Regional Water Supply Sufficient For
the Next Half-century
New Adaptation Strategies Can Offset Reductions
in Water Supply from Climate Change

For immediate release: 2/29/08
For more information, Contact:
Andy Ryan, Seattle Public Utilities, (206) 684-7688

SEATTLE — Using new University of Washington climate change data, two of the region’s largest water suppliers have projected they will have enough water to supply their customers for at least a half a century — without the need for expensive new sources.

The local water supply assessments are in sharp contrast to predictions that at least 36 U.S. states will face water shortages within five years because of a combination of rising temperatures, drought, and population growth. Scientists have predicted that by 2050 up to 2 billion people worldwide could be facing major water shortages.

“Global warming is going to have an enormous impact on the world’s drinking water supply” said Seattle Mayor Greg Nickels, “but by using local climate change models like those being developed by UW scientists, we will be able to design low-cost, effective solutions to meet the region’s water needs far into the future.”

Everett Public Works and Seattle Public Utilities assessed the impacts of climate change on their water supplies utilizing three scenarios developed by the UW’s Climate Impacts Group (CIG), as part of the work done for the regional planning process initiated by King County. The CIG researchers developed the climate scenarios using data from three global climate models run with two different greenhouse gas emission pathways, developed by the Intergovernmental Panel on Climate Change (IPCC).

“We are very happy that our data were incorporated into the analysis performed by the utilities to estimate the impacts of climate change to their individual systems,” said Richard Palmer, professor of civil and environmental engineering and principal in the Climate Impacts Group. “Climate change will decrease the safe yield of the region in the future. These impacts may require operational changes, system expansions and other adaptation strategies.”

The potential impacts on supply vary between the two cities, but the assessments indicate supplies are projected to decrease over time. For example, in 2050, the middle case scenario projects a decrease in supply of 6 percent for Everett and 13 percent for Seattle. However, forecasted demands are projected to be met in 2050, even with this potential decrease in supply.

“As drinking water suppliers, we take climate change and any potential impact on our water supply seriously,” said Tom Thetford, public works director for the City of Everett. “We have utilized the best available climate information so we can project how any change in climate may affect the supplies we manage. While there does not appear to be much of a near-term impact, we are planning for the longer-term impact.”

Each of the water suppliers is developing adaptation options to help prepare for and offset the longer term impacts of climate change. Seattle Public Utilities, for example, has identified low- to no-cost adaptation options that would restore the supply that is projected to be lost in 2050.

“Seattle has developed and is analyzing a portfolio of adaptation options that we can deploy to offset the reductions in supply,” said Seattle Public Utilities Director Chuck Clarke.

“Some examples of these options include refilling our reservoirs to a higher level and drawing them down deeper. Conservation is another key option for this region. These are options we can pursue now or in the next few years at very little cost,” Clarke said.

Given the dynamic and somewhat speculative nature of climate change research, the utilities are committed to doing additional assessments of climate change impacts on water supply on a regular basis. The utilities are also committed to supporting efforts that increase the usefulness and availability of climate information so that water suppliers can improve their ability to assess potential impacts and refine their adaptation options. Improvement in forecasting changes in precipitation patterns and greater use of regional climate models are two areas of interest to utilities.

Visit the utilities websites at:

• Everett Public Works

• Seattle Public Utilities

The City of Everett’s Public Works Department maintains the infrastructure of the city including drinking water, wastewater treatment and maintenance of streets and storm water drains. The department has an environmental education program that offers school programs and presentations to community groups on these topics. The Public Works Department has more than 200 professionals dedicated to serving the City of Everett.

Seattle Public Utilities provides a reliable water supply to more than 1.3 million customers in King County, and provides essential sewer, drainage, and solid waste services to City of Seattle customers.

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Seattle Public Utilities