A peripheral canal to carry water around the Sacramento-San Jaoquin Delta is the best potential strategy to revive a threatened ecosystem and maintain quality water for Californians, according to a report released today by the Public Policy Institute of California.
Currently, water is drawn from the Sacramento River and funneled south through the Delta to pumps that deliver water to people throughout the state. This method disrupts natural water flow, threatens native fish (five of which are listed as threatened or endangered), among other problems, according to the report.
Recently, court rulings have restricted water exports from the Delta because of this. And earlier this month officials said the Delta smelt could join the endangered species list.
The report concluded that because of sea level rise, land subsidence, changing runoff patterns and earthquakes, "change is inevitable for the Delta" and that the current policy was "risky and unsustainable."
Delta water levels are expected to increase by one to three feet, perhaps more, over the coming century. Without large investments to raise Delta levees, this rise in sea level will cause many levees to fail, pushing seawater into the Delta. Even if levees could be sustained, sea level rise will increase the salinity of Delta waters.
Researchers examined nine strategies for managing the Delta and considered their environmental, economic and water supply performance. The methods considered included continuing to pump exports through the Delta, diverting water upstream and conveying it around the Delta through a peripheral canal, combining the current pump-through-Delta policy with the peripheral canal (dual conveyance), or ending exports altogether.
The present strategy of responding to emergencies only as they happen puts California in the position of making Delta policy by default rather than by deliberate consideration of the best long-term alternatives.
The researchers concluded that the peripheral canal method was the most cost efficient as well as the most viable and sustainable method long-term, according to the report.
But they also qualified their conclusion.
Selecting an export strategy does not, in itself, solve the Delta's problems...many technical regulatory, financial, governance, and policy decisions must accompany the implementation of a long-term strategy. In particular, no matter which export strategy is selected, there will have to be investment in improvements of aquatic habitats within the Delta to increase the likelihood of fish recovery.