Castaic Lake Water Agency officials are hailing a Gov. Jerry Brown-backed plan that they liken to “heart surgery” for the future of the Santa Clarita Valley’s water supply, an official said Monday.

The state’s Natural Resource Agency recently released several chapters of the plan, which state officials are calling a major milestone in the seven-year effort to restore the Sacramento-San Joaquin Delta ecosystem and provide a reliable water supply for two-thirds of California’s population.

“It has two co-equal goals,” said CLWA General Manager Dan Masnada, referring to the Bay Delta Conservation Plan. “One is to enhance water-supply reliability, and the other is to provide environmental benefits and protections.”

Some local environmentalists question whether the documents being released reflect a thorough investigation of environmental impacts, suggesting that they may be intended at promoting the necessity of an underground.

The draft chapters made public last week described the anticipated ecological effects and proposed governance structure of the BDCP.

The 50-year plan seeks the recovery of native fish and wildlife species in the Sacramento-San Joaquin River Delta while also stabilizing water deliveries for 25 million Californians and 3 million acres of farmland, according to the BDCP website.

On top of attaining positive goals, the plan would have numerous necessary benefits for the Santa Clarita Valley, Masnada said.

“One is enhanced reliability of supply,” he said. “Right now, this reliability is dictated by Delta operations,” he said, noting that in drought years, which are frequent in SoCal, the need to protect certain species affects water supply and pumping operations.

There’s also always a potential for a disaster that could significantly disrupt our supply, a risk that geologists and seismologists have calculated, he said.

“The experts have determined that theres 2-in-3 chance a catastrophic earth will occur within the vicinity of the delta that could result in levy failure,” Masnada said.

“The other benefit, which is probably as important is the water-quality benefit — if the BDCP were constructed today, we wouldnt have to be talking about the chloride problem,” Masnada said. “The (chloride level) goes from about 60-80 (milligrams per liter of cholride) to about 10 (milligrams per liter).”

The state’s Regional Water Quality Control Board recently fined local government officials more than $200,000 for failing to meet a deadline on building a plant that would reduce local chloride levels for Santa Clarita Valley effluence.

The maximum level is 118 m/g per liter, which many feel is unfair because currently the SCV’s State Water Project supply comes in at more than half that.

Officials with the Santa Clarita Organization for Planning and the Environment have expressed concern with the amount of water that would need to be drawn from the delta if the tunnels were built.

“The environmental community is generally concerned about the bay delta plan because many feel it’s written in a way that the end result of the environmental study would be that we need the tunnels,” said Lynne Plambeck, president of SCOPE.

“They’re pretty extensive. The estimated costs with the interest in in the bond is somewhere around $50 billion,” she said.

“Well (the BDCP) certainly isn’t cheap,” Masnada said. “But it’s not a ‘boondoggle,’” he said, acknowledging opposition that has been critical of the plan’s cost.

“At the beginning of the Brown administration, we made a long-term commitment to let science drive the Bay Delta Conservation Plan,” said California Secretary for Natural Resources John Laird.

“With the public unveiling of the effects analysis, we make that a reality. Science has, and will continue to drive, a holistic resolution securing our water supply and substantially restoring the Delta’s lost habitat,” according to a Natural Resource Agency statement.

The BDCP has been substantially modified since an earlier draft of the plan was released in February 2012.

In July, Governor Brown, joined by Secretary of the Interior Ken Salazar, announced revisions to the plan, including a reduction from five to three intakes along the Sacramento River and a 40 percent reduction in the capacity of the proposed intakes and conveyance facility, from 15,000 cfs to 9,000 cfs.

Those revisions have led to significant changes in Chapter 5, “Effects Analysis.” The chapter is a core element of the BDCP. It represents a systematic, scientific evaluation of the potential beneficial, adverse and net effects of the BDCP.

This analysis, based upon literature review and 68 different scientific models, is intended to provide federal and state fish and wildlife agencies the information they need to decide whether and on what terms to issue permits and authorizations for the BDCP.