Data Release for Secondary Hydrogeologic Regions of the Conterminous United States (ver. 2.0, June 2022)

The U.S. Geological Survey (USGS) previously identified 62 Principal Aquifers (PAs) in the U.S., with 57 located in the conterminous states. The USGS characterized...美国地质调查局（U.S. Geological Survey, USGS）此前已在美国境内识别出62处主要含水层（Principal Aquifers, PAs），其中57处分布于美国本土毗邻各州。美国地质调查局随后对……进行了特征描述。