1. Base of principal aquifer for the Elkhorn-Loup model area, North-Central Nebraska Author/Creator: McGuire, Virginia L. Publication/Creation: [Reston, Va.?] : U.S. Dept. of the Interior, U.S. Geological Survey, 2008 Resource Type: Map Edition: Version 1.0. Access & Availability: Loading
2. Base of the upper layer of the phase-three Elkhorn-Loup groundwater-flow model, north-central Nebraska Author/Creator: Stanton, Jennifer S., cartographer Publication/Creation: [Reston, Va.] : U.S. Department of the Interior, U.S. Geological Survey, 2013 Resource Type: Map Access & Availability: Loading