Durham_BasisOfDesignReport_25Apr18.pdf

Prepared by:

AECOM

Rocky Hill, CT 60445033 April, 2018

Basis of Design Report – Durham Waterline Remedial Design Durham Meadows Superfund Site Durham, Connecticut

EPA Contract No. EP-S1-06-01 EPA Task Order No. 0072-TA-TA-01D5 EPA Project Officer: Heidi Horahan EPA Task Order Project Manager: Ed Hathaway

TO72-BODR-22018-500 April 2018 i

Contents

1.0 Introduction ............................................................................................................... 1-1

1.1 Background .......................................................................................................................... 1-1

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

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

2.0 Hydraulic Analysis .................................................................................................... 2-1

2.1 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 ...................................................................... 3-1

3.1 Summary of Permit Requirements ...................................................................................... 3-1

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

4.0 Subsurface Investigation Program ........................................................................... 4-1

4.1 Cherry Hill Water Storage Tank .......................................................................................... 4-1

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

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

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

5.0 Design Criteria .......................................................................................................... 5-1

5.1 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 ii

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

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

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

6.1 Contract Packaging.............................................................................................................. 6-1

List of Appendices Appendix 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 back pocket of report)

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

Appendix D3. Geotechnical Design Memoranda: Durham Meadows Waterline RD, Revised February 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 and Maine Water Company (Rev. October 2016)

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

Appendix H Value Engineering Screening of the Remedial Design Memorandum (Rev. January 30, 2015)

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

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List of Tables Table 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 Figures Figure 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

TO72-BODR-42018-500 April 2018

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1.0 Introduction

1.1 Background

This Basis of Design Report (BODR) for the Durham Meadows Waterline task order was prepared to define the technical parameters used to design the remedy. The rationale for the selected remedy is presented 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) were originally 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 the 2005 RI and FS. Three study areas were included; the Durham Manufacturing Area (DMC), the Merriam Manufacturing Area (MMC), and the Site-wide Groundwater Study Area, each described in below. This BODR addresses the Alternate Water Supply for the Site-wide Groundwater Study Area which includes a buffer zone of residences located near the contaminated area.

1.2 Site Description and History

The Durham Meadows Superfund Site is located in the town of Durham, Connecticut, and includes an area of groundwater contamination generally centered on Main Street. The Site includes historic Main Street in Durham center, and contains industrial and residential properties. It is generally bounded by Talcott Lane to the north; Brick Lane, Ball Brook and Allyn Brook to the East; wetlands west of Maple Avenue to the west; and, based on recent sampling, the intersections of Maple Avenue and Fowler Avenue with Main Street to the south.

The Site is centered around the Durham Manufacturing Company (DMC), a currently operating manufacturing facility located at 201 Main Street (the “DMC Study Area”), and the former location of Merriam Manufacturing Company, Inc. (MMC) at 281 Main Street. The Merriam Manufacturing Company Study Area, or “MMC Study Area,” includes the property on which the MMC plant was formerly 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 disposal of wastewater in lagoons or sludge drying beds, spills at both facilities, and inadequate drum storage practices at MMC, among other things, contributed to the contamination at each facility and in the overall area of groundwater surrounding both facilities (the “Site-wide Groundwater Study Area”).

Contamination from volatile organic compounds (VOCs) has been detected in soil and groundwater on both industrial properties, as well as in residential drinking water wells surrounding the MMC and DMC facilities. As of September 2017, there are 54 locations where GAC filtration units and/or bottled water are necessary due to groundwater contamination. Regular monitoring occurs at 28 additional locations, 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-wide Groundwater Study Area, the remedy includes a connection to the city of Middletown’s Water Distribution System to distribute an alternative source of public water to all residences currently affected by groundwater contamination and a buffer zone of residences located near the contaminated area. The city of Middletown is located north of the town of Durham. This alternative addresses 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 the city of Middletown south along Route 17 to residences within the Study Area providing potable water to all impacted residents and reducing current and future risk to human health from ingestion of groundwater. This alternative will provide a permanent source of drinking water to all residences currently affected by groundwater contamination and a buffer zone of residences located near the contaminated 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 the water 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 areas within the town of Durham that could be provided with a public water supply at some point in the future, with the main focus being the Superfund Site area. EPA fully considered the long-term planning input from the state and local communities when developing the design for the water line to be provided to the Durham Meadows Superfund Site.

Through a contract with the town of Durham, Fuss & O’Neill, Inc. (F&O) developed the “Durham Water System Extension Feasibility Study Update” (F&O, 2012; herein referred to as the F&O Report) and an “Environmental Impact Evaluation of the Durham Water System Extension” (F&O 2012a). These reports were originally prepared in 2010 and revised in November 2012. The F&O Report identified nine (9) areas with the town of Durham with documented well contamination problems. The Superfund Site-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 within the city of Middletown to provide potable water to the affected areas in Durham. Although the 2012 F&O Report states that Middletown has little excess capacity, the CT DPH has informed the EPA that Middletown has updated its water supply plan and that CT DPH has agreed that Middletown now has enough capacity and safe yield to supply water (including fire protection) to all identified areas within the 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 wells beyond Area A, into a portion of the Durham Center Area, defined as “Area I” in the F&O report, south of Allyn Brook. Based on these findings, a decision was made to extend the Superfund Site boundary south of Allyn Brook to the intersection of Maple Avenue and Main Street, to incorporate areas of known 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 to prevent future migration of the contamination. As a result, the design was revised to include the RSD 13 schools adjacent to the DMC facility location. The RSD schools were identified as “Area E” in the F&O report, and include the Coginchaug High School, the Korn Elementary School, and the Strong Middle 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 (Area E), and each of the other areas (B through H), as well as the new piping, the proposed Cherry Hill Storage 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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1.3 Purpose

The overall project objective is to provide potable water to all properties located within the Site-wide Groundwater Study Area. This includes the abandonment of existing drilled and dug wells on private property 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 the Superfund site and to also not restrict the opportunity for the state and community to serve other areas in the future. Based on the F&O report and AECOM’s scope of work under contract to EPA, the design includes the following:

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

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

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

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

· For all other areas outside of the Superfund Site, including study areas B through I (except as identified), stub line connections along the main trunk as needed in order to serve these areas in 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 on Talcott Ridge Drive and Watch Hill Drive; and

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

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

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

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

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

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Figure 2. Recommended Infrastructure Improvements for RD Project

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

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2.0 Hydraulic Analysis

2.1 Purpose

The purpose of the Hydraulic Analysis is to evaluate the proposed expansion of the Durham Water system and connection to the Middletown water system. The analysis included the recommended expansion as well as potential future build out of the water system in Durham. Modifications to the Middletown system will include construction of a new water storage tank and construction of a new water main from the tank to the Durham municipal boundary. The water infrastructure in Durham will include water mains and appurtenances to serve the areas indicated. Design of the modifications to the 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 System

Middletown. 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 Durham system from the existing Long Hill pumping station. Planned increases in water supplies in Middletown are also assumed to have been implemented prior to connection to the expanded system in Durham.

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

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

2.3 Recommended Water System Expansion

The F&O report recommended development of the water system in Durham to include the Core Area consisting of the Superfund site and other areas. The expanded water distribution system would include water mains from the intersection of Main Street at Higganum Road in Durham, north to the Durham/Middletown town line. In Middletown the water distribution system would be expanded from the Durham/Middletown town line north to the Cherry Hill Tank. The future build-out of the water distribution system, which was included in the model, is expected to include all areas shown in Figures 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 proposed Cherry Hill Storage Tank. Ground elevations within the Durham service areas range from 150 to 480 feet. Section 19-13-B102(f)(1) of the Regulations of Connecticut State Agencies (RCSA) requires that all service connections have a minimum water pressure at the main of 25 psi under normal operating conditions 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

2-2 fire protection is provided, within the distribution system as measured in the street. Pressure reducing devices should be installed where static pressures will exceed 100 psi. The F&O Report recommended that this tank's ground elevation would be 430 feet with an overflow elevation of 505 feet. Further evaluation of the service area by AECOM found that there is an existing water service on Talcott Ridge Road in Middletown that is at elevation 406 feet. This is the controlling elevation for tank levels to maintain adequate system pressures. Figure 3 shows the critical elevations in the Cherry 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 booster pumping when this area is connected to the system to maintain adequate pressures. Lower elevations occur in the Durham Center area will require installation of a pressure reducing valve. The following additional infrastructure is necessary in areas to account for elevations and system pressures expected:

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

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2. If the water supply is expanded to Area H in the future, a future booster pump station will be required along Main Street just north of Acorn Drive for Area "H". The ground elevation ranges from approximately 400 feet to 480 feet. This matches or is higher than the ground elevation of the Cherry Hill Storage Tank (440 feet). Pressures in this area would be less than acceptable given 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 CT DOT property across from the intersection of Talcott Ridge Road to provide domestic water service to 23 single residential homes location on Talcott Ridge Drive and Watch Hill Drive. The proposed Talcott Ridge water booster station and pressure zone will be supplied by the Cherry Hill 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 booster station the water pressure at the Talcott Ridge Drive cul-de-sac (elevation 410), which is the highest location 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 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 was interpolated based on model results, and therefore is not discussed in Section 2.4.

2.4 Model Development

The water distribution model of the Proposed Durham water system was developed in the Bentley software WaterGEMS version 8.i. using the model provided by the Middletown Water Department to incorporate existing infrastructure. Pipe alignments in the model were developed to match those shown on Figure 2 as preliminarily developed by Fuss & O’Neil. The pipe sizes in the distribution model were initially based on the pipe sizes presented in Table 5-2 of the F&O report with some changes 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, firefighting and emergency storage.

The results of an analysis of potential tank volumes to meet these storage requirements are presented in 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 Tank Diameter

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AECOM’s model indicated that the PRV location will be along Main Street between the Middlefield Road and Haddam Quarter Road as shown on Figure 4. The modeled pressure setting was 55 psi to determine 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 maintain pressures and fire flows in the future if water supply is extended to Area H. This area would include either 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 the hydraulic model.

2. Evergreen Terrace may need to be included which would also include the addition of Royal Oak Drive (Option 2). The pressures in the additional area included in Option 2 would be marginal, as indicated in the hydraulic model, if Option 2 is not implemented. If implemented, additional cost would 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 from the area encompassed by Options 1 and 2. However, future connection of this area would also require the construction of a new booster pump station in order to meet minimum flow and pressure requirements. Therefore, the selection of Option 1 versus Option 2 would be based on a cost-benefit analysis of the options and the available funding at the time of the improvements. The design of this booster 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 and subsequently 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 summarized below:

· Single family 300 gpd

· Two family 450 gpd

· Multi-family 675 gpd

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

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

· 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 day and maximum day demands (gpm calculations) were based on 24 hours per day of operation.

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Figure 4. 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 represent the existing demands in Middletown served by the Long Hill pump station. In addition, the Durham Center 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 hour demands. Table 2 lists the projected demands for each area. Figure 6 shows the location of the existing Middletown demands.

Table 2. Demands used in Model

Area Average Day, gpm

Maximum Day, 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

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

Table 3. Needed Fire Flow Analysis

Address Name Building Area (ft2)

Fire Protection

Approximate Needed Fire Flow (gpm)

Fire Flow Duration

(hr)

Tank Storage To Support Fire Flow

(gallons)

Municipal and Commercial Properties of Concern in Durham

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

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

Fairgrounds Durham Fairgrounds (largest building)

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

350 Main Street Adams Commons (2 story wood frame)

10,340 Not Sprinklered 3,000 3hr 540,000

35 Winsome Road

Claremont Corporation 29,220 Not Sprinklered 2,500 2hr 300,000

201 Main Street Durham Manufacturing Warehouse

23,650 Not Sprinklered 2,250 2hr 270,000

337 Main Street Adams Country Barn (Partial 2nd story)

4,414 Not Sprinklered 2,250 2hr 270,000

144 Pickett Lane Korn Elementary School 29,826 Part.

Sprinklered 2,250 2hr 270,000

30 Townhouse Rd

Durham Town Hall 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’s Automotive 6,072 Not Sprinklered 1,250 2hr 150,000

236 Main Street First Church of Christ 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 Automotive Repair 4,440 Not Sprinklered 1,000 2hr 120,000

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

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Address Name Building Area (ft2)

Fire Protection

Approximate Needed Fire Flow (gpm)

Fire Flow Duration

(hr)

Tank Storage To Support Fire Flow

(gallons)

135 Pickett Lane Coginchaug Regional High School

N/A Sprinklered 750 2hr 90,000

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

Commercial Properties of Concern in Middletown

2055 South Main Street Tisbury LLC 36,885 Sprinklered Unknown

2081 South Main Street Oaks LLC 59,557 Sprinklered Unknown

2303 South Main Street

Jem Wire Products 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 a fire flow of 2,500 gpm would be the largest fire flow that could be provided within the system. The duration of this event would be 2 hours. As indicated in Table 3, there would be some structures for which the needed fire flows would be provided by other means available to the Durham Fire Department. For modeling purposes, these fire flows were simulated at the intersection of Main Street and Higganum Road, the furthest location from a tank within the entire system including areas beyond the Superfund site.

C. Model Scenarios Evaluated

To facilitate the design of the storage tank and pump station, the system was evaluated under full build-out conditions to ensure the piping from the pump station to the tank and the transmission main on Main Street (Rte 17) are large enough to convey future demands. These facilities must be designed 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

§ Full Build-Out - 0.44 MGD

- 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

§ Full Build-Out - 0.23 MGD

D. Evaluation Criteria

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

· Normal Operations:

- Steady State Analyses

- 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 residual pressure of 20 psi

- Extended Period Hydraulic Analyses

- Maximum Day Demands - Minimum system pressures greater than 30 psi and maximum 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 20 psi. 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 for booster chlorination

E. Modeling Results

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

· Normal Operations:

- Steady State Analyses

- Maximum Day Demands

§ 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 a Booster Pump Station to meet minimum pressures, as shown in the attached model 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 -

§ Initial Tank elevation set at 476 feet

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

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

§ Pressures

§ Served directly from Long Hill PS:

§ Minimum 21.4 psi at 214 Talcott Ridge Road

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

§ Downstream of PRV:

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

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

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

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

§ Long Hill Pump(s)

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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 installation of the PRV on the main line

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

§ J-1336 through J-1339

§ J-1343 through J-1347

§ Pressure at booster station suction on Main St. 48.3 psi

- Peak Hour Demands –

§ Initial Tank elevation set at 491 feet

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

§ Pressures

§ Served directly from Long Hill PS:

§ Minimum 34.7 psi at 214 Talcott Ridge Road.

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

§ Downstream of PRV:

§ Minimum 52.0 psi at Haddam Quarter Road at Oak Terrace

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

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

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

§ Long Hill Pump(s)

§ Flow 741.3 gpm at 161.2 feet

§ Cherry Hill Tank

§ Flow 914.8 gpm (Filling)

§ Locations (represented by model nodes) that would need to be serviced by a Booster Pump Station to meet minimum pressures, as shown in the attached model schematic in Figure 6:

§ J-1336 through J-1339

§ J-1343 through J-1347

§ Pressure at booster station suction on Main St. 65.7 psi

- Available Fire Flow

§ Initial Tank elevation set at 462 feet

§ Long Hill pumps off

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

§ Minimum acceptable pressure = 20 psi for area evaluated

§ Minimum available fire flows:

§ Served directly from Long Hill PS:

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

§ Maximum 3,500 gpm at several locations

§ Downstream of PRV:

§ 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 507.6 feet during the 24-hour simulation. Tank level variation illustrated in Figure 7.

§ Pressures

§ Served directly from Long Hill PS:

§ Minimum 35.0 psi at 214 Talcott Ridge Road.

§ Maximum 104.1 psi at Main Street and Winsome Road.

§ Downstream of PRV:

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

§ 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 as scheduled.

§ Long Hill Pump 2 runs from 3:50 pm when the Cherry Hill tank level drops 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 a pump is running.

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

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§ PRV located on Main Street just north of intersection of Haddam Quarter Road, with a pressure setting of 55 psi, § Flow through valve ranged from a minimum of 63.1 gpm up to a maximum of 559.8 gpm with an average of 120 gpm.

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

- Maximum Day Demands plus Fire Flow –

§ Initial Tank elevation set at 495 feet

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

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

§ Pressures

§ Served directly from Long Hill PS:

§ Minimum 20.0 psi at 214 Talcott Ridge Road

§ Maximum 104.6 psi at Main St. and Winsome Road

§ Downstream of PRV:

§ 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 as scheduled.

§ Long Hill Pump 2 runs from 3:50 pm when the Cherry Hill tank level drops 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 a pump is running.

§ 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 of

2609.8 gpm with an average of 136.6 gpm.

§ Head loss through the valve ranged from a minimum of 73.0 feet up to a maximum 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 of connecting to the Durham Center system without including the recommended improvements at this time. The modeling also considered the elimination of the 8-inch water main to loop across Old Cemetery Road between Maple Avenue and Main Street and the addition of the 12-inch main at Wallingford 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 piping improvements in Durham Center, water can be supplied at adequate pressures under all normal demand conditions. The analysis did find that for steady state conditions the fire flow scenarios indicate the greatest impact from the modified piping configuration to connect to the Durham Town Center 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 steady state fire flow would be about 1,360 gpm at either of the two evaluated fire flow locations in Durham Center; at the end of the 8-inch water main on Cherry Lane, and at Main Street and Higganum Road which 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 Maple Avenue and Main Street and the addition of the 12-inch main at Wallingford Road and Main Street along Maple Avenue to the Durham Center system connection. These are recommended improvements 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 as for 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 pressures will remain above 40 psi for all non-fire scenarios up to maximum day demand conditions and above 20 psi for all fire flow scenarios. A maximum non-fire demand of 1523 gpm could be supplied which is 91 percent of the full peak demand of 1673 gpm. The pump results indicate that a single pump would be running for average day and maximum day demand conditions and that two pumps would be running for maximum day demand, peak hour demand and fire flow scenarios. The pump controls would need to be set so the pump speed is varied to maintain a constant pressure at the Long Hill pump station. Figure 8 illustrates the operating points of the pump for these scenarios with the pump curve shown for reference.

Water Quality Analyses

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

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

Model Label Elevation

Initial Conditions

- Average Demands

Full-Build Out - Average Demands

Initial Conditions -

Maximum Demands

Full-Build Out -

Maximum Demands

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 1523.25

187.79 + 1,330 gpm FF

310.12 + 1,215 gpm FF Junction Results

Pressure (psi) 984 (Talcott Ridge Road 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 (Durham Fairgrounds) 232 82.33 82.29 82.27 82.13 71.76 71.60 52.80

Pump Results Flow (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

Initial Conditions

- Average Demands

Full-Build Out - Average Demands

Initial Conditions -

Maximum Demands

Full-Build Out -

Maximum Demands

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 Results Flow (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 Main Street P-6058 57.08 152.88 177.76 296.16 1463.31 1507.76 1507.16

16-inch Main in Talcott Ridge 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 Main Street P-6058 0.09 0.24 0.28 0.47 2.33 2.41 2.40

16-inch Main in Talcott Ridge 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 and full build-out conditions. The analyses indicated that the average water age in the Cherry Hill tanks would be on the order of 4-6 days under full build-out conditions and on the order of 6-8 days under initial conditions. This may be too long of a duration for the chlorine residual added at the Middletown WTP to remain above levels required by Connecticut DPH (0.2 mg/l). Furthermore, the water age in the Durham Center area would be on the order of 8 days under full build-out conditions and on the order of 10-11 days under initial conditions.

In addition to the water age analysis conducted using the WaterGEMS hydraulic model, a separate analysis of chlorine decay and trihalomethane formation was conducted that confirmed that the chlorine decay under some conditions would drop residuals lower than 0.2 mg/l within the water ages indicated by the model. Furthermore, the THM formation analyses indicated that with booster chlorination, 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 be added with a tank mixing system at the Cherry Hill tank to lower THM levels.

2.5 Talcott Ridge Drive Boosted Pressure Zone

The Talcott Ridge Drive Water Booster Station is intended to provide only domestic water service to 23 single family homes located on Talcott Ridge Drive and Watch Hill Drive in Middletown Connecticut as indicated in Figure 9.

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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 proposed to serve the Town of Durham. Available fire protection flows are expected to be in excess of 2,500 gallons per minute (GPM).

Service Area Flow Requirements

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