Description of the Massachusetts Military Reservation

The Massachusetts Military Reservation (MMR) covers approximately 34 square miles and includes parts of the towns of Bourne, Sandwich, Mashpee, and Falmouth. It began operations in 1912 and was a major installation of the U.S. Air Force from 1948 until 1973. Since 1973, the facility has been used primarily by the Massachusetts National Guard and the U.S. Coast Guard.

The MMR currently has a year-round population of approximately 2000 people living in on-base housing maintained by the U.S. Coast Guard. The population increases by a few thousand during Reserve and Air National Guard Activities.

In 1986 the National Guard Bureau’s Installation Restoration Program (IRP) began to investigate groundwater contaminant plumes and potential source areas at the MMR. Since 1986, numerous groundwater studies have been undertaken by the National Guard Bureau’s IRP and the USGS. Remediation efforts have also been undertaken.

Description of Landfill-1

The Main Base landfill, Landfill-1, has been designated Area of Contamination (AOC) LF-1. It occupies 100 acres and is bounded by Turpentine Road and Frank Perkins Road to the east and west, respectively, and Herbert Road and Connery Avenue to the north and south, respectively. The nearest on-base housing is located 4800 ft to the southwest. The nearest off-base housing is located 2 miles to the east.

The landfill served as the primary solid waste disposal facility at MMR beginning in 1944. Until 1984, the landfill was used for unregulated waste disposal by the U.S. Army, Air National Guard, U.S. Air Force, U.S. Navy, U.S. Coast Guard, U.S. Department of Agriculture Experiment Stations, and Veterans Administration. After 1984, waste disposal was regulated. The landfill ceased operations in 1989.

Wastes were deposited in five cells, named for the year in which waste disposal began: 1947, 1951, 1957, 1970, and Post-1970. A sixth disposal area, the Kettle Hole, was also used for waste disposal.

Wastes reported to have been disposed in the landfill include general refuse, fuel tank sludge, herbicides, solvents, transformer oils, fire extinguisher fluids, blank small arms ammunition, paints, paint thinners, batteries, DDT powder, hospital waste, municipal sewage sludge, coal fly ash, and possibly live ordnance.

Landfill-1 Groundwater Plume

In 1983, LF-1 was identified as a potential source of contamination of MMR water supply Well G. Subsequent investigation revealed groundwater in the vicinity of LF-1 to have been contaminated with volatile and semi-volatile organic chemicals, inorganic chemicals, and pesticides. It was concluded that LF-1 was the most likely source of Well G contamination.

Contaminants detected in groundwater at LF-1 include trichloroethene, 1,2-dichloroethene, toluene, xylenes, benzene, ethylbenzene, acetone, 2-butanone, 2-hexanone, arsenic, and manganese.

For more information about the MMR or the LF-1 plume, visit the MADEP/MMR Website:

Hydrogeology of Western Cape Cod

The geology of Cape Cod was shaped by glacial activity approximately 15,000 years ago, during the late Wisconsonian stage of the Pleistocene Epoch. The Buzzards Bay Moraine and Sandwich Moraine were deposited along the western and northern portions of Western Cape Cod. These moraines are made up of a poorly sorted mixture of sand, gravel, silt, clay, and boulders. The Mashpee Pitted Plain is a broad glacial outwash plain that lies between the two moraines. The plain is made up of fine and coarse sand and gravel. The thickness of unconsolidated deposits ranges from approximately 100 feet at the Cape Cod Canal to 325 feet at the Buzzards Bay Moraine.

The glacial deposits overlie bedrock of the Paleozoic Era.

A single aquifer underlies Western Cape Cod. The aquifer is unconfined, with the water table generally located approximately 50 feet below the ground surface. The aquifer is fed by recharge resulting from precipitation. Of the 40 to 47 inches of precipitation received by the Western Cape each year, an estimated 18 to 22 inches recharges the aquifer.

Recharge results in a groundwater mound beneath the Western Cape. The high point of the mound is located beneath the northern portion of the MMR. Near the high point, groundwater moves radially outward. Near the coast, the direction of groundwater movement is determined largely by the shape of the coastline.

Most lakes and streams are hydraulically connected to the groundwater system. Fluctuations of groundwater levels are typically reflected in water levels in nearby lakes and ponds. Many streams are fed by groundwater discharge.

Groundwater is the sole source of drinking water on western Cape Cod. Public water supply systems provide water for approximately 70% of the population. The remainder of the population relies on domestic wells. Average daily demand on western Cape Cod has increased by more than 40% between 1975 and 1989. For the period 1986-1990, the average daily demand for western Cape Cod was 6.4 million gallons per day (mgd). Summer season demand is almost twice that of off-season.

References

Effects of Simulated Ground-Water Pumping and Recharge on Ground-Water Flow in Cape Cod, Martha’s Vineyard, and Nantucket Island Basins, Massachusetts, U.S. Geological Survey Open-File Report 94-316 (John P. Masterson and Paul M. Barlow), 1994.

Hydrogeologic Framework of Western Cape Cod, Massachusetts, U.S. Geological Survey Open-File Report 96-465 (John P. Masterson, Byron D. Stone, Donald A. Walter, and Jennifer Savoie), 1996.

Installation Restoration Program Ashumet Valley Groundwater Operable Unit Remedial Investigation Report Massachusetts Military Reservation Cape cod, Massachuestts Volume I - Text Draft, ABB Environmental Services, April 1995.

Installation Restoration Program Interim Remedial Investigation Main Base Landfill (AOC LF-1), ABB Environmental Services, March 1992.

MADEP/MMR Website, http://www.magnet.state.ma.us/dep/sero/mmr/mmr.htm, 1997.

Movement and Fate of Solutes in a Plume of Sewage-Contaminated Ground Water, Cape Cod, Massachusetts: U.S. Geological Survey Toxic Waste Ground-Water Contamination Program, U.S. Geological Survey Open-File Report 84-475 (Ed. Dennis LeBlanc), 1984.

ROD Interim Remedial Action Main Base Landfill (AOC LF-1) Source Area Operable Unit, ABB Environmental Services, January 1993.

Use of Particle Tracking to Improve Numerical Model Calibration and to Analyze Ground-Water Flow and Contaminant Migration, Massachusetts Military Reservation, Western Cape Cod, Massachusetts, U.S. Geological Survey Open-File Report 96-214 (John P. Masterson, Donald A. Walter, and Jennifer Savoie), 1996.

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