Originally constructed in 1892, the Town of Stoughton’s Muddy Pond water supply consists of several collection wells adjacent to Muddy Pond, which collect groundwater flow and transport it northerly by gravity via a 24‐inch vitrified clay and reinforced concrete transmission main. Flow proceeds through a screening house adjacent to Muddy Pond prior to treatment and entering the Town of Stoughton’s distribution system.
The water supply was taken offline in 2013 due to a tenfold increase in turbidity and water color changes. EP was called to conduct preliminary field investigations, during which ponding was observed at the surface above the pipeline, and it was suspected that the pipeline had collapsed in multiple locations. EP worked with the Town and MassDEP to install a temporary bypass pumping system in November 2015 to pump raw water around the collapsed transmission main while the Town worked on a permanent solution.
EP worked with the Town and MassDEP to design and permit a satellite wellfield, consisting of three wells, to replace and/or supplement the existing Muddy Pond collection wells. The initial plan was to install a single well to supplement or replace the Muddy Pond collection well system, however, exploration testing determined that a wellfield with three wells would provide more water.
In 2017, six eight-inch test production wells were installed, three of which, TW-6, TW-7 and TW-8, would become the final production wells. MPA testing confirmed the production wells were not under the influence of surface water.
Working with the Town of Stoughton, EP developed a permanent solution for the Muddy Pond water supply. The existing Muddy Pond collection system and three production wells are being used in tandem as a single source water supply. EP designed two new pump stations and a well field. The Collection Wells Pump Station located adjacent to the existing screen house (which remains in place) near Muddy Pond. Raw water from the collection wells flows by gravity to the existing screen house, and a centrifugal suction lift pump and vacuum priming system pumps the raw water directly from the screen house to the proposed Muddy Pond Pump Station. The three 8‐inch replacement test wells serve as the redundant production wells; submersible pumps pump raw water from the production wells to the Muddy Pond Pump Station. The collection wells system and the replacement wells transmission mains will combine prior to entering the approximately 573 gallons per minute (gpm) Muddy Pond Pump Station where the raw water is chemically treated for pH adjustment and disinfection prior to entering the Town’s distribution system.
Overall, EP provided engineering services associated with the installation of test and replacement wells, investigation of the existing gravity collection system, permitting and reporting with MassDEP, preliminary design, and final design, bidding assistance and construction of the replacement stations.