Delta smelt

[CN] – Citing the need to protect dwindling salmon populations, California drought regulators are mulling large-scale changes that would divert water meant for farmers and water suppliers to the state’s besieged Sacramento-San Joaquin River Delta.

The California State Water Resources Control Board issued a new report Wednesday that recommends keeping more water in the Sacramento River for most of the year to help flush out and improve the water quality of the vital delta, California’s most important water source.

The struggling delta is the largest freshwater estuary on the West Coast, providing more than 25 million Californians with drinking water and irrigation to a host of Central Valley farmers. With California dealing with a sixth year of drought, major changes to the delta’s management plan would likely signal sweeping cuts to farmers and water suppliers.

Regulators said unimpaired Sacramento River flows should be increased to between 35 and 75 percent during certain stretches of the year to support salmon and the 3-inch delta smelt.

The water board acknowledged that while the report is based on the best science available, flow-related studies are still evolving.

“While perfect science is not available and exact mechanisms behind flow-related functions are not fully understood, there is a significant and compelling amount of information supporting the need for additional flow and related measures to protect fish and wildlife beneficial uses in the Bay-Delta, one of the most widely studied estuaries in the world,” the 388-page report states.

Last month, the board released a report recommending that more water be kept in the San Joaquin River as well. The Sacramento and San Joaquin rivers drain into the delta before finally reaching the San Francisco Bay.

The delta acts a massive water savings account where the state’s largest rivers accumulate before having their supplies divvied up and transferred to millions of Central Valley farmers and Southern Californians through a series of pumps, canals and aqueducts.

Scientists and environmentalists argue the critical water source has been abused and mismanaged, leaving warm and low-quality water for fish migrating from the San Francisco Bay back into the state’s river systems. The delta argument has intensified in recent years because of the state’s historic drought, which has already left farmers and cities with less water.

Wednesday’s announcement also figures to impact the state’s largest-ever proposed public waterworks plan, the California WaterFix, which calls for 30-mile-long twin tunnels underneath the delta at an estimated cost of $15 billion.

Gov. Jerry Brown’s contentious plan to divert water from the delta has been bashed by environmentalists and delta communities who say the tunnels will further damage the lifeline of California’s water supply.

The twin tunnels project – a major focus of Brown’s fourth and final term as governor — is based off current delta flows and would likely need a overhaul if regulators demand more water be kept in the delta.

The water board says the report is a working draft and that the final draft will be reviewed by an independent science board. An environmental review is also planned and will be developed as the water quality plan progresses.

A public workshop is scheduled for Dec. 7 and public comments can be submitted until Dec. 16.