Hydrostratigraphic mapping of the Milford-Souhegan glacial drift aquifer, and effects of hydrostratigraphy on transport of PCE, Operable Unit 1, Savage Superfund Site, Milford, New Hampshire

Abstract

Estimates of hydraulic conductivity from effective grain size (D90) for selected hydrostratigraphic units, OU1 area, Savage Superfund site, Milford, New Hampshire .14 7. Relative ranking of radioactive elements based on concentration, hydraulic conductivities, and borehole natural gamma-ray counts for selected hydrostratigraphic units, OU1 area, Savage Superfund site,

Numerical modeling of groundwater flow in the crystalline-rock aquifer in the vicinity of the Savage Municipal Water-Supply Well Superfund site, Milford, New Hampshire

“…The surficial aquifer of the Milford quadrangle, which covers the entire model area, was mapped by Koteff (1970). The Milford-Souhegan River Valley is directly underlain by alluvium and glacially derived sand and gravel that in turn overlie thin, discontinuous glacial till mantling bedrock (Harte, 2010). The sand and gravel and till units are discontinuous, but one of the two is generally present because bedrock exposure is limited.…”

“…The sand and gravel and till units are discontinuous, but one of the two is generally present because bedrock exposure is limited. The highly permeable sand and gravel ranges from 50 to 130 ft in thickness and constitutes most of the MSGD aquifer (Harte and Mack, 1992;Harte, 2010). The horizontal hydraulic conductivity of the most permeable units was simulated at 450 feet per day (ft/d) in the MSGD aquifer model by Harte and others (1999).…”

“…North and south of the Milford-Souhegan River Valley, the landscape is dominated by abundant glacial deposits, including till and glacial outwash, with relatively sparse bedrock outcrops (Koteff, 1970). The till has a hydraulic conductivity typically less than 10 ft/d (Harte, 2010).…”

“…Areal was set at least one order of magnitude greater than that of the till, following regional and local hydraulic information on stratified drift deposits and tills (Toppin, 1987;Melvin and others, 1992;Harte, 2010). The k h of the till was initially set at 3 ft/d, similar to k h rates for the till in previously published MSGD aquifer models.…”

Bedrock geology and outcrop fracture trends in the vicinity of the Savage Municipal Well Superfund site, Milford, New Hampshire

“…The study site is directly underlain by alluvium and glacially derived sand and gravel of the Souhegan River valley that in turn overlie thin, discontinuous glacial till mantling bedrock (Harte, 2010). The highly permeable sand and gravel ranges in thickness from 50 to 130 ft and comprises the Milford-Souhegan glacial-drift aquifer (Harte, 2010;Harte and Mack, 1992;Weston, Inc., 2012). North and south of the valley, the landscape is dominated by abundant glacial deposits, including both till and glacial outwash, with relatively sparse bedrock outcrops (Koteff, 1970).…”