Ground-water availability in parts of the Chicopee and Mill River basins, near Wilbraham, Massachusetts

Ground water in the Wilbraham area occurs in glacial drift and in underlying bedrock. Stratified sand and gravel deposits form the principal unconsolidated aquifers. These aquifers are generally less than 50 feet thick in most of the study area; however, an area in north-central Wilbraham, near the Chicopee River, is underlain by stratified drift deposits more than 200 feet thick that may be capable of yielding more than 300 gal/min (gallons per minute) to individual wells. Bedrock aquifers are generally of two types: Triassic and Jurassic sedimentary rock lies west of a north-south trending fault, and Paleozoic metamorphic, and igneous rock lies east of the fault. The median yield of wells in sedimentary bedrock is 15 gal/min; yields range from 2 to 110 gal/min. The median yield of wells in crystalline rock is 5 gal/min; yields range from less than 1 to 60 gal/min. (Woodard-USGS)