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Hydrology and numerical simulation of groundwater flow and streamflow depletion by well withdrawals in the Malad-Lower Bear River Area, Box Elder County, Utah

Scientific Investigations Report 2017-5011
Prepared in cooperation with the Utah Department of Natural Resources, Division of Water Rights


The numerical groundwater flow model in this report (GBCAAS v. 2.0) supersedes the numerical groundwater flow model documented in Brooks and others, 2014, Steady-state numerical groundwater flow model of the Great Basin carbonate and alluvial aquifer system: U.S. Geological Survey Scientific Investigations Report 2014–5213, 124 p. (Available at https://pubs.usgs.gov/sir/2014/5213/.)

By: , , and 
https://doi.org/10.3133/sir20175011

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Abstract

The Malad-Lower Bear River study area in Box Elder County, Utah, consists of a valley bounded by mountain ranges and is mostly agricultural or undeveloped. The Bear and Malad Rivers enter the study area with a combined average flow of about 1,100,000 acre-feet per year (acre-ft/yr), and this surface water dominates the hydrology. Groundwater occurs in consolidated rock and basin fill. Groundwater recharge occurs from precipitation in the mountains and moves through consolidated rock to the basin fill. Recharge occurs in the valley from irrigation. Groundwater discharge occurs to rivers, springs and diffuse seepage areas, evapotranspiration, field drains, and wells. Groundwater, including springs, is a source for municipal and domestic water supply. Although withdrawal from wells is a small component of the groundwater budget, there is concern that additional groundwater development will reduce the amount of flow in the Malad River. Historical records of surface-water diversions, land use, and groundwater levels indicate relatively stable hydrologic conditions from the 1960s to the 2010s, and that current groundwater development has had little effect on the groundwater system. Average annual recharge to and discharge from the groundwater flow system are estimated to be 164,000 and 228,000 acre-ft/yr, respectively. The imbalance between recharge and discharge represents uncertainties resulting from system complexities, and the possibility of groundwater inflow from surrounding basins.

This study reassesses the hydrologic system, refines the groundwater budget, and creates a numerical groundwater flow model that is used to analyze the effects of groundwater withdrawals on surface water. The model uses the detailed catalog of locations and amounts of groundwater recharge and discharge defined during this study. Calibrating the model to adequately simulate recharge, discharge, and groundwater levels results in simulated aquifer properties that can be used to understand the relation between pumping and the reduction in discharge to rivers, springs, natural vegetation, and field drains. Simulations run by the calibrated model were used to calculate the reduction of groundwater discharge to the Malad River (stream depletion) in response to a well withdrawal of 360 acre-ft/yr at any location within the study area. Modeling results show that streamflow depletion in the Malad River depends on both depth and location of groundwater withdrawal, and varies from less than 1 percent to 96 percent of the well withdrawal. The relation between simulated withdrawal and reductions in Malad River streamflow, Bear River streamflow, and spring discharge are shown on capture maps.


Suggested Citation

Stolp, B.J., Brooks, L.E., and Solder, J.E., 2017, Hydrology and numerical simulation of groundwater flow and streamflow depletion by well withdrawals in the Malad-Lower Bear River Area, Box Elder County, Utah: U.S. Geological Survey Scientific Investigations Report 2017–5011, 113 p., 6 appendixes, https://doi.org/10.3133/sir20175011.

ISSN: 2328-0328 (online)

Study Area

Table of Contents

  • Abstract 
  • Introduction 
  • Hydrologic Conditions 
  • Conceptual Groundwater Model 
  • Groundwater Budget 
  • Previous Groundwater Budget 
  • Numerical Groundwater Flow Model 
  • Summary 
  • References
  • Appendix 1–6
Publication type Report
Publication Subtype USGS Numbered Series
Title Hydrology and numerical simulation of groundwater flow and streamflow depletion by well withdrawals in the Malad-Lower Bear River Area, Box Elder County, Utah
Series title Scientific Investigations Report
Series number 2017-5011
DOI 10.3133/sir20175011
Year Published 2017
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Utah Water Science Center
Description Report: xii, 113 p.; 6 Appendixes
Country United States
State Utah
County Box Elder County
Online Only (Y/N) Y
Additional Online Files (Y/N) Y
Google Analytic Metrics Metrics page
Additional publication details