_water/pdf/Storage_Tank_Project_Application.pdf

Approval to construct the new water supply system was provided by the CT DPH on February 15,2018. A copy of the approval is included in Appendix E.

A CT DPH Sale of Excess Water permit was issued to the City of Middletown on July 11, 2016. Acopy is provided in Appendix E.

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A Certification of Completion Report will be required after project construction is complete:

http://www.ct.gov/dph/lib/dph/drinking_water/pdf/Certification_of_Completed_Water_or_Treatment_Works.pdf

3.2 Identified Resources and Mitigation during ConstructionA. Floodplains

The most recent FEMA flood maps for the project area were reviewed to identify areas of potentialflooding. The maps reviewed, including FEMA map number 09007C0206G and map number09007C0118G (both dated August 2008), are included in Appendix E. There are no floodplainsidentified in the project area except at four water main stream crossings. The water main will crossAllyn Brook on the west side of the Maple Avenue box culvert bridge; just north of Picket Lane at thedual box culvert between the RSD13 Middle School and High School, slightly upstream of the boxculvert; and on Maiden Lane under the culvert which carries the brook across the road. The watermain will cross Hersig Brook just north of the High School below the existing pipe that carries thebrook across the driveway. The changes to the existing bridges and culverts will not impact floodstorage or flood conveyance, and all stream crossings will be restored to “as-existing conditions” withno changes in elevations.

A portion of the Durham Fairgrounds is in a FEMA AE designated area (areas subject to inundation bythe 1-percent-annual-chance flood event). The only work in this area will involve decommissioningone of the two Fairground wells and converting the other to a monitoring well. This work will not impactthe floodplain. Another FEMA AE designated area is located along the south side of Old CemeteryRoad; however there will be no impact to this area from the work.

B. Wetlands

AECOM’s Wetlands Delineation Memo (presented in Appendix C) has been updated to include asummary of findings in the expanded project area. During the field evaluation, AECOM identifiedand delineated any wetlands and watercourses observed within 150 feet of the project route whereaccess could be attained. A total of twelve different wetland systems and seven watercourses weredelineated along the project route. Wetland-W1 is near the proposed access road for the tank(Figure 2). Wetland-W2 demarcates the top of bank, hydric soils and floodplain soils along AllynBrook near Old Cemetery Road This delineation was modified in September 2014 to include alluvialsoils in this area, and to demarcate the wetland limits along the south bank of Allyn Brook as well asthe west side of Maple Avenue, as indicated in the revised Figure 3. Wetland-W3 demarcates awetland system containing a small fire pond on the west side of Maple Avenue and includes anintermittent watercourse which flows beneath Maple Avenue through an 18” diameter culvert(Figure 3). Wetland- W4 demarcates the top of bank and hydric soils along Hersig Brook (StreamS3), Wetlands-W5 and W6 demarcate the limits of forested wetland located along the north side ofMaiden Lane and, and Wetland-W7 demarcates the top of bank along a perennial stream (S4) that istributary to Hersig Brook. Wetland-W8 demarcates a roadside stormwater swale and Wetland W9 islocated on the south side of Maiden Lane (Figure 4). Wetland W114R is north of Maiden lane andincludes wetlands that are part of Ball Brook, a tributary of Allyn Brook. Wetland SMW1 is a roadsidewetland directly across from the entrance to Talcott Ridge Road. Wetland W10 is a small Detentionpond wetland just northeast of the intersection of Acorn Drive and South Main Street. Two intermittentstreams that outfall the local storm drain systems are nearby.

Mitigation measures employed during the construction activities to protect the adjacent wetlandsinclude but will not be limited to the use of erosion control devices such as silt fences and hay bales.Stilling basins will be utilized to remove sediment from dewatering activities. Construction equipment

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will not be allowed to enter wetland areas except for the proposed brook crossings at DurhamFairgrounds and Pickett Lane where the alignment must be installed off-road. All refueling operationswill be undertaken in upland areas to prevent accidental spills of fuel into the wetlands. All erosioncontrol devices will be checked on a regular basis to assure proper functioning. Any accumulatedsediment will be removed periodically and repairs to siltation control devices will be undertaken on anongoing basis to assure protection of the wetlands. Any construction activities that require limitedwork within the wetlands will be performed under the supervision of a wetland scientist. Appropriateconstruction mats will be employed for construction equipment to operate from. Any disturbance ofthe wetlands will be repaired as soon as practicable with appropriate wetland plants and the areaseeded and mulch applied to promote proper growth.

C. Cultural Resources

AECOM completed a thorough historical and archaeological evaluation to assess potential impacts oncultural resources within the project area, as required by the Section 106 of the National HistoricPreservation Act (NHPA). A historical effects evaluation was conducted in 2015 and 2016 to identifyhistorically significant architectural resources and to analyze the effects of the project on thoseresources. A Section 106 Finding Documentation Report, which identified the resources along withmeasures to mitigate potential impacts, was submitted to the Connecticut State Historic PreservationOfficer (CT SHPO) in March 2016. The report concluded that, although the project would have aneffect on the Durham Main Street Historic District, no adverse impacts would occur. The CT SHPOconcurred with the findings.

A Phase 1A Archaeological Assessment was completed to determine the potential for encounteringNational Register-eligible archaeological resources in areas where subsurface disturbance will occuras a result of project actions. Proposed locations within the project area were identified for furtherevaluation. The report was submitted to the CT SHPO in April 2016, and CT SHPO concurrence wasreceived on May 3, 2016. A Phase 1B Archaeological reconnaissance Survey, which involved ashovel test pit survey, was conducted between November 2015 and January 2018. A reportsummarizing the results was submitted to the CT SHPO in January 2018 for review and approved bythe CTSHPO on May 2, 2018. The report concluded that the project will have No Effect on NRHP-eligible archaeological resources. The CT SHPO approval letter is included in Appendix E.

D. Biological Resources

AECOM corresponded with Connecticut DEEP regarding the Natural Diversity Data Base (NDDB) onseveral occasions during the project design to identify habitat mapping updates in the project areas asnecessary. Based on the latest correspondence dated March 8, 2016, March 12, 2016 and July 28th

2017 for work areas in Middletown and Durham NDDB identified portions of Maple Avenue, OldCemetery Road and small areas on Talcott Lane and Main Street (SR-17) that are located inenvironmentally sensitive areas. In addition, a species of special concern (Wood Turtle, Glyptemysinsculpta) is indicated in the several areas within the project: of the access driveway to the Cherry HillTank off Talcott Ridge Drive, the Meter Vault at the intersection with SR-17 and Acorn Drive, andareas near the Allyn Brook and Hersig Brook crossings. In addition, several wetland and aquaticdependent species were noted in the vicinity of the proposed Allyn Brook crossings, including SlimySculpin (Cottus cognatus). The letters and attachments noted above are included in Appendix E.Based on the NDDB response, the following BMPs will be used in the construction of the project to theextent possible: Recommendations for protection of these rare species habitats include the following:

· If possible, stream crossings will not be constructed during the months of late August throughSeptember or from Mid-March through May, as these are the times that amphibians andreptiles are most active near wetlands.

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· If possible, stream crossings will be constructed in November when stream flows are low andamphibian activity has slowed.

· Silt fencing should be installed around work areas prior to construction where applicable toexclude Wood Turtles from the work area. The use of erosion control products that areembedded with netting should not be used since these can snare turtles.

· To protect wood turtles, silt fencing should be used around stockpiles of dirt to exclude themfrom nesting. Nesting season is in early spring and late summer.

· Vehicles and machinery should not be parked in turtle habitat. Turtle habitat includeswetlands and undisturbed forest floor.

· Construction contractor should be apprised of the possible presence of turtles and theirdescription. Any turtles discovered should be moved to an appropriate area as outlined in theNDDB recommendations.

· A subsequent NDDB request should be submitted if construction has not begun on thisproject by July 28th, 2019.

· Work conducted during early morning and evening hours will occur with special care not toharm basking or foraging individuals.

All efforts will be made to comply with these requirements as much as possible. The majority of thework involved with installing the water main and service laterals will be confined to existing street right-of-ways and developed land, therefore it is expected that there will be minimal impact toenvironmentally sensitive areas. All construction will be limited to the smallest practicable area tominimize impacts to the habitats of fauna which utilize the area for nesting and feeding including thosementioned above.

E. Water Quality Issues

Proper construction procedures including limiting activities within wetlands and the installation oferosion control measures will be implemented during construction. The installation of erosion controldevices such as silt fences, hay bales and sediment basins will assure that no sediment from theconstruction activities will enter any surface water or wetlands. Erosion and sedimentation controlsmust be placed before construction begins and must remain in place until the soil on site is fullystabilized.

Groundwater was not observed in the majority of the borings drilled along the water main route duringthe subsurface investigation program; however groundwater levels may fluctuate seasonally or duringprecipitation events. If it is encountered during construction, groundwater analysis may be required inArea A before groundwater can be discharged to determine if the groundwater is contaminated. Itmay be necessary to contain, test, and treat the water prior to discharge. Appropriate handling anddischarge procedures shall be determined in the event that contaminated groundwater is encounteredduring trench excavation activities.

F. Contaminated Soil

Aside from soil that will be encountered on the DMC property during trenching activities to install thewater service line to the building, excavation of contaminated soil is not anticipated. However, theConstruction Contractor will be required to follow the procedures outlined in the CT DEEP’s Guidancefor Utility Company Excavation during all trenching and other subsurface activities. A copy of theguidance is included in Appendix E.

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G. Coastal Resources

There are no coastal resources within the project area.

H. Socio-Economic/Environmental Justice Issues

The installation of the water main will benefit the residents and businesses within the project area ofDurham by providing a clean source of potable water. The new water main will also benefit the City ofMiddletown by generating revenue for the City through the sale of water to Durham and throughupdates to the City’s infrastructure related to construction of the water main. Additional benefitsinclude fire protection for Durham and enhanced fire protection for Middletown.

I. Miscellaneous Items

Anticipated short-term environmental impacts resulting from the project may include noise, airpollution, and dust. Noise, air pollution, and dust are all temporary problems associated withconstruction equipment and construction activities. By limiting the work hours, the amount of noise,which may be bothersome to neighbors, can be controlled. Air pollution from vehicle exhaust is atemporary condition that will end once the construction activities cease.

The project area will be maintained to reduce airborne dust particles dust free as is practicable. Roadsweeping and the placement of water on dry soil that is prone to disturbance on a routine basis willcontrol dust created from the construction activities. Trees and tree limbs should be assessed forpotential cutting and/or removal during the construction stage. The installation of temporarypavement, loaming, seeding and mulching will be undertaken as soon as practical upon testing andacceptance of the water main.

Construction adjacent to and within resource areas as well as the discharge of groundwater fromtrench and well abandonment activities will be temporary conditions that the contractor will face duringthe construction process. Both of these issues will be considered and addressed during the designprocess. Appropriate design elements such as the use of construction mats to avoid damage towetlands and the use of stilling basins to remove sediment prior to discharge as well as the installationof silt fencing adjacent to the work area will be specified to reduce the long-term impacts to theresource areas.

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4.0 Subsurface Investigation Program

AECOM conducted geotechnical sampling along the pipeline route and at the location of the proposedCherry Hill Water Storage Tank, and environmental sampling at select locations along the pipelineroute. The results of these activities are summarized below, and explained in greater detail in theGeotechnical Design Memoranda provided in Appendix D.

4.1 Cherry Hill Water Storage TankThe tank site is located off Talcott Ridge Drive on top of Cherry Hill in Middletown, CT. A subsurfaceinvestigation consisting of three test borings was performed by New England Boring Contractors ofGlastonbury, CT from June 11 to June 12, 2013 and observed by an AECOM representative. Thelocations of the test borings are depicted on the Contract Drawings, included in Appendix A. Theboring logs from the subsurface investigation are included in the Geotechnical Design Memoranda forthe tank site, provided in Appendix D1.

The three test borings depths ranged from 14.1 to 20.0 feet below the ground surface. Soil sampleswere collected at five foot intervals from the ground surface to the top of bedrock. Bedrock wasencountered and typically cored 5 feet in all test borings.

Subsurface conditions generally consist of the following order of their occurrence below groundsurface:

· Topsoil overlying fine to medium sand: approximately 5 feet thick,

· Glacial Till and Weathered Rock: approximately 5-10 feet thick,

· Bedrock: Identified as Sandstone: recovery ranged from 20 to 50 percent, with rock qualitydesignation (RQD) values of 0-20 percent.

Groundwater was not observed during drilling activities. Because saturated soils were notencountered, the following geotechnical analyses were deemed as unnecessary and were notperformed: grain size, moisture content, and Atterberg Limits. As groundwater was not encountered,dewatering activities will likely not be required, unless seasonal fluctuations of the water table orperched groundwater dictate otherwise.

AECOM made the following observations and recommendations related to the tank site geotechnicalevaluation:

1. The topsoil is not considered suitable for foundation support. It is recommended that the site beexcavated to the hard glacial till and weathered rock layer and the tank be supported by a matfoundation with 6-inch crushed stone below. Boulders, if encountered at foundation subgrade,should be over-excavated, replaced with crushed stone and compacted as specified.

2. A gross allowable bearing pressure of 5 tons per square foot (tsf) is recommended for the matfoundation of water storage tank embedded a minimum of 4 feet below the ground surface forfrost protection.

3. A modulus of subgrade reaction of 200 pounds per cubic inch (pci) is recommended for thestructural design of soil supported mat foundation for the proposed water storage tank.

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4. Seismic Design Requirements: a site class C is recommended for this site in accordance with the2009 International Building Code. The foundation soils are considered not susceptible toliquefaction.

5. For lateral earth pressure calculations on the below grade structure walls, equivalent fluid unitweights of 65 pounds per cubic foot (pcf) are recommended. A uniform vertical surcharge load of300 pounds per square foot (psf) at grade is recommended for the foundation walls. The resultinglateral pressure is 150 psf along the wall height for below grade structure walls.

6. Foundation preparation shall be in accordance with Detail 2-9.1.1 included in Appendix B of theGeotechnical Design Memorandum provided in Appendix D of this report.

7. Pipe lines and other below grade utility systems should be supported by compacted granularbedding and backfilled with compacted acceptable materials as specified in Specification Section02210 Earth Excavation, Backfill, Fill, and Grading.

4.2 Pipeline Foundation (from connection to Middletown line through andincluding Area A and a portion of Area I)

A subsurface investigation program consisting of a total of forty-one (41) soil test borings wasperformed by New England Boring Contractors, Inc. of Glastonbury, CT, with oversight provided byAECOM representatives. The work was conducted from August 19 to August 28, 2013. An additionalthree (3) soil test borings were performed by Northern Drill Services on September 22, 2014 for theextension along Maple Street past Allyn Brook. The boring logs from the subsurface investigation areincluded in the Geotechnical Design Memoranda/Geotechnical Data Report for the water line,provided in Appendix D2 as amended. The locations of the test borings are shown on the ContractDrawings, and included in Appendix A. Test borings for the proposed waterline were drilled toapproximately five feet below the proposed pipe invert depth. Soil samples were collected fromground surface or below the pavement and at 5-foot intervals until the end of borings. Uponcompletion, the test borings were backfilled with cuttings, tamped and topped with an asphalt patch inthe paved areas, and restored to original condition in non-paved areas

Groundwater was not observed during drilling in the majority of the borings. The groundwater levelranged from 4.8 to 10.5 feet below the ground surface when encountered in some test borings. Itshould be noted that groundwater levels may fluctuate with precipitation, season, constructionactivities, run-off controls, and other factors. As a result, water levels during construction may varyfrom those observed during the subsurface investigation.

Based on field observation, samples were collected from a total of six borings for grain size analysesby GeoTesting Express of Boxborough, MA. Generally, the subsurface materials encountered alongthe pipeline route are characterized by mostly fine to coarse sandy material with varying amount ofgravel and fines contents overlying glacial till or weathered rock at different depths in most of theborings, with a few exceptions where cohesive soils were observed.

During the subsurface investigation program, several samples were also collected for environmentalanalyses, including volatile organic compounds (VOCs) and extractable total petroleum hydrocarbons(ETPH). The purpose of the environmental sample collection is to provide limited information to theconstruction contractor for the purpose of determining proper disposal requirements for any excesssoil. It will be the responsibility of the Contractor to determine disposal or reuse options for any excesssoil, and to characterize that soil as required by the receiving facility.

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The samples were analyzed via the EPA’s Contract Laboratory Program (CLP) for Routine AnalyticalServices (RAS). Sample locations were selected based on current or historic activity, such as gasstation operations or other commercial operations that might have resulted in soil contamination.Results, including laboratory reports, are provided in Appendix D2, as Attachment 3 to theGeotechnical Data Report. For evaluation purposes, results were compared to the GA, GAA PollutionMobility Criteria (PMC) included in the Connecticut Remediation Standard Regulations (CT RSRs). NoVOCs above the PMC were detected in the samples, although low concentrations of TCE andchloroform were detected in the 1 to 3 foot interval of boring B20. No other VOCs were detected.ETPH above the CT RSRs PMC of 500 mg/kg was detected in the 1 to 3 foot interval of B21 (1,200mg/kg). No other PMC exceedances for ETPH were detected. No staining or other indication of apetroleum release was noted at this boring location.

4.3 Pipeline Foundation (extension to a portion of Area F including the RSD#13 school system)

A subsurface investigation program consisting of a total of fifteen (15) soil test borings was performedby General Boring Contractors, Inc. of Prospect, CT, with oversight provided by AECOMrepresentatives. The work was conducted from July 7 to 9, 2015 in the area of the schools includingPickett Lane and Maiden Lane. Test borings were advanced using 3 ¼ -inch hollow stem augers. Theboring logs from the subsurface investigation are included in Appendix D3. The locations of the testborings are shown on the Contract Drawings. Test borings for the proposed waterline were drilled to adepth from 12 to 27 feet. Soil samples were collected from ground surface or below the pavement andat 5-foot intervals until the end of borings. Upon completion, the test borings were backfilled withcuttings, tamped and topped with an asphalt patch in the paved areas, and restored to originalcondition in non-paved areas.

Twenty-one (21) soil samples from the subsurface investigation were submitted to GeoTestingExpress in Acton, MA for laboratory testing. A schedule of the laboratory testing is provided in Table 1and the laboratory test results are provided in Attachment 2 of the November 2015 GDR in AppendixD3.

Bedrock was encountered in test boring SB-1 along Pickett lane at 14.5 feet below ground surfaceand was cored from 15 to 17 feet. The bedrock is identified as red brown sandstone. Recovery is100% and Rock Quality Designation (RQD) is provided as 80%.

Groundwater was observed in four (4) of the borings during drilling; SB-2,SB-3, SB-4 and SB-5 in therange of 6 to 9 feet. It should be noted that groundwater levels may fluctuate with precipitation,season, construction activities, run-off controls, and other factors. As a result, water levels duringconstruction may vary from those observed during the subsurface investigation.

The following geotechnical recommendations are provided based upon review of the waterline routesubsurface conditions and anticipated waterline layout:

1. Pipe Trench Preparation. Based on the limited lab testing results, some of the on-site soils maynot be suitable for backfill above the pipe due to fines content higher than the requirements forbank-run gravel. It is assumed that up to 30% of the on-site material will be replaced with borrowand properly disposed of off-site, and that 70% of the on-site material may be suitable for backfillpurposes, but not as structural backfill beneath structures.

2. Loose Material. Although loose material was rarely observed during drilling, it may exist at isolatedlocations along the proposed waterline alignment depths. Loose material is not consideredsuitable as support for pipe foundations. In areas where loose subgrade materials are

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encountered, it is recommended that a geotechnical engineer observe the exposed subgrade todetermine if the subgrade soils are suitable for pipe support. The loose material should be eitherproof rolled or removed and replaced with crushed stone as shown in modified Detail 2-1.1.21 inAppendix D3.

3. Dewatering. While not anticipated to be necessary for a majority of the pipeline construction in thepublic ways based on findings during the boring program, water levels during construction mayvary from those observed during the subsurface investigation. Any dewatering discharge shouldbe in conducted in accordance with 40 CFR Part 122 and 61 FR 19284, May 1, 1996.

4. Excavation Support Systems. Trench box excavation is anticipated for most of the proposedwaterline installation. However, the Contractor should be given the choice of utilizing sheeting forsections wherever the proposed installation may interfere with existing utilities. The Contractormay also utilize open cut in locations where space allows. Open cuts shall comply with OSHAregulations. In areas where the horizontal distance between the edge of the trench excavationand the bottom of existing structures is less than twice the vertical distance between the bottom ofthe trench excavation and the bottom of existing structures, temporary sheeting (earth retentionsystem) will be required to prevent the undermining of existing structures. Major utilities may alsobe protected with temporary sheeting as determined by the Contractor on a case by case basis.During installation of the proposed waterlines, the contractor shall be responsible for protectingexisting utilities crossing the proposed trench. Wherever necessary, permanent utility supportsshall be provided in accordance with Detail 2-1.8 Typical Support for Utilities in Appendix D.

5. Allyn Brook Crossing along Maple Avenue. Pipeline crossing Allyn Brook along Maple Avenueshould be installed with protective measures for scour of the brook at flood stage.

6. Allyn Brook Crossing along Pickett Lane Extension. Pipe jacking is not recommended forcrossing along Pickett lane between test borings SB-1 and Sb-2 due to close proximity of theexisting culvert to bedrock. The crossing will be performed in open cut method similar to theMaple Avenue crossing. Pipeline should be installed with protective measures for scour of thebrook at flood stage.

Additional detail is provided in Appendix D.

4.4 Water Meter Vault and Talcott Ridge Booster StationThe Water Meter Vault will be constructed on a vacant parcel of land, owned by the City ofMiddletown, located on the corner of South Main Street (Route 17) and Acorn Drive in Middletown.The Talcott Ridge Booster Station will be constructed on South Main Street in Middletown on thenorthern portion of the CTDOT property across from the intersection of Talcott Ridge Road. Asubsurface exploration program consisting of drilling and sampling two (2) test borings, one at eachlocation, was performed by General Boring of Prospect, Connecticut between September 27 and 28,2017. An AECOM geologist observed and logged the borings during drilling. The results aresummarized in the section.

The borings ranged in depth from 20.1 to 22.8 feet below ground surface. Bedrock was encounteredand cored at both locations. Groundwater was not encountered at the meter vault location, and wasobserved at 8 feet below ground surface at the booster station location.

More detail, including geotechnical recommendations, boring logs and geotechnical laboratory results,are included in Appendix D4.

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5.0 Design Criteria

5.1 Reference StandardsAECOM, in preparing the detailed drawings and specifications for the Project, is adhering to thefollowing reference standards that are applicable to the work:

· Guidelines for the Design and Operation of Public Water System Treatment, Works andSources, State of Connecticut Dept. of Public Health, Water Supplies Section, Jan. 1999,updated 2006.

· Recommended Standards for Water Works, Great Lakes--Upper Mississippi River Board ofState and Provincial Public Health and Environmental Managers.

· Purchasing Standards for Waterworks Material, Connecticut Water Company and MaineWater Company (Rev. October 2016), attached in Appendix F.

· General Requirements, Water main and Service Installation, City of Middletown Water andSewer Department, (January 2017), attached in Appendix G.

· American Water Works (AWWA) D110: Wire- and Strand-Wound, Circular, PrestressedConcrete Water Tanks.

· Water Main Design and Construction Guidelines, State of Connecticut Department of PublicHealth Drinking Water Section. Effective October 1, 2006

· Storage Tank Design and Construction Guidelines, State of Connecticut Department of PublicHealth Drinking Water Section. Effective August 2006

Additional references are included in the Contract documents.

5.2 Elevated Storage TankBased on the findings of the F&O report, discussions with the Middletown Water and SewerDepartment and life cycle cost considerations, a Type III wire wound, precast concrete tank will beprovided as part of the project. The tank shall conform to the requirements of AWWA D110 aspreviously referenced. Tank sizing information and operating parameters are described in detail inSection 2, Hydraulic Analysis.

The tank will be equipped with an internal mixing system designed to prevent short circuiting and tominimize water quality issues associated with excess water age. A passive mixing system that willrely on the flows from the Long Hill Pump Station was considered and incorporated in the design asrequested by the Middletown Water and Sewer Department. This system will include a series of one-way “duck-bill” unidirectional valves and associated piping in order to create the needed mixing actionwithin the tank. However, due to the extended schedule for connection of all the Areas to be servedby the system, a recirculating pumping system will be provided to maintain constant minimum flowsthrough the mixing system, especially in the early years when demand is lowest.

The tank will be fed via a single new 20-inch diameter water main sized to both fill the tank and supplythe expanded distribution system based on the tank levels and system demands. The 20-inch watermain from the tank to the first hydrant at Talcott Ridge Drive was provided in an effort to minimizefriction losses in that section of pipe and to avoid being required to raise the water level in the tank to

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compensate for the friction losses and maintain the required minimum 20 psi pressure at the highpoint on Talcott Ridge Drive.

In addition to the instrumentation and control system (as described later in Section 5.6), an altitudevalve vault will be constructed near the inlet of the tank. The vault will be equipped as follows:

· One 12-inch diameter altitude valve: the altitude valve will be diaphragm operated such thatwhen a preset high water level is reached in the tank; the valve will close, preventing the tankfrom overflowing. In conjunction, the tank instrumentation will stop the pumps at the Long HillPump Station. The valve will be a single flow direction into the tank

· One 16-inch diameter check valve: the check valve will be oriented to allow flow out of thetank only and is designed to prevent the tank from overflowing in the event that the pumpstation does not shut down at the high water level.

· Other appurtenances including, but not limited to a drain sump, heater, dehumidifier andventilation equipment will also be provided in the altitude valve vault.

The tank will be equipped with an emergency overflow pipe in the event of a failure of theinstrumentation or altitude valve. The overflow will discharge to a catch basin that will direct flowsthrough drainage piping along the access road to the drain outlet at the wetlands. A modified rip rapapron will provide energy dissipation and erosion control for the ground protection at the discharge.

In accordance with the request of the City of Middletown, the tank will also be provided with two roofhatches, with appropriate safety railing and two side access portals. Security measures will includelocks on tank access ladders, locks on the roof hatches, and fencing around the tank site.

5.3 Water Distribution Pipe and Support ServicesWater mains and appurtenances to be furnished and installed within the City of Middletown willconform to the referenced Middletown Water and Sewer Department General Standards. PurchasingStandards for Waterworks Material, Connecticut Water Company will be used for water mains andappurtenances to be furnished and installed within the limits of the Town of Durham.

The following design criteria will apply:

· The pipelines will be located within the various streets based on the following criteria:

- Avoidance of existing buried utilities (for example drainage structures, gas mains, orelectrical conduits)

- Avoidance of existing overhead electric, phone and cable wires and poles

- Avoidance of existing curbs and sidewalks

- The location of existing trees is a secondary consideration with respect to location of thepipelines. During the construction phase of the project, a field assessment will berequired by the General Contractor to determine the need for cutting and/or removal oftrees and limbs.

- In local streets, consideration will be given to the potential for future utility construction. Inthese cases, the water mains will be moved to one site of the street or the other based onthe above considerations.

- In certain cases, especially within narrow town roads, the water main may be located ator near the center line of the road for constructability purposes.

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- The Allyn Brook crossings will be constructed using open trench method at two locationsto eliminate impacts with the existing bridge and simplify construction; 1) on the west sideof Maple Avenue along the Town’s Fairground property, 2) on the south side of PickettLane on the Town’s school district property.

- The Allyn Brook (Hersig Brook) crossings at Maiden Lane and Pickett Lane, near theHigh School, will be constructed using open trench method within the roadway below theculvert pipe (from each side of the crossing) to minimize impacts to the existingheadwalls.

· Pipeline sizing shall be in accordance with the Hydraulic Model completed by AECOM andfurther described in Section 2, Hydraulic Analysis.

· All water mains will be installed with a minimum cover of 4’-6”. If a situation arises where thisminimum cannot be maintained, the water main will be insulated to protect against freezing.

· All street intersections, outside of the Durham service area (Area A, and the impactedportions of Area E and Area I), shall be provided with branch connection stubs for futurephases of the project. Stubs shall be extended as needed such that future constructionimpacts to existing roads and walks will be minimized.

· All street intersections with branch connections (both inside and outside of the Durhamservice area) will be provided with main line and branch valves needed to properly isolateportions of the distribution system in the case of water main breaks or other emergencies.

· All properties along the water main route will be provided with new service connections.Service connections to properties located within the Durham service area will include finalconnection and hook up to existing houses. The connections will be constructed from thewater main to each existing house. The General Contractor will retain a licensed plumber tomake all interior connections required for final hookup of existing structures. Finally, since thenew service connections will include work on private property each one will be unique and willbe separately detailed in the contract documents.

· Service connections to vacant lots along the entire length of the water main improvements willbe installed and ended at the property line with a new curb stop.

· A booster pump station will be constructed on the northern portion of the CT DOT property onSouth Main Street in Middletown across from the intersection of Talcott Ridge Road. Thebooster station will provide domestic water service to 23 single residential homes location onTalcott Ridge Drive and Watch Hill Drive. The booster station will be equipped with sumppump, heater, dehumidifier and other appurtenances as needed. Two alternative types ofbooster station pumps were considered for the proposed facility. The first type utilizes asubmersible turbine well type pump installed within a buried steel or stainless steel pressurecanister with a pump access cap to the pumps and check valves for maintenance orreplacement. The second type of booster pump considered is a vertical multistage centrifugalpump similar to the small pumps currently in service at the Long Hill booster station. Inconcurrence with the EPA and the City of Middletown Water and Sewer Department, thevertical multistage pumps were selected. Additional detail is provided in Subsection 5.6 andin Section 2, Hydraulic Analysis.

· A new meter vault will be constructed in Middletown near the Durham/Middletown town line.The vault will be equipped with a 10-inch compound turbine flow meter in accordance with therequirements of the City of Middletown Water and Sewer Department. The vault will also beequipped with sump pump, heater, dehumidifier and other appurtenances as needed.

· A new pressure reducing valve vault will be constructed as described in Section 2, HydraulicAnalysis. Based on the results of the Hydraulic Model, the location of the pressure reducing

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vault will be near the intersection of Route 17 and Middlefield Road. The vault will also beequipped with sump pump, heater, dehumidifier and other appurtenances as needed.

· As part of the overall construction contract, existing private wells located in the Durhamservice area will be decommissioned by the contractor upon successful installation of newwater service connections. The decommissioning will be in accordance with the requirementsof the State of Connecticut. Each private well decommissioning will be separately detailed inthe contract documents along with the specified service connections.

5.4 Site Civil WorksThe majority of site and civil works will occur at the Cherry Hill tank site and will generally consist ofthe following:

· Installation of erosion and sedimentation control measures. In addition, the construction ofthe access road will likely require a wetlands permit. Any erosion and sedimentation control,or other requirements of the permit will be incorporated into the access road design.

· Clearing and grubbing for the proposed access road and tank.

· Construction of approximately 2,200 linear feet of access road to the tank site. The accessroad will include an 18 foot wide paved driveway, with open drainage ditches and culverts asapplicable and as approved by the City of Middletown IWWA

· Preparation of contractor staging and lay-down areas for use during the construction of thetank.

· Final grading and site restoration of the tank site and other areas disturbed duringconstruction.

Site and civil work to be completed as part of the water main construction will occur mainly withinexisting local and state roads. Restoration in existing roads will include limited trench widthrestoration and paving, or full reconstruction and curb to curb paving, as appropriate. Restorationwithin state highways will comply with CTDOT requirements, while restoration of local roadways willcomply with the requirements of Durham and Middletown, as appropriate. Additionally, all other areas,disturbed in the execution of the work, including the two referenced stream crossings aligned outsidethe roadway, shall be restored to original condition or better unless otherwise indicated in the ContractDocuments. This shall include, but not necessarily be limited to lawns, driveways, plantings, etc.

5.5 Hydrants and ValvesHydrants and valves shall be initially located based on accepted spacing as follows:

Hydrants Maximum Spacing of 500 feet

Valves Maximum Spacing of 1000 feet

Based on the project specific conditions, maximum valve spacing will only be reached on Route 17.Generally, within the Town of Durham, spacing will be dictated by the need to valve off and isolatesections of water main at the many intersections within that area of the project.

The local Fire Departments were provided with the drawings and requested to provide input relative tothe hydrant locations. Adjustments in the locations have been made based on input from the Durhamand Middletown Fire Departments and from the Middletown Water Department.

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Hydrants and valves to be furnished and installed within the City of Middletown will conform to thereferenced Middletown Water and Sewer Department General Standards. Purchasing Standards forWaterworks Material, Connecticut Water Company standards will be used for hydrants and valves tobe furnished and installed within the limits of the Town of Durham.

5.6 Operation and Control StrategyOperation and control of the new water distribution system will be based on existing demands, waterelevation in the Cherry Hill Tank and supply from the existing Long Hill Pump Station in Middletown.Based on the results of the Hydraulic Model, the existing fire pumps in the station are sufficiently sizedto feed the proposed Cherry Hill tank. However, to address varying operating conditions, includingtank water levels and the phasing of the system expansion into Durham, variable speed drives will beinstalled to allow flow control of the pumps. This feature will provide operational flexibility toMiddletown Water Department in maintaining Cherry Hill Tank level while meeting varying waterdemands.

Additional changes to Long Hill Pump Station include the installation of a packaged tablet chlorinationsystem to boost chlorine residual in the pumped flows to the Cherry Hill Tank and the new watersystem serving Durham using an adjustable low concentration feed. The skid-mounted system iscomplete with valves, pumps (including a spare), mixing tank and control panel.

At the Cherry Hill Tank, a Trihalomethane (TTHM) removal system including aeration and mixing areprovided that are designed for continuous operation during periods of high potential TTHMs with theability to make manual speed adjustments for seasonal changes in conditions.

The above noted systems will be controlled as follows:

· The Long Hill Pump Station will be controlled by the elevation in the Cherry Hill tank. This willbe accomplished by connecting existing SCADA equipment in the Pump Station via radiotelemetry to the instrumentation provided at the Cherry Hill Tank.

· Daily demand variations in the distribution system will be met with the storage volume in theCherry Hill Tank. As demands are met, the water levels in the tank will drop in response tothe demand. Once the water level in the tank reaches a pre-set low water level, the pumpstation will be started to refill the tank.

· Once the tank water level reaches a pre-set high water level, the pump station will bestopped.

· The operating range of the tank is described in detail in Section 2, Hydraulic Analysis.

· The instrumentation and control outputs from the new tank, the Talcott Ridge Booster Station,and the Meter Vault will be integrated into the existing Long Hill SCADA system. Outputs willinclude, but not necessarily be limited to tank elevation, High and Low Water Level Alarms,water flow rates and totals, and other safety alarms as required by the City of Middletown.

· The booster chlorination system will include a supply water pressure reducing valve, inlineheater, booster pump, injection with automatic control valve and chlorine analyzer. Thefactory supplied control panel will be prewired to provide complete operating controls, circuitrelays, control switches, indication and alarm lights, and all appurtenances. Outputs from thecontrol panel that will be integrated with SCADA will include but are not limited to; not-in-auto,pump fault, mix tank low/ level alarms.

· The TTHM removal system will include a factory supplied control panel prewired to provideoperating controls, circuit relays, control switches, indication and alarm lights and allappurtenances for local control. In AUTO, the equipment shall operate continuously.

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Equipment will shut down on fault detection. Outputs from the control panel that will beintegrated with SCADA will include but are not limited to; not-in-auto alarm, equipment faultalarm, and running indication.

· The Talcott Ridge Booster Station will include two vertical multistage centrifugal boosterpumps with variable speed drives. The booster station design includes an 8” diameter bypassconnection with check valve that will allow water flows to bypass the booster station at thestation suction pressure for water main flushing or for abnormal conditions such as a poweroutage or pump station malfunction. Since the pumps have minimum stable flowrequirements, provisions for system storage volume to allow the pumps to cycle on and offare provided in the design. Two bladder style hydropneumatic tanks will provide sufficientstorage at the pump minimum flow rates to keep the number of pump starts to less than 10per hour as recommended by the pump motor manufacturer. Redundant hydropneumatictanks will be provided to allow for removal of one tank from service for maintenance whilekeeping the booster station in full operation. All of the instrumentation data, control signals,and alarms would be transmitted to the Water Department SCADA system via a radio link asis currently done at the existing Long Hill booster station and proposed for the Cherry HillTank. Three phase 480V/60 Hz electrical service will be provided with a natural gas poweredstandby generator to provide power during normal utility outages.

5.7 Water Quality ModelingWater quality modeling of the proposed pipeline and storage system was performed in order toestimate the impact that water age could have on the supply to Durham.

Introduction. The water quality as delivered by Middletown Water Department to their existing LongHill tank is well in compliance with the Connecticut Department of Public Health (CTDPH)requirements for potable water. The issue of water quality in this context is with respect to theexcessive water age which inevitably will result with the extension of the water supply system. Waterage impacts water quality in the following ways:

· Loss of disinfectant through chlorine decay/demand over time and subsequent exposure tobacterial risk

· Development of disinfection by-products

· Potential for stagnation and taste & odor issues

The need for disinfection and control of disinfection by-products (DBPs) represents a case ofcompeting objectives which many municipal water suppliers struggle with. While disinfection can beeasily assured by use of additional chlorine, this will provide an opportunity for the formation of DBP’swhich are formed when chlorine reacts with organic compounds. The formation of DBPs is alsodirectly proportional to increased water age and water temperature.

Disinfection by-products are regulated as primary drinking water standards and suppliers must strike abalance between the application of disinfectants and the formation of DBPs. There are two maincategories of DBPs, TTHMs and haloacetic acids (HAAs). Only TTHMs are of concern for the subjectproject. HAAs will not be discussed further. For the Durham Meadows water system extension project,the worse-case residence time in the distribution system is estimated at 17 days, based on a 1 MGtank, from Long Hill Pump Station to Durham Center. Clearly, this will require chlorination “boosting” toensure that residual chlorine can be maintained at the far reaches of the system. Adding chlorine tothe water, however, will react with the organic compounds that might be present in the finished water,creating additional DBPs to the ambient levels of DBPs that were already present. In order to modelthis problem, AECOM conducted a sampling and simulation study.

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Baseline Sampling. Baseline sampling was conducted in October 2015 to evaluate the existing waterquality with respect to chlorine decay and the potential for additional DBP formation. The watersampling was conducted at the Long Hill Pump Station. This represents the oldest water from theexisting Middletown system, and to which future chlorination boosting will be practiced. Table 7below summarizes the baseline water quality sampling results. Refer to Appendix I of this report forthe Protocol outlined in detail.

The results of the baseline testing are consistent with very good finished water quality. The keyparameters with respect to additional formation of DBP’s is the ambient (background) levels of TTHMsand the total organic carbon (TOC), detected at 60 ug/L and 1.74 mg/L, respectively. The CTDPHstandard for TTHM’s is 80 ug/L, measured quarterly and reported as a site–specific running annualaverage. Therefore, a result of 60 ug/L is not particularly concerning. However, the presence of TOC,though also considered low and not otherwise alarming, does provide the necessary precursor for theadditional formation of TTHM’s.

In summary, the chlorine added to this water for the purposes of providing a measurable chlorineresidual, will react with the existing TOC, thus forming TTHM’s, which will be additive to the existing60 ug/L and potentially resulting in levels which could exceed the 80 ug/L regulatory limit.

Table 7. Summary of Results of Baseline Sampling

Simulated Distribution System Modeling. With the baseline sampling completed, simulateddistribution system (SDS) studies were conducted, in order to answer the following questions:

· How much chlorine should be added to the Long Hill Pump Station sample to overcome thechlorine demand and still have a residual after the representative water age?

· How much additional TTHM formation can be expected as a result of adding the chlorine tothe sample and holding it for a period of time simulating the water age?

Parameter ResultsHardness (mg/L CaCO3) 52Alkalinity (mg/L CaCO3) 60.5pH (s.u.) 7.4Fe & Mn (mg/L) NDCL2 (total & free) mg/L 0.49/ND

Nitrogen (nitrate) mg/L NDTotal coliform (col/100 ml) PosE.Coli (col/100 ml) Neg

TTHM (ug/L) 60 (EPA limit = 80)Chloroform (ug/L) 46TOC (mg/L) 1.74

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The information obtained from these SDS studies was used in the design of the chlorine boosterstation and will help predict the potential TTHM levels. The SDS tests had the following basic steps:

1. Collect 5 identical samples from the Long Hill Pump Station.

2. Measure the initial TOC, TTHMs, temperature, and free chlorine residual (these results arereferred to as the initial conditions)

3. For Sample 1, no additional chlorine, but to samples 2 through 5, chlorine added in successivelyincreasing concentrations.

a. Sample 1 = ambient level of chlorine (measure at 0.49 mg/L)

b. Sample 2 = 1.0 mg/L

c. Sample 3 = 2.0 mg/L

d. Sample 4 = 3.0 mg/L

e. Sample 5 = 4.0 mg/L

4. Hold the samples in the dark, at ambient temperature (14 C), for 17 days and routinely measurethe free and total chlorine

5. At the end of 17 days (or if free chlorine residual is not detected), measure the TTHMs of thesample.

The detailed sampling and lab instructions are enclosed in Appendix I. The results of the chlorinedecay samples are summarized in Table 8. The results show that the 17-day residual chlorineconcentrations are essentially linear with respect to the initially applied chorine dose. As expected, thehighest chlorine residual is associated with the highest initial chlorine. For example, the Sample 1(SAM-1) to which no additional chlorine was added showed that after 17 days, the residual chlorinewas reduced from 0.49 mg/L down to 0.05 mg/L. In contrast, SAM-5 which was brought to over 4mg/L as the initial concentration showed a residual of 3.24 mg/L after 17 days. Generally, the chlorinedemand of the Long Hill Pump Station water was low, with each sample except SAM-5 showing a lossof approximately 0.5 mg/L total chlorine after 17 days. This has much to do with the high water qualityin the first place.

It should be cautioned that the sterile lab environment cannot not simulate all of the conditions which areal distribution system will present, such as the loss of residual from biofilms, inorganic scale, andother “pipe wall” effects. Therefore, it is not possible to predict the exact ideal booster chlorinationdose. Nonetheless, according to the SDS results, in order to maintain a desirable chlorine residual atday 17 the applied dose to the Long Hill Pump Station water could be expected at 1.5-2.0 mg/L. Thiscan be expected to result in a TTHM concentration that would be slightly above the 80 ug/L standard.Table 8 illustrates this, whereby the TTHM concentration in the sample collected from Long Hill wasfound at 49 ug/L, and increased proportionally over time, to levels ranging from 63 ug/L to 95 ug/L asa function of the applied dose of chlorine.

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Table 8. Summary of Chorine Decay and TTHM Formation

Minimizing TTHM Formation. Methods for minimizing the TTHM formation potential includeminimizing water age and chlorine residual as much as practical. For the Durham extension, this willrequire careful control of the applied chlorine and also practicing flushing to replace old water withfresh water.

Other strategies include aeration of the proposed storage tank. Aeration can very effectively stripchloroform, which is a major component of the TTHMs. Referring to Table 5, the 60 ug/L TTHM wascomprised of 46 ug/L chloroform (or nearly 77 %). This presents very favorable conditions forreduction of TTHMs. If the TTHMs could be reduced in storage, then the additive TTHM formationdownstream of the tank (which will still occur) would be added to an initially lower concentration. Itshould be noted that stripping of chloroform will not result in concurrent removal of chlorine.

Design Strategies for Water Quality. Three strategies have been employed in the design tomaintain the chlorine residual and address the potential for TTHM formation.

Tank size was reassessed, considering a number of factors; including water age, system demands,pressure requirements, and construction methods. A smaller tank than considered during the earlierstages of the design was selected as one means of reducing water age.

To address chlorine residual, a chlorine booster station will be installed at the Long Hill Pump Station;and to address TTHMs, a tank aeration system will be included in the Cherry Hill Storage Tank.

Booster Chlorination System. The booster chlorination station design is based on the use ofcalcium hypochlorite and the intended dose to the system is in the range of 1 -3 mg/L as Cl2applied.

DAY SAM-1 SAM-2 SAM-3 SAM-4 SAM-5TTHM Initial

(ug/L) 0 49

0 0.44 0.95 1.82 3.02 4.25

1 0.37 0.89 1.8 2.98 4.05

2 0.41 0.9 1.77 2.9 3.9

3 0.31 0.81 1.7 2.88 3.78

4 0.28 0.79 1.65 2.76 3.76

5 0.23 0.75 1.6 2.72 3.6

8 0.12 0.67 1.51 2.58 3.5

10 0.06 0.62 1.49 2.56 3.42

12 0.05 0.55 1.38 2.48 3.34

15 0.05 0.5 1.33 2.4 3.26

17 0.05 0.48 1.3 2.38 3.24

TTHM Final(ug/L) 20 63 83 89 92 95

Resid

ual F

ree

Chlo

rine

(mg/

L)

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Calcium hypochlorite systems utilize tablets, or “briquettes”, instead of liquid chemical. These systemsare flow paced, with a weigh scale and pressure regulation for fully automatic control. These systemsare ideal for small flows. Another major advantage is that calcium hypochlorite will not formperchlorate as can occur with sodium hypochlorite (bleach) systems that experience low chemicaluse.

TTHM Removal System. The TTHM treatment system uses simple low horsepower equipment tomix and aerate the chlorinated water to release TTHMS into the atmosphere. The system is designedto continuously mix the tank volume and draw feed water through the floating circulator and spraynozzle machine while the blower directs air into the top of the tank to react with TTHMs released fromthe chlorinated water. The gaseous TTHMs are vented from the headspace at the top of the storagetank. The release of TTHMs does not impact chlorine residual desired, but significantly reduces thepotential for TTHMs to form in the distribution system. During periods when TTHM formation is less,the floating spray nozzle can be speed adjusted to save energy while keeping the low-energysubmersible mixer located at the bottom of the tank to maintain continuous tank mixing and treatment.

5.8 Water Supply Well AbandonmentApproximately 125 water supply wells will be abandoned. The abandonment will include isolating thewell from the building(s) it serves, removing the pump and related equipment, and backfilling the wellwith low-permeability materials. Work shall be performed in accordance with the Connecticut WellDrilling Code requirements for well abandonment, except that 1) deviations as described in the letterfrom Connecticut DCP to Connecticut DEEP, dated July 23, 2014 (included in Appendix E), may beused in lieu of the Code requirements, and 2) permits will not be required in accordance withSuperfund NCP Section 300.400 (e)(1). Since the wells must be chlorinated prior to being backfilled,any water that threatens to overflow from the top of the well onto the ground during backfilling will becollected and transported to a central location for storage, treatment, and disposal.

Since the pumps, wiring, and piping are not expected to contain significant and persistent levels ofcontamination, the owner will be given the option to retain them. Materials that are not retained byowners will be recycled or disposed by the contractor.

5.9 Water Supply Well Conversion to Monitoring WellA long-term monitoring (LTM) program for groundwater is being developed by EPA and CT DEEP.The only LTM wells that are within the scope of this contract are the five existing supply wells that areto be converted to monitoring wells.

The five water supply wells that are to be converted to LTM wells have been sampled numeroustimes. The sampling has shown that two of the five wells, DMC #1 and DMC #2, have high levels ofcontamination; one well, at Hill Hollow Condominiums, has low levels of contamination; and two wells(one at the regional School, and one of the two Fairgrounds wells) are not contaminated. Other thanremoving internal well equipment as necessary to allow sampling, no alterations of these wells areplanned under this contract.

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6.0 Contract Packaging

6.1 Contract PackagingAfter careful evaluation, AECOM recommends that the Project be packaged as a single contract. Thework to be included under the contract includes:

· Precast Concrete Tank – Cherry Hill

· Tank Access Road

· Valve and Meter Vaults

· Booster Station

· Water Mains and Appurtenances

· Chlorine Booster and VFD Controls at Long Hill Pump Station

· TTHM Treatment at Cherry Hill Tank

· SCADA and Control improvements to Long Hill Pump Station

This approach offers a number of advantages to both the municipalities and the agencies. Generally,the advantages to a single contract package include streamlining of the bidding process, elimination ofinter-contract coordination and conflicts, streamlining of project scheduling and elimination of limit-of-work conflicts. Perhaps most importantly, however, a single contract will result in the GeneralContractor having total system responsibility for scheduling, construction, startup, and operations. Inaddition, all subcontractors will be directly answerable to the General Contractor who will coordinateand schedule their work.