Loma Alta Slough Wetlands Enhancement Project Underway

The City of Oceanside has begun an effort to restore the Loma Alta Slough, a coastal wetland at the mouth of Loma Alta Creek in South Oceanside. Construction started in May and is expected to continue through April 2027. The $6 million project is funded by grants from the U.S. Fish and Wildlife Service, the State Coastal Conservancy, the National Fish and Wildlife Foundation, and the Ocean Protection Council.

About the Loma Alta Slough

The slough is a seasonally tidal estuary at the end of the seven-mile-long Loma Alta Creek. It is a highly dynamic system, shifting between salt water and brackish water throughout the year as conditions change at the ocean inlet. The slough provides nesting and foraging habitat for sensitive species, including the Ridgway's Rail and the tidewater goby.

In Oceanside's early years, the slough was an expansive coastal salt marsh covering more than 40 acres. Over the past 50 years, development in the surrounding floodplain shrunk the wetland to about eight acres. Today the slough's perimeter is bordered by public use areas, private property, and critical city infrastructure, including the La Salina Wastewater Treatment Plant.

Why Restoration is Important

As the wetland decreased, it has experienced degraded water quality and chronic flooding of nearby properties. To address these ongoing impacts, the City began purchasing property around the slough to make this restoration project possible.

Project Details

The project will restore 5.8 acres of wetland and upland habitat through dredging and removal of fill, marsh plain grading and channelization, restoration planting, and long-term biological monitoring. New floodplains and marsh channels are being excavated north of the slough to create additional wetland habitat with improved drainage and planting areas.

Expanding the slough is expected to increase habitat size and function, improve water quality, reduce flooding, and accommodate the wetland's natural upward migration over time.

New Public Access

A new 1,050-foot pedestrian nature trail with ecological signage will run along the slough's northern boundary. The trail will eventually connect South Coast Highway with the Pacific Ocean at Buccaneer Beach, giving the community a new way to experience the wetland up close.

Looking Ahead

By reconnecting historic floodplains within an urbanized watershed, the Loma Alta Slough Wetlands Enhancement Project aims to protect wildlife and city infrastructure for generations to come. The City expects the project to serve as a regional model for restoring urban wetlands.