Interior Releases Report Highlighting Impacts of Climate Change to Western Water Resources

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Here’s the release from the U.S. Department of Interior (Kendra Barkoff/Dan DuBray):

Secretary of the Interior Ken Salazar today released a report that assesses climate change risks and how these risks could impact water operations, hydropower, flood control, and fish and wildlife in the western United States. The report to Congress, prepared by Interior’s Bureau of Reclamation, represents the first consistent and coordinated assessment of risks to future water supplies across eight major Reclamation river basins, including the Colorado, Rio Grande and Missouri river basins.

“Water is the lifeblood of our communities, rural and urban economies, and our environment,” said Secretary Salazar, “and small changes in water supplies or the timing of precipitation can have a big impact on all of us. This report provides the foundation for understanding the long-term impacts of climate change on Western water supplies and will help us identify and implement appropriate mitigation and adaptation strategies for sustainable water resource management.”

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;
– 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
– an 8 to 20 percent decrease in average annual stream flow in several river basins, including the Colorado, the Rio Grande, and the San Joaquin.

The report notes that projected changes in temperature and precipitation are likely to impact the timing and quantity of stream flows in all western basins, which could impact water available to farms and cities, hydropower generation, fish and wildlife, and other uses such as recreation.

“Impacts to water are on the leading edge of global climate change, and these changes pose a significant challenge and risk to adequate water supplies, which are critical for the health, economy, and ecology of the United States,” added Reclamation Commissioner Mike Connor.
Reclamation is already working with stakeholders across the West to achieve a sustainable water strategy to meet our nation’s water needs. Through the WaterSMART Basin Studies Program, Reclamation is developing and evaluating options for meeting future water demands in river basins where water supply and demand imbalances exist or are projected.

Reclamation is also continuing to implement actions to mitigate and adapt to changing climate. For example, at Hoover Dam, new wide head range turbines are being installed that will allow more efficient power generation over a wider range of lake levels than existing turbines. In addition, through the WaterSMART program, Reclamation continues to work with water users across the West to implement conservation and recycling measures and promote the efficient use of finite water resources. The Department of the Interior has also established Landscape Conservation Cooperatives and Climate Science Centers to help assess vulnerabilities to the natural and cultural resources management by the Department, and spearhead activities to adapt to the stresses of climate change.

“The WaterSMART program provides a strong foundation for the Department’s efforts to improve water conservation and help water-resource managers make sound decisions about water use,” said Assistant Secretary of the Interior for Water and Science, Anne Castle. “As climate change adds to the challenges we face in managing our water supply, meaningful engagement between the River Basin states and the Department of the Interior will continue to be essential.”

To develop the report, Reclamation used original research and a literature synthesis of existing peer-reviewed studies. Projections of future temperature and precipitation are based on multiple climate models and various projections of future greenhouse gas emissions, technological advancements, and global population estimates. Reclamation will develop future reports to Congress under the authorities of the SECURE Water Act that will build upon the level of information currently available and the rapidly developing science to address how changes in supply and demands will impact water management.

The Bureau of Reclamation is the largest wholesaler of water in the country, providing water to more than 31 million people and to one out of five Western farmers for irrigation of more than 10 million acres of farmland. Reclamation is also the second largest producer of hydroelectric power in the western United States with 58 power plants generating nearly a billion dollars in power revenues and producing enough electricity to serve 3.5 million homes.

The SECURE Water Act Report, with fact sheets highlighting climate challenges and impacts in the eight western river basins, is available online at

More information about Reclamation’s WaterSMART program is available at

More coverage from John Flesher writing for the Associated Press. From the article:

A report released Monday by the Interior Department said annual flows in three prominent river basins — the Colorado, Rio Grande and San Joaquin — could decline by as much 8 percent to 14 percent over the next four decades. The three rivers provide water to eight states, from Wyoming to Texas and California, as well as to parts of Mexico.

The declining water supply comes as the West and Southwest, already among the fastest-growing parts of the country, continue to gain population.
Interior Secretary Ken Salazar called water the region’s “lifeblood” and said small changes in snowpack and rainfall levels could have a major effect on tens of millions of people.

The report will help officials understand the long-term effects of climate change on Western water supplies, Salazar said, and will be the foundation for efforts to develop strategies for sustainable water resource management.

More coverage from the Huffington Post. From the article:

Meant to assess the risks of climate change, the report noted that fluctuations in temperature and precipitation are expected to cause significant changes in the future. Among the projections are temperature increases between 5 and 7 degrees Fahrenheit, and a decrease in snowpack. [Department of Interior Secretary Ken Salazar] said the report is meant to provide the starting blocks for strategies geared toward sustainable water resource management.

More coverage from Amy Joi O’Donoghue writing for the Deseret News. From the article:

…warmer conditions may result in more stresses to fisheries and specific aquatic species and facilitate an acceleration in the growth of non-native or invasive species. Such warming would also pose substantial risks to farmers because reservoirs would be subject to “significant” evaporation, decreasing water supplies to farm fields and pasture lands…

Salazar said the water report will serve as a blueprint for Colorado River water users on steps that need to be taken in light of changing climates and increased demands.

More coverage from The Pueblo Chieftain (Chris Woodka):

The report consolidates previous studies on Western water in eight major basins, including the Colorado River, Rio Grande and Missouri River basins that affect Colorado. The Arkansas River basin was not included. The report does not provide solutions to future water woes, but lays a foundation to build on, Salazar said. “This report provides the foundation for understanding the long-term impacts of climate change on Western water supplies and will help us identify and implement appropriate mitigation and adaptation strategies for sustainable water resource management,” he said…

Colorado water groups are struggling with how much more water can be developed under the Colorado River Compact, with estimates ranging from none to 900,000 acre-feet. Climate change throws in curves both on the demand side — growing seasons will be longer — and the supply side of the equation. For the South Platte, which flows into the Missouri River, projections show a 10 to 12 percent drop in river flows, despite an overall increase in moisture throughout the larger Missouri watershed. The South Platte is the most densely populated region within the watershed, particularly in the Denver metro area, although it is relatively close to the headwaters in Colorado.

The good news for the Colorado River basin is that water storage projects have been designed to deal with the historically wide variability of flows. The Colorado River has a higher proportion of storage to flows than other rivers included in the study.

More Reclamation coverage here.

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