Hot off the press from Reclamation!
The Upper Rio Grande Impact Assessment (URGIA) report is part of the WaterSMART Program. By the way, 'SMART' is an acronym: Sustain and Manage America's Resources for Tomorrow. Gotta have a good APE (Acronym-Producing Expression) if you want to get a program to go anywhere (I'm serious here, folks).
Read the news release: Download URGIA_Final_News_Release
Here is what it says on the URGIA homepage:
Increasing temperatures and changes in the timing of snowmelt runoff could impact the amount of water available on the upper Rio Grande in the future. The study was conducted by the Bureau of Reclamation in partnership with Sandia National Laboratories and the U.S. Army Corps of Engineers. It includes a detailed evaluation of the climate, hydrology and water operations of the upper Rio Grande basin of Colorado and New Mexico. Also included is an evaluation of the potential impacts associated with climate change on streamflow, water demand and water operations in the basin.
Some of the news:
Decreases in overall water availability. Supplies of all native sources to the Rio Grande are projected to decrease on average by about one third, while flows in the tributaries that supply the imported water of the San Juan-Chama Project are projected to decrease on average by about one quarter.
Changes in the timing of flows. The seasonality of flows is projected to change. Anticipated changes include earlier snowmelt runoffs as well as increased variability in the magnitude, timing, and spatial distribution of streamflow and other hydrologic variables. Projections indicate that this basin will experience a decrease in summertime flows and less of a decrease (or potentially even an increase) in wintertime flows.
Increases in the variability of flows. All simulations used in this study project an increase in the month-to-month and inter-annual variability of flows over the course of the century. The frequency, intensity, and duration of both droughts and floods are projected to increase.
Plenty more where those came from:
Flood Control Operations. Floods are projected to become more extreme with climate change, and thus flood control operations would be needed more often in the future, even as overall supplies decrease.
Water Quality. Concentrations of nitrogen, phosphorus, suspended solids, and salt may increase in the future in response to increased evaporation rates for surface water and increased precipitation intensity, which would wash a greater volume of pollutants into the river, despite a decreased overall flow volume.
The Rio Grande Compact. Analyses presented in this report assume that Colorado would use its ability for priority administration to assure its obligations are met under the Rio Grande Compact. The analyses assume that New Mexico would take additional management actions to meet its obligations under the Rio Grande Compact, although in this study, Reclamation makes no assumptions about what those management actions would be. The irrigation system would be significantly impacted.
“I didn’t even say that! Now you’re just making up quotes and attributing them to me! I’ll kill you, you goddam son of a bitch!” —Mark Twain