Proceedings of the 2019 Mississippi Water Resources Conference

Year: 2019 Authors: Guira M.N., Peterson S.M.

The U.S. Geological Survey Mississippi Alluvial Plain project is updating groundwater models of the Mississippi Embayment and Mississippi River Valley Alluvial aquifer to provide key information and decision support for stakeholders through a decision support system. Groundwater withdrawals from the Mississippi River Valley Alluvial aquifer sustain agricultural production in the Shellmound, Mississippi area, but groundwater declines have heightened concerns about long-term sustainability of the resource and led to consideration of artificial recharge or other water management activities. To support evaluation of the effects of potential water management activities in the Shellmound area, aquifer characteristics derived from high-resolution airborne electromagnetic surveys (AEM) are being integrated into a groundwater flow model. The Shellmound model area is about 1000 square kilometers covering part of northwestern Mississippi.

Aquifer characteristics derived from the AEM data at multiple resolutions will be objectively evaluated through automated groundwater model calibration, for example, using 1 layer to represent the alluvium as opposed to ten. Each model will use the same hydrologic input data and be calibrated against equivalent calibration targets. Subsequent comparison between model calibration data and simulated outputs for variously-resolved groundwater flow models will provide information about the level of detail in the vertical discretization that most improved the Shellmound Inset groundwater flow model. The comparison will also provide information about the maximum level of detail in the vertical discretization that can be supported from the AEM and supporting data available for model calibration.