DEGLACIATION AND OVERBURDEN GROUND WATER RESOURCES OF BRANDON, VT

The Vermont Geological Survey conducted field mapping in 2005-06 and this study recognized significant new aspects of the area's deglacial history and their impact on overburden aquifer resources in the town.

Upland ice margins are recognized by cols where glacial melt water flowed down valley with outwash sediment deposited in Sugar Hollow. Later ice margins have extensive kame terraces with sand and gravel deposited by melt water leading distally into inwash fans where sand and some gravel was deposited against and/or under the ice. Ice retreat to the last recognized ice margin opened the Neshobe River to deposit an extensive delta into Lake Quaker Springs. Concurrently, kame moraine sediment accumulated to the north through Fernville. Ice completely retreated from town and lake level dropped from Quaker Spring to Lake Coveville. During/after this lake transition, the Neshobe River down-cut through its Quaker Springs delta and deposited 2 transitional fans. The river then built a new delta into Lake Coveville. As the glacier finally withdrew from the northern Champlain Lowland, the lake level dropped from Coveville to Lake Fort Ann I. The Coveville delta was breached and a new, lower Fort Ann I delta accumulated. Longshore currents and waves in all 3 lakes deposited sand spits and formed beaches of sand and/or gravel along the lake shores.

Subsurface data from water well logs were consulted to determine the 3-dimensional distribution of glacial deposits. This enabled better interpretation of deglacial history and identification of overburden ground water resources. Depth-to-rock data were contoured at 40ft intervals and highlight overburden in glacially deepened troughs that might contain aquifers capable of sustaining high yields. One trough at the base of the Green Mtns is a promising aquifer prospect. Fire District #1 wells 001, 002 and 003 and Fire District #2 well 001 tap an aquifer system represented by the Neshobe River Quaker Springs delta and the Fernville kame moraine/delta complex. This aquifer underlies where the Neshobe empties into this trough from the mountains. Recharge potentials were assessed based upon knowledge of the surficial geology, overburden thickness and stratigraphy.