Hydro-Climate Symposium

Oral

397365 - Assessing the Compounding Impact of Precipitation and Land Use Change on Runoff in a Semiarid Watershed

Author(s)

• NJ

  Neelam Tahneen Jahan

  Graduate Student
  University of Texas at El Paso

Co-Authors: Maryam Samimi, El Paso, Texas – University of Texas at El Paso; Saurav Kumar, El Paso, Texas – University of Texas at El Paso; Ali Mirchi, El Paso, Texas – University of Texas at El Paso

Intense precipitation events raise the risk of flash floods in the New Mexico-Texas-Mexico border region. Compounding effects of changing land use and precipitation pattern can influence rainfall-runoff processes that govern flash flooding in this southwestern semiarid HUC-8 scale watershed that, paradoxically, has substantial water conflict potential by 2025 due to changing climate and increasingly competitive demands for over-appropriated water resources. Using Soil and Water Assessment Tool (SWAT), we investigate the impact of changes in precipitation intensity and land use on runoff and arroyo flows in the dry, mountainous terrains, as well as streamflow in the Rio Grande River. The baseline watershed simulation model shows that episodic arroyo flows are heavily governed by intermittent, intense precipitation events. Two extreme precipitation scenarios (24-hr precipitation with 100-year and 200-year recurrence intervals) will be modeled using NOAA precipitation frequency estimation data. The effect of these precipitation scenarios will also be assessed under future land use/land cover scenarios using the USGS FOREcasting-SCEnarios (FORE-SCE) 2050 land use maps under A1B, A2 and B1 storylines developed by the Intergovernmental Panel on Climate Change (IPCC), representing different economic growth paths. Results improve understanding of timing and magnitude of runoff associated with precipitation and land use patterns, which has important implications for planning watershed management practices that mitigate flash flooding and sediment transport while providing opportunities for increasing water availability through groundwater recharge.