Ground-water studies in Saratoga County, New York

Heath, Ralph; Mack, F; Tannenbaum, Jordan

Ground-water supplies adequate for domestic and farm needs and small industries are available throughout Saratoga County in east central New York. The ground-water aquifers consist of unconsolidated deposits of till, sand, and gravel, and consolidated sandstone, shale, carbonate, and crystalline rocks. Large supplies are available from some sand and gravel aquifers that occupy parts of the large valleys. Till, an unsorted mixture of particles ranging in size from clay to boulders, is the principal unconsolidated deposit in the western two-thirds of the county. Small supplies of water are generally derived from large diameter dug wells extending only a few feet below the water table. The depths of 98 dug wells, most of which draw from till, average 17 feet. Stratified deposits of sand and gravel underlie large areas in the eastern part of the county and parts of the stream valleys in the other areas. In the eastern part these deposits are predominantly a fine to coarse sand which is underlain by clay. In these deposits supplies of water adequate for domestic needs can generally be obtained from small diameter driven wells. The depths of 36 driven wells average 20 feet. With proper development yields of over 30 gpm (gallons per minute) have been obtained. A special study was made of a thin sand deposit in Saratoga National Historical Park near the Hudson River. The deposit consists mainly of fine to coarse sand with a maximum thickness of 25 feet and occupies an area of about one-half square mile. Principal discharge from the deposit is a flow of about 35 gpm from a spring developed at the contact with the underlying clay. A pumping test conducted on a 2-inch-diameter well equipped with a 60-gauze screen 5 feet long jetted to a depth of 25 feet indicated a permeability of 700 gpd/ft^2 (gallons per day per square foot) and a storage coefficient of 0.16, which indicates water-table conditions. In the first k minutes of the test the aquifer responded as an artesian aquifer, apparently in response to silty layers. The sand and gravel deposits in the stream valleys are capable of yielding as much as 800 gpm to a single screened well. Ground water in the valley of Kayaderosseras Creek near the reactor site at West Milton, in the southwestern part of the county, occurs under water-table and artesian conditions. The water-table aquifer is a layer of sand and gravel 25 feet thick which yields 750 gpm to a well with horizontal collectors parallel to and 25 feet from the creek. The artesian aquifer is composed of sand and some gravel 75 feet thick which is separated from the water-table aquifer by 25 feet of silt. The artesian aquifer has a transmissibility of 125,000 gpd/ft^2 and a storage coefficient of about 0.0003. Yields of 156 wells tapping the bedrock aquifers average 13 gpm. Nine wells in the Precambrian crystalline rocks occurring in the northwest and northcentral part of the county yield an average of 6 gpm. Twelve wells in the Potsdam Sandstone and Theresa Dolomite, bordering the crystalline rocks, yield an average of 19 gpm. Twenty-five wells in the carbonate rocks which border the sandstone or, where they are absent, border the crystalline rocks yield an average of 31 gpm. One-hundred and ten wells in the shale that underlies most of the eastern and southern parts of the county yield an average of 9 gpm. The report contains maps of the principal unconsolidated deposits and bedrock formations in the county together with records of several hundred selected wel 1 s.