Proposed Delta mega tunnel needs more review

May 2012, Vol. 67 No. 5

State and federal agencies are proposing a giant canal or tunnel to divert a portion of California’s Sacramento River flow out of the San Joaquin Delta, carrying the water directly to export pumps already running near Tracy.

It’s believed that diverting the water from farther north than Tracy would both restore a natural salinity balance to the estuary and protect the diverted water from floods and earthquakes.

But it remains unclear whether a more northerly diversion point is safer for fish, and Delta residents fear the project will damage the region's farm economy.

Estimated to cost about $13 billion, the project is key to the proposed Bay Delta Conservation Plan. The plan remains unfunded and far from approval.
And according to an independent report from the National Research Council, paid by the U.S. Department of the Interior, recent efforts have been ineffective in meeting goals because management is distributed among many agencies and organizations, which hinders development and implementation of an integrated, comprehensive plan.

The plan calls for twin 33-foot-diameter tunnels that would carry a portion of the Sacramento River's flow deep under the Delta on a 37-mile path underground to the present head of the California Aqueduct, near Tracy.

Pumps that now serve that aqueduct and its nearby federal counterpart kill millions of fish every year and are blamed for altering the habitat of the estuary itself, once among the world's most productive fisheries.

The tunnel project is intended to move the intakes upstream, to locations presumed to be less harmful to fish and their habitat. It would also secure the freshwater diversions from threats such as earthquakes, floods and sea level rise, ensuring that the 25 million Californians who depend upon that water do not go without.

The tunnel is the centerpiece of the Bay Delta Conservation Plan, an effort to balance water demand and wildlife protection. After three years of often-contentious meetings and innumerable studies, a draft environmental impact report is anticipated later this year.

California’s Department of Water Resources is expected to make a formal decision in 2013 on whether to proceed. It would be subject to approval by state and federal wildlife agencies.