If the work doesn't start soon, officials have said, it will be sidelined for months by the breeding cycle of the endangered least Bell's vireo, which nests between March and September in the riverbed.

News of the delay came Friday as forecasters were warning that a series of rainstorms would pound Southern California this weekend.

In response, the city and the Army Corps of Engineers enacted an emergency response plan, positioning a crane at the river's College Avenue bridge to remove debris that could wash downstream.

Meanwhile, representatives from the city, the Corps, and the state Department of Fish and Game will meet next week to try to resolve any remaining issues on the clearing work, officials said.

"If we don't get an agreement worked out on Tuesday, there's a slim chance we'll be able to do any significant clearing this winter," said Ruth Villalobos, a planning division chief with the Corps.

"There may be some (clearing) for emergency reasons," she added, but any major work would have to wait until fall.

The city has battled to get the 7.2-mile riverbed cleared since 2000, when the Corps completed a system of flood control levees along the San Luis Rey and planted vegetation to meet state environmental laws. The growth of that vegetation has since choked the river, officials have said.

In the last year, the riverbed was the scene of a series of arson fires, and in October officials feared that a wildfire raging near Fallbrook could shoot down the brushy riverbed toward Oceanside.

The latest wrinkles in the clearing effort involve protecting the endangered steelhead trout and setting aside 63 acres of land to make up for habitat that will be destroyed when the riverbed is cleared.

Congressman Darryl Issa, who has been pushing for the river clearing since 2005, when he helped obtain federal funding for the project, wants the work done now, his chief of staff, Dale Neugebauer, said Friday.

Issa plans to speak with representatives from the three agencies Monday, Neugebauer said.

"Our goal continues to be to get the clearing done before the breeding season starts," he said. "It would be unacceptable to us not to have the clearing done because of some additional ... requirement by a state agency."

Kevin Hunting, deputy director of the state Department of Fish and Game, said it's not his agency that is holding the project up. He said the habitat requirement has been included in four draft permits that have been sent to the city since November.

"I see a clear path to getting this done," Hunting said, emphasizing that the department recognizes how important the clearing project is. "I'm not sure why others feel it can't happen."

Meanwhile, to deal with this weekend's storms, Riverside-based contractor Hal Hays will have a crane ready to remove any trees or other debris that might be swept downstream and caught on bridge piers, said Joe Arranaga, deputy public works director for the city.

More equipment will be mobilized and available if needed, he said.

City leaders said they're glad the emergency plan is in place, but are growing frustrated by the delays in the clearing work.

Councilman Rocky Chavez has put an update on the project on Wednesday's agenda. Once the clearing is done by the Army Corps, the city is expected to take over regular maintenance of the riverbed.

However on Friday, Councilman Jerry Kern said he's at the point where he'd like the city to develop a containment plan for floods or fire and wants the Army Corps of Engineers to refund $23 million the city paid for the levee project.

"Pay us back or deliver the 250-year flood control channel," said Kern. "No more of this fooling around."

Mayor Jim Wood and Councilman Jack Feller expressed similar sentiments.

"My issue is the safety of my citizens from fire and floods, but at some point I might just have to say we won't accept this contract," Wood said. Doing so, he said, would cut the state Department of Fish and Game out of the picture.

"It's kind of a pushy-shovey thing between the state and the feds," he said. "Somebody is going to have to give a little. The people of Oceanside have given more than anybody else."

Said Feller, "If we are not allowed to start this process, we very well could have multiple tragedies as far as flooding and bridges collapsing all the way down the line. I blame the agencies for unrealistic, unreasonable restrictions."

Contact staff writer Marga Kellogg at (760) 901-4067 or mkellogg@nctimes.com