Lower Rio Grande Basin study shows shortfall in future water supply

"Basin studies are an important element of the Department of the Interior's WaterSMART initiative and give us a clearer picture of the possible future gaps between water demand and our available supplies," Commissioner Connor said. "This study of the lower Rio Grande basin will provide water managers with science-based tools to make important future decisions as they work to meet the region's diverse water needs. In addition, the study will help inform water management discussions between the U.S. and Mexico through the International Boundary Water Commission."

Among the findings and conclusions of the Lower Rio Grande Basin Study:

Climate change is likely to result in increased temperatures, decreased precipitation and increased evapotranspiration in the study area. As a result of climate change, a projected 86,438 acre-feet of water per year will need to be added to the 592,084 acre-feet per year of supply shortfall predicted in the existing regional planning process in 2060, for a total shortfall of 678,522.

Water supply imbalances exacerbated by climate change will greatly reduce the reliability of deliveries to all users who are dependent on deliveries of Rio Grande water via irrigation deliveries.

The Study includes an acknowledgment that all water management strategies recommended through the recently adopted regional water plan are part of a needed portfolio of solutions for the Study Area.

Seawater desalination, brackish groundwater desalination, reuse and fresh groundwater development were examined as alternatives to meet future water demands. The study found that brackish groundwater development was most suitable. Further analysis was conducted; it was found that regional brackish groundwater systems would best meet the planning objective. An appraisal-level plan formulation and evaluation process was conducted to determine potential locations of each regional brackish groundwater desalination system.

The Lower Rio Grande Basin Study was developed by Reclamation and the Rio Grande Regional Water Authority and its 53 member entities. It was conducted in collaboration with the Texas Region M Planning Group, Texas Water Development Board, Texas Commission on Environmental Quality and International Boundary and Water Commission. It covered 122,400 square miles. The study cost $412,798 with the RGWRA paying for 52 percent of it.