Executive Summary. 1.0 Introduction. 2.0 Existing Conditions A GI01956

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1 1.0 Introduction The Town of Easton, M is proactively evaluating its wastewater treatment and disposal practices, and seeking a cost-effective, long-term solution to wastewater treatment and disposal for the Town. The Town is one of many communities in the region that is deliberating such a solution, presenting options that may ultimately unite them in attaining their mutual, wastewater management goals. With the expertise of environmental engineering firms, the Town has comprehensively evaluated the management and effectiveness of the current on-site septic systems. It is seeking alternatives that would mediate its current on-site, septicsystem problems while accommodating economic growth within the community. The Town of Easton retained Camp Dresser & McKee, Inc. (CDM) in September 2003 to review, refine and complete a Draft Comprehensive Wastewater Management Plan (CWMP) that SE Consultant s, Inc. had prepared between ugust 2000 and May CDM s primary objective was to collaboratively work with the Wastewater Management Study Committee (WMSC) to develop a recommended plan to provide the Town with a blueprint for a future wastewater management plan. This CWMP s purpose is threefold in that it: Establishes long-term wastewater needs for the community. Prioritizes wastewater needs areas. Develops and screens viable alternatives for wastewater management in the Town. The importance of this CWMP cannot be overstated. It is essential that the Town maintain high water quality in its public water supply; attenuate the indirect impacts of prominent, on-site, subsurface disposal systems, as well as the indirect impacts of sewer systems; protect the community s natural resources including areas of critical environmental concern (CEC); and understand the cost to both the Town and its residents of the potential options presented in the CWMP for wastewater collection, treatment, and disposal. The recommended plan of this CWMP would provide the Town of Easton with the best, cost-effective, long-term solution to its wastewater management objectives. 2.0 Existing Conditions It is projected that Easton s population will increase from 22,300 residents in 2000 to 29,500 residents in Currently, the Town is unsewered, primarily relying upon about 6,500 individual, on-site subsurface disposal systems to manage it wastewater needs. It also has three large conventional Title 5 systems (between 2,000 and 10,000 gallon per day (gpd)) and three very large conventional Title 5 systems (>10,000 gpd) systems, which serve condominium complexes. Four small (<40,000 gpd) wastewater treatment plants with on-site subsurface disposal serve three condominium complexes in the Town and the Easton School complex. ES-1

2 Based on subsurface conditions in the Town, two-thirds of the Town s land area is considered severely limited for septic systems. Easton also has plentiful surface water resources and high groundwater throughout the Town, which can compromise the effectiveness of on-site systems. 3.0 Summary of Town Needs ssessment Seventeen study areas in Easton were delineated, each study area possessing similar natural features, and/or environmental conditions as well as similar zoning, lot size and land use characteristics. Each study area was then assessed based on human and environmental factors that influence the success of conventional on-site wastewater management systems including: lot size and density of the built environment, proximity to environmental resources, suitability of soils for septic systems, and North Easton Village the history of on-site systems with poor performance. Of these 17 study areas, five South Easton study areas (North Easton Village, South Five Corners Easton, Five Corners, Turnpike Street, and Easton Center), identified as Tier 1, were Turnpike Street ranked as having the greatest and most Easton Center immediate need for an off-site wastewater management solution. Three study areas Old Foundry (Old Foundry, North Washington Street, North Washington Street and Hockomock), identified as Tier 2, were considered to have significant need Hockomock but not as immediate as the Tier 1 areas. Pratts Corner For the remaining nine study area it was determined that an on-site solution is Massapoag likely feasible. Eastman Street Figure ES-1 presents the Study rea ranking and Figure ES-2 presents the Needs reas. Focusing on the Tier 1 Needs reas, intown treatment and disposal alternatives were investigated as well as regional alternatives that would connect Easton to existing wastewater collection and treatment facilities in adjacent communities. These evaluations are summarized in the following sections. Flyaway Pond Black Brook Bay Road Ssouth Beaver Brook Bay Road North Stonehill Final Score Figure ES-1 Study rea Ranking ES-2

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4 4.0 Summary of In-Town Treatment and Disposal Locations Fifty sites were identified as technically feasible for in-town treatment and disposal locations. These fifty sites exhibited appropriate soil condition for groundwater disposal of treated effluent, did not exhibit significant wetlands or flooding potential, were at least five acres in size and essentially undeveloped. Of those, the following twelve sites were identified as preferred sites for treatment and groundwater disposal based on physical, political and regulatory criteria, including topography, distance to the needs area, adjoining land uses, and site ownership. Twelve Preferred Sites: Main Street Site (1.2) Picker Field (2.1) Militia Park (2.3) Town Forest (4.2) Borderland State Park (4.5) Fox Mountain (5.5) Stonehill College North/Holy Cross Fathers (8.2) Old Pond/New Pond (13.1) Depot Street Parcel (14.5) Pine Oaks Golf Course (15.2) Wheaton Farm (17.2) Easton Rod & Gun Club and djacent Land (17.3 and 17.5) detailed evaluation of these twelve preferred sites was conducted, resulting in the following seven most feasible sites for wastewater treatment and disposal. Figure ES-3 presents the site evaluation. Seven Most Feasible Sites: Main Street Site Militia Park Town Forest Stonehill College North/Holy Cross Fathers Old Pond/New Pond Depot Street Parcel Easton Rod and Gun Club and djacent Land Site location and size was used to determine which of the five Tier 1 needs area or areas could be best served by which site or sites. ES-4

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6 5.0 Regional Solutions CDMs analysis of the feasible wastewater treatment and management options for the Tier 1 needs areas in Easton revealed that there may be opportunities to connect to existing wastewater treatment facilities in the region, or to the Massachusetts Water Resources uthority (MWR) Deer Island Wastewater Treatment Plant (WWTP) via Stoughton. There may also be opportunities for Easton to collaboratively work with adjacent communities to establish a united solution to wastewater treatment and disposal, however, a detailed evaluation of a new, independent regional solution is beyond the scope of this work. The most feasible opportunities for regional solutions, in order of priority, are as follows: Pump the North Easton Village, South Easton and Easton Center areas to Brockton s 18.1-mgd WWTP. Pump the Five Corners needs area to Mansfield s 3.14-mgd WWTP in Norton, M. Pump the Turnpike Street and South Easton needs areas to Taunton s 8.4-mgd WWTP via Raynham, M. Pump all five needs areas to the MWR s Deer Island WWTP through the Stoughton, M WWTP. (This option would not be considered further until intown solutions and the above regional options are exhausted.) 6.0 Detailed Evaluation lternatives 6.1 North Easton Village The North Easton Village Needs rea is the highest priority needs area in Tier 1 as it is the most densely developed area with a median lot size of about 11,000 square feet. In addition, the area is entirely within the Town s aquifer protection district of the Town s most productive drinking water wells. The most feasible in-town solution for the North Easton Village is to pump its wastewater to a two-acre parcel adjacent to Moreau Hall for treatment and then flow to the Stonehill College site for subsurface groundwater disposal of treated effluent. Wastewater flow from this area is estimated at mgd. Technically and economically, the most feasible regional alternative for the North Easton Village needs area is to pump its wastewater to Brockton and connect to Brockton s collection system at Torrey Road and Tosca Road for conveyance to Brockton s wastewater treatment facility for treatment and disposal. Since Brockton s draft NPDES permit, as currently proposed, prohibits additional flows to the Brockton facility from communities not currently served by Brockton, the Town should continue to work with the City, State and federal officials, and the surrounding towns to revise the permit to be less restrictive and allow additional flows from adjacent communities. The Town should also work with the state officials ES-6

7 to revise current state regulations in a way that promotes regional as well as local solutions. 6.2 South Easton The South Easton Needs rea is the second highest-prioritized needs area in Tier 1. Having the largest percentage of commercially and industrially zoned land, the community would desire to develop the commercial and industrial areas within the needs area to increase its tax base, but would be incapable of doing so without sewering. Of the three in-town areas that potentially could serve South Easton, the Stonehill College site, the Depot site and the Town Forest site, the Stonehill College site presently appears to be the most viable one. The estimated wastewater flow from South Easton is mgd. Technically and economically, the most feasible regional alternative for the South Easton Needs area is to pump its wastewater to the Brockton collection system at Belmont Street and Tosca Road for conveyance to Brockton s WWTP for treatment and disposal. However, as discussed above, regulatory issues must be addressed to implement this option. 6.3 Five Corners The Five Corners Needs rea is a small area having widely recognized, poor performance of its on-site sewerage disposal systems. The Old Pond/New Pond and the Depot sites are the most feasible in-town options for Five Corners. However, upon further evaluation, the Depot site became the ultimate preferred site because of the prospective in-town issues associated with the modification of the Old Pond/New Pond conservation land to serve as a wastewater treatment and disposal site and the inability of the site to serve multiple needs areas. The estimated wastewater flow from the Five Corners area is mgd. The most viable regional option for wastewater treatment and disposal for Five Corners is to pump its wastewater to Mansfield for conveyance, treatment and disposal at Mansfield s WWTP in Norton. Since the Town of Mansfield is concurrently preparing their own CWMP a mutually beneficial solution for each community may be feasible. 6.4 Turnpike Street There are many condominium developments in the Turnpike Street needs area that require frequent maintenance and replacement of their on-site wastewater management systems. This is not an effective long-term solution to wastewater management. The Depot Street site is the most viable and cost-effective in-town solution to Turnpike Street, likely in combination with other needs areas in town. new treatment facility would be located at the Depot Street site and groundwater disposal would be achieved with an open-bed disposal system. The estimated wastewater flow from the Turnpike Street needs area is mgd. ES-7

8 Being the southernmost needs area in the community, the most attractive regional solution for the Depot Street area is to pump its wastewater to the Taunton WWTP via Raynham for treatment and disposal. The hydraulic capacity of the collection systems in Raynham and Taunton would have to be confirmed to finalize this option. However, it appears that removal of infiltration and inflow in the Taunton and Raynham collection systems could provide hydraulic capacity in the system for Easton. 6.5 Easton Center The Depot Street and the Town Forest sites are the only viable, in-town disposal sites for Easton Center, the last needs area in Tier 1, composed mostly of older residential homes. However, Depot Street is preferred based on its central location and ability to easily accommodate other needs areas. The only viable regional alternative for wastewater treatment and disposal for Easton Center is to pump its wastewater to the Brockton WWTP. This alternative would only be contemplated if Brockton could first accommodate North Easton Village and South Easton. 7.0 On-Site Wastewater Management Implementation of an off-site solution for the Tier 1 needs areas may take a significant amount of time. nd, although the need for wastewater management in the Tier 2 needs area is not as significant as that of the Tier 1 needs areas, it definitely requires immediate attention. Because of this, the CWMP proposes a more progressive, immediate plan for wastewater management for Easton. The Easton WMSC recommends establishing a town-wide voluntary septic management program, the minimal EP-recommended management plan, called the Homeowner wareness model. This program focuses on public education and homeowner awareness, and the maintenance of septic systems to increase the protection of public health and local water resources. This program s primary objectives are to ensure that on-site systems are sited, designed and constructed in compliance with regulatory standards, and that system owners are informed of maintenance needs through the receipt of brochures or newsletters along with their mailed tax bills. The voluntary management system s success would depend solely on the active participation of, and cooperation between, the individual homeowners and the local regulatory authority, the Easton Board of Health (BOH). 8.0 Recommended Plan Regional solutions to wastewater management are the most cost-effective solutions, being about 60 percent less expensive on a present worth basis for the top five needs areas in total than the in-town solutions for those areas. s such, the regional alternative is the preferred recommended plan. However, given the present regulatory attitude towards regional alternatives, it is recommended that a parallel path that pursues alternative local solutions be available for the top five needs areas, and that a septic system management program be implemented to effectively manage the present on-site systems. ES-8

9 Wastewater collection in the top five needs areas would be common, regardless of the wastewater treatment and disposal option that the Town considers. Slight modifications to the collection system design may be required, depending upon the disposal location, but the analysis herein assumed costs to be equal. Sewering of the top five needs areas in Easton represents a significant financial commitment over the next 15 to 20 years. For the five Tier 1 needs areas, a total of 51.8 miles of pipeline, along with 23 pump stations, would be required. Figure ES-4 graphically depicts the below-described solutions. 8.1 Preferred Regional Treatment The regional solution assumes that North Easton Village, the northern half of South Easton, and Easton Center would discharge about 0.70 mgd to the Brockton, M WWTP; that Five Corners would discharge about 0.10 mgd to the Mansfield, M WWTP; and that Turnpike Street and the southern half of South Easton would discharge about 0.40 mgd to the Taunton, M WWTP, via Raynham, M. Sewering of the top five needs areas would be positive overall for the environment because of the elimination of failing septic systems. Presently, failing septic systems are resulting in detrimental impacts to the environment and to public health because many of these failing systems are within the Town s aquifer protection district. The proposed treatment facility would remove the nitrogen that a conventional Title 5 system does not remove. Since the high priority sewer needs areas are primarily the high-density residential and commercial areas, the Town can manage growth in the community and can focus the growth on development that will add to the community s tax base. Discharging wastewater to treatment facilities in the region would not result in an inter-basin transfer, and could benefit the water balance in the region through pro-active infiltration/inflow removal. Since Easton presently and solely relies on on-site systems, sewering of the community would require the establishment of a Sewer Department. dditionally, inter-municipal agreements would have to be established with the host communities. The construction of new wastewater facilities would entail a significant financial commitment on behalf of the Town, for both the operation and maintenance of the facilities, as well as for payment of the debt service associated with the new facilities. preliminary assessment of the potential annual costs to both the Town and the homeowner receiving sewer service is presented below. The total capital cost for the regional plan would be nearly $67 million for sewers, pumps stations, force mains and connection fees to adjacent communities. This would result in an annual debt service of about $5.2 million, assuming a 20-year general obligation bond at a 5.5 percent interest rate. nnual operating expenses would include payments to adjacent communities for the transmission and treatment of wastewater, as well as for the operation and maintenance of the sewer system. These costs would amount to approximately $2.1 million. ssuming that the costs of local construction would be borne entirely by betterment assessments, the cost for operation and maintenance would be borne by the users of the system, and the Town would make no subsidy payments from taxes, the average annual total homeowner cost would be $1,550 ($450 for operating cost and $1,100 for betterment for 20 years.) ES-9

10 Environmental Impacts Regional or In-Town Solution -Elimination of failing septic systems. -No inter-basin transfer required. -Growth managed by community. Institutional Impacts Regional Solution -New Sewer Department would be required. -Inter-municipal agreements would be required. In-Town Solution -New Sewer Department would be required. -Property negotiations with Stonehill College would be required. -Depot Street parcel would need to be purchased. Regional Solution Easton Center Brockton WWTP North Easton Village Taunton WWTP Raynham 0.70 mgd 0.40 mgd Stonehill College South Easton Turnpike Street Mansfield WWTP 0.60 mgd 0.33 mgd Depot Street Five Corners 0.10 mgd Implementation Plan Regional or In-Town Solution -Continue to collaborate with neighboring communities. -Concurrently pursue In-Town treatment and disposal options. -Negotiate with state and federal regulatory agencies. Financing Plan Regional Solution -Total Estimated Capital Costs: $67M - Total nnual Homeowner Cost: $1,550 In-Town Solution -Total Estimated Capital Cost: $95M - Total nnual Homeowner Cost: $2,500 In-Town Solution 0.27 mgd Town of Easton, M Comprehensive Wastewater Management Plan Figure ES-4 Recommended Plan

11 8.2 lternate In-Town Treatment and Disposal The alternate in-town treatment and disposal solution assumes that up to 0.6 mgd of wastewater from North Easton Village and South Easton would be collected and pumped to a 2-acre parcel adjacent to Moreau Hall parcel for treatment, then to Stonehill College for subsurface disposal. The 0.10 mgd of wastewater that the Five Corners needs area generates, the 0.23 mgd of wastewater that the Turnpike Street area generates and the 0.27 mgd that the Easton Center area generates would be conveyed to the Depot Street parcel for treatment and groundwater disposal through an open-bed system. s with the regional alternative, sewering the top five needs areas would be positive overall for the environment because of the elimination of failing septic systems. Development of in-town parcels for wastewater treatment and disposal would result in some environmental impacts, including: the construction of a treatment facility adjacent to one of the Town s elementary schools, Moreau Hall; the construction of a subsurface effluent disposal area at Stonehill College within the Town s watershed protection district; and the construction of a new treatment and disposal system at the Depot Street parcel, which is within the Hockomock Swamp CEC. The southeastern half of the site is also designated as a rare species habitat, requiring sensitivity to any construction therein. More so than the regional approach, however, this approach is beneficial in that it does serve to keep water local. Implementation of the in-town solution would require a negotiated agreement between Easton and Stonehill College and the Depot Street property owner, as well as final hydrogeologic testing to confirm the applicability of the sites. gain, sewering of the community would require the establishment of a Sewer Department. The total capital cost for the in-town plan is nearly $95 million for sewers, pumps stations, force mains, treatment and disposal facilities. Using the same assumptions as presented above, the average annual total homeowner cost would be increased to $2,500 ($850 for operating cost and $1,650 for betterment for 20 years.) ES-11