In Easthampton the Hendrick Street wellfield has had trichloroethylene (TCE) contamination since 1984. According to the EPA, TCE is a colorless or blue organic liquid with a chloroform-like odor. It is used primarily as a degreaser. Long-term exposure to TCE has the potential to cause liver damage and cancer. For this reason the EPA has set a Maximum Contaminant Level (MCL) of 5 Parts Per Billion (PPB) for TCE. The Town of Easthampton has recently completed a treatment plant to remove TCE from groundwater pumped from the Hendrick Street wellfield.
In March of 1997 the Massachusetts Department of Environmental Protection reported finding TCE above the MCL in 20 private wells located within the Barnes Aquifer in Holyoke and Southampton.
Potential sources of contamination are underground storage tanks, businesses which use hazardous wastes, linear sources (sewer, power, roads), defoliants (which is used to clear way for power lines), road salting, agricultural chemicals, houses and businesses with private septic tanks, and the improper storage or disposal of solvents which are used to clean used equipment.
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Easthampton
Glaciers are continuously moving ice masses which can erode, transport and deposit large quantites of material. Climate warming at the end of the Pleistocene caused the ice to melt faster. The snout of the glacier began to melt back faster than the ice was moving forward. This led to northward retreat of the ice front (however, the ice was still moving southward). There were brief periods of cooler climate during this time which allowed the ice front to maintain its position for short periods of time. During these stable periods the ice was still moving southward carrying debris eroded from under the ice. This debris accumulated at the ice front building thick ridges of unconsolidated sediment.
The Barnes Aquifer is made up of sediment deposited by meltwater streams flowing off the ice. Melting of the continental glaciers produced huge quantities of water and sediment. Meltwater streams were effective in sorting the sediment eroded by the ice. The silt and clay size material was transported into lakes or carried all the way to the sea while the sand and gravels were deposited within the channels and floodplains of the meltwater streams or in deltas at the margins of glacial lakes. When the glaciers left the area the meltwater streams dried up and the sorted sands and gravels were left behind.
Lake Hitchcock
As the ice front retreated northward up the Connecticut River Valley, a large glacial lake formed at the ice front. This lake was dammed by glacial sediment filling the valley near New Britain, Connecticut. At its maximum, this lake, now known as Lake Hitchcock, extended from central Connecticut northward to St Johnsbury in Vermont. Meltwater streams emerging from the ice at the snout of the glacier deposited sands and gravels into the lake in the form of ice-contact deltas. The size of these deltas was controlled by the size of the meltwater stream and the amount of time the ice front remained at any one place.
Forming the Aquifer
The ice front paused or retreated very slowly as it moved across the Westfield, West Holyoke, Southampton and southern Easthampton area. This allowed the building of a large delta whose sediments form much of the Barnes Aquifer (Stage 1). The ice front began to retreat much more rapidly as it moved north of the Plains area of Easthampton. During the more rapid retreat of the ice, meltwater streams emerging from the ice into the lake did not have time to build a delta. Instead, sands and gravels were deposited as a relatively thin apron at the bottom of the lake Aquifer (Stage 2). After the ice front retreated north of Easthampton, these sands and gravels were buried by glacial lake sediments composed of alternating bands of silty sand and clay (varves). These lake sediments extend up the sides but not over the tops of the deltas Aquifer (Stage 3). Eventually the sediments which dammed Lake Hitchcock were eroded and the lake catastrophically drained exposing the sediments which make up the Barnes Aquifer.
The Barnes Aquifer is composed of well-sorted, sands and gravels which were deposited by meltwater streams flowing into a glacial lake. The coarse grain-size and excellent sorting of the sediment accounts for its having a high permeability.
The water in the aquifer is continuously moving at a rate of a few meters per year. The aquifer gets recharged from precipitation falling on the recharge area. The primary recharge areas are those places where the sands and gravels are exposed at the surface. This is primarily the delta surfaces. Not all the precipitation that falls on the recharge area reaches the groundwater. About half is lost to evapotranspiration, the process by which trees absorb water from the ground and evaporate it from their leaves. Groundwater in the aquifer is eventually discharged to surface water as base flow to streams. Base flow is groundwater which seeps into the stream channel and sustains stream flow during periods between precipitation events.
Groundwater Usage.
The aquifer provides Easthampton with 100% of its water supply. Easthampton has three principal wells, Hendrick Street (including the Pines Well), Nonotuck Park, and Lovefield Street( Maloney) Well. (See map) Currently 6.1 million gallons per day can be pumped from these wells.
The City of Westfield has 8 wells with a combined capacity to pump 13 million gallons per day. Wells #3 and #4 located south of the Westfield River have been closed since March of 1989 when traces of the agricultural pesticide ethylend dibromide (EDB) were found in the well water. This reduced the capacity by 4 million gallons per day.
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