Stakeholder driven watershed modeling to inform drought-adaptive water management in the Rio Grande Project Area

The semi-arid Rio Grande-Rio Bravo (RGRB) Basin in southwestern U.S. has growing water conflict potential due to increasing demand for already-stressed water resources to support irrigated agriculture, growing urban areas, and riparian ecosystems while facing increasing aridity. The multitude of stakeholders from disparate water demand sectors complicates reaching consensus about “water futures” in this borderland region. In this research, we apply watershed modeling to support stakeholder engagement in the dialogue about water sustainability. An initial, comprehensive stakeholder survey revealed broad interest in better understanding plausible impacts of climate change on surface water and groundwater availability and associated implications for irrigated agriculture. To this end, we applied Soil and Water Assessment Tool (SWAT), a semi-distributed public-domain hydrologic simulation model, under a range of extreme climate scenarios to evaluate key components of the regional water budget, including streamflow, evapotranspiration, and groundwater recharge-discharge within the Rio Grande Project area. Using stakeholder interaction as a guiding principle for watershed modeling and climate change impact assessment, we provide insights into changes in hydrologic fluxes, and potential effectiveness of cropping change as an adaptation strategy to cope with water scarcity under different scenarios. Furthermore, we discuss outcomes of using watershed simulation results to frame discourse with a group of small scale farmers about adaptive water and land management practices under reduced water availability.