The California Coastal Commission has approved two additional rounds of dredging for Carlsbad’s Agua Hedionda Lagoon, one to be completed this winter and another in the 2027-28 season. The outer basin of the lagoon just south of Tamarack Avenue has been dredged periodically since the mid-1950s, first to supply a reliable source of seawater for the Encina power plant, and now for the seawater desalination plant that operates at the lagoon’s edge. Sand dredged from the lagoon is used to widen three different sections of the nearby Carlsbad State Beach, from about Pine Avenue to below the southern edge of the lagoon near the end of Cannon Road. 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. This winter’s operation is expected to produce at least 400,000 cubic yards of material. The lagoon maintenance was first done by the owners of the power plant, which used the seawater for cooling. However, a new, more efficient power plant that went online Dec. 12, 2018, doesn’t need seawater, and the old plant was demolished. Now the lagoon is kept open for the desalination facility, and it’s owners are responsible for the maintenance dredging. The two dredge cycles were approved Thursday without comment as part of the Coastal Commission’s consent calendar. Along with the desalination plant, several other commercial, recreational and environmental preservation activities benefit from keeping the lagoon open. One is the Hubbs SeaWorld Research Institute’s fish hatchery that has raised white seabass on the edge of the lagoon’s outer basin, between Carlsbad Boulevard and the railroad trestle, since the 1980s. The fish are released into the ocean to supplement the stock taken by commercial fishermen. And until this year, the Carlsbad Aquafarm grew shellfish, primarily oysters and mussels, for 70 years before losing its lease with the property owner, NRG Energy. The North Coast YMCA operates a water park with kayaking, paddleboards and other activities in the lagoon’s middle basin, between the railroad trestle and Interstate 5. And the inner basin has a private business, California Watersports, that rents personal watercraft, kayaks and other aquatics gear.