A draft plan to restore endangered habitat and fish species in the California Bay Delta east of San Francisco is incomplete and contains major scientific gaps, according to a new report out today from the National Academies' National Research Council (NRC). The plan was released last November, and the review was ordered by the secretaries for the U.S. departments of the Interior and Commerce.
The Delta is the hub of California's freshwater system, draining runoff from the northern Sierra through the Sacramento and San Joaquin rivers into an estuary and out through the San Francisco Bay. Water diverted by pumping stations at the southern end of the Delta provides drinking water to about 25 million people, as well as irrigation water to farmers in the Central Valley, one of the most productive set of agricultural lands in the world.
But virtually all agree that the current system is unsustainable.
Water diversions and habitat loss have driven numerous fish species in the delta to the brink of extinction. At the same time water demand is increasing, residents continue to move into the region, and new challenges such as climate change and sea level rise are expected to further degrade habitat and water quality. To make matters downright scary, a major earthquake along one of the fault lines that crisscross the region could wipe out freshwater supplies to millions of people.
Fixing these problems, however, has run afoul of conflicting interests held by numerous entrenched groups. In hopes of getting around these barriers, members from many of these groups—including federal and state fisheries and wildlife agencies, water supply managers, irrigation districts, and environmental groups—came together in 2006 and began hammering out the Bay Delta Conservation Plan (BDCP).
A centerpiece of the plan, to be implemented over 50 years, is a 65 km long tunnel designed to ferry water from the Sacramento River north of the delta around the estuary to farmers in the Central Valley and cities in southern California. Diverting the water before it entered the delta would end the practice of sucking massive volumes of water out from the southern delta, which often harms fish and distorts the region's ecosystem. The final BDCP is intended to provide the scientific underpinning needed to gain authorizations under federal and state endangered species laws to build the water diversion tunnel.
However, the NRC panel has found it lacking. "The BDCP is incomplete, and there are large gaps in the underlying science," says Henry Vaux Jr. an emeritus resource economist at the University of California, Berkeley, who chaired the NRC panel. Most notably, the plan lacks an "effects analysis," a systematic scientific look at how the tunnel and other provisions in the plan will affect fish and other species in the region.
Vaux notes that this effects analysis is now underway. But the plan suffers other problems as well. For one, it's not clear whether the aim is simply basic habitat restoration or also providing a more stable freshwater supply for farmers and municipalities. If the latter, the panel concluded, it would make more sense do the effects analysis first and use the results to pick the best alternative for moving water through or around the Delta.
Another problem is that the science in the report is fragmented. "Because the science is not well integrated, we are getting less out of the science than we could," Vaux says. Finally, Vaux adds, the authors of the plan don't state how much water they plan to channel through the tunnel. "That makes it very hard to evaluate it scientifically," Vaux says.
Vaux says that he's hopeful that these components can be added as the CBDP evolves. So despite taking years and costing nearly $150 million, the BDCP apparently has a long way to go before its scheduled completion in 2013.