A California plan to bore two massive water tunnels under the fragile Sacramento-San Joaquin Delta hit a barrier this week when the US Environmental Protection Agency said the plan could violate the federal Clean Water Act and further degrade the delta's ecosystem.
The decision is the latest in a series of setbacks for the $25 billion (S$31.22 billion) water plan to divert water from the Sacramento River above the delta, sending it through massive underground tunnels to provide water for two-thirds of the state's population, from San Jose to San Diego, and to thousands of farms.
The tunnels would be part of the proposed Bay Delta Conservation Plan and would create roughly 150,000 acres (60,000 hectares) of wetlands to offset any environmental damage caused by the tunnels.
The EPA supports the project's goals of improving water reliability and restoring habitat, but it warned in a Tuesday letter made public on Thursday that diverting water around the delta could increase the amount of naturally occurring toxins, salts and pesticides in the estuary, threatening the ecosystem and people who draw delta water.
The agency's letter warned the proposal could "result in violations of Clean Water Act water quality standards." The EPA also expressed concern that the project could harm the delta's many threatened fish species, including the pinky-sized delta smelt, whose declining numbers often cause water cutbacks to farms in California's breadbasket.
Democratic state Senator Lois Wolk, who represents parts of the delta, said the EPA warning confirmed fears about damage to the ecosystem and community. "It is time to consider the many other options offered for delta restoration that do not include the tunnels," she said.
Proponents of the water project said the issues brought up by the EPA will be addressed in future drafts. "If they are accurate, there are a lot of ways to mitigate those damages," said Gerald Meral, former secretary of the California Natural Resources Agency, in charge of the Bay Delta Conservation Plan. "There isn't anything they've raised that's fatal to the project." Earlier this week, the Department of Water Resources said it would delay finalizing the 40,000-page draft of the water project. The state plans to release an updated draft by early next year.