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Inset Groundwater-Flow Models for the Cache and Grand Prairie Critical Groundwater Areas, Northeastern Arkansas

Scientific Investigations Report 2024-5088
Water Availability and Use Science Program
By: , , , , , and 
https://doi.org/10.3133/sir20245088

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Abstract

The water resources in the Mississippi alluvial plain, located in parts of Missouri, Kentucky, Tennessee, Mississippi, Louisiana, and Arkansas, supports a multibillion-dollar agricultural industry that relies heavily on pumping of groundwater for irrigation of crops and aquaculture. The primary source of groundwater for agricultural-related pumping is the Mississippi River Valley alluvial aquifer, which has declined in storage for decades; secondary groundwater sources include the middle Claiborne aquifer and Wilcox aquifer system. Two areas in northeastern Arkansas that lie within the Mississippi alluvial plain, part of the Cache and Grand Prairie regions, have been designated as Critical Groundwater Areas owing to decades of groundwater declines that resulted from past and current water use. The multidisciplinary Mississippi Alluvial Plain project, led by the U.S. Geological Survey, and funded by their Water Availability and Use Science Program, included objectives to develop numerical groundwater models in focus regions, including the part of the Cache and Grand Prairie regions of northeastern Arkansas. Two inset models were developed using the child model capabilities of MODFLOW 6, the U.S. Geological Survey’s Modular Hydrologic Model simulation software. Both models, called the Cache model and Grand Prairie model, simulated the groundwater system and surface-water/groundwater interactions for the Mississippi River Valley alluvial aquifer and underlying Tertiary-age aquifers and confining units to the Midway confining unit. Each model was spatially discretized into 500-meter x 500-meter orthogonal cells on a grid with 5-meter constant-thickness vertical layers that represented the Mississippi River Valley alluvial aquifer and increasing thickness layers for the aquifers and confining units below the alluvial aquifer. The Cache and Grand Prairie models were calibrated with the PEST++ iterative ensemble smoother Version 5 and employed high dimensional parameterization schemes of 13,740 and 30,436 parameters, respectively. The Cache mean absolute residual for groundwater-level observations within each model domain for the priority well was 1.58 meters. Grand Prairie mean absolute residuals for the alluvial aquifer and middle Claiborne aquifer groundwater-level observations were 2.71 and 10.78 meters, respectively. The groundwater budgets for the Cache and Grand Prairie models were characterized by substantial outflows to irrigation wells, which constituted about 52 and 54 percent of all outflows, with the primary source of water to those wells being releases from unconfined aquifer storage.

Suggested Citation

Traylor, J.P., Duncan, L.L., Leaf, A.T., Weisser, A.R., Dietsch, B.J., and Guira, M., 2024, Inset groundwater-flow models for the Cache and Grand Prairie Critical Groundwater Areas, northeastern Arkansas: U.S. Geological Survey Scientific Investigations Report 2024–5088, 152 p., https://doi.org/10.3133/sir20245088.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Acknowledgments
  • Abstract
  • Introduction
  • Groundwater-Flow Models
  • Assumptions and Limitations
  • Summary
  • References Cited
  • Appendix 1. Geologic and Hydrostratigraphic Units for Northeastern Arkansas
  • Appendix 2. Temporal Discretization for the Cache Model and Grand Prairie Model
  • Appendix 3. Measured Versus Simulated One to One Plots By Observation Group and Histograms of Residuals for the Cache Model
  • Appendix 4. Measured Versus Simulated Plots of Water Levels at Select Observation Wells for the Calibrated Cache Model
  • Appendix 5. Measured Versus Simulated One to One Plots by Observation Group and Histograms of Residuals for the Grand Prairie Model
  • Appendix 6. Measured Versus Simulated Plots at Select Observation Wells for the Calibrated Grand Prairie Model
  • Appendix 7. Summary of Calibrated Aquifer Property Pilot Point Values for the Cache Model and Grand Prairie Model
  • Appendix 8. Calibrated Well Pumping Multiplier Parameters for Each Crop Type or Data Source by Stress Period for the Cache Model and Grand Prairie Model
  • Appendix 9. Prior and Posterior Ensemble Parameter Distributions for the Cache Model and Grand Prairie Model for Select Parameter Groups
Publication type Report
Publication Subtype USGS Numbered Series
Title Inset groundwater-flow models for the Cache and Grand Prairie Critical Groundwater Areas, northeastern Arkansas
Series title Scientific Investigations Report
Series number 2024-5088
DOI 10.3133/sir20245088
Year Published 2024
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Nebraska Water Science Center, Lower Mississippi-Gulf Water Science Center, Upper Midwest Water Science Center
Description Report: xi, 152 p.; 13 Figures: 8.50 x 11.00 inches; Data Release; Dataset
Country United States
State Arkansas
Other Geospatial Cache and Grand Prairie Critical Groundwater Areas
Online Only (Y/N) Y
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
Additional publication details