California lawmakers are expressing support for a lower-cost alternative to a proposed federal-state overhaul of the Sacramento-San Joaquin Delta.

The new plan -- written by environmentalists and backed by several regional water agencies -- offers a way to avoid a massive diversion from the delta of 4.7 million acre-feet per year to supply water for 25 million Californians.

The plan's backers say building a tunnel under the delta and imposing water-saving measures will cost $14 billion to $16 billion. That's cheaper, they say, than the state-federal plan, which is estimated at $14 billion for two 35-mile tunnels. That plan doesn't include restoration of habitat for fish and other species living in the delta, which could cost an additional $4 billion.

Lawmakers say they want officials to consider the smaller tunnel package when they release a draft analysis of the plan later this year. A more comprehensive plan than just the tunnels could allow less exporting from the delta, which is home to many threatened and endangered species that depend on river flows and habitat around the rivers.

"It's absolutely essential that it be seriously considered and become part of the environmental review," said Rep. John Garamendi (D-Calif.), who represents the delta region. "There has to be an adjustment in policy, because we're headed down a road that won't work."

Garamendi, who served as deputy secretary of the Interior Department under President Clinton, said he was hoping for a change no matter who replaces outgoing Interior Secretary Ken Salazar, who announced his resignation earlier this week. "There has to be an adjustment regardless of who the secretary is," he said. "A change in the secretary could lead to a change in policy or at least a change in process."

Water agencies in both Northern and Southern California have also signed onto the plan, asking government officials to consider it as they weigh alternatives for the delta. More details on the state and federal plan are expected later this winter, a spokesman for the California Natural Resources Department said. A draft environmental review on that plan is due out for public comment in the spring.

"Up to now, the [Bay Delta Conservation Plan, or BDCP] process has been strongly focused on advancing a large capacity conveyance which, along with the suite of associated conservation measures, will be burdened with large uncertainties and for which a solid business case has not yet been made," officials from water agencies in San Diego, San Francisco and other cities said in a letter Wednesday. The uncertainties, they said, include effects on endangered species and water quality, as well as costs to water users, "political controversy, and potentially lengthy litigation."

"The way water agencies plan is different from the way BDCP has planned," said Barry Nelson, a senior water policy analyst for the Natural Resources Defense Council. "That small facility would cost a lot less money. If you invest those savings strategically, maybe you can end up with a package that works dramatically better for everyone."

The environmentalists' plan would have one pipe drawing water from the Sacramento River into a tunnel capable of handling 3,000 cubic feet of water per second. Water users south of the delta would receive an average of 4 million to 4.3 million acre-feet per year, less than the state currently pumps and less than it is envisioning under the two-tunnel plan, which would have a total capacity of 9,000 cubic feet per second and three intake pipes (E&ENews PM, July 25, 2012).

The plan would make up for the reduced exports by spending $5 billion on water recycling and conservation, for about another million acre-feet of savings, and building a storage facility to hold up to 1 million acre-feet for dry years.

California officials said they were already planning to study most of the plan's individual components in their analysis of alternatives, which is due out in the spring. Interior Department officials did not respond to a request for comment.

"We appreciate the proposal put forward," said Natural Resources Department spokesman Richard Stapler. "Most parts of what's proposed will already will be looked at either in BDCP or as a broader discussion on integrated water management." Water storage, however, is outside the scope of the plan, he said.

Other lawmakers representing the delta region -- Democratic Reps. Doris Matsui, Jerry McNerney, George Miller and Mike Thompson -- said they support consideration of the alternative plan.

"I remain extremely concerned about the direction that the state is moving with the BDCP," Matsui said in a statement. "Since the beginning of the process, I have long advocated for an incremental approach that begins with a 3,000 cfs intake project, and believe that the recent proposal by the NRDC and others should be studied as one of the alternatives in the BDCP."

Representatives of Central Valley districts -- Republican Reps. Devin Nunes, Kevin McCarthy, Tom McClintock and Jeff Denham -- failed to return calls requesting comments on the plan.

Water managers in the Central Valley, however, objected to the plan, saying it doesn't ensure deliveries to farmers who depend on San Joaquin River water provided by the Interior-managed Central Valley Project.

"A big concern of ours is it seems to totally ignore agricultural water users' needs," said Ron Jacobsma, general manager of the Friant Water Authority, which draws about 1.2 million acre-feet per year from the Central Valley Project.

"It really seems to be focused on the environment and urban conservation, and some of the claims relative to water supplies that could be developed or saved through those conservation efforts don't evidence themselves as additional supplies necessarily to agriculture."