Dredging begins this week at Agua Hedionda Lagoon for the first time in four years, work needed to keep water flowing to the Carlsbad desalination plant with the bonus of boosting sand on nearby beaches.
Workers set up a temporary dock Monday in the outer lagoon along Carlsbad Boulevard south of Tamarack Avenue. The dock will be used by a small tugboat and a barge with equipment to vacuum sand and pump it through a pipe in a watery slurry onto the shoreline from Pine Avenue to just north of Cannon Road.
The work will take place weekdays from 7 a.m. to 7 p.m. through late April, city officials said. The sidewalks along Carlsbad Boulevard will remain open. Crews will direct visitors around where replenishment is occurring on the beach.
“This year up to 400,000 cubic yards of sand will be placed on Carlsbad beaches,” according to a city news release. “The exact amount and placement depend on current and historical beach sizes, how people use each beach and the need to protect nearby rocky ocean habitats.”
The lagoon was last dredged in the winter of 2020-21, when about 300,000 cubic yards of sand were removed and piped onto the beach.
Removing sediment from the outer lagoon between the boulevard and the railroad bridge keeps it deep enough to provide water for the nearby Carlsbad desalination plant. The plant’s operator, Channelside Water Resources, is responsible for the work.
Before the desal plant went online in December 2015, the lagoon was dredged every few years since the 1950s to provide water for the San Diego Gas & Electric Co.’s Encina power plant. However, a new, more efficient power plant that doesn’t need seawater was completed in 2018, and the old power plant was demolished.
As a result of the dredging, Agua Hedionda is deeper than most of San Diego County’s other coastal lagoons, up to about 20 feet near the mouth. That allows it to host a number of commercial and recreational activities including the Hubbs SeaWorld fish hatchery, jet ski and paddleboard rentals, a small private marina and a YMCA water camp.
The Carlsbad Aquafarm grew shellfish, primarily oysters and mussels, in the outer lagoon near the power plant for 70 years before losing its lease last year with the property owner, NRG Energy.
Most of the county’s other coastal lagoons also have been dredged in recent decades, though less frequently, to preserve wetlands habitats and for other environmental reasons. None of the others allow boating or commercial activities.
Batiquitos Lagoon on the border of Carlsbad and Encinitas is expected to be dredged again in about one year. It was last cleaned out in 2019, when the sand was placed on South Ponto Beach.
