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Area of influence and zone of contribution to superfund-site wells G and H, Woburn, Massachusetts

Water-Resources Investigations Report 87-4100

By:
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Abstract

Groundwater contamination by chlorinated volatile organic compounds detected by the Massachusetts Department of Environmental Quality Engineering in 1979 forced the closing of public supply wells G and H in the City of Woburn, MA. The EPA has ranked the wells G and H site on the National Priorities List as a CERCLA (Superfund) site and currently is conducting a feasibility study to determine a remedial action cleanup plan for the site. A 30-day aquifer test was conducted to determine the hydraulic properties of the stratified drift aquifer in the vicinity of the wells, and to determine the area of influenced and zone of contribution to wells G and H under pumping conditions. The estimated transmissivity of the aquifer in the vicinity of well G was 29,700 sq ft/day, with a storage coefficient of 0.20. The average horizontal hydraulic conductivity in the vicinity of the well ranged from 125 to 350 ft/day. The estimated transmissivity of the aquifer at well H was 17,600 sq ft/day, with a storage coefficient of 0.16. The average horizontal hydraulic conductivity ranges from 130 to 215 ft/day. The area of influence after 30 days of pumping well G at 700 gal/min and well H at 400 gal/min was oblong in shape, and approximately 3000 ft long and 1700 ft wide, as measured at the midpoint between wells G and H. The area of influence of wells G and H described in this report is considered to be a ' snapshot ' representative of the hydrologic and pumping conditions of the 30-day aquifer test. Most of the water pumped by the wells is obtained directly from the part of the aquifer immediately surrounding both wells and from induced infiltration of surface water from the overlying river and wetland. The remaining part of the zone of contribution is that area of the Aberjona River drainage basin up-gradient and outside the area of influence of wells G and H. A small amount of the surface water in the river entering the northern end of the study area, which is derived from groundwater discharge and surface water runoff in the up-gradient drainage area, is induced from the river to the wells under pumping conditions. The size of the area south of wells G and H that contributes water to the wells is variable, dependent on pumping rates and hydrologic conditions. (Author 's abstract)

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Area of influence and zone of contribution to superfund-site wells G and H, Woburn, Massachusetts
Series title:
Water-Resources Investigations Report
Series number:
87-4100
Edition:
-
Year Published:
1987
Language:
ENGLISH
Publisher:
U.S. Geological Survey,
Description:
86 p. :ill., maps (some col.) ;28 cm.