Groundwater Modeling Analyses to Inform Aquifer Management Decisions in the Southern Nebraska Panhandle

In the southern Nebraska Panhandle, a cooperative modeling effort has been developed called the Western Water Use Management Modeling between North Platte Natural Resources District (NRD), South Platte NRD, and initially the Nebraska Department of Natural Resources to create a robust modeling tool for water resource management decisions. The NRDs are local governmental entities responsible for regulating and managing ground water pumping over several counties. This modeling effort extends from the Wyoming-Nebraska border in the west to Ogallala, NE in the east and from Alliance, NE (in the middle of the Nebraska Panhandle) in the north to the Nebraska-Colorado border in the south. The primary surface water bodies within the model are the North Platte River, South Platte River, and Lodgepole Creek. The principal ground water system in the area is the High Plains Aquifer that locally consist of alluvial, Ogallala, and Arikaree aquifers. This modeling utilizes three partially integrated models that consist of a surface water operations model of the North Platte River system that provides estimated pumping, canal operations and recharge, and river operations; a regionalized soil water balance model to estimate crop consumptive use, ground water pumping, and recharge; and a ground water model to provide storage and movement of water through the alluvial and High Plains aquifers. These models are being utilized by the NRDs for day to day operations and regional to sub-regional management decisions. Recent analyses of the High Plains Aquifer have been conducted using several different pumping allocation and climate scenarios to provide future estimates of aquifer drawdown and saturated thickness. Ultimately, the results of these analyses are used to help educate and inform the public and to provide the NRD Boards with information to aid their aquifer management decisions in determining the next increment of ground water pumping allocations.