California Delta Would Build Tunnels to Pump Water
Mar 02, 2012
FRESNO, Calif. California could soon build two giant tunnels to boost water deliveries to farms and cities and improve habitat for fish, according to documents released by the California Natural Resources Agency.
The Bay Delta Conservation Plan is a federal and state initiative financed by California's water contractors. Its goal is to restore and protect the Sacramento-San Joaquin Delta ecosystem and guarantee a stable water supply for millions of Californians.
The preliminary version of the 50-year plan released Wednesday calls for building two tunnels to divert water from the Sacramento River around the delta and keep water pumps away from fish. Documents show the tunnels would ferry about 5.9 million acre feet a year to the pumps - an increase from the current 4.7 million acre feet.
An acre-foot is enough water to cover one acre, one foot deep.
That proposal, said Karla Nemeth, program manager for the plan at the Resources Agency, is the maximum capacity being considered, but the project has not been finalized yet and its size could be reduced.
The plan also outlines the creation of nearly 120,000 acres of new habitat to mitigate the tunnels' impact and put dwindling fish species on a path to recovery. That includes about 80,000 acres of floodplains and tidal marshes for fish habitat and about 40,000 acres of native grasslands and other habitat for wildlife species.
The plan also looks at water flows, predators and other stress factors such as climate change.
"The plan demonstrates that the status quo in the delta is going to be pretty brutal for delta fisheries unless we do something," Nemeth said. "Temperature and increased salinity due to sea level rise will have a negative impact on fish, so additional habitat would help mitigate that."
The entire project would cost an estimated $25 billion, with construction of the conveyance project estimated at $13 billion.
Currently, federal management plans - the so-called biological opinions - limit the amount of water pumped from the delta in order to protect fish species.
While more water would be taken out of the delta by the new conveyance system, the BDCP project would actually help species, Nemeth said.
Building the tunnels would move the point of diversion, she said, so that the impact of artificial flow changes caused by the current water pumps on salmon, sturgeon and other species would be reduced and fewer fish would be caught and killed in the delta project pumps.
Documents show the project initially could harm some species but would benefit them in the long run, so officials are making adjustments to mitigate that, Nemeth said.
Officials say they hope to finalize the plan by the end of June, when it will be open to public comments. It still needs state and local approval before construction can begin.
The BDCP would eventually be included in the comprehensive management plan for the delta area. But in order to be included, the BDCP must be approved by state wildlife and water agencies and can't violate other laws meant to protect wildlife.