Results of a monitoring program of continuous water levels and physical water properties at the Operable Unit 1 area of the Savage Municipal Well Superfund site, Milford, New Hampshire, water years 2000-03

Effects of a remedial system and its operation on volatile organic compound-contaminated ground water, Operable Unit 1, Savage Municipal Well Superfund Site, Milford, New Hampshire, 1998-2004

“…Continuously monitored water levels Hydrogeology from well B95-9 inside the barrier ( fig. 2, table 1) showed that water levels generally did not decrease below 257 ft (Harte, 2005) although the net extraction inside the barrier increased by a factor of six from 1999 to 2003.…”

“…The low observed gradients inside the barrier indicate recharge is diffuse and likely from upward flow from the bedrock. In contrast, steep gradients (head differences greater than 0.5 ft; Harte, 2005) in the overburden across the barrier from wells that straddle the barrier indicate the barrier penetrates the overburden in those locations. This is additional evidence indicating upflow from bedrock is an important factor in the overburden water budget of the interior barrier area.…”

“…From 1999 to 2003, the net amount of water extracted inside the barrier (net extraction) increased in an attempt to decrease heads inside the barrier for the purpose of maintaining inward hydraulic gradients around the barrier and allowing the efficient use of the SVE wells; the SVE wells work most efficiently when water levels inside the barrier are less than 255 ft. Continu ously monitored water levels from well B95-9 show that water levels generally did not decrease below 257 ft (Harte, 2005), although the net extraction inside the barrier increased from 9.6 to 62 gal/min from 1999 to 2003 (table 5).…”

“…A computed water budget of the net extraction of water inside the barrier indicated bedrock upflow was a large percentage (approximately 50 percent) of the source of water to IW-1 and IW-2 extraction wells (Harte, 2004). Monitor ing of continuous water levels in the overburden and bedrock wells showed that net extraction of overburden water from inside the barrier caused bedrock water levels to decrease (Harte, 2005). The presence of PCE in bedrock wells may indicate contaminant transport between the PCE source in the overburden and underlying bedrock.…”

“…Previous studies by the USGS of the study site include construction and calibration of two ground-water-flow models (Harte and others, 1999;Harte and Mack, 1992), evaluation of effects of ground-water withdrawals on advective transport of contaminated ground waters (Harte and Willey, 1997), analysis of PCE trends for pre-and post-barrier conditions (Harte and others, 2001), and description of results of a monitoring pro gram of continuous water levels from water years -2003(Brayton and Harte, 2001Harte, 2005). Furthermore, solute transport of PCE was investigated and a transport model cali brated for the OU1 and OU2 areas (Harte, 2004).…”