Digital map of the configuration of the base of the principal aquifer in the Elkhorn-Loup Model area, north-central Nebraska

The U.S. Geological Survey (USGS), in cooperation with the Lewis and Clark Natural Resources District (NRD), Lower Elkhorn NRD, Lower Loup NRD, Lower Platte North...美国地质调查局（U.S. Geological Survey, USGS）与刘易斯与克拉克自然资源区（Lewis and Clark Natural Resources District, NRD）、下埃尔克霍恩自然资源区（Lower Elkhorn NRD）、下卢普自然资源区（Lower Loup NRD）及下普拉特北部... 开展合作