About the Aquifer
The Barnes Aquifer supplies water to four municipalities within the Connecticut Valley of western Massachusetts including the cities of Westfield and Holyoke as well as the towns of Easthampton and Southampton. Currently 11 municipal wells supply 5 million gallons of water per day to 60,000 people in these communities. The water is held within sand and gravel deposits which were layed down approximately 14,000 years ago by a retreating continental glacier. Meltwater streams flowing off the ice deposited sands and gravels into glacial Lake Hitchcock.

Melting Glaciers

This area has been covered by continental glaciers numerous times during the last 2 million years (Pleistocene Epoch). The Laurentide ice sheet last covered the area approximately 15,000 years ago. This ice sheet was centered at Hudson Bay, Canada and extended south to Long Island, New York.

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.