Abstract

Conjunctive-Use Optimization Modeling of the Mississippi River Valley Alluvial Aquifer: Evaluation of Groundwater Sustainable Yield

Author(s): Czarnecki, J.

The Mississippi River Valley alluvial aquifer (the alluvial aquifer) is a water-bearing assemblage of gravels and sands that underlies about 32,000 square miles of Missouri, Kentucky, Tennessee, Mississippi, Louisiana, and Arkansas. The alluvial aquifer ranks third among the most productive aquifers in the United States. In 2000, more than 9 billion gallons per day of water were pumped from the alluvial aquifer by more than 45,000 wells, primarily for irrigation and for fish farming. Since the widespread agricultural use of the aquifer began, several large cones of depression have formed in the potentiometric surface, resulting in lower well yields and degraded water quality in some areas.

Conjunctive-use optimization modeling was done to assist water managers and planners by estimating the maximum amount of groundwater that hypothetically could be withdrawn from alluvial wells and from hydraulically connected streams without violating hydraulic-head or streamflow constraints. Optimization models showed that continued pumping at 1997 rates are unsustainable without violating head constraints imposed as a part of Arkansas’s Critical Groundwater Area criteria. Streamflow constraints specified within the model were based partly on minimum flow requirements for maintaining either navigation requirements, water quality, or fish habitat. Continuously pumping at 1997 rates resulted in water levels dropping below the hydraulic-head constraints (either half the aquifer thickness or 30 feet of saturated thickness), making those rates unsustainable. Optimized sustainable pumping was obtained such that water levels were maintained at or above the hydraulic-head constraints, and streamflow was maintained at or above minimum flow requirements. No single value of groundwater sustainable yield exists, as it depends on the specification of water-level and streamflow constraints, and the specification of potential groundwater and stream-withdrawal locations and their maximum allowable withdrawal rates.







 

Technical Presentations

  • Delta Water Quality
  • Delta Water and Agriculture
  • Wetlands
  • Water Quality
  • Sediments
  • Non-Point
  • Management and Sustainability
  • Wood Treatment
  • Modeling
  • Soil and Water Treatment

Workshops

Responsible Site Design: Implementing Innovative Stormwater Management Strategies

The primary goal of the workshop is to create a dynamic learning experience that examines the role of stormwater management in the built environment. The workshop will focus on integrating ecologically sound water management approaches into site design. After the workshop, attendees will be familiar with the following concepts and technical issues:

  • Knowledge of the stormwater treatment chain
  • Knowledge of the impact of land use codes on stormwater management
  • Application of a design process that mitigates the effects of stormwater on-site
  • Knowledge of the relationship between land use codes and design for innovative stormwater management

Information

For information contact:
Jessie Schmidt
MWRRI
Box 9680
Mississippi State, MS 39762
662-325-3295
jschmidt@cfr.msstate.edu