California regulators have released a plan to change how the state governs the pumping of water from the Sacramento-San Joaquin River Delta, a proposal that would give water agencies more leeway in how they comply with the rules.

The Delta is the central hub of California’s water system, providing water for nearly 30 million people and 4 million acres of farmland. As the state has relied heavily on its water, the Delta’s ecosystem has suffered, and native fish populations have declined.

“We believe we need a new approach,” said Eric Oppenheimer, executive director of the State Water Resources Control Board. “We need a plan that balances ecosystem needs and human water demands.”

The draft Bay-Delta plan, which the board released Wednesday, takes “an innovative approach that pairs voluntary actions with a strong regulatory backstop” to protect the Sacramento River and the Delta, as well as San Francisco Bay, Oppenheimer said.

The plan, which is similar to a previous draft released in December, is controversial. Environmental advocates say it would starve the Delta of needed water and threaten fish that are already in severe decline.

If the plan is adopted in October by the State Water Resources Control Board, it would give water agencies two ways of complying with Delta water quality rules. They could either limit pumping to maintain required minimum levels of water in rivers and the estuary, as has traditionally been done, or take part in “voluntary agreements,” in which water agencies commit to ensuring certain river flows for the environment while contributing funds for projects that restore habitat for fish and other wildlife in the Delta.

This approach, which state officials call the Healthy Rivers and Landscapes program, is endorsed by Gov. Gavin Newsom and has strong support among water agencies that serve farms and cities.

It’s a “collaborative, modern and holistic approach” that will effectively protect and restore the Bay-Delta ecosystem, said Stephen Pang, state relations advocate for the Assn. of California Water Agencies, which represents about 470 public agencies.

Participating agencies have agreed to begin a collaborative effort to restore wetlands and a science program to guide the endeavor. State officials say agencies have committed $2.9 billion under the program, much of which will go toward restoring aquatic habitat for fish in the Delta.

Gary Bobker, program director of the environmental group Friends of the River, said this approach, however, would let big water suppliers “write their own ticket” and take too much water out of the Delta.

“It’s a plan that is doomed to fail,” Bobker said.

He and other environmental advocates say the voluntary deals struck by major water agencies would be disastrous for threatened and endangered fish, including salmon, steelhead, green sturgeon, longfin smelt and Delta smelt. They have called for more stringent flow requirements to help fish recover.

Bobker said it’s not a surprise that most major water agencies are rallying around these voluntary deals because it lets them continue largely “business-as-usual” operations while the ecosystem continues to deteriorate.

“We are starving the Bay-Delta estuary now, and we know that that needs to change if we actually want to preserve that ecosystem and all the benefits it provides,” he said. “The board is abdicating its responsibility.”

State officials say if the more collaborative approach falters and a water agency fails to meet commitments, they still have the option of putting them back under the traditional regulations.

“We think it creates a great degree of buy-in from public water agencies,” Oppenheimer said.

The update of the Bay-Delta plan has been years in the making.

The last substantial changes to the plan date to 1995 for much of the watershed. In 2018, the state water board released new rules intended to increase flows in the San Joaquin River.

The update will set rules for the Sacramento River and the rest of the Delta, where pumps operated by state and federal agencies send water flowing in aqueducts to farms and cities.

The state water board is accepting comments on the plan until Sept. 18 and will consider whether to adopt the plan at a hearing Oct. 28-29.