1. Altitude of the potentiometric surface in the Mississippi River Valley alluvial aquifer, spring 2018 Author/Creator: Geological Survey (U.S.), cartographer Publication/Creation: Reston, Virginia : U.S. Department of the Interior, U.S. Geological Survey, 2020 Resource Type: Map Access & Availability: Loading
2. Altitude of the potentiometric surface in the Mississippi River Valley alluvial aquifer, spring 2020 Author/Creator: Geological Survey (U.S.), cartographer Publication/Creation: Reston, Virginia : U.S. Department of the Interior, U.S. Geological Survey, 2021 Resource Type: Map Access & Availability: Loading