Simulated water sources and effects of pumping on surface and ground water, Sagamore and Monomoy flow lenses, Cape Cod, Massachusetts

• DOI: 10.3133/sir20045181
• Publication Date: 2018-08-15T18:40:06Z
• Authors: Donald A. Walter; Ann T. Whealan
• Keywords: Cape; Surficial aquifer

The sandy sediments underlying Cape Cod, Massachusetts, compose an important aquifer that is the sole source of water for a region undergoing rapid development. Population increases and urbanization on Cod lead to two primary environmental effects relate directly supply: (1) adverse land use quality in (2) pumping can adversely affect environmentally sensitive surface waters, such as ponds streams. These considerations are particularly Sagamore Monomoy flow lenses, which underlie largest most populous areas Cod. Numerical models lenses were developed simulate ground-water-flow conditions delineate at table contributing wells estimate natural changes recharge waters. About 350 million gallons per day (Mgal/d) recharges this area; (about 65 percent) discharges coast remaining 28 into A total about 24.9 Mgal/d, or 7 percent, withdrawn supply; pumped returned hydrologic system return creating state near mass balance aquifer. Areas contribute production 17 square miles; some 10 from flows through prior reaching wells. Current (2003) steady-state reduces simulated ground-water levels by more than 4 feet; projected (2020) may reduce additional 3 feet these same areas. future streamflow 9 cubic second (ft3/s), corresponding 5 percent respectively, streamflow. Natural varies with time, over both monthly multiyear time scales. Monthly cause pond vary between 1 2 average year; annual recharge, be much larger variations, period years. Streamflow, also response factor year periods. On average, ranges 15.8 Mgal/d March 45.3 August. Pumping distribution seasonally lowering depleting streamflows, summer months. Maximum drawdowns August exceed 6 feet, current pumping. Simulated pumping, relative representing 2003 conditions, decrease drawdown generally during month year. Over periods, seasonal lower periods reduced recharge. depletion individual streams but ft3/s combined drought below levels. Water Mary Dunn Pond, area large predicted decline 10.6 feet: 6.9 2.3 1.4 results indicate does not substantial