Major Project at Redwood Creek Restores a Fragile and Important Ecosystem in Marin
San Francisco, CA: Comprehensive restoration work of the Redwood Creek at Muir Beach will continue this summer and fall, after the completion of a successful first phase of work last year. The 8.9 square mile Redwood Creek watershed begins high on Mount Tamalpais, passes through the redwood cathedral at Muir Woods National Monument, and empties into the Pacific Ocean at Muir Beach in the Golden Gate National Recreation Area. The goal of the project—begun in 2009 and estimated to take four years to complete—is to make the creek a functional, self-sustaining ecosystem once again by realigning the creek; restoring wetlands, an intermittent tidal lagoon, and dunes; and also creating and maintaining habitat for sustainable populations of the endangered coho salmon and threatened steelhead trout.
Work on the site is being carefully sequenced to allow the existing ecosystem to function while the new site enhancements are constructed. Construction began in early 2009 and will be limited to August through October each year, which is typically the rainy season.
The main highlights of the second phase of work at Redwood Creek include:
• Construction of 650 linear feet of the new creek alignment and three side channels. The new creek alignment will be fully connected as the main channel in a couple of years, once riparian vegetation is established and the channel has stabilized.
• While work on the creek is still under progress, a new 4 feet wide culvert under the levee road is being installed to temporarily connect the new channel and allow water to drain and fish to move back and forth.
• Removal of gravel from about 1,200 linear feet of existing creek that will be used to line the bed of the new channel.
• Removal of non-native Monterey cypress and Monterey pine trees at the lower end of the Green Gulch pasture to make room for a California red-legged frog pond and to create large woody debris for the new channel. All large trees that are removed will be used to create log structures in the new creek channel for salmon habitat.
• Realignment of about 500 linear feet of the Coastal Trail, to replace an eroded leg of the Coastal Trail. The natural hill slope will be rebuilt where the eroded leg of the Coastal Trail currently occurs.
Once an expansive 46-acre network of wetlands, dunes, and a 13-acre open freshwater lagoon, the area has suffered more than a century of ecological degradation from agriculture, recreation, and road construction. These processes completely altered the creek’s alignment, flow, and connection to the floodplain—and affected its ability to support the southernmost continually returning natural population of the endangered coho salmon in western United States. Redwood Creek is currently constrained by a small bridge, the levee road, and the Muir Beach parking lot, which needs to be moved to connect it to its historic floodplain for better salmon habitat and sediment transportation.
“This project is so much more than just improving habitat for endangered species,” said Frank Dean, acting superintendent of the Golden Gate National Recreation Area. “The strengthened connection between Redwood Creek and its historic floodplain, increased native plant cover and resulting wildlife cover, reduced flooding, improved access, and expanded education and volunteer stewardship opportunities make the Redwood Creek Restoration Project one of the most important of its kind on the West Coast.”
In the winter of 2009, scientists estimated that a total 45 adult coho salmon returned to the Redwood Creek spawning grounds.
Here is an outline of work already accomplished on the site and projects still ahead:
• Restored a 1.4-acre area adjacent to the existing tidal lagoon to a native brackish wetland
• Expanded the tidal lagoon to improve coho salmon and steelhead trout habitat
• Created an emergent wetland for California red-legged frog breeding habitat
• Reconfigured the southern end of the parking lot to increase natural creek function and reduce flooding
• Additional wetland and creek restoration
• Creation of additional ponds for California red-legged frogs
• Permanent parking lot reconfiguration
• Construction of a new Pacific Way Bridge and adjacent, multi-use, and accessible trail
• Redesign of Coastal Trail alignment
• Installation of new bathroom and other visitor amenities near the existing parking lot
The Redwood Creek Restoration Project at Muir Beach, a project of the National Park Service in partnership with the Golden Gate National Parks Conservancy, recently completed the first phase of a multi-year effort to restore critical habitat and ecosystem function.
The current phase of this project is made possible by funds from the California Dept. of Fish and Game, U.S. Fish and Wildlife Service, State Coastal Conservancy, the National Park Service, and Parks Conservancy members. Two programs of the U.S. Department of Transportation—SAFETEA LU (Safe Accountable Flexible Efficient Transportation Equity Act: A Legacy for Users) and PLHD (Public Lands Highway Discretionary)—are also supporting our work on the Coastal Trail.