Lower Redwood Creek Restoration at Muir Beach
Golden Gate National Parks Conservancy, Muir Beach, 2009 – 2011. In July 2009 Hanford began a three-year project with the Golden Gate National Parks Conservancy (GGNPC), partnered with the National Park Service, to restore Lower Redwood Creek and Big Lagoon in the Golden Gate National Recreation Area (GGNRA). Redwood Creek, which connects to the Pacific Ocean at Muir Beach, was restricted through historical ranching and recreation developments. Impacts included levees, lagoon filling, and channel relocation. Work included lagoon expansion, fill removal, channel realignment and pedestrian bridge replacement.
Acres Restored: 116
Cubic Yards Moved: 140,0000
Land Type: Coastal Riparian
Contract amount: $4.5m
Project Period: 2009-2011
The primary goal of the project was to increase rearing habitat for the federally listed coho salmon and steelhead populations that have historically used the watershed.
Project activities included construction the new alignment for Redwood Creek, three tributary channels and backwater channel, connection of new alignment to existing channel, backfilling existing channel, installation of log structures, harvest and replacement of native streambed gravel, levee removal, construct pedestrian bridge, and construction of two additional California red-legged frog ponds.
The lagoon phase of work included substantially increasing the size of the tidal lagoon by excavating an off-stream tidal basin and constructed seven log structures along the perimeter of the lagoon. To mitigate the re-introduction of invasive kikuru grass, crews screened over 1,000 CY of sand to remove root remnants prior to placing sand back into lagoon.
All phases of the project were subjected to a range of environmental permits. Permits required simultaneous channel construction and bridge construction activities to be carefully coordinated. Additionally, numerous bypass systems were installed and maintained in a manner to reduce impacts to adjacent habitat and human neighbors.
The lower Redwood Creek reach from Pacific Way to the Pacific Ocean was restored to a more natural, sinuous waterway unimpeded by levees and other human impacts.
The creek channel was completed with installation of 1,500 CY of salvaged native streambed gravel (harvested from the existing channel prior to backfill) and 5,000 CY of imported material. The new channel received vegetated soil lifts to aid in strengthening creek banks that are adjacent to the community road.
Large woody debris was installed throughout the channel to create complexity and habitat. Hanford installed 215-feet of new pedestrian bridge that spanned the restored floodplain and creek. Additionally, the project increased breeding habitat for the California red-legged frog, also a federally listed species.