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Black Diamond, Washington

This city of 4,000 people lies within the foothills of the Cascade Mountains in southern King County, 30 miles southeast of downtown Seattle. The city is named for the Black Diamond Coal Company which owned a coal mine here as well as much of the town itself from the 1880s to the 1930s.

Black Diamond used TDR to preserve various open space resources including land surrounding Lake Sawyer.

In 2005, Black Diamond and King County, assisted by the Cascade Land Conservancy, entered into several agreements that used TDR and $1 million of King County’s Conservation Futures Tax to permanently preserve over 2,500 acres of open space and working forests. Specifically, King County allowed Black Diamond to expand its Urban Growth Area, permitting 329 acres to be annexed into Black Diamond and developed by its owners, the Plum Creek Timber Company.

In return, an easement was placed on 1,600 acres of adjacent land, known as Ravensdale Ridge, permanently creating a greenbelt northeast of Black Diamond that Plum Creek can only use as a working forest. This easement also protects more than 10 miles of trails for hiking, mountain biking and horseback riding. Plum Creek also agreed to give King County another 645 acres of open space, including portions of the Ravensdale Creek stream corridor, which is critical to the water quality of Lake Sawyer. In addition, this action was used as a match for another $3.6 million worth of funding from the U.S. Forest Legacy Program, allowing the preservation of thousands of additional acres of working forests southeast of Black Diamond. As a bonus, the agreements created 388 acres of open space within the City including the transfer of the 165-acre Lake Sawyer Park from the County to the City and a dedication of 91 acres of land from Plum Creek to the City.