January 20, 2017

Mr. Guilford Mooring, P.E., Superintendent Amherst Public Works Department 586 South Pleasant Street Amherst, MA 01002

Subject: Final Alternate Water Supply Study Report Amherst, T&H No. 4609

Dear Mr. Mooring,

In accordance with our agreement, Tata & Howard is pleased to present you with final the Alternate Water Supply Study Report for the Town of Amherst Water Department. The study summarizes the alternatives available for a more reliable water supply. Alternatives include developing new sources and maximizing existing sources.

During the course of this project, Ronald Ponte, P.E. served as Senior Project Engineer, Meagan Heslin, P.E. served as Assistant Project Engineer, Karen Gracey, P.E. provided technical reviews and the undersigned served as Project Officer.

At this time, we wish to express our appreciation to the Town for their participation in this study and for their help in collecting information and data. Special thanks are given to Ms. Amy Rusiecki, P.E. and Mr. Stephen Call for contributions to this report. On behalf of our project team, we appreciate the opportunity to assist the Town with this important project. We look forward to discussing the findings of this report with the Town and Universities. Please feel free to contact us should you have any questions or require additional information in this regard.

Sincerely,

TATA & HOWARD, INC.

Paul B. Howard, P.E. Senior Vice President

Enclosure

Tata & Howard 67 Forest Street | Marlborough, MA 01752 T: 508-303-9400 | F: 508-449-9400 www.tataandhoward.com

Other Offices MA | NH | CT | ME | VT | AZ | TX

Amherst Alternate Water Supply Study

SECTION 1 - Introduction

1.1 General

Tata & Howard was retained by the Town of Amherst, Massachusetts Public Works Department to conduct an Alternate Water Supply Study. The study evaluates existing and future system demands, existing water supply sources and alternatives for additional supply for the water system including developing a new source, upgrading an existing surface water treatment plant, and maximizing existing sources.

The Town of Amherst is currently able to meet system demands but should plan for future growth and resiliency. The Town supports growing university populations and downtown commercial and service industry. The Town sees increased demands during the school year and lower demands in the summer months, which is contrary to other municipalities.

Each alternative was reviewed for necessary distribution system improvements, potential water treatment requirements, and required permitting. The costs associated with each alternative are also discussed. This report presents an analysis of the current water supply and recommendations to augment the existing supply sources and satisfy future water demands.

Page 1

Amherst Alternate Water Supply Study

SECTION 2 - Existing Water Distribution System

2.1 Distribution System

The Town of Amherst’s water distribution system consists of approximately 130 miles of pipe ranging in diameter from two to sixteen inches. Asbestos cement pipe accounts for approximately 25% of piping; the remainder being cast iron, ductile iron, and small amount of PVC and galvanized. The downtown area of the Town has the oldest sections of pipe, which is mostly cast iron and galvanized steel. All recent replacements and extensions of the distribution system are cement lined ductile iron pipe. The distribution system is flushed annually.

The University of Massachusetts Amherst owns and operates its own water distribution system of approximately 70,000 feet of main ranging in size from six to twelve inches in diameter. The campus is connected to the Town’s water system with four meter vaults, each containing a pair of compound fire meters to measure flow in each direction. The university also has a 1.5 million gallon storage tank located adjacent to Amherst’s water tank off East Pleasant Street.

The Town also supplies service connections in Belchertown and Pelham. The Pelham connections experience low water pressure when the Centennial Water Treatment Plant is not in operation at the end of the summer and early fall. The Town updated a small pump station in 2011 that boosts water pressure to the Pelham connections during this time. The pump station is below grade and adjacent to the Pelham Police Station. It has two booster pumps, a pressure reducing valve, and pressure gauges. There is back-up power provided to the station.

2.2 Existing Water Supply Sources

The Town of Amherst has four surface water supplies and five active groundwater supply sources. The Town has a sixth permitted groundwater well that was never completed due to high iron and manganese levels. All six of the groundwater wells are located in the Lawrence Swamp Aquifer in the Hop Brook Basin in the Connecticut River watershed. Amherst has a total grandfathered registered withdrawal volume of 3.34 mgd under WMA Registration #1-06-008.02 and a permitted withdrawal volume of 1.21 mgd. The Town is currently allowed to withdraw up to 4.55 mgd of raw water from the Connecticut River Basin under the Water Management Act (WMA) Permit #9P-1-06-008.01. The Permit Extension Act enacted in 2010 and amended in 2012 extended the term of the WMA permit through November 2017. The Town has an approved baseline of 3.80 million gallons per day (mgd) under the new Sustainable Water Management Initiative (SWMI) regulations. Withdrawals above the baseline trigger additional requirements under SWMI discussed in Section 6. Table No. 2-1 presents the approved maximum daily withdrawal rates for the system’s groundwater sources.

Page 2

Amherst Alternate Water Supply Study approximately a half mile east of the intake reservoir. It has a surface area of seven acres and storage capacity of 30 million gallons. The Hill Reservoir dam and intake structure were rebuilt in 1990. Both Hill and Hawley Reservoirs do not feed the treatment plant directly. Water flows from each reservoir through a stream to the Intake Reservoir.

The Intake Reservoir is a one acre impoundment with a storage capacity of 2 million gallons. Water from the intake reservoir flows through a 12-inch transmission main to the Centennial Water Treatment Plant located approximately a half mile from the Intake Reservoir.

Wells No. 1 and 2 Well No. 1 (01G) and Replacement Well No. 2 (08G) are gravel packed wells located on the eastern edge of the Lawrence Swamp in the southeastern section of Town, south of the Central Vermont railroad tracks and the Norwottuck Rail Trail. The wells are within 200 feet of each other and are manifolded together onsite and feed a single 12-inch transmission main to the chemical injection facility. The two wells are enclosed in a half acre impoundment, surrounded by a chain link fence. Wells No. 1 and 2 are automatically controlled based on the level in the East Pleasant Street Tank. Well No. 1 and original Well No. 2 were installed in 1958. Replacement Well No. 2 was installed in 2008 approximately 20 feet to the west of the original Well No. 2. The original Well No. 2 has been decommissioned and abandoned after the well screen failed.

Well No. 1 is 10 inches in diameter and 96 feet deep with a 10-foot screen. Replacement Well No. 2 is located approximately 20 feet northwest of the original Well No. 2 (04G). The 18-inch by 24-inch well is 84 feet deep with a 12-foot screen. The wells are metered separately and feed into a 12-inch water main to the chemical injection facility. Water from Well No. 1 and 2 is treated with sodium hydroxide for corrosion control and sodium fluoride for fluoridation.

Well No. 3 Well No. 3 (02G) is located east of Warren Wright Road in the Town of Belchertown. The 18- inch diameter well was installed in 1969 to a depth of 96 feet with a 15-foot screen. Water from Well No. 3 is treated with sodium hydroxide for corrosion control and sodium fluoride for fluoridation. Well No. 3 turns on and off based on the level in the East Pleasant Street Tank.

Well No. 4 Well No. 4 (05G) is a gravel packed well located in the center of Lawrence swamp in the southern section of town. The well was installed in 1980 and is 18-inches in diameter and 140 feet deep with a 30-foot screen. This well experiences high concentrations of iron and manganese and is pumped through a mile long 16-inch transmission main to the Baby Carriage Brook Water Treatment Plant. The well is approved for 1,218 gpm (1.74 mgd) and was redeveloped in 2010. This source is manually operated during high demand periods.

Well No. 5 Well No. 5 (06G) in located north of the intersection of Bay Road and Hulst Road in Amherst, in Lawrence Swamp. The 8-inch diameter well was drilled in 1981 and is 57 feet deep with a 10- foot screen. The pump was replaced in 2005. The well has air intrusion problems and it is not a reliable water supply source and is only used when the other sources cannot maintain levels in the storage tanks. Water from Well No. 5 is treated with sodium fluoride for fluoridation. Page 5

Amherst Alternate Water Supply Study

Well No. 6 Well No. 6 (07G) was drilled in February 1991 and approved for a yield of 820 gpm (1.18 mgd) by the MassDEP. The well is an 18-inch by 24-inch gravel packed well with the well screen set from 153 feet to 168 feet below grade. The well was never completed due to high concentrations of iron and manganese.

Brickyard Well Field During a severe water shortage in the 1960s, the Town installed multiple wells off Route 9 near the Belchertown Town line. A pump test in 1968 indicated that the area could produce 0.4 mgd. The 17 wells, ranging in depth from 40 to 100 feet, were located near the Town landfill and automobile salvage yard. Low levels of volatile organic compounds (VOC) were detected in the monitoring wells in 1977 and 1978. The Town discontinued use of the well field due to its proximity to the VOC contamination and the newly constructed Wells No. 4 and 5. The wellfield was formally abandoned and decommissioned in 1991.

2.3 Water Treatment Plants

The Town of Amherst Public Works Department operates three water treatment facilities.

Centennial Water Treatment Plant The Centennial Water Treatment Plant is a 1.5 mgd facility that treats water from the Pelham Reservoir system. The plant was built in 1982 and is located on Amherst Road in Pelham. The primary components of the treatment process are three package filtration units manufactured by Roberts Filtration Group. Each unit, installed within a 46 foot long by 10 foot wide steel tank, consists of two flocculation basins, a sedimentation basin with inclined tube settlers, and a dual media anthracite over silica sand filter. Polymer addition, gas chlorination, and chloramination systems are also included in the treatment process.

Due to water quality concerns, the plant has never operated at full capacity. The building is in disrepair and in need of an upgrade. The plant experiences high color raw water during the summer months. The organics removal during this time is relatively poor, resulting in high trihalomethane (THM) and haloacetic acid (HAA) in the distribution system. The water quality of the finished water deteriorates at higher loading rates, reducing the functional capacity of each filter unit by half.

Atkins Water Treatment Plant The Atkins Water Treatment Plant was constructed in 1994 and is located off Market Hill Road approximately 1.5 miles west of the Atkins Reservoir. The plant contains many treatment technologies, some of which are not currently in operation. The available treatment processes include ozonation, polymer addition, static mixing, upflow clarification, filtration, chloramination, pH adjustment, and fluoridation. The ozonation and granular activated carbon filtration are not currently in use. The plant has the capability to add alum for coagulation and phosphates for corrosion control, but currently do not.

Page 6

Amherst Alternate Water Supply Study

The upflow clarification and filtration process are contained in three prefabricated “Trident” modules, each with a capacity of 0.75 mgd. The treated water is stored in two clear wells with a total volume of 500,000 gallons. The plant has an emergency generator in case of a power outage. The generator can power all treatment plant equipment.

Baby Carriage Brook Treatment Plant The Baby Carriage Brook Treatment Plant treats water from Well No. 4. It was built in 1981 and is located off Southeast Street approximately one mile west of the well. The plant historically operates from Mid-August through Mid-November to provide water to meet the increased demands associated with the return of students to the local colleges and universities. A variable frequency drive was installed at Well No. 4 and the full pump capacity is 1,250 gpm. The plant was designed to remove iron and manganese with pressurized GreensandPlus filter media. Chlorine is added to disinfect and sodium fluoride is fed at the well house.

Previously, the plant utilized the addition of chlorine and potassium permanganate to provide oxidation of iron and manganese as well as disinfection. A chemical feed study conducted by Tata & Howard in 2015 recommended eliminating the potassium permanganate and simplified the chemical feed process while optimizing the treatment performance.

2.4 Water Storage Facilities

The Town of Amherst has four storage tanks for the water distribution system. All the tanks are welded steel tanks equipped with an access ladder, roof hatch, roof vent, and valve vault. Three tanks are owned by the Amherst Water Department and the fourth is owned by the University of Massachusetts.

Bay Road Tank The Bay Road Tank has a one million gallon capacity and measures 64 feet in diameter and 40 feet high. The overflow elevation is 471 feet (USGS). The tank is located at the end of a quarter mile long dirt access road off Bay Road in South Amherst. There is a gate at the access road to deter motor vehicles. The tank has an 8-inch overflow pipe with a wire mesh screen that ends approximately 24 inches above grade. The valve vault contains an altitude valve and a seven day water level chart recorder by Fischer and Porter.

East Pleasant Street Tank The East Pleasant Street tank is located on the University of Massachusetts campus off East Pleasant Street. The tank was built in the 1930s and has a 35-foot diameter and is 66 feet high with an overflow elevation of 471 feet. It has a storage volume of 475,000 gallons. The controls for the entire operation of the water supply pumps are based on the levels in this tank, which change seasonally. This tank does not have a separate overflow pipe, excess water cascades out through the vent screen which runs along the perimeter of the tank.

UMass Tank The UMass Tank is a 1.5 million gallon storage tank located adjacent to the East Pleasant Street Tank. This tank is owned and operated by the University of Massachusetts. It has a 62 feet diameter with an overflow elevation of 471 feet. Page 7

Amherst Alternate Water Supply Study

Village Park Tank The Village Park Tank was constructed in 1976 and is located about a quarter mile east of the UMass Tank. The capacity is 1.68 million gallons and is 78 feet in diameter and 49 feet high. The overflow elevation is 471 feet. There is a 10-inch overflow pipe that runs down the outside of the tank and ends about 24-inches above grade. The tank has an eight foot high perimeter chain link fence with an access gate. The valve vault contains an altitude valve and a seven day water level chart recorder by Fischer and Porter.

2.5 Interconnections The Town of Amherst has two interconnections with the Town of Hadley for emergency water. The first is on Greenleaf Drive and the second is on Meadow Street. A metered vault was installed in 2014 on Meadow Street with a magnetic meter registering flows in both directions. The hydraulic grade line in Hadley is lower than that of Amherst, therefore, water from Hadley would need to be pumped into Amherst. The Greenleaf Drive interconnection is hydrant to hydrant.

2.6 Operational Procedures The surface water supplies are utilized first, followed by the groundwater supplies. Well No. 4 is operated manually when the Centennial WTP is traditionally taken off line in the late summer months and early fall. Well No. 5 is manually operated when needed to meet demand.

Atkins WTP is a Grade 3 facility. Centennial and Baby Carriage are Grade 2 facilities. Atkins require eight hours per day of manned trained operation and Centennial and Baby Carriage Brook require four hours per day of operation. However, daily operations at Centennial and Baby Carriage Brook require six to eight hour per day of operation. Well Nos. 1, 2, and 3 are rotated as the lead pump to meet demand. The pumps automatically operate on and off as needed to fill the storage tanks. These wells require a combined four hours of operation per day.

Page 8

Amherst Alternate Water Supply Study

3.4 Average Day Demand

Average day demand (ADD) is the total water supplied to a community in one year divided by 365 days. This term is commonly expressed in millions of gallons per day (mgd). This demand includes all water used for domestic (residential), commercial, industrial, agricultural, and municipal purposes. The municipal component includes water used for system maintenance such as hydrant flushing and fire flows. In addition, the ADD includes unaccounted-for water attributed to unmetered water uses and system leakage. According to the 2010 through 2015 ASRs, the ADD for the Amherst system ranged from 2.68 mgd to 2.96 mgd.

3.5 Maximum Day Demand

Maximum day demand (MDD) is the maximum one-day (24-hour) total quantity of water supplied during a one-year period. This term is typically expressed in mgd. MDD is a critical factor to be considered when determining the adequacy of a water supply system. The distribution system must be capable of meeting maximum day demands with coincident fire demands to be considered adequate. Estimates of the projected maximum day demand and an allowance for the required fire flow are used to evaluate or design pumping, transmission and storage facilities. The greatest MDD for the Town of Amherst in the last five years is 4.4 mgd.

Page 11

Amherst Alternate Water Supply Study growing with new commercial and residential buildings planned. The commercial growth is not represented in these numbers. A five percent buffer is included to account for uncertainty in the projections. The Town currently has the approved WMA withdrawals to meet the projected demand if these projections are accurate.

4.3 Adequacy of Existing Water Supply Sources

In 1987, the Water Management Act (WMA) program was implemented by the MassDEP to regulate withdrawal of water from the State’s watershed basins. Under this program, all new sources withdrawing more than 100,000 gpd and existing sources exceeding their registered withdrawal volume by 100,000 gpd are required to obtain a withdrawal permit under the WMA. When first implemented, the registered withdrawal volume for a public water system was based on that system’s historical pumping rate of the water supply source(s) between 1981 and 1985. Permits can be renewed and amended as system demands increase and additional supply sources are utilized. The WMA program considers the need for the withdrawal, the impact of the withdrawal on other hydraulically connected water suppliers, the environmental impacts of the withdrawal and the water available in the river basin or subbasin (the basin safe yield) prior to issuing a permit. It is important to note that the basin safe yield is different from the safe yield of a supply. In accordance with the WMA permit application instructions, the basin safe yield is the total water available to be withdrawn from a river basin or subbasin, whereas the safe yield of a well is the volume of water the well is capable of pumping under the most severe pumping and recharge conditions that can be realistically anticipated.

All Amherst groundwater supply sources are located within the Lawrence Swamp Aquifer in the Connecticut River Basin. They are all located in the same subbasin, which is classified as a Cold Water Fishery. It is recommended that Amherst pursue future water supplies outside of the Hop Brook subbasin.

MassDEP guidelines recommend that a system consider projected summer average day demand (SADD). SADD is estimated by averaging demands from the three maximum months for the past five years. For most municipalities, these months are during the summertime. However, Amherst experiences maximum demands during the school year. The three highest demand months were used for this analysis. In 2010, 2013, 2014, and 2015 the highest demand months were April, September, and October. As shown in Table No. 4-4, the SADD ranged from 3.09 to 3.32 mgd. The SADD peaking factor is determined by dividing the SADD by the annual ADD for each of the past five years. These peaking factors are averaged to estimate the future summer peaking factor. Once projections are finalized, the projected SADD can be determined and compared to the adequacy of the water supply.

Page 13

Amherst Alternate Water Supply Study

SECTION 5 - Alternatives Analysis Six alternatives were evaluated to determine which would be practical, cost-effective solutions to meet the Town of Amherst’s growing demand. Alternatives include utilizing Well No. 6, upgrading the Centennial WTP, increasing operation of Well No. 4, replacing Well No. 5, developing a new source in Sunderland, dredging the Atkins Reservoir, and connecting the Pelham Reservoirs to the Atkins WTP.

5.1 Utilization of Well No. 6

Well No. 6 is permitted under the Water Management Act for withdrawals of 1.18 mgd, but the Town does not utilize the additional supply. Utilizing Well No. 6 was evaluated as an alternative to meet growing water demand. Due to high iron and manganese concentrations, the well was never completed and connected to the system after obtaining permit approval. The potential to connect Well No. 6 to the distribution system could increase the Town’s ability to meet increasing demands.

Due to the high iron and manganese concentrations, flow from Well No. 6 would need to be treated at Baby Carriage Brook WTP. This involves installing a transmission main, providing electricity to the site, and potential land acquisitions in addition to expanding the treatment plant to accommodate the additional flow. At $200 per linear foot, the cost to pump to Baby Carriage WTP would be approximately $1,830,000. This includes an approximately 1.6-mile transmission main, submersible pump, and power to the site. This does not include the cost to expand the treatment plant.

Even though this well is permitted, the aquifer cannot support the additional withdrawal. All five Amherst wells and Belchertown well draw from the Lawrence Swamp Aquifer. The estimated yield of Well No. 6 was estimated using the upstream watershed area. Every square mile of upstream watershed area corresponds to approximately 0.5 mgd of estimated yield. There is approximately 4.4 square miles of upstream area from Well No. 6 as shown on Figure No. 5-1. This corresponds to 2.2 mgd of estimated yield. This calculation, known as the New England Method, provides a rough estimate of yield in the aquifer and is used for screening purposes. However, the approved capacity of the other wells, Nos. 1, 2, and 4, in the upstream watershed need to be subtracted from this value. This leaves the estimated yield of Well No. 6 as a negative value. The New Source Approval application dated October 1992 indicates Well No. 6 was intended to be a backup source to Well No. 4 and a redundant supply source for reliability. Connecting Well No. 6 to the distribution system will not improve the reliability of the water supply sources for Amherst.

Page 15

Amherst Alternate Water Supply Study

5.2 Upgrade Centennial WTP

Tata & Howard reviewed the recommendations associated with upgrading the existing Centennial Water Treatment Plant as outlined in the Tighe & Bond reports entitled “Centennial Water Treatment Plant Upgrade Evaluation and Preliminary, November 2010” and Centennial Water Treatment Plant Pilot Study Report, March 2015.”

Summary of Previous Alternatives Studies The initial 2010 report basically evaluated and recommended upgrading of the existing facility, which included: 1. Upgrade of the Roberts treatment units including the following: a. Repainting of the tanks. b. Replacement of the flocculation mixers and drives c. Replacement of the tube settlers d. Replacement of the filter media and underdrain systems e. Replacement of the filter surface wash system with an air scour system. 2. Installation of an ultraviolet primary disinfection system. 3. Modification of the existing raw water splitter box. 4. Evaluate and if necessary, replace hypolon baffles in the chlorine contact tank. 5. Replacement of the existing raw water, backwash control, effluent, and drain valves on the Roberts units. 6. Installation of a magnetic flow meter on the raw water header for control of the raw water pumps/flow rate. 7. Replace the HVAC system at the water treatment plant and raw water pump station. 8. Replace interior and exterior lighting. 9. Replace gutters and downspouts. 10. Repair skylights. 11. Paint workroom floor. 12. Repair or partially replace corroded areas at the bottom of the interior metal wall panels. 13. Upgrade the chlorine and ammonia rooms to meet current safety recommendations. 14. Relocate the polymer transfer pump so as to be more accessible. 15. Install underground storage tanks to receive spent filter backwash water and clarifier sludge blowdown, and eliminating existing lagoons. 16. Replace existing Amherst Road control valve and booster pump with a new package pump/flow control valve station. 17. Replace the motor control center and generator at the water treatment facility. 18. Replace the raw water pump station motor control center. 19. Connect the treatment plant to the Amherst sewer system by installing a sewer in Amherst Road.

The above work was assumed to be broken up into three construction contracts, whose cost breakdowns were listed in Tables 5-1, 5-2, and 5-3 of the report, and included the following: 1. In general, Table 5-1 was comprised of items 1 through 16 above, with a 2010 estimated cost of $2,100,000, including engineering and contingencies. 2. Table 5-2 was comprised of items 17 and 18 above, with a 2010 estimated cost of $261,000, including engineering and contingencies. Page 17

Amherst Alternate Water Supply Study

3. Table 5-3 was for the construction of the sewer connection (item 19), with a 2010 estimated cost of $1,720,000, including engineering and contingencies.

A table of several lower priority items, Table 5-4, was also included and primarily listed work associated with the building exterior, including replacement of the metal wall and roof panels, building insulation, windows, doors, louvers, and miscellaneous structural repairs. The estimated 2010 cost for the proposed improvements totaled $804,000 including engineering and contingencies.

The Town was concerned that rehabilitating the existing processes would not restore the plant to its original capacity, or improve its performance. In response, Tighe & Bond prepared a memorandum in October of 2012 that evaluated four potential treatment options that could be implemented within the footprint of the existing treatment facility. These included dissolved air floatation (DAF), Trident (upflow clarifier), membrane filtration, and the Actiflo ballasted floc system. In each case, Tighe & Bond assumed that UV primary disinfection would not be required due to improved organics removal of all systems evaluated. Based on initial construction costs being relatively similar, it was recommended that the Town pilot the DAF, Trident, and Actiflo processes concurrently, and compare the results against the existing treatment system. However, due to budget constraints, the Town decided to pilot only one of the processes and selected DAF based on the recommendation of Tighe & Bond.

Warm and cold water temperature piloting was performed in July and December, 2014. Pilot testing yielded that DAF would yield very good water quality under either condition, and that UV would not be required as a primary disinfectant due to improved organics removal, which yielded total trihalomethane (TTHM) and HAA5 formation to less than the regulatory limits of 80 µg/l and 60 µg/l, respectively.

Revised recommendations for the Centennial WTF utilizing the DAF process were summarized in the 2015 report. The major differences between the 2010 report and this report were: 1. The flocculation/sedimentation portion of the three existing Roberts package equipment would be reconfigured to accommodate the DAF equipment, including revised partitioning, new flocculator mixers, PVC collection pipes, hydraulic effluent weirs, single control panel, and air/water saturation system including: a. Two saturator tanks (1 a standby) including valves and packing b. Two air compressors (1 a standby) c. Three recycle pumps, each capable of 12% recycle flow rate per operating DAF tank (2 operational and 1 standby) d. Saturated water dispersion headers and nozzles 2. A $20,000 “adder” was included for the use of GAC in lieu of in-kind anthracite filter media replacement. 3. The chemical feed systems at the WTF would be modified as follows: a. Chlorine, ammonia, and sodium fluoride feed equipment would remain, with the fluoride equipment being relocated to accommodate the other changes noted below. b. The two existing polymer feed systems (one currently not used) would be replaced with a polyaluminum chloride (PACl) feed system consisting of bulk and day tanks, and pumps. Page 18

Amherst Alternate Water Supply Study

c. The caustic feed system would be relocated, with new bulk and day tank being provided. d. Although polymer may not be needed in full-scale operations, a feed system would be provided which would utilize polymer deliveries in 55-gallon drums. 4. Due to the higher sludge waste volumes associated with the DAF hydraulic sludge removal system (automated discharge weir) the holding tanks proposed in the 2010 report would have to be increased from 80,000 gallons to 123,000 gallons each, for the three tanks. 5. UV as a primary disinfectant was eliminated.

Table 6-1 of the report is similar to Table 5-1 of the 2010 report, revised to reflect exceptions items 1 through 4 listed in the paragraph above, and with costs adjusted to 2015, yielding an estimated cost of $3,500,000, including engineering and contingencies.

Table 6-2 is identical to Table 5-2 in the previous report, with costs adjusted to 2015, yielding an estimated cost of $289,000, including engineering and contingencies.

Prior to the 2015 report, the sewer recommended in the 2010 report was constructed; hence Table 5-3 in the previous report was eliminated.

Table 6-3 is identical to Table 5-4 in the earlier report, with costs adjusted to 2015, yielding an estimated cost of $900,000, including engineering and contingencies.

In order to compare the cost of the “priority” work from the 2010 report (Table 5-1) to that of the 2015 report (Table 6-1), T&H utilized the Engineering News-Record (ENR) Construction Cost Indices for the area to upgrade the construction costs to 2016, and used the same factor of 20 percent of construction cost to cover estimating both engineering costs and contingencies. Similarly, Tables 6-2 and 6-3 were adjusted as well. The resultant costs are presented below:

1. Opinion of Probable Cost - High Priority Plant Upgrades a. Recommendations of 2010 report: 1) Construction $1,717,500 2) Engineering & Contingencies (40%) $687,000 Total $2,404,500 Say $2,500,000

b. Recommendations of 2015 report: 1) Construction $2,574,400 2) Engineering & Contingencies (40%) $1,029,800 Total $3,604,200 Say $3,700,000

2. Opinion of Probable Cost – MCCs and Generator: a. Construction $214,000 b. Engineering & Contingencies (40%) $85,600 Total $299,600 Say $300,000 Page 19

Amherst Alternate Water Supply Study

3. Opinion of Probable Cost – Low Priority Structural Work: c. Construction $667,700 d. Engineering & Contingencies (40%) $267,100 Total $934,800 Say $940,000

Evaluation of Previous Recommendations In general, T&H considers many of the recommendations made by Tighe & Bond, to be valid. However, T&H does offer the following for consideration:

1. DAF Floated Sludge Withdrawal and Disposal: Floated sludge (float) must be periodically removed for the surface of the DAF tank, approximately every 2-3 hours. Roberts Water Treatment Technologies offers two methods of float removal, hydraulically-actuated weir and rotary brush. The costs presented in the 2015 report are based on the use of the hydraulic weir.

The hydraulic weir at the end of the DAF tank lowers to provide a ¾” crest over the 10- foot weir, for approximately three minutes, which wastes 750-800 gallons (250-267 gpm). This equates to approximately 6,400-6,500 gallons per day per tank, for a total of approximately 20,000 gallons per day for all three tanks over a 24-hour period.

The rotary scrapper frequency of operation will be the same, however, the float is mechanically removed just below the water surface, resulting in less water being wasted. Roberts estimates that the above total waste volume would be reduced to 6,500 gallons per day, which equates to a flow of 87 gpm.

As stated in the previous reports, the hydraulic weir option would allow the reuse of the existing tanks. The tanks would be sandblasted both inside and out, re-partitioned to accommodate the revised flocculator/DAF tank areas and equipment, and repainted. The rotary scraper option would require all new tanks to be provided due to the complexity in attempting to accommodate the rotary design within the existing tanks. Based on estimated costs provided by Roberts for both options, the rotary scraper option would increase the overall cost by $1,000,000. This additional cost is for two tanks, one operating and one standby. This cost does not include demolition of the existing tanks and concrete pads and installation of the new tanks and concrete pads. Construction of new tanks is not a cost effective option.

2. Filter Modifications: T&H agrees with the Tighe & Bond recommendation that the revisions to the filter basins include the switch from the current surface wash system, to an air scour system as this has been shown to improve media cleaning, hence improved long-term filter performance, as well as reducing the amount of waste water.

Page 20

Amherst Alternate Water Supply Study

Based on data presented in the report, there was no conclusive decision made on the use of granular activated carbon (GAC) media in lieu of the present sand/anthracite media. In general, GAC typically requires lower backwash rates, thereby reducing the total volume of spent backwash water. However, based on the relatively small size of the filters (100 square foot surface area), the quantity of water to be saved is not notably significant, especially since improved process performance would reduce the number of treatment units in operation from the current three, to only two for average daily flows of one mgd or less.

One potential advantage to the use of GAC is the possibility of operating the filters as biologically active GAC. The development of bacterial growth on the filters would result in improved organics removal, which could aid in the reduction of TTHMs.

3. Spent Washwater Equalization Tanks: For the non-DAF option, T&H concurs with the estimated waste volume of 80,000 gallons. However, the need for two tanks is questionable, especially since the intent is to act as an equalization basin to control discharge rate to the sewer. A second tank would allow for one tank to be removed from service for cleaning or inspection, but since the Town has alternate water supplies available, the treatment facility can be shutdown for the brief period.

For the DAF option, T&H questions the feasibility of discharging the float to the holding tanks, especially if consideration is to be given to recycling spent washwater back to the head of the facility. Unlike the current treatment process whereby a settleable floc is required, DAF requires the formation of a pinpoint floc that can easily be floated to the surface by the formation of micro-bubbles in the DAF process. As such, the float sent to the tank may not settle and would simply be returned to the process, possible affecting new floc formation, while increasing the DAF loadings and potentially increasing chemical requirements. By segregating the float, the proposed 126,000 gallon, three-tank residuals holding system could be reduced to one or two 80,000 gallon tank(s).

Dependent on the feasibility and long-term cost, if any, for discharging the spent backwash water to the sewer, and the Town’s need to conserve water, T&H recommends that the holding tank design include a floating decant and variable speed driven decant pumps to return the spent washwater to the head of the plant at a rate of 5-10% of the treatment plant production rate. Water would be collected in the tank, allowed to settle for a period of time (1-2 hours) and then returned at a rate that would assure that sufficient free volume remains to accommodate the next batch of filter backwashes. After a period of time determined by experience (approximately four times a year), the settled sludge would be gravity discharged or pumped to the sewer.

Under the Tighe & Bond proposal whereby all sludge and spent filter backwash water is collected and discharged to the sewer at a controlled rate, the 80,000 gallon volume associated with the non-DAF option would require a flow of 56 gpm over 24 hours (111 gpm over 12 hours), whereas the 123,000 gallon DAF option would require a flow of 85 gpm (171 gpm over 12 hours). If segregation of the float was performed and spent

Page 21

Amherst Alternate Water Supply Study

washwater were recycled, a 20,000 gallon holding tank could be drained to the sewer at a rate of 14 gpm over 24 hours (28 gpm over 12 hours).

Recommendations T&H cannot make a single recommendation at this time due to the need for the Town to consider several factors: 1. Allowable sewer flow rates and sewer charges, if any, for the disposal of filter backwash waste and/or DAF sludge. 2. The Town’s need to conserve water (recycle or not). 3. The need for the treatment facility to operate 12 months out of the year. 4. Financial constraints.

If the Town’s alternate water supplies can handle current and future water demands during the warm-weather months without the Centennial facility being in operation, then implementation of the 2010 report recommendations would be recommended based on the ability to produce satisfactory water quality during the fall, winter, and spring seasons; and the reduced chemical costs. Daily average plant production would be lower during this period, resulting in less wastewater production (only two treatment units in operation for flows up to one mgd), which could further impact the decision to recycle spent filter backwash water. Since the facility would be shutdown for two to three months, a single spent washwater holding tank could be provided, which could be maintained during shutdown.

If the Centennial facility is to be operated year-round, then the upgrade to DAF is recommended. Should recycling be necessary or preferred, then it is recommended that the floated sludge volume be segregated from the spent backwash water holding tank(s). If it is feasible to shutdown the facility for one to three days for inspection and/or maintenance of the holding tank, then only one tank of 80,000 gallon capacity is required.

The decision of when to upgrade the motor control centers (MCCs) would also hinge on which option the Town pursues. If simply upgrading the existing facility, then the only foreseeable electrical modification that would impact the existing in-plant electrical distribution system would be abandonment of the existing two speed flocculator drives, and installation of variable frequency drives (VFDs) for the mixers, which could be incorporated in the DAF control panel; and starter(s) for the filter air scour blower(s). Hence, replacement of the MCC could be postponed to a later date. However, the switch to DAF would include not only the starter for the air scour blower, but also VFDs for the DAF saturator pumps. It may be feasible to replace the MCC at this time depending on space requirements for installation of the new drives, and the ability of the existing electrical system to accommodate the additional loads.

5.3 Increase Operation of Well No. 4

Well No. 4 is only used in the late summer and early fall when the Centennial WTP is offline. The Town indicated that the plant is perceived to be expensive to operate as it uses a lot of power. Previously, the energy usage was high and the chemical feed system was complicated with the addition of potassium permanganate. However, the plant has been operationally optimized to increase efficiency. GreensandPlus replaced the greensand media around 2010 and eliminated the Page 22

Amherst Alternate Water Supply Study that the excessive air was caused by pumping at a rate greater than the well and aquifer can safely produce.

Well No. 5 would need to be replaced to reliably produce the permitted volume of water. The replacement well can be designed to be larger than the current 8-inch well, therefore, more efficient. A pump rate of 350 gpm is close to the limit that an 8-inch diameter well can produce due to inefficiencies and limiting the size of the pump. A larger well will create less drawdown and should not lead to the same air intrusion issues.

For a withdrawal of 0.5 mgd, the replacement well is required to be located within 250 feet of the original well and still needs to maintain a 400-foot Zone I. Figure No. 5-2 shows the land owned by the Town of Amherst Water Department. The Town owns the Zone I, but inadequate area beyond that limit. Replacing the well north of the original well would not be in compliance with MassDEP regulations, but could potentially be approved. The new location would move away from homes and farmland near the Zone I.

The process to replace Well No. 5 would require site investigations, permitting with the Massachusetts Department of Environmental Protection (MassDEP) and local Conservation Commission, design, and well construction as outlined below.

A test well exploration program and short term pump test is recommended to estimate the potential yield of the replacement well. The program would include installation of 2½ inch diameter test wells up to approximately 250 feet from the existing well but more likely within close proximity due to the Zone I issue. Installation would include up to 240 vertical feet of 2½ inch diameter casing and approximately 24 feet of screen. Following completion of test well installation, a 4- hour pump test to estimate potential yield and water quality sampling would occur.

Upon successful completion of the test well exploration, the services of a Massachusetts Registered Professional Surveyor should be retained to document the exact location, elevation, and proximity to the existing well and property bounds for the recommended location of the replacement well.

Following successful completion of test well exploration and survey, the Town may proceed with submittal of a Proposal for Replacement Well, including a Pump Test Proposal, to the MassDEP. The Proposal for Replacement Well would include justification for the replacement well, summary of exploratory drilling efforts, and discussion of Zone 1 ownership.

As part of the Proposal for Replacement Well, a Pump Test Proposal would be submitted to the MassDEP to outline the proposed aquifer testing program scope and protocol, proposed well design and operation scheme, planned use or decommissioning of the original source, and characterization of land uses within the Zone I.

The estimated cost for test well exploration, survey services, and completion of a Proposal for Replacement Well, including a Pump Test Proposal, is $40,000. This includes engineering, permitting, installation, and contingency.

Page 24

Amherst Alternate Water Supply Study

5.5 Develop Well

The Town has identified two locations to develop a new well in partnership with . The and have been identified as potential well sites.

The estimated yield of a well at each location was calculated using the upstream watershed area of the subbasin, with each square mile providing one half mgd of estimated yield. The upstream watershed of is 2.39 square miles, which corresponds to an estimated yield of 1.20 mgd. . In addition, a different method was used to estimate yield at . Based on limited data from a pump test at , the estimated yield is 1.38 to 1.88 mgd. To be conservative, the lower estimate will be assumed.

The upstream watershed area of is 1.19 square miles, which corresponds to an estimated yield of 0.59 mgd.

Due to the location in the subbasin, it was determined that should produce more than . See Figure No. 5-3 for maps of both locations showing the upstream watershed area. If the Town wants to pursue development of a well , is preferred. Installing a well at site could potentially add approximately 33 new customers, along the transmission main route, for the Amherst Water Department.

In addition, previous water quality tests conducted in 2003, 2007, and 2014 indicate that has low concentrations of metals, sodium, nitrates, and negligible concentrations of volatile organic compounds (VOCs).

5.5.1. New Source Development Development of a new groundwater source is a multi-step process and governed through the new source approval process by the Massachusetts Department of Environmental Protection (MassDEP). First, exploratory drilling is conducted to identify a potential groundwater source. This has been completed for the potential Sunderland well site, which is located on Plumtree Road on the Nielsen property, but we recommend budgeting $30,000 for exploratory drilling if the drilling from previous years’ is not satisfactory.

The next step is the preparation and submittal of the Request for Site Exam, Pump Test Proposal and Water Management Act (WMA) Program site screening requirements to evaluate the viability of the potential source. The application includes a project narrative, description of the land use surrounding the new source, a discussion of the Zone I ownership of the source, a description of the pump test procedures, environmental controls and protections to be undertaken, a site screening worksheet, Water Conservation Plan and an alternatives analysis. The estimated fee to prepare the Request for Site Exam, Pump Test Proposal and site screening requirements is $15,000.

Page 27

Amherst Alternate Water Supply Study

Upon approval from MassDEP, the next phase is conductance of an extended pump test on the wellfield to evaluate the potential safe yield and water quality of the source. The Pump Test phase includes design and construction of the proposed production wells and performing an extended pump test, which is a minimum of five days. During the pump test, the proposed production wells are pumped continuously, and water levels in the pumping wells, observation wells, staff gauges and piezometers are recorded to evaluate the potential impacts of the withdrawal. Upon completion of the pump test, a Pump Test Report is required for submittal and approval by MassDEP. The report includes a water quality analysis, summary and analysis of the wellfield pumping and water level drawdown in the surrounding observation wells along with recommendations on the potential safe yield of the new source, treatment of the source, if required, and Zone II delineation. Additional work required during this phase includes survey of the well site, completion of the Water Management Act (WMA) permit application and submittal of Environmental Notification Form (ENF). The estimated cost for the Pump Test and Pump Test Report is $205,000.

Upon approval of the new source by MassDEP, the next phase is for the design of the pumping station with chemical feed systems for disinfection and pH adjustment, if required. It is assumed that treatment is not required. Work during this phase includes the design of the pumping station and preparation of specifications and drawings for the construction of the pumping station/chemical feed facility and connection of the wellfield to the system including site and structural design, plumbing, HVAC, and electrical work, and integration into the Town’s SCADA system. The design includes wetlands delineation and soil borings of the pumping station site. In addition, permitting with the local Conservation Commission, Massachusetts Historical Commission, Army Corps of Engineers, and the local Planning Board is anticipated. The estimated fee for the pumping station design and permitting is $175,000.

Construction of the pumping station is estimated to cost approximately $1,750,000 and includes connecting the wellfield to the pumping station, construction of the pumping station, connecting the station to the distribution system, and integrating the wellfield and pumping station into the Town’s existing SCADA system.

During construction of the pumping station, construction administration and part time resident observation up to 120 person hours will be provided. Construction administration includes attending monthly construction meetings, shop drawing review for conformance with the contract documents, processing payment requests from the contractor, preparation of as-built drawings, and completion of the O&M Manual. The estimated fee for construction administration and resident observation is $105,000.

The total estimated cost to develop is $2,280,000, excluding legal fees and purchase of the property. Table No. 5-3 contains a summary of costs associated with this alternative. The construction of the pumping station includes approximately 7,300 linear feet of water main to connect to the existing system.

Page 29

Amherst Alternate Water Supply Study

In addition, removing the sediment from the reservoir is potentially problematic. The sediment can act as a confining layer stopping the water in the reservoir from infiltrating into the ground. The soil type in the area of Atkins Reservoir is favorable for infiltration.

5.7 Connect Pelham Reservoirs to Atkins WTP

The option to connect the Pelham Reservoirs to the Atkins WTP was explored. The goal would be to treat water from the Pelham Reservoirs when the Centennial WTP cannot adequately treat the high-color raw water during the summer months. The Atkins WTP is capable of treating the low quality raw water to high finished water standards. It is in excellent condition, but would need to be expanded to treat the additional capacity from the Pelham Reservoirs.

This alternative requires an approximately 4-mile transmission main. The cost of the pipeline plus a booster pump station is likely around $4.7 million, not including the expansion of the plant. The cost related to this option does not make it a cost effective alternative.

5.8 Purchase Water from MWRA

The Massachusetts Water Resources Authority (MWRA) provides wholesale drinking water primarily to the Boston metropolitan area, but also some central and municipalities, including South Hadley Fire District #1. The South Hadley Fire District #1 obtains a maximum of 600 million gallons annually and a maximum of 3.8 mgd from the MWRA. The Town of Amherst could connect to the MWRA through the South Hadley Fire District #1. South Hadley Fire District connects directly off the 36-inch MWRA Chicopee Valley Aqueduct on Fuller Street in Ludlow. This water is treated at the William A. Brutsch Water Treatment Facility in Ware, MA.

The most direct route to connect to the MWRA in South Hadley would cross the Mount Holyoke Range and will not be a practical route. The next most direct route starts at the intersection of Brainerd Street and Route 116 in South Hadley where there is an existing 16-inch diameter main and an interconnection between Water District #1 and Water District #2. The route would continue north along Route 116 and then continue on Route 47 north to Route 9 to the Amherst/Hadley town line. There are significant elevation changes along this route that will likely require pump stations and pressure reducing valves. This route is approximately 65,000 linear feet and at $200 per linear foot, the cost for connecting to the Amherst system will be about $13,000,000. This cost excludes land acquisition, pumping, storage, wheeling fees, and permitting costs as well as MWRA’s entrance fee. The current MWRA entrance fee is $4,800,000 per mgd. In addition to construction costs and the entrance fee, MWRA charged $3,239.66 per million gallons of purchased water for fiscal year 2015. South Hadley Fire District #1 could potentially be unwilling to transfer water through their system from the MWRA. If they are willing, they could potentially increase MWRA’s rates or require a transfer fee.

The Town could also consider purchasing raw water from the MWRA. Since the water from the is treated just south of the reservoir, Amherst would have to connect upstream of the treatment plant. Amherst could treat the raw water at the Atkins WTP; a plant expansion may be necessary. Approximately 80,000 linear feet of transmission main would be required to Page 31

Amherst Alternate Water Supply Study connect the Quabbin Reservoir to the Atkins WTP. At $200 per linear foot, purchasing raw water from the MWRA would cost $16,000,000, excluding land acquisition, pumping, storage, wheeling fees, and permitting costs as well as MWRA’s entrance fee. The Town could potentially negotiate a rate lower than the treated water cost per million gallons.

The MWRA draws water from the Quabbin and Wachusett Reservoir, which are located in the Basin and Nashua River Basin, respectively. Therefore, water purchased from the MWRA would be subject to the Interbasin Transfer Act (IBTA). In addition, the project includes new water services across municipal boundaries and involves installation of a pipeline over 5 miles long. Therefore, the project will be subject to review by the Massachusetts Environmental Policy Act (MEPA) office. MEPA requires an Environmental Notification Form (ENF) and Environmental Impact Report (EIR). The project would also require a Permit to Access State Highway with MassDOT for water main installation.

Page 32

Amherst Alternate Water Supply Study

SECTION 6 - SWMI Requirements Massachusetts Department of Environmental Protection issued revised Water Management Act (WMA) regulations in 2014 that were designed to balance human water needs with the health of rivers and streams. Amherst was involved in the pilot project for the draft Sustainable Water Management Initiative (SWMI) permitting beginning in 2012. The Town of Amherst is requesting additional withdrawals above baseline, which results in minimization and mitigation requirements under SWMI.

6.1 Streamflow Criteria

The potential new well in Sunderland is in subbasin 14041 and has a biological category (BC) of 5, which corresponds to a streamflow criterion greater than 65%. This indicates the simulated existing conditions from 2000 to 2004 of the aquatic habitats are severely impaired. The Subbasin has a groundwater withdrawal category (GWC) of 4. This indicates that the ratio of 2000-2004 August groundwater withdrawals to August median streamflow of greater than 25%, but less than 55%. Despite high biologic category and groundwater withdrawal category, Subbasin 14041 has a net groundwater depletion of less than 25%. Net groundwater depleted factors in groundwater recharge to the basin, the BC and GWC do not. A mitigation plan is required as part of the WMA permit application for subbasins that are 25% or more net groundwater depleted. In addition, there are no coldwater fishery resources in the subbasin.

Since the Town is requesting additional withdrawal over the baseline and if approved, the withdrawal would increase their GWC, the WMA permit application would be Tier 3. There is potential for GWC to backslide to a higher level. The MassDEP anticipates WMA Permit consultation with the Town of Amherst to begin in 2018.

The groundwater withdrawals to unaffected streamflow ratio is 29.7%, which corresponds to GWC 4. In order to remain a GWC, the Town can only withdraw an additional 0.154 mgd from the subbasin, which is considerably less than the estimated yield for the Sunderland well. Appendix A contains information from the SWMI database for subbasin 14041. The additional withdrawal from subbasin 14041 would violate streamflow criteria and will cause the subbasin to slide into a more degraded GWC. The Town must prove that there is no other feasible alternative water source that is more environmentally friendly. If approved, the Town will be required to mitigate and minimize the additional withdrawals.

Since the Town has Well No. 6 permitted already, there is a possibility that the withdrawal can be transferred to another location. This possibility should be pursued with MassDEP.

6.2 Minimization Requirements

A minimization plan will be required if the well in Sunderland is approved. Minimization is defined in 310 CMR 36 as “measures that reduce withdrawals from, or return groundwater to, the subbasin from which a withdrawal is made, or other management measures intended to improve streamflow.”

Page 33

Amherst Alternate Water Supply Study

Minimization plans include minimizing depletion of groundwater during the late summer months by optimizing the use of groundwater and surface water sources that are less groundwater depleted. It also includes an analysis of the feasibility of measures that return water to the subbasin to improve streamflow. These can include stormwater recharge, infiltration and inflow into the sewer system, and groundwater discharge of wastewater. The Town will also have to employ conservation measures more stringent than standard permit conditions, including restricting nonessential outdoor water use.

6.3 Mitigation Requirements

WMA regulations define mitigation as “activities undertaken that offset the impacts of ground or surface water withdrawals by improving streamflow or aquatic habitat.” Tier 3 Permit Application requirements call for a mitigation plan with an implantation schedule submitted as part of the application.

The Town will need to provide direct mitigation activities that can be volumetrically quantified. This includes activities that return stormwater to groundwater and improvements to the sewer collection system that reduce infiltration and inflow. If the Town cannot provide enough mitigation through direct mitigation and demand management, the Town will need a higher ratio of indirect mitigation. Indirect mitigation cannot be volumetrically quantified. These activities include dam removal, streambank restoration, and habitat restoration. The MassDEP will consider the proximity of the mitigation to the withdrawal point when determining equivalence of mitigation measures to withdrawal impacts.

Page 34

Amherst Alternate Water Supply Study

SECTION 8 - Conclusions and Recommendations 8.1 Conclusions

This study reviewed the existing systems demands, water supply sources, and possible supply alternatives. Staying ahead of demands is important for the Town of Amherst, especially given the growing university populations and downtown commercial and service industry. An evaluation of the different alternatives and the associated advantages and disadvantages of each option is presented in Table No. 8-1. The alternatives include developing a new well in Sunderland, upgrading the Centennial Water Treatment Plant, and maximizing existing sources.

Page 36