Nottmeier, Anna M. Pugh, Aaron L. 20250314 vector digital data Denver, CO U.S. Geological Survey https://doi.org/10.5066/P9025EEW Dataset is the 2015 Wilcox aquifer raster, in southern Arkansas. The raster was interpolated using 20-foot contours, which were constructed from 8 wells with groundwater-level altitude data. Groundwater-level measurements were used in the construction of a potentiometric surface of the Wilcox aquifer and represent synoptic conditions from April through June 2015. The potentiometric-surface mapping is part of an ongoing cooperative agreement between the U.S. Geological Survey, Arkansas Department of Agriculture - Natural Resources Division, Arkansas Geological Survey, Natural Resources Conservation Services and the Union County Water Conservation Board, whose purpose is to quantify current groundwater resources, evaluate changes in these resources over time, and provide the information needed to address future human-related and environmental stresses. 20150428 20150616 observed Complete None planned -93.6519 -92.7346 34.4321 33.5166 ISO 19115 Topic Category geoscientificInformation USGS Thesaurus water resources groundwater groundwater flow hydrogeology groundwater level Marine Realms Information Bank (MRIB) keywords aquifer effects of groundwater extraction USGS Metadata Identifier USGS:65987afad34e3265ab15a892 Common geographic areas Arkansas USGS Groundwater Information: Principal Aquifers of the United States Mississippi embayment aquifer system Wilcox aquifer Please see 'Distribution-Info' for details. There is no guarantee concerning the accuracy of the data. Any user who modifies the data is obligated to describe the types of modifications they perform. Data have been checked to ensure the accuracy. If any errors are detected, please notify the originating office. The U.S. Geological Survey strongly recommends that careful attention be paid to the metadata file associated with these data. Acknowledgment of the U.S. Geological Survey would be appreciated in products derived from these data. User specifically agrees not to misrepresent the data, nor to imply that changes made were approved or endorsed by the U.S. Geological Survey. Please refer to <http://www.usgs.gov/privacy.html> for the USGS disclaimer. Anna M. Nottmeier U.S. Geological Survey, Lower Mississippi-Gulf Water Science Center Hydrologist mailing and physical

Fayetteville Field Station

University of Arkansas - Genesis Technology Incubator

700 W. Research Center Blvd

Fayetteville AR 72701 501-515-4331 anottmeier@usgs.gov Arkansas Department of Agriculture-Natural Resources Division, Arkansas Geological Survey, and Natural Resources Conservation Services ArcGIS Desktop 10.5 and ArcGIS Pro 3.1.3 The Topo to Raster tool in ArcMap was used to assure 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, 2017a). Within the limitations of the scale dataset, the groundwater-flow directions show good agreement with previously constructed potentiometric-surface maps Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. Representative and uniform data distribution is important when developing a potentiometric-surface map. A geographic information system was used to conduct a spatial analysis of the well sites. Well location data were retrieved from the USGS NWIS (U.S. Geological Survey, 2016) and plotted using ArcGIS (ESRI, 2018; ESRI, 2023). Groundwater-level measurements were converted from depth below land surface, in feet, to groundwater-level altitude, in feet above North American Vertical Datum of 1988 (NAVD 88). Cunningham, W. L. Schalk, C. W. 2011 publication U.S. Geological Survey Techniques and Methods 1–A1 Reston, VA U.S. Geological Survey http://pubs.usgs.gov/tm/1a1/ Digital and/or Hardcopy 20150428 20150616 observed Cunningham and Schalk, 2011 Source information used in support of the development of the dataset. Environmental Systems Research Institute (ESRI) 20170101 application/service Redlands, CA Environmental Systems Research Institute (ESRI) http://pro.arcgis.com/en/pro-app/tool-reference/3d-analyst/how-topo-to-raster-works.htm Digital and/or Hardcopy 20150428 20150616 publication date ESRI, 2017a Source information used to construct raster. Environmental Systems Research Institute (ESRI) 20170101 tabular digital data Redlands, CA Environmental Systems Research Institute (ESRI) http://pro.arcgis.com/en/pro-app/tool-reference/3d-analyst/contour.htm Digital and/or Hardcopy 20150428 20150616 publication date ESRI, 2017b Source information used to construct contours. Environmental Systems Research Institute (ESRI) 2018 application/service Redlands, CA Environmental Systems Research Institute (ESRI) https://desktop.arcgis.com/en/ Digital and/or Hardcopy 20150428 20150616 observed ESRI, 2018 Program used to construct 2015 potentiometric-surface map and plot well points. Environmental Systems Research Institute (ESRI) 2023 application/service Redlands, CA Environmental Systems Research Institute (ESRI) https://www.esri.com/en-us/home Digital and/or Hardcopy 20150601 20150616 observed ESRI, 2023 Program used to construct 2015 potentiometric-surface rasters and plot well points. Nottmeier, Anna M. Pugh, Aaron L. 2025 vector digital data Denver, CO ScienceBase - U.S. Geological Survey https://doi.org/10.5066/P9025EEW Digital and/or Hardcopy 20150601 20150612 observed Nottmeier and Pugh, 2025 Groundwater well locations and water-level measurements used to construct the potentiometric surface. U.S. Geological Survey 2016 application/service Reston, VA U.S. Geological Survey http://dx.doi.org/10.5066/F7P55KJN Digital and/or Hardcopy 20150428 20150616 observed U.S. Geological Survey, 2016 Access to water-resources data collected in 2015 U.S. Geological Survey - Water Resources Division 1988 publication U.S. Geological Survey Circular 878-C Reston, VA U.S. Geological Survey https://doi.org/10.3133/cir878C Digital and/or Hardcopy 1988 publication date U.S. Geological Survey - Water Resources Division, 1988 The eight-character string identifying an aquifer. Codes are defined by the "Catalog of Aquifer Names and Geologic Unit Codes used by the Water Resources Division. Online aquifer code list can be accessed at https://help.waterdata.usgs.gov/aqfr_cd. The first step was to identify and compile locations of groundwater wells in the study area that were measured during a previous groundwater-level survey of the Wilcox aquifer in the spring 2012. 2014 The second step was to measure wells during the spring of 2015. Groundwater levels from 8 wells in southern Arkansas and 29 wells in northern Arkansas, cased completely in and open to the Wilcox aquifer were measured from April to June 2015 and are available from the USGS National Water Information System (U.S. Geological Survey, 2016). Groundwater-level measurements were measured using a calibrated steel or electric tape graduated in hundredths (0.01) of a foot (ft). The steel and electric tapes were calibrated prior to the collection of water-level measurements. Calibration was performed by comparing the steel or electric tapes to a standardized steel tape used only for calibration. 2015 Third step was to identify, compile, and verify field measurements that were measured from April through June 2015, in the Wilcox aquifer. Groundwater-level measurements were converted from depth below land surface, in feet, to groundwater-level altitude, in feet above North American Vertical datum of 1988 (NAVD 88). 2018 Well data were imported into ArcGIS Topo To Raster tool. Topo to Raster is an interpolation method specifically designed for the creation of hydrologically correct digital elevation models (DEMs), which imposes constraints to ensure connected drainage structure and correct representation of ridges and streams from input contour data (ESRI, 2017a). Once the raster was constructed, 10-ft contours were generated in northern Arkansas and 20-ft contours in southern Arkansas by using Contour (Spatial Analyst), a tool that creates line feature class of contours (isolines) (available through ArcGIS 3D Analyst toolbox) (ESRI, 2017b). Contours in northern and southern Arkansas were constructed based off the number of wells in each region. There were more well points in northern Arkansas so 10-ft contours were used. In southern Arkansas there were fewer well points so 20-ft contours were used. 2019 Raster Grid Cell 323 250 1 Albers Conical Equal Area 29.5 45.5 -96.0 23.0 0.0 0.0 row and column 324.3129064000045 324.31290640000935 meters North_American_Datum_1983 GRS 1980 6378137.0 298.257222101004 2e_Wilcox_southern_raster.tif Raster geospatial data file. U.S. Geological Survey Value Unique numeric values contained in each raster cell. ESRI 129.85101318359 389.10052490234 Feet U.S. Geological Survey - ScienceBase ScienceBase mailing and physical

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 United States 1-888-275-8747 sciencebase@usgs.gov Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also contains copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner whenever applicable. The data have been approved for release and publication by the U.S. Geological Survey (USGS). Although the data have been subjected to rigorous review and are substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, the data are released on the condition that neither the USGS nor the U.S. Government may be held liable for any damages resulting from authorized or unauthorized use. Although the data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and/or contained herein. Users of the data are advised to read all metadata and associated documentation thoroughly to understand appropriate use and data limitations. Digital Data ArcGIS 10.5 and ArcGIS Pro 3.1.3 ESRI Polyline Shapefile Zip file contains the Polyline Shapefile, as well as the associated metadata files. https://doi.org/10.5066/P9025EEW No fees are applicable for obtaining the dataset. 20250314 Anna M. Nottmeier U.S. Geological Survey, Lower Mississippi-Gulf Water Science Center Hydrologist mailing and physical

Fayetteville Field Station

University of Arkansas - Genesis Technology Incubator

700 W. Research Center Blvd

Fayetteville AR 72701 501-515-4331 anottmeier@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998