Alternative sources of large seasonal ground-water supplies in the headwaters of the Susquehanna River basin, New York

Abstract

The bedrock ridges that form the northern divide of the Susquehanna River basin have been breached by glacial erosion in at least 29 localities. The resulting broad valleys, which bisect the drainage divide, are called "through valleys." Through valleys resemble major river valleys in width and in being underlain by a few hundred feet of glacial deposits, including water-yielding sands and gravels. However, they differ from major river valleys in that they are drained only by small headwater streams. Therefore, large temporary ground-water withdrawals are feasible, and such withdrawals during summer or fall would not greatly deplete naturally low streamflow at points downstream because the lowered water table could not induce river water that originated elsewhere to seep into the aquifer. Seasonal withdrawals from through valleys would be limited by three constraints: maximum acceptable lowering of the water table; hydraulic properties of the aquifer, which control well yield and the extent to which ground-water discharge to headwater streams would be reduced; and the degree to which recharge from winter and spring runoff would exceed normal rates as long as the water table remained below normal.