Paleohydrology of the Lower Colorado River Basin and Implications for System Risk

Recent risk assessments of future Colorado River water supply have not fully incorporated the contributions of the Lower Colorado River Basin (LCRB) to the system, particularly the periodic inflows from the Gila River. We have developed new reconstructions of LCRB hydrologic variability from tree-ring records, including estimates of as-managed Gila inflows under the climate conditions of the past. We incorporated these reconstructions into an updated assessment of water supply risk for the Colorado River Basin, using the water-balance model introduced by Rajagopalan et al. (2009). Our results indicate the potential for management of the Gila inflows to non-trivially reduce overall system risk. They also point to the need for improved data on the natural and as-managed hydrology of the LCRB.

Reference:
Rajagopalan, B., Nowak, K., Prairie, J., Hoerling, M., Harding, B., Barsugli, J., Ray, A., and Udall, B. (2009). Water Supply Risk on the Colorado River: Can Management Mitigate? Water Resources Research 45, W08201, doi: 10.1029/2008WR00765.