Interior Department Releases Report Underscoring Impacts of Climate Change on Western Water Resources

Date: March 22, 2016
Contact: Jessica Kershaw (Interior), Interior_press@ios.doi.gov

WASHINGTON – Putting the national spotlight on the importance of water sustainability, the Department of the Interior and the Bureau of Reclamation released a basin-by-basin report that characterizes the impacts of climate change and details adaptation strategies to better protect major river basins in the West that are fundamental to the health, economy, security and ecology of 17 Western states.

The SECURE Water Act Report, produced by Interior’s Bureau of Reclamation and its state and local partners, was released following today’s first White House Summit on Water in observance of World Water Day.

“One of the greatest challenges we face is dealing with the impacts of climate change on our nation’s water, which is really the lifeblood of our economy,” said Interior’s Deputy Secretary Michael L. Connor.  “We need to continue to develop collaborative strategies across each river basin to ensure that our nation’s water and power supplies, agricultural activities, ecosystems, and other resources all have sustainable paths forward.”

The report identifies climate change as a growing risk to Western water management and cites warmer temperatures, changes to precipitation, snowpack and the timing and quality of streamflow runoff across major river basins as threats to water sustainability. Water supply, quality and operations; hydropower; groundwater resources; flood control; recreation; and fish, wildlife and other ecological resources in the Western states remain at risk.

The report, which responds to requirements under the SECURE Water Act of 2009, shows several increased risks to western United States water resources during the 21st century. Specific projections include:

• A temperature increase of 5-7 degrees Fahrenheit by the end of the century;
• A precipitation increase over the northwestern  and north-central portions of the western United States and a decrease over the southwestern and south-central areas;
• A decrease for almost all of the April 1st snowpack, a standard benchmark measurement used to project river basin runoff; and
• A 7 to 27 percent decrease in April to July stream flow in several river basins, including the Colorado, the Rio Grande, and the San Joaquin.

These projections will have specific basin-level impacts that include:

• Southern California: In Southern California, warming and population growth are projected to increase water demand, reliance on imported water and the use of groundwater in the area, leading to development of alternative water supplies, such as recycled water.
• Colorado River Basin: Reductions in spring and early summer runoff could translate into a drop in water supply for meeting irrigation demands and adversely impact hydropower operations at reservoirs.
• Klamath and Truckee River Basins: Warmer conditions may result in increased stress on fisheries, reduced salmon habitat, increased electricity demand, increased water demands for in-stream ecosystems and increased likelihood of invasive species’ infestations.
• Columbia and Missouri River Basins: Moisture falling as rain instead of snow at lower elevations will increase the runoff during the wintertime rather than the summer, translating to reductions for meeting irrigation demands, adversely impacting hydropower operations, and increasing wintertime flood-control challenges.
• Sacramento and San Joaquin River Basins: Earlier season runoff combined with a potential for increasing upper watershed evapotranspiration may reduce the capacity to store runoff in Reclamation’s Central Valley Project and state water resources reservoirs.
• Rio Grande Basin: Reduced snowpack and decreased runoff likely will result in less natural groundwater recharge. Additional decreases in groundwater levels are projected due to increased reliance on groundwater pumping.

"Reclamation, its customers and stakeholders have adapted to various climate conditions for more than 100 years," the Bureau of Reclamation Commissioner Estevan López said.  "Now changing climate is creating a greater challenge; but through collaboration and cooperation, we will work to ensure a sustainable and secure water supply now and into the future."

While climate change poses significant risks to Western water resources management, Reclamation is already addressing vulnerabilities through adaptation strategies being developed with water managers across the West. For example, under the WaterSMART Program, collaborative basin studies evaluate the impacts of climate change and identify a broad range of potential options to resolve current and future water supply and demand imbalances. 

Reclamation has forged collaborative relationships in 15 of the 17 Western states with a diverse  group of non-Federal partners, including state water resource agencies, tribal governments, regional water authorities, local planning agencies, water districts, agricultural associations, environmental interests, cities and counties. These partnerships focus on identifying and developing adaptation strategies to address the vulnerabilities related to drought and climate change.

In addition to the new Report, the Interior Department launched an online tool enabling the public to visualize the regional impacts and potential adaptation options. The tool allows users to check, by basin, how temperature, precipitation and snowpack are projected to be affected by climate change and how climate change may affect runoff and water supplies. The viewer can also check the projected flow of a river at specific points and times of the year and display adaptation options.

The Report and visualization tool provides a five-year update on the river basins listed in the SECURE Water Act—the Colorado, Columbia, Klamath, Missouri, Rio Grande, Sacramento-San Joaquin and Truckee river basins— as well as other Western river basins.

During the White House Summit, the Administration announced new efforts and commitments from the federal government and more than 100 external institutions to enhance the sustainability of water in the United States. For more information, click here.

The SECURE Water Act Report, fact sheets on projected climate change impacts on the eight western river basins, and the visualization tool are available at www.usbr.gov/climate/secure.

The Bureau of Reclamation is the largest wholesaler of water in the Nation.  It provides more than 10 trillion gallons of water each year for municipal use and provides water to approximately 10 million acres of irrigated farmland that collectively produce 60 percent of the Nation’s vegetables and 25 percent of the Nation’s fruits and nut corps.  Additionally, Reclamation is the largest supplier of hydroelectric power in the Western United States, operating 53 power plants that serve 3.5 million households.