Hydrogeologic Framework for Characterization and Occurrence of Confined and Unconfined Aquifers in Quaternary Sediments in the Glaciated Conterminous United States—A Digital Map Compilation and Database

First posted December 13, 2018 For additional information, contact: Director, Central Midwest Water Science CenterU.S. Geological Survey400 South Clinton StreetIowa City, IA 52240 The U.S. Geological Survey has created a hydrogeologic framework for Quaternary sediments in glaciated areas of the conterminous United States that categorizes, maps, and characterizes the glacial sediments at and beneath the land surface. The hydrogeologic framework divides the glaciated United States into 17 distinct hydrogeologic terranes using a geologic approach based on previous mapping, and was characterized using the Glacial Environments and Surficial Sediments geodatabase compiled from the Quaternary Atlas of the United States map series, the Surficial Materials Map of the United States, and several Integrated Geologic Map Databases for the United States; a groundwater use database compiled from public-supply, water-well data; and a lithologic database compiled from State-managed well records and geologic logs. This framework is to be used to assess the occurrence and characteristics of confined and unconfined glacial aquifers, their distribution and extent, and their potential intrinsic susceptibility and vulnerability.