Hydrogeology and Simulated Groundwater Availability in Reaches 3 and 4 of the Washita River Aquifer, Southern Oklahoma, 1980–2017

Scientific Investigations Report 2023-5072
Prepared in cooperation with the Oklahoma Water Resources Board
By: , and 

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Abstract

The 1973 Oklahoma Groundwater Law (Oklahoma Statutes §82–1020.5) requires that the Oklahoma Water Resources Board conduct hydrologic investigations of the State’s aquifers to determine the maximum annual yield for each groundwater basin. Because more than 20 years have elapsed since the final order was issued, the U.S. Geological Survey, in cooperation with the Oklahoma Water Resources Board, conducted an updated hydrologic investigation and evaluated the effects of potential groundwater withdrawals on groundwater flow and availability in reaches 3 and 4 of the Washita River aquifer in southern Oklahoma for a study period spanning 1980–2017. A hydrogeologic framework and conceptual model were developed to guide the construction and calibration of a numerical model of the Washita River aquifer. The numerical model was calibrated to water-table-altitude observations at selected wells, base-flow observations at selected U.S. Geological Survey streamgages, and the conceptual-model recharge.

Three types of groundwater-availability scenarios were run using the calibrated numerical model. These scenarios were used to (1) estimate equal-proportionate-share pumping rates, (2) quantify the potential effects of projected well withdrawals on groundwater storage over a 50-year period, and (3) simulate the potential effects of a hypothetical 10-year drought. With Washita River main-stem inflows, the 20-, 40-, and 50-year equal-proportionate-share pumping rates under normal recharge conditions were about 3.08 acre-feet per acre per year for reach 3 and about 3.80 acre-feet per acre per year for reach 4. Projected 50-year pumping scenarios were used to simulate the effects of modified well withdrawal rates. Because well withdrawals were less than 1 percent of the calibrated numerical-model water budget, changes to the well pumping rates had little effect on Washita River base flows and groundwater storage in the Washita River aquifer. A hypothetical 10-year drought scenario was used to simulate the potential effects of a prolonged period of reduced recharge on groundwater storage. Groundwater storage at the end of the drought period was 4.6 percent less than the groundwater storage of the calibrated numerical model at the end of the drought period.

Suggested Citation

Rogers, I.M.J., Smith, S.J., Gammill, N.C., Gillard, N.J., Lockmiller, K.A., Fetkovich, E.J., Correll, J.S., and Hussey, S.P., 2023, Hydrogeology and simulated groundwater availability in reaches 3 and 4 of the Washita River aquifer, southern Oklahoma, 1980–2017: U.S. Geological Survey Scientific Investigations Report 2023–5072, 83 p., https://doi.org/10.3133/sir20235072.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Hydrogeology of the Washita River Aquifer and Surrounding Units
  • Hydrogeologic Framework of the Washita River Aquifer
  • Conceptual Groundwater-Flow Model
  • Numerical Groundwater-Flow Model
  • Groundwater-Availability Scenarios
  • Model Limitations
  • Summary
  • References Cited
Publication type Report
Publication Subtype USGS Numbered Series
Title Hydrogeology and simulated groundwater availability in reaches 3 and 4 of the Washita River aquifer, southern Oklahoma, 1980–2017
Series title Scientific Investigations Report
Series number 2023-5072
DOI 10.3133/sir20235072
Year Published 2023
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Oklahoma-Texas Water Science Center
Description Report: xii, 83 p.; 2 Data Releases
Country United States
State Oklahoma
Other Geospatial Washita River Aquifer
Online Only (Y/N) Y
Google Analytic Metrics Metrics page
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