Annual Inlet Excavation

Reconnecting San Elijo Lagoon with the Pacific Ocean 

Because of North County's transportation corridors across the lagoon, one 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. 


When early settlers arrived, only beach and dunes separated the lagoon from the ocean. The inlet was open most of the year, sometimes closing during the late summer, but opening again with the combined force of winter rains and surf. The inlet migrated between north and south according to the prevailing forces of the season.


It has been decades since San Elijo Lagoon was naturally connected to the Pacific Ocean. Human modifications to hydrology occurred at a rapid pace after the 1880s. The first bridge and berm crossing the lagoon was constructed by the railroad in 1887, followed by Pacific Coast Highway in 1891 and, in 1965, Interstate 5, which divided the wetland in half.

This "partitioning" of the lagoon created altered flows for both fresh and saltwater, leading to accelerated sediment deposition, dramatically-reduced water quality, and a reduction in native estuarine habitats due to increased runoff from development upstream. During the winter storm cycles the inlet often became blocked by an accumulation of sand in the tidal channel. As temperatures rose in the spring, the demand for oxygen increased, and, without the circulation provided by the ebb and flow of the tides, the entire lagoon became stagnant, smelly and mosquito-ridden. The lagoon inlet, rarely, if ever, opens naturally.


In 2001, a long-term financial endowment was established for the Conservancy to actively fund maintenance of tidal flushing. Efforts to keep the lagoon open to tidal circulation have shown that significant ecological benefits result from increased tidal flushing, as evidenced by:

But, left unattended, the inlet could again close from buildup of sand transported by high incoming tides, surf, and storm surges.







June 8-16, 2016

Inlet Photomonitoring Slideshow






View Slideshow

See daily photomonitoring, August 2012 - September 2013 (inlet excavation occured June 2013) of San Elijo Lagoon's only channel to the Pacific Ocean. The inlet is restricted by a railroad and highways. Watch the slow accumulation of sand and cobble that becomes trapped in this passage, thereby restricting water flow.

Improved Tidal Circulation is Funded By:

County of San Diego Department of Environmental Health:

Doug Gibson, Executive Director | Principal Scientist
(760) 436-3944 x 707
doug [at] sanelijo [dot] org