Annual Inlet Excavation



Reconnecting San Elijo Lagoon with the Pacific Ocean 

Work is underway for the annual San Elijo Lagoon Inlet Excavation at the mouth of the lagoon.

The Conservancy's Camino del Norte stream gauge measured 16.5 inches of rain during this year's wet season (October to present). Due to the heavy rains there is less sand to remove from the inlet compared to more typical years. This year's total sand removal will be approximately 20,000 cubic yards, or an amount that would fill about 50 dump truckloads. Sand will be deposted south of the inlet.

THE WAY IT WAS

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.

A MODIFIED LAGOON

It has been decades since San Elijo Lagoon was naturally connected to the Pacific Ocean. Coastal development occurred at a rapid pace after the 1880s. The first bridge and berm crossing the lagoon was constructed by the railroad in 1881, 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 freshwater 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 becomes blocked by an accumulation of sand in the tidal channel. As temperatures rise in the spring, the demand for oxygen increases. Withhout the circulation provided by the ebb and flow of the tides, the entire lagoon can become stagnant. The lagoon inlet, rarely, if ever, opens naturally.

WHY WE EXCAVATE

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:

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

 

SAND EXCAVATION
OCCURS: May 15-19, 2017

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:

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