A massive proposal to build new plumbing in the Sacramento-San Joaquin Delta, California's most important water supply, began trickling out Thursday as state officials released hundreds of pages of draft planning documents.

Known as the Bay Delta Conservation Plan, the documents lay out the first gritty details of Gov. Jerry Brown's proposal to improve water delivery across the state.

The centerpiece is a $14 billion pair of giant tunnels, 40 feet in diameter and 35 miles long, that would divert a portion of the Sacramento River's flow out of the Delta and directly to existing water export canals near Tracy.

Among other things, the documents provide the first precise locations for three tunnel intakes along the Sacramento River – all between Clarksburg and Courtland in Sacramento County. Two of these intakes would stretch nearly a half-mile each along the river's edge.

The documents also describe in detail numerous other construction impacts which would, in large measure, occur in Sacramento County. As proposed, the project would take more than a decade to build and require new power lines, electrical substations, barge landings, tunneling shafts, staging areas and waste disposal areas.

In addition, the plan calls for restoring 145,000 acres of wildlife habitat – nearly one-fifth of the entire Delta – which is likely to disrupt many local farms.

The documents released Thursday are considered preliminary drafts. They preview formal documents expected in July, which state and federal wildlife officials will use to decide whether to approve the project. No public vote is required.

Mark Cowin, director of the California Department of Water Resources, said the preliminary documents are being released to give the public a chance to digest the complex plan.

"California has struggled with how to deal with the Delta for decades," said Cowin, whose agency oversees the Delta project. "This plan isn't about waging war. It's about resolving some of the most critical resource conflicts in California."

Water from the Delta serves 25 million Californians and 3 million acres of farmland from San Jose to San Diego. This water demand has contributed to the collapse of numerous fish species in the Delta, the largest estuary on the west coast of the Americas.

In total, the plan seeks to restore 57 imperiled native wildlife species, 11 of which are fish. Others include the Swainson's hawk and sandhill crane, birds that will benefit from specific types of habitat restoration.

"We're talking about a restoration potentially observable from space," said Chuck Bonham, director of the California Department of Fish and Wildlife.

The finished documents will constitute a habitat conservation plan that would guide Delta water diversions for 50 years. It is probably the largest such plan ever conceived in the nation. The intent is to manage the habitat and wildlife as a whole, rather than on a species-by-species basis.

Water users cheered the plan and said the broader approach is long overdue.

Dan Nelson, executive director of the San Luis & Delta-Mendota Water Authority, represents farmers working 1.2 million acres, half of it in Westlands Water District. He has been critical of pumping cutbacks to protect individual fish species such as the Delta smelt.

"California's water supply system is broken," Nelson said. "Science has shown us that a comprehensive plan is essential to meet the future needs of our cities, farms, and wetlands."

Others expressed deep concern about the local impacts. Bob Wright, an attorney at Friends of the River in Sacramento, said the project could "absolutely unhinge" the character of the region.

"They're not putting a dollar value on destroying the scenery of the area disrupted by these massive intakes," Wright said.

The conservation plan aims to do what has not been possible before: Find a complex balance between water demand and wildlife protection.

The tunnels, according to the plan, would serve this goal in two main ways: They would protect the freshwater supply from floods, earthquakes and rising sea level; and with modern fish screens in place, they would protect fish from being sucked to their deaths in the water diversion pumps.

The current diversion pumps, located in the South Delta near Tracy, do not have fish screens and kill millions of fish annually. Because of their location, they also reverse natural flow patterns, confusing fish and disrupting aquatic habitat.

Under Endangered Species Act rules, these problems have, as recently as January, resulted in unpredictable cuts in water diversions. Planners hope the new tunnel system would avoid these effects, resulting in more consistent water deliveries from year to year.

The tunnels and associated infrastructure would be funded by state bonds issued by DWR and repaid by water rate increases in the communities that receive the water. The funding details were not among the documents released Thursday but are expected later.

Crucial to the project's success is whether the tunnels would preserve enough natural outflow in the Sacramento River to avoid habitat disruptions, and to allow fish to safely migrate past the intakes.

At stake, among other things, is the health of Sacramento River chinook salmon runs. These fish spawn upstream, then migrate past the intake locations to grow into California's largest commercial salmon fishery in the ocean.

The plan anticipates between 4.8 million and 5.6 million acre-feet of water would be available annually for diversion to farms and cities.

How this volume of diversion would affect the environment near the new intakes is still unclear. Such questions will be explored in the next round of document releases, expected March 27.

Contact The Bee's Matt Weiser at (916) 321-1264. Follow him on Twitter @matt_weiser. Fresno Bee staff writer Mark Grossi contributed to this report.

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