California Report Examines Climate Change Impact On Water Resources

On July 10, the California Department of Water Resources (DWR) announced it released a technical report that offers a first look at changes that may affect California's water resources in the future.

The report, "Progress on Incorporating Climate Change into Management of California's Water Resources" is an adjunct to an executive order issued by Gov. Arnold Schwarzenegger on June 1, 2005 that sets greenhouse gas reduction goals for California.

"Given the complexity of California's water system and uncertainties about the impact of climate change, our work is at an early stage," according to DWR Deputy Director Jerry Johns. "But this report will contribute to an ongoing dialogue on how our systems may need to change in the future as more information becomes available."

Prepared for the governor and the state Legislature, the DWR paper describes the mathematical modeling of four climate change scenarios and the corresponding results. The report shows that climate change could significantly impact California's water picture in many ways, including:

  • Loss of Sierra snow pack and the seasonal water storage it provides.
  • More rain and less snow, impacting both water supply reliability and hydropower generation.
  • More variable precipitation and extreme weather events, such as floods and droughts -- the latter resulting in more energy-intensive groundwater pumping.
  • Higher water temperatures, possibly affecting listed fish species.

The climate change report is consistent with the recently-released California Water Plan Update, DWR officials said. That report recommends that state agencies work with researchers to monitor, predict and prepare for the effects of global climate change on water systems and the environment.

The report can be accessed at

This article originally appeared in the 07/01/2006 issue of Environmental Protection.

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