WARMING POSING DILEMMA SANTA CLARITA VALLEY WATER MAY BE AFFECTED IN FUTURE.

Byline: ALEX DOBUZINSKIS Staff Writer

SANTA CLARITA -- The Sacramento-San Joaquin River delta is more than 300 miles away.

Global warming is a phenomenon scientists are trying to decipher.

But for residents of the Santa Clarita Valley, the effects of the little-understood global warming phenomenon on the distant delta could determine their water supply and the area's potential for growth.

Scientists predict that as ocean levels rise because of global warming, salt water could intrude on the delta. That would hurt Santa Clarita and other areas reliant on fresh water that passes through the delta.

To slow global warming, Gov. Arnold Schwarzenegger this week signed legislation to put a 25 percent dent in greenhouse gas emissions by 2020, using a mix of caps and market mechanisms.

In the coming years, scientists will study the success of the legislation in slowing global warming's effects on the state's water supply, including the decreasing Sierra Nevada snowpacks that feed the delta.

And local water providers, such as the Castaic Lake Water Agency, will look to the state to take a leadership role in handling global warming.

``The state needs to continue doing its job in determining (first) what the impacts of global warming will be for supply, and second taking ... necessary actions to minimize the impacts of global warming on our supply,'' said Dan Masnada, general manager of the water agency, which manages state water piped to Santa Clarita.

One thing is not in doubt: Officials and scientists agree global warming is occurring. Most agree that global warming is a result of human-caused carbon dioxide emissions. The question is, how fast is it occurring.

``It's one of the uncertainties about climate change, is how fast (temperature is) going to go up,'' said Peter Gleick, president of the Oakland-based Pacific Institute for Studies in Development, Environment and Security. ``The faster climate changes, the worse things are for California.''

Two-thirds of the state's population lives in Southern California, and much of the water to supply that population comes from the wetter regions of Northern California.

Santa Clarita gets half its water from the State Water Project, a system that supplies water to farmers and some municipalities via aqueducts. The system relies on water flowing from the Sierra Nevada and surrounding highlands into the Sacramento-San Joaquin River Delta.

Scientists have offered a range of predictions for the possible effects of global warming on the Water Project. A Department of Water Resources report has predicted that water conveyed from south of the delta could actually increase by 1 percent if the climate gets wetter -- or it could decrease by 10 percent if things get drier.

``We could get an increase; (it) might not be a problem,'' said Roos Maury, chief hydrologist in the division of flood management for the Department of Water Resources. ``But I'm not really betting that we're going to get a wetter climate when it's warmer.''

Maury predicts that if temperatures increase by 3 degrees Celsius because of global warming, a third of the Sierra Nevada snowpack would be lost.

While the amount of precipitation might stay the same, water could run off from the mountains earlier in the winter. Much of that water could be lost, since the threat of flooding prevents agencies from storing too much runoff water in reservoirs, experts said.

Because of saltwater intrusion, officials have considered building a canal that would move water around the edge of the delta. But that would cost money, and agencies such as the Castaic Lake Water Agency could be called on to chip in.

Recognizing the threat of global warming, Schwarzenegger and other state officials have taken a measure at odds with federal policy on global warming by moving to reduce harmful emissions. Schwarzenegger signed Assembly Bill 32, the California Global Warming Solutions Act, in two highly public ceremonies Wednesday, and British Prime Minister Tony Blair joined in via satellite to mark the occasion.

``We will lead in the world, and countries like India, China, and Brazil and Mexico will see that we are doing a great job with this, and they will get inspired and they will join us,'' Schwarzenegger said. ``And I think that eventually, also, the federal government may join us and will join us. I'm absolutely convinced of that.''

Under its agreement with the state, Santa Clarita can expect to get about 73,000 acre-feet of water annually from the Water Project. Now, it uses 40,000 acre-feet a year, Masnada said.

But the region is growing rapidly, which means higher demands on the State Water Project. Eventually, the Santa Clarita Valley will hit a point where a lack of water will prevent its growth, Masnada said.

``Global warming is one of a number of things that ultimately impacts when that point in time comes,'' he said.

But the Castaic Lake Water Agency isn't making predictions about global warming, Masnada said. It will look to the state for those numbers, and some of the answers.

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