Clogged channel on city property blamed for repeated flooding of major east-west freeway
Carlsbad declared a storm-related emergency last week to expedite cleaning sediment and debris from the Buena Vista Creek channel, a problem that for years has contributed to the flooding of state Route 78 at El Camino Real.
The clogged storm channel on Carlsbad city property takes water from the freeway, where Caltrans spent millions of dollars last year on unrelated work to resurface the road, replace underground culverts, update signage and complete other improvements.
“The problem is with eastbound lanes (of Route 78) from El Camino Real,” said Steve Welborn, a public information officer for Caltrans.
“That area gets flooded when the Buena Vista Creek gets inundated,” Welborn said. “The channel is built up with sediment and vegetation, and that brings water into our (freeway).”
Carlsbad City Manager Scott Chadwick declared the emergency Thursday, and the expected ratification of his declaration is on the consent calendar for the Carlsbad City Council’s meeting Tuesday. Approval of the declaration will help the city obtain permits and grant money for the work, estimated to cost $771,000.
“It’s been a conversation that’s been going on for a few years,” Welborn said. “There’s not a lot we can do about it as a state agency, because it’s not in our jurisdiction, but we want to help them any way we can.”
The segment of Route 78 between El Camino Real and College Boulevard has shut down multiple times this winter for several hours or longer until water drains from the roadway, most recently on Feb. 5.
“The current atmospheric river and the prior one in January 2024 have increased sediment and vegetation in the Buena Vista Creek, diminishing its capacity and risking significant damage to nearby property and infrastructure,” Chadwick said in a report submitted to the Carlsbad City Council.
“Emergency removal of sediment and vegetation is necessary to ameliorate the risk,” Chadwick said.
Carlsbad hasn’t determined when the work will start or how long it will take, Transportation Director Tom Frank said Friday.
“We are currently in the process of procuring a contract and coordinating with various public agencies to determine the scope of the work,” Frank said. “We won’t know the duration until we get a contractor on board and finalize the work plan.”
Caltrans conducted extensive work on Route 78 last year as part of a $22 million “rehabilitation plan” for the entire system of culverts between Interstates 5 and 15. Nine of 16 culverts beneath the highway east of El Camino Real were replaced, some up to 240 feet long and as deep as 60 feet. Some were 70 years old.
The Buena Vista Creek drains a watershed that includes parts of Carlsbad, Oceanside, Vista and San Marcos into the Buena Vista Lagoon. Much of the concrete-lined lower creek and the lagoon are filled with silt and weeds.
Carlsbad has a capital improvement project now in the environmental review stages to remove the sediment and vegetation and make other repairs to its part of the creek channel, according to the city’s report. The recent severe storms have added urgency by creating debris flows, or a “sediment-dominated slurry ... during short-duration, high-intensity rainfall.”
The work will require a permit from the U.S. Army Corps of Engineers, despite the emergency declaration, and reviews by the state Department of Fish and Wildlife, the Regional Water Quality Control Board and other agencies.
The San Diego Association of Governments in 2020 approved a plan to excavate sediment from the Buena Vista Lagoon and rework its channel as part of its proposed restoration.
The lagoon project could be shovel-ready in another year or two, but so far no money has been allocated for construction, estimated in 2019 to be more than $80 million.