Geology and ground-water resources of Oswego County, New York

Unconsolidated deposits of Pleistocene and Holocene age form a nearly continuous cover in Oswego County. Pleistocene deposits consist of lodgment and ablation tills, outwash, kame, beach and wave-delta sand and gravel, and lacustrine sand, silt, and clay. Holocene deposits consist of peat and muck deposited in wetlands , and alluvial silt, sand, and gravel deposited in stream valleys. Unconsolidated deposits contain sufficient water for domestic and small farm needs except in areas mantled by silt and clay. Sand and gravel deposits are the best source of large quantities of water. Aquifers in glacial outwash are common in the eastern Tug Hill region, whereas kame, esker-kame, and beach aquifers predominate in the eastern and central regions. The principal sand and gravel aquifer, known as the Lacona-Williamstown aquifer, is 20 miles long, 0.5 to 3 miles wide, and 10 to 85 feet thick. Wells tapping the aquifer yield from 220 to 800 gallons per minute. Fracturing, rather than rock type, is the controlling factor in the water-producing capacity of bedrock. Bedrock near or at land surface provides adequate supplies for domestic and farm needs. Shallow wells in bedrock have water of fair to good quality, but material content increases with depth. (USGS)