Modeling Groundwater Levels in the Northern High Plains of Texas

Abstract

Future changes in groundwater policy and the use of alternative technologies will have to be adopted for the Northern High Plains of Texas due to the depleting underlying Ogallala aquifer, the major source of water for irrigation. The objective of this study was to calibrate and validate an integrated regional groundwater model using observed groundwater levels between 1939 and 2007 in four heavily irrigated counties (Dallam, Sherman, Hartley, and Moore counties) located in the northwest corner of the Northern High Plains of Texas. For this purpose, the study area was divided into 1km cells and the MODFLOW-2000 model was calibrated and validated. Results indicate that the groundwater model was calibrated and validated satisfactorily by reproducing and comparing groundwater levels with correlation coefficients of 0.98 in both cases and with normalized root mean square errors of 5.0% and 4.3% respectively. The calibrated model is being used to evaluate the implications of five different agricultural management policy scenarios on groundwater levels between 2010 and 2060. Simulation results should assist water planners to estimate specific irrigation water uses and promote the use of alternative technologies in the 4-county area, and to potentially implement new policies for sustainable development of the Ogallala aquifer.