Management of Surface Water and Groundwater Resources in the Brazos River Basin, Texas

Abstract:

Freshwater sustainability is highly uncertain in the arid and semi-arid regions due to changes in climate as well as increased water demands in agricultural, municipal and industrial sectors. Such uncertainties affect reliability of highly complex water resources systems, such as Brazos River Basin (BRB), which is dependent on both surface and groundwater resources. The BRB is the second-largest river basin by area in Texas and it produces largest average annual flow volume in any basin within the state. Thus, the objectives of this study are: a) To estimate surface water and groundwater availability in the Brazos River Basin, Texas and b) To enhance reliability of water systems in the River Basin under changing climatic conditions.

To address these objectives, an integrated surface water – groundwater model, SWAT-MODFLOW, will be implemented. The SWAT-MODFLOW model will be calibrated and validated to capture observed streamflow and groundwater levels at multiple sites within the basin using historical climate forcings. The model simulation will be performed under different climatic conditions (e.g., droughts) to estimate surface water and groundwater availability and their interactions in the Brazos River Basin. Subsequently, the Texas Commission on Environmental Quality’s (TCEQ) Water Rights and Analysis Package (WRAP) will be implemented to estimate the effects of droughts on the reliability of multiple reservoirs within the BRB. The results of this study will be integrated in the decision-support tools, which will be useful to water managers and policy-makers.