DOI: 10.5066/f74747xs
title: Ozark aquifer regional potentiometric surface dataset in, Arkansas, Kansas, Missouri, and Oklahoma, November 2014-January 2015

description: This dataset represents synoptic data and conditions of water levels of the Ozark aquifer as documented in the U.S. Geological Survey Scientific Investigations Map 3348 (https://pubs.er.usgs.gov/publication/sim3348). The Ozark aquifer, within the Ozark Plateaus aquifer system, is the primary groundwater source in the Ozark Plateaus physiographic province. The construction of a regional potentiometric-surface map of the Ozark aquifer is needed to aid assessment of current and future groundwater use and availability. The regional potentiometric-surface mapping is part of the U.S. Geological Survey (USGS) Groundwater Resources Program initiative (http://water.usgs.gov/ogw/gwrp/activities/regional.html) and the Ozark system groundwater availability project (http://ar.water.usgs.gov/ozarks), which seeks to quantify current groundwater resources, evaluate changes in these resources over time, and provide the information needed to simulate system response to future human-related and environmental stresses. The dataset includes �Ozark aquifer groundwater well point dataset, SIM3358� and �Ozark aquifer water-level contour dataset, SIM3348�. Groundwater-level data from 178 wells cased completely in and open to the Ozark aquifer are available from the USGS National Water Information System (NWIS; data available at http:// waterdata.usgs.gov/nwis). Groundwater wells were determined to be completed within Ozark aquifer geologic units by evaluating lithology from geophysical logs, groundwater driller logs, total depth, casing depth, publications, and available historical groundwater-level data. Groundwater-level data were collected for Arkansas, Kansas, and Missouri; however, groundwater-level data were not collected for Oklahoma because of the local practice of completing wells in both the Springfield Plateau and Ozark aquifers and a lack of completion data to indicate wells that were completed solely in the Ozark aquifer. Groundwater-level measurements were converted from depth below land surface, in feet, to groundwater-level altitude, in feet. Well altitudes, used to calculate groundwater-level altitudes, originally reported with respect to the National Geodetic Vertical Datum of 1929 (NGVD 29), were converted to the North American Vertical Datum of 1988 (NAVD 88), for consistency. Groundwater-level contours were generated by using the interpolation method TopotoRaster in ArcMap. This tool is specifically designed for the creation of hydrologically correct digital elevation models while imposing constraints that ensure a connected drainage structure and a correct representation of the surface from the provided contour data (Esri, 2011). Once the raster surface was created, 100-ft contours were generated by using Contour (Spatial Analyst), which is a spatial analyst tool (available through ArcGIS Spatial Analyst Toolbox) that creates a linefeature class of contours (isolines) from the raster surface (Esri, 2008). Contours were manually adjusted based on topographical influence, a comparison with the regional map of Imes and Emmett (1994), and data point water-level altitudes to more accurately represent the potentiometric surface.