Water Resources Research Act Program

Details for Project ID 2020TX224B

Impact of climatic extremes on net subsurface discharge considering hydrologic linkage among vadose zone-unconfined aquifer-stream in Rio Grande basin

Institute: Texas
Year Established: 2020 Start Date: 2020-03-01 End Date: 2021-02-28
Total Federal Funds: $5,000 Total Non-Federal Funds: $10,002

Principal Investigators: Zhuping Sheng

Abstract: Increasing pressures on freshwater availability due to the rapid population growth and changing climate in the State of Texas calls for a more advanced technique to estimate and forecast its vulnerability to climatic extremes. In the present study, a newly developed predictive modeling framework is introduced to examine freshwater availability, especially in a semi-arid region in Southwest Texas. Net subsurface discharge (NSD) and streamflow, which are outputs of the modeling framework, are selected as an indicator to show freshwater vulnerability in the future. In order to represent future climatic extremes, downscaled CIMP5 RCP scenarios will be used and the impact of altered climatic variables on NSD and streamflow will be analyzed. USGS stream gauges installed along with the Rio Grande network provide stream discharge data on a sub-hourly basis, leading to the possibility of calculating measured net subsurface discharges using differential gauging method. The modeling framework calibrated for a historic baseline period 2016-2019 through the differential gauging method is providing a basis for future NSD and streamflow forecasts for the period 2020-2029. The predictions of NSD and streamflow under different future emission scenarios can be a viable tool to examine how vulnerable the Rio Grande is against climatic extremes.