Crow Marsh Natural Area
Crow Marsh Natural Area consists of three parcels comprising 28 acres owned by King County. These parcels are located at the eastern end of Lake Twelve in the Rock Creek Valley near Black Diamond, just north of SE Green River Gorge Road. King County holds a conservation easement on about 97 adjacent acres owned by Cascade Land Conservancy (CLC). Together the King County and CLC lands protect ~90-acre Crow Marsh.
Lake Twelve, its tributaries, and Crow Marsh at the outlet of Lake Twelve form the headwaters for Rock Creek. Crow Marsh contains a variety of wetland types: emergent, scrub-shrub, and cedar/hemlock forested wetland, as well as open water and sphagnum bog. This large wetland complex plays an important role in water quality and water quantity support of the Rock Creek system. The site contains Rock Creek from approximately river mile 7.4 to 8.2. Although Rock Creek's seasonal flow above river mile ~2.6 limits upstream use by salmonids, Lake Twelve and Crow Marsh support rainbow and cutthroat trout among other fish species, and provide habitat for many species of birds.The upland portions of the site are used for birding and nature observation on an occasional basis. There are no formal trails leading to the water, and dense vegetation and wetland conditions limit access to much of the site. Visitors to the Weyerhaeuser lands on Ravensdale Ridge to the north can reach the site via trail and road connections. King County's easement on Weyerhaeuser roads to the north does not allow King County to grant public access on those roads, nor can King County grant access to the conservation easement properties. A WDFW fishing dock with limited parking (requires WDFW parking pass) is located just west of the site on SE Green Valley Road. This WDFW site provides excellent access to Lake Twelve.
The Crow Marsh Natural Area Site Management Guidelines are available in Adobe Acrobat format, in sections for faster download. For help using Acrobat files, please visit our Acrobat help page.
Crow Marsh Natural Area Site Management Guidelines