In collaboration with several landowners across 500 feet of San Geronimo Creek, SPAWN has installed many large woody debris structures in the creek to slow bank erosion that was threatening private property and increased the instream complexity of the stream by reducing channel incision, creating pools, sorting sediments, and retaining stream gravels. The large woody debris structures help slow water downs, capturing gravels for spawning, adult and creating pools to provide cover and insect prey in pools for juvenile coho. 

The project is also partnering with Lagunitas School District to restore 3,000 square feet of riparian habitat at the Lagunitas School, removing a dilapidated storage shed and sandbox from the banks of Larsen Creek, and planting hundreds of native plants and trees with the assistance of students and volunteers.

This project was funded by the California Department of Fish and Wildlife and Turtle Island Restoration Network. Engineering and design was provided by GeomorphDesigns and construction was done by Dragonfly Stream Enhancement and SPAWN.

Project Impact


Feet of San Geronimo Creek restored


Square feet of riparian habitat restored


Native species planted by students and volunteers

Project Background

This project originated from a request by a resident to have SPAWN assist in the stabilization of an eroding stream bank below a home. After many meetings and discussions with neighbors along the creek, SPAWN was able to rally homeowners together to address bank erosion that was threatening homes while also improving the complexity and quality of the instream habitat for salmonids. In total, six landowners came together to participate in the project, all of whom have benefited from stabilized stream banks and improved in-channel complexity and habitat. This project serves as a great model for how landowners in the San Geronimo Valley can work together with SPAWN to address needs of private property owners and improve habitat for coho simultaneously. 

From Roy’s Dam to Roy’s Riffles

Removing the Top-Priority Barrier

for Central California Coho Salmon

Read the Article

Project Timeline

The instream wood installation work was completed in October 2020. Revegetation, site maintenance, and restoration monitoring is ongoing by SPAWN.