Topanga Lagoon Restoration Planning Phase 1

Location: Los Angeles County

Project Type: Restoration Planning

Status: Current

Cost: $664,810

Funding Gap: $460,000

Area Affected: 41 acres

Project Footprint: 1500 feet stream miles

Assembly District: 50

Senate District: 27

Congressional District: 33

Project Lead/Grantee:
Resource Conservation District of the Santa Monica Mountains, Rosi Dagit (

The Topanga Lagoon Restoration Planning Project will advance the long-term planning effort for the restoration of Topanga Lagoon. Steelhead in the Santa Monica Bay are on the brink of extinction and Topanga Creek is the only stream with a reproducing population. However, the conditions in Topanga Lagoon are not optimal to support growth and rearing opportunities for steelhead and the existing narrow channel opening under the bridge over Pacific Coast Highway (PCH) limits the opportunities for steelhead to enter Topanga creek or for smolts to emigrate.  The remnant lagoon is currently less than two acres and is bordered by 35-foot tall banks of fill.

The proposed project consists of developing three conceptual restoration alternatives to restore ecological function, increase resiliency to sea level rise and climate change, and enhance the visitor experience.  The project area is approximately 23 acres and includes several structures that could be modified and utilized for visitor activities, including low cost overnight accommodations. The remains of a Native American village have also been documented on the site and will be considered as part of the plan for the site. The project would provide as much as 15 acres of restored lagoon/wetlands/ transition habitat, improve water quality at Topanga Beach by improving natural processes, and reduce flood hazards by expanding the lagoon’s footprint. The outcomes will include a plan with three restoration alternatives (including No Project) at 30% conceptual design and an updated Caltrans Bridge Project Study Report.