Intensified Atmospheric Rivers Due to a Warmer Climate: What are the Potential Hydrological Changes in the SRP Basins?

Rodrigo Valdés-Pineda1, Itinderjot Singh2, Eleonora Demaria3; Francina Dominguez2, and Juan B. Valdés1

1University of Arizona. Department of Hydrology and Atmospheric Sciences

2University of Illinois Urbana-Champaign. Department of Atmospheric Sciences

3Southwest Watershed Research Center, USDA-ARS, 2000 E Allen Road, Tucson, AZ

Recent studies have found that Atmospheric Rivers can be intensified as a consequence of a warmer climate. These intensified narrow bands of enhanced water vapor transport lead to spatio-temporal changes in precipitation and temperature; and these changes are strongly related to the spatio-temporal distribution of hydrologic fluxes at catchment scale i.e. streamflows, snow water equivalent, evapotranspiration, and soil moisture distribution, among others. The objective of this talk is to describe and quantify the hydrological changes derived from the five most intense ARs events that affected the Salt and Verde River basins in Central Arizona between 1980 and 2010. These two basins are important for the Salt River Project (SRP) that produces hydroelectricity and store water for the megacity of Phoenix. The intense ARs events were simulated for a control and a future scenario using the WRF regional climate model. Deltas in precipitation and temperature were calculated for each AR event, and then used to generate perturbed daily precipitation and temperature fields to feed the Variable Infiltration Capacity (VIC) Model. The model was calibrated and validated to simulate control and future scenarios of daily streamflows for both basins. The changes of the hydrological fluxes derived from the VIC model results (control versus future scenario) are analyzed and discussed in terms of their spatio-temporal distribution, and their potential effects in the storage capacity of the SRP system.