Federal fishery agencies Monday pushed forward a controversial water project that would change the way Northern California supplies are sent to the Southland.

The U.S. Fish and Wildlife Service and the National Marine Fisheries Service concluded that the construction of new diversion points on the Sacramento River and two massive water tunnels would not jeopardize the existence of endangered species in the Sacramento-San Joaquin Delta, which is the hub of California’s waterworks.

The release of the documents marks a major — but by no means final — step in the long, twisting path of the proposal, which has been in the planning stages for more than a decade.

Called biological opinions, the reviews analyze the project’s likely effects on endangered and threatened species, including the vanishing delta smelt, winter-run Chinook salmon and Central Valley steelhead.


The analysis will shape operating rules for the diversions — and thus how much water the tunnels carry to the big delta pumps that supply San Joaquin Valley growers and Southland cities.

The agencies that depend on delta water will scrutinize every line of the opinions before they decide whether to fully commit to funding the project, which is expected to cost $17 billion.

The question for the Metropolitan Water District of Southern California, the Westlands Water District and others will be whether the tunnels stabilize their delta water deliveries enough to justify the cost.


If they decide it doesn’t and withdraw their support, the proposal will die. Though Monday’s news was good for them, their reactions were restricted to offering thanks that another planning milestone had been reached.

Even if the districts give thumbs up, the tunnels still need several state and federal permits before construction can begin. And opponents are expected to challenge approvals in court, which could stall the project for years.

“The science in this decision was cherry-picked and not representative of the true scope of harm to endangered species who depend on a healthy San Francisco Bay-Delta estuary for their survival,” said Barbara Barrigan-Parrilla, executive director of Restore the Delta, an anti-tunnel group. “We believe the court will overturn this.”

Delta growers vehemently oppose the tunnels, which would require years of disruptive construction in their backyards and would suck up good-quality fresh water before it reaches their irrigation ditches.


Environmentalists argue the tunnels will inevitably be used to send more water south, further depleting flows vital to the delta’s faltering ecosystem.

“The system today is not adequately protective and now we’re approving something that makes things worse. It’s a real head-scratcher,” said Doug Obegi, a staff attorney with the Natural Resources Defense Council, an environmental group that has successfully challenged previous biological opinions on delta water exports.

“It sure seems like politics is trumping science in the delta again,” he argued.

Dubbed the California WaterFix by the state, the proposal calls for construction of three new diversion points on the Sacramento River in the north delta, along with two massive underground tunnels that would carry water 35 miles to existing government pumping plants in the south delta.


The powerful pumps now draw entirely from the south delta, causing delta channels to flow backward and pulling imperiled native fish to their deaths. That triggers endangered species protections that limit pumping, cutting delta deliveries.

By reducing withdrawals from the south delta, the new diversion points would lessen the reverse flows and — backers hope — loosen the pumping restrictions.

In draft reviews, federal biologists were consistently skeptical of the proposal. They warned that taking large amounts of fresh water from the north delta would create a new set of problems for migrating Chinook salmon and delta smelt, a tiny fish that is found no place else in the world.

The Fish and Wildlife Service found that construction and operation of the river intakes and twin tunnels would destroy smelt habitat that will become increasingly important as climate change and sea- level rise alter delta conditions.


The National Marine Fisheries Service concluded that as far as winter-run Chinook salmon are concerned, the new diversion would change river flow patterns and temperatures for the worse, hurting overall survival of the endangered species.

In the final opinions released Monday, the agencies conceded that project construction and operation would adversely affect imperiled species — but not to the point of jeopardizing their existence or destroying critical habitat. The agencies also said planned habitat restoration programs would offset the tunnel impacts.

Officials also noted that a separate environmental review is now underway of State Water Project and federal Central Valley Project operations that will include the tunnels — and could result in further restrictions.

bettina.boxall@latimes.com


Twitter: @boxall

UPDATES:

4 p.m. This article was updated with more details and quotes from opponents.