USA: Dredging Kicks Off at San Elijo Lagoon

With the passing of winter’s strongest storm surges, it’s time for spring cleaning at San Elijo Lagoon’s ocean passage.

From May 13 to May 17, earthmovers will be seen at the Cardiff State Beach lagoon inlet to reconnect San Elijo Lagoon to its Pacific headwaters.

San Elijo Lagoon Conservancy (SELC) is the organization overseeing the process.

“Water movement is essential for preventing depletion of oxygen, thus maintaining water quality and the overall health of the entire reserve,” said Doug Gibson, Executive Director and Principal Scientist at SELC.

“The lagoon’s inlet and channel appears open, but is 80% blocked, and maintenance is necessary to improve tidal circulation to achieve optimum conditions.”

Inlet excavation involves the laborious task of moving approximately 25,000 cubic yards of sand out of the lagoon inlet, and back on to the beach.

Grunion spawning will not be affected as the dredging operation is timed not to coincide with this biological event.

This small opening, just south of San Elijo State Beach Campground, is the lagoon’s only access to the Pacific Ocean. Keeping the inlet open to the ocean is critical to maintaining the health of San Elijo Lagoon and the coastal water quality.

The inlet becomes intermittently blocked by an accumulation of sand in the tidal channel during winter storm cycles.

The cool weather helps keep oxygen levels in the lagoon in the safe zone.

As temperatures rise in the spring and the demand for oxygen increases, an inlet operation is conducted.

Typically, the sand berm that forms west of Pacific Coast Highway 101 is breached by excavation equipment.

Larger dredging operations remove sand accumulations east of Highway 101 and under the bridge.

Clean sand removed from the tidal channel is deposited south onto Cardiff State Beach.

Left unattended, the inlet would remain closed much of the year.

Efforts over the past decade have improved tidal circulation, with significant ecological and recreational benefits.

This delicate process is designed to prevent stagnation of the shallow-body ecosystem, which improves habitat for all plants and animals that reside in the lagoon.

Several fish populations depend on the lagoon as a nursery.

Without a constant connection to the ocean, future generations will not thrive.

This is a visual event, akin to watching giant “beach toys” sculpt the opening of the lagoon.

A major dredging operation to remove accumulated sand and cobbles can cost as much as $100,000.

This water quality enhancement work is conducted through the support of California Coastal Conservancy, U.S. Fish & Wildlife Service, County of San Diego, and conservancy membership.

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Press Release, May 14, 2013