Climate Change Impacts on San Juan – Chama Project Reliability
Jesse Roach1, Dagmar Llewellyn 2
1Sandia National Laboratories, 2United States Bureau of Reclamation
The Colorado River Basin provides important supplies to municipal and agricultural users outside of the basin boundaries, including the Rio Grande Basin in New Mexico. The San Juan – Chama (SJC) inter-basin diversion moves water from the Colorado River basin into the Rio Grande basin. The SJC project, since it began operations in 1971, has never experienced a shortage, and as recently as 1999 was estimated to have a firm yield of 96,200 acre-feet per year (AF/yr). In the past 10 years, cities in the Rio Grande Valley have begun to augment local supplies with direct diversion of SJC water, making the reliability of those supplies ever more important. This poster presents results from the Upper Rio Grande Impact Assessment (URGIA) on the reliability of the SJC project under a changing climate. URGIA is an activity within the United States Bureau of Reclamation’s West Wide Climate Risk Assessment. URGIA analysis suggests that a 96,200 AF/yr yield will not be firm if the future is at all similar to that characterized by the suite of general circulation models (GCM) simulations utilized in Phase 3 of the Coupled Model Intercomparison Project (CMIP3). According to URGIA simulations, the SJC project will experience supply shortages in more than 10% of simulation years in the 2020s, more than 25% of simulation years in the 2050s, and more than 35% of simulation years by the 2090s.