Residents want cattails removed from Buena Vista Lagoon

Residents near the Buena Vista Lagoon at the border of Oceanside and Carlsbad are asking state officials to speed up the planned removal of the thick layer of cattails that line the water’s edge.

The cattails harbor breeding spots for the mosquitoes that plague neighborhoods around the 220-acre lagoon in summer and fall. The thick vegetation also hinders the aerial spraying of larvicide, done twice a month from May through September, making it less effective.

“This is a huge public safety issue,” said Mayor Esther Sanchez, during a discussion of the issue at a recent meeting of the Buena Vista Lagoon Joint Powers Committee. Mosquitoes, beside being a biting nuisance, spread a number of diseases including West Nile virus, which kills several people each year in San Diego County.

Most, if not all, of the cattails eventually will be eliminated as part of the lagoon’s proposed restoration, which includes the removal of the weir or low dam at the mouth to allow tidal flushing. County officials signed off on plans for that project in May 2020 after nearly 20 years of negotiations between residents and the various agencies involved.

Still, additional planning in needed, and so far there’s no money for construction, estimated to cost $65 million. That means it will be at least several more years before the bulldozers arrive.

A view of cattails near the Buena Vista Audubon Nature Center on the Oceanside-Carlsbad border.

A view of cattails near the Buena Vista Audubon Nature Center on the Oceanside-Carlsbad border.

(Eduardo Contreras / The San Diego Union-Tribune)

In hopes of speeding up the cattail removal, the joint powers committee formed a subcommittee in March to look into faster ways to achieve that goal.

“Some members of the public are anxious to have the cattails removed immediately, and argue they will die off anyway, once the weir is removed,” said Oceanside City Planner Jeff Hunt. “However, the state Department of Fish & Wildlife has indicated the cattails provide habitat for wildlife species and some form of a plan is needed before the cattails can be removed.”

An endangered species of bird, the light-footed clapper rail, sometimes nests in the cattails and reeds of Buena Vista, which because of the weir is the only freshwater lagoon in San Diego County. The county’s other lagoons are open to the sea and contain saltwater.

Because of the presence of the clapper rail, the cattails may have to be removed in stages, Hunt said. How that would happen is one of the details to be worked out before the project can proceed.

Also, there’s no guarantee of money for a short-term fix, which could be expensive.

The removal of about 5 acres of cattails cost $500,000 recently at Talone Lake, said Tim Dillingham, a programs supervisor for the state Department of Fish and Wildlife. Despite its name, Talone Lake is an abandoned livestock pond near the Walmart shopping center at College Boulevard and Highway 76 in Oceanside.

“We need to find out how many acres we are talking about,” Dillingham said at the joint committee meeting. “It could be less per acre to do a larger area.”

Buena Vista Lagoon is the largest of almost 50 areas that San Diego County regularly treats with larvicide, including 10 in Oceanside and four in Carlsbad. Other locations include Libby Lake and Guajome Regional Park in Oceanside, Laguna Riviera City Park in Carlsbad, and the San Elijo Lagoon on the border of Encinitas and Solana Beach.

Thick vegetation such as the cattails prevents the granular larvicide, which is dropped from a helicopter, from reaching the water where it can be effective, Dillingham said. The larvicide contains natural bacteria that stops the development of mosquito larvae without harming people, pets, plants or other wildlife, according to a San Diego County fact sheet on the product.

Dillingham is working with county vector control employees to get more information on the cattail issue, he said.

“There’s a lot going on behind the scenes right now,” said Jim Petronella, a Carlsbad resident who represents the Buena Vista Lagoon Foundation on the cattail ad hoc committee.

Buena Vista Lagoon grows shallower and more reedy every year as storm water and irrigation runoff fill it with sand and silt. Without periodic excavation, it would eventually fill with sediment and turn into a meadow.

The last time the lagoon was dredged was in 1983, when the eastern end was scraped to remove unwanted sediment left by unusually large storms in the previous few years.

Historical records show that when Spanish explorers discovered the lagoon in 1769, it was a small valley with water that “flowed out of several springs” and collected in “stagnant pools, covered with rushes and grass.”

Property owners first installed flood control gates and pipes in 1940 to raise the water level and provide a year-round supply of water. The present-day weir was installed in the early 1970s after the previous structure washed out.