1. Changes between early development (1930-60) and recent (2005-15) groundwater-level altitudes and dissolved-solids and nitrate concentrations in and near Gaines, Terry, and Yoakum Counties, Texas Author/Creator: Geological Survey (U.S.), cartographer Publication/Creation: Reston, Virginia : U.S. Department of the Interior, U.S. Geological Survey, 2016 Resource Type: Map Access & Availability: Loading