The Impact Area Groundwater Study Program at the Massachusetts Military Reservation is a large and complex effort by the Department of Defense to identify and remediate contamination of the Cape Cod sole-source aquifer by military ordnance compounds. Several contaminant plumes composed of explosive compounds and perchlorate emanate from training and test firing ranges and a central impact area that overlie the sand and gravel aquifer. The plumes are up to a mile long and radiate outward from the top of the water-table mound beneath western Cape Cod. The success of the cleanup is based on sound scientific and technical understanding of contaminant fate and transport. USGS scientists support the IAGWSP team through innovative field and modeling investigations, methods development, and access to the USGS's extensive knowledge of the Cape Cod aquifer and ongoing research at the USGS Cape Cod Toxic Substances Hydrology Research site at the MMR.

October 2009 – Western Cape Cod Water Table Varied Less than 2 Feet during 2009 Water Year
The altitude of the water table at the top of the Sagamore Lens of the Cape Cod aquifer varied less than 2 feet during the 2009 water year (Oct. 2008 to Sept. 2009). The water table dropped about 0.7 feet during fall 2008 but rose about 1.1 feet during May to October 2009 owing to an unusually wet spring and early summer. The water table-altitude is monitored continuously by the USGS in cooperation with the AEC at four wells on and near Camp Edwards northwest of Snake Pond. The data are available online in near real time.

USGS Scientific Investigations Report 2006-5054
Groundwater levels near the top of the western Cape Cod water-table mound, Massachusetts Military Reservation, 2002-2004
Abstract Full PDF

USGS Water-Resources Investigations Report 03-4133
Diffusion and drive-point sampling to detect ordnance-related compounds in shallow groundwater beneath Snake Pond, Cape Cod, Massachusetts, 2001-02
Abstract Full PDF

USGS Water-Resources Investigations Report 03-4053
Simulation of advective flow under steady-state and transient recharge conditions, Camp Edwards, Massachusetts Military Reservation, Cape Cod, Massachusetts
Abstract Full PDF

USGS Water-Resources Investigations Report 02-4143
Simulated changes in the sources of ground water for public-supply wells, ponds, streams, and coastal areas on western Cape Cod, Massachusetts
Abstract Full PDF

USGS Water-Resources Investigations Report 99-4174
Simulated pond-aquifer interactions under natural and stressed conditions near Snake Pond, Cape Cod, Massachusetts
Abstract Full PDF

October 2009 – Passive Sampling Methods Show Promise for Monitoring Perchlorate and Explosive Compounds in Groundwater
Field tests of three passive-sampling methods for the long-term monitoring of ordnance-related compounds in groundwater were conducted in six wells in the Impact Area at the MMR in summer 2009. Concentrations of perchlorate and explosive compounds in water samples collected by two diffusion methods – rigid porous polyethylene membranes and regenerated cellulose membranes and one grab-sample method – the Hydrasleeve – were similar to concentrations measured in pumped samples. A field test of the Hydrasleeve method is currently underway in more than 25 wells at the MMR.

February 2009 – Oxygen and Hydrogen Stable Isotopes Help Delineate Potential Paths of Ordnance-Related Contaminants in Groundwater Near a Pond
Profiles of the ordance-related compounds and oxygen and hydrogen stable isotopes were used to evaluate the probable path of a contamination plume that extends from the Impact Area at the MMR to a kettle pond near the base. Profiles of perchlorate and explosive compounds from two direct-push borings on an island in the pond confirmed evidence from an earlier study that the contaminants did not discharge into the upgradient side of the pond. Profiles of oxygen and hydrogen stable isotopes from borings and wells on the downgradient side of the pond indicated that the contaminants would be more than 100 feet below the shoreline if they ever traveled that far (LeBlanc and others, 2008)

October 2008 – New Groundwater Modeling Methods Used to Improve Model Calibration and Examine Model Uncertainty
New features of the USGS groundwater computer program MODFLOW-2000 were used to improve the calibration and examine the prediction uncertainty of the USGS regional groundwater-flow model of western Cape Cod. By using the inverse (statistical) capabilities of the computer program, the match between simulated and observed groundwater levels and streamflows was improved and insights were gained into the relative effect of hydrogeologic properties on the flow system. The inverse capabilities were also used to examine the uncertainty of model predictions such as the flow paths in the aquifer (Walter and LeBlanc, 2007).

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