Delta Water report offers estimate, misses real effect

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San Francisco Chronicle

Laura King Moon

Wednesday, August 18, 2010

The State Water Board's recent report suggesting that much of Northern California's water supply should be redirected to benefit fish underscores the importance of addressing the ecological crisis in the Sacramento-San Joaquin River Delta. But as the State Water Board itself cautioned, this report does not explain how to restore the delta ecosystem while meeting human water needs, nor how much water fish need if other factors affecting the ecosystem are addressed.

Today's delta is nothing like that before the Gold Rush. Levees have eliminated 95 percent of the estuary's original wetlands. Non-native species now comprise 95 percent of the delta's living plants and species. Food supplies for fish are a fraction of those in other estuaries because of rock-walled levees and the lack of suitable habitat. Pushing more water through the barren delta channels will not make for a better ecosystem.

When the State Water Board released this non-binding report to consider new flow criteria for fish, it cautioned against misuse of the information because of the limited focus of the analysis. The report explicitly does not consider, for example, the competing needs of different types of fish, such as how depleting reservoirs upstream of the delta could endanger salmon in the rivers during dry years.

The report also does not address how flow needs would be affected by pollution reduction or creation of new marsh and floodplain habitat. Because scientists don't know exactly how much water is needed to restore fish populations, the report uses a simplistic assumption that flows should be restored to patterns that existed in the 1920s, and does not consider how restoring flows to this level would affect 25 million Californians and millions of acres of agriculture that rely on supplies from the watershed.

The draft report provided estimates of the water supply impacts in an appendix, showing that water users up and down the state would have their current supplies reduced by as much as 67 percent. The final report does not include the appendix, and more careful analysis is needed. But our preliminary analysis suggests tremendous hardship for many water districts throughout the state, including the Bay Area, where more than 70 percent of supplies comes from somewhere in the Sacramento-San Joaquin Delta watershed.

The delta needs a more thorough and balanced solution, based on hard facts about real-world impacts and the best available science. Necessary elements will include more habitat, less pollution and a better water-conveyance system that can separate the movement of water supplies from the natural movements of the tidal estuary. Water districts, environmentalists and federal and state agencies are seeking such a balanced approach through the Bay Delta Conservation Plan. Within this comprehensive plan, flows represent one important piece of a much larger challenge to put the delta on a path to sustainability.

Laura King Moon is the assistant general manager of the State Water Contractors.

This article appeared on page A - 8 of the San Francisco Chronicle
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