Suitability Map to Identify Water Scarcity Remediation Opportunities for Disadvantaged Communities in Tulare Lake Basin, CA, USA

The Tulare Lake Basin in the Central Valley of California is one of the world's most productive agricultural regions. Decades of water resources exploitation by large landowners have left disadvantaged communities (DACs) and ecosystems highly vulnerable to climate-induced surface water shortages and groundwater shortages due to unregulated pumping. As state regulation begins to address these issues, a need exists to design adaptive and appropriate management systems to increase resilience of agricultural communities. Managed aquifer recharge is one strategy that could potentially help ensure water security in DACs. Targeted recharge near DACs could stabilize groundwater tables and maintain or better groundwater quality in supply wells. In this study we present a geospatial analysis of publicly available datasets to determine DAC vulnerability to groundwater shortages and to identify potential groundwater recharge locations that might improve DAC resilience to future climate-induced groundwater shortages. Groundwater level, land subsidence, census, pesticide application, and domestic well log datasets were combined in ArcGIS to first estimate the vulnerability of DACs to changes in groundwater supply. We use the same data in combination with the Soil Agricultural Groundwater Banking Index, land use and land cover data, and surface water conveyance infrastructure data to develop location recommendations for managed aquifer recharge projects. We then use a particle tracking algorithm on simulated groundwater flow data to site specific source areas upgradient of DACs where recharge will benefit domestic wells in DACs. This research produces new understanding of factors contributing to DAC vulnerability and DAC resilience to changes in resource availability. The suitability map will be made available as a web-based tool to help facilitate discussions of fundamental changes in land use and management that may be necessary to achieve sustainable supply and quality of water resources. The methods developed will be generalizable to other regions facing similar water scarcity challenges, and can be adapted to understand the implications of other resource scarcities.