ALBUQUERQUE, N.M., -- In an arid area where surface water is already fully allocated, climate change can be an uncertain variable to water managers.
In December 2013, the U.S. Bureau of Reclamation, the Albuquerque District, U.S. Army Corps of Engineers, and Sandia National Laboratories issued the West-Wide Climate Risk Assessment: Upper Rio Grande Impact Assessment (URGIA), which investigates historic and future climate trends in the Rio Grande Basin.
“While there are many, many studies on climate change impacts to the Colorado River, there are virtually none for the Rio Grande,” District technical writer and URGIA study partner Ariane Pinson said. “Because of the topographic diversity of the Upper Rio Grande, and because it is the place where different climate systems interact, climate change in the region is not well-captured in studies that speak for the Southwest or the Rocky Mountains as a whole. In addition, the trends work is the only comprehensive look at changes that are already happening in the Upper Rio Grande.”
In recent decades, the region has been warming by approximately 0.63°F (0.35°C) per decade, with overnight temperatures in mountain snowpack areas warming at almost twice this rate. The climate models project that the Upper Rio Grande is likely to warm by an additional 5 to 7°F (3 to 4°C) during the 21st century while precipitation is likely to decline slightly. The models also project decreasing snowpack, an earlier and small spring snowmelt runoff, and an increase in the frequency, intensity and duration of both droughts and floods. Flows in the Rio Grande are projected to decline significantly, particularly in late summer and early fall.
Based on this study, USACE work is likely to be impacted in several areas. Precipitation is likely to become more concentrated into larger storm systems producing larger and possibly more frequent flood events in the basin, thus affecting the District’s flood risk management mission.
Reduced water availability and decreased water quality may affect ecosystem restoration efforts in the Rio Grande. Hydropower is generated at Abiquiu for Los Alamos County, and lower average and late summer stream flows are likely to reduce the ability of this facility to generate electricity. And both drought and flood events may reduce the availability of facilities for water-based recreation.
Pinson said that the assessment “provides a strong foundation for future water resources planning in the region.”