The Site encompasses approximately 3 acres, located along Fourmile Creek in Boulder County, Colorado. The Black Swan Good Samaritan Project is roughly 4 miles upstream from the confluence of Fourmile Creek and Boulder Creek in Boulder Canyon. The entire restoration project begins the upstream property of 4726 Fourmile Canyon Drive and continues downstream through the property at 11 Logan Road. Mine waste material with elevated heavy metals was found on the west side of the Fourmile Creek at the property located at 4389 Fourmile Canyon Drive. Historic mining activity upstream of the 4389 Fourmile Canyon Drive property has adversely affected the Fourmile Creek watershed, including tailings and waste rock materials.
In 2010, a large fire occurred, burning approximately 6,181 acres and destroying houses and trees. A high-intensity rain fall event occurred across Boulder County in 2013 and caused flash flooding in many watercourses, including Fourmile Creek. This caused concern from Pine Brook Water District for the water supply and soil quality in the area due to the heavy metals in mine tailings resulting from erosion.
Both arsenic and chromium found at the Site are hazardous substances as defined by Section 101(14) of the CERCLA of 1980. Fourmile Creek is a source of drinking water for local residents in Boulder County.
