Recharge Feasibility of Tucson Stormwater Infrastructure
Jack Flanigan1, Eleonora Demaria2, Martha Whitaker1, and Nathon Strom1
1Department of Hydrology & Atmospheric Sciences, The University of Arizona, Tucson, AZ
2Pima County Regional Flood Control District, Tucson, AZ
The Pima County Regional Flood Control District (PCRFCD) manages stormwater detention basins that attenuate flooding in several developed watersheds in Pima County. This includes the Rita Ranch Detention Basin 12 miles southeast of downtown Tucson, Arizona. While observational evidence indicates this basin receives enough stormwater to accommodate a Sonoran Desert mesoriparian ecosystem, its potential water intake and output during storm events is unknown due to a lack of sensors. In addition, it is unclear whether it is feasible for the Rita Ranch Detention Basin to contribute to aquifer recharge. This study employs HYDRUS-1D to assess the basin's aquifer recharge feasibility using a water balance approach by implementing Tucson Water cross-sectional data for soil profiling and single-ring infiltrometer tests for the top soil layer’s hydraulic conductivity. The model incorporates velvet mesquite tree root water uptake parameters and daily meteorological data from 2011 to 2023. Preliminary simulations suggest that after meeting plant water needs, excess ponding water exits the soil column bottom, indicating potential local aquifer recharge. In semi-arid environments like Tucson, stormwater collection and retention are crucial for sustainable water management, as these basins can help replenish over-allocated water resources, support local ecosystems, and mitigate flood risks.