Thompson Lake Boat Launch Cleanup Protects Human Health
In 2000, the U.S. Environmental Protection Agency (EPA) completed a time critical cleanup action at Idaho Department of Fish and Game’s Thompson Lake Boat Launch. The cleanup protects people from contacting high levels of metals in soils. This boat launch is on the Coeur d’Alene River, in the lower Coeur d’Alene Basin, upstream of Harrison, Idaho.
The boat launch area formerly contained an unpaved dirt parking area and an old, dilapidated boat ramp. Lead levels above 3,500 milligrams per kilogram were found in surface soils and sediments. The shoreline had very little vegetation, which exposed recreational users to contaminants and bank soils to erosion.
Beginning in fall 1999, EPA removed sediments from the shoreline about ten feet inland and five feet down to groundwater level. Workers placed geotextile fabric against the bank face, and put riprap on top of this to prevent erosion. The riprap extends several feet into the river. The parking lot was paved and the boat launch rebuilt.
In March 2004, the Coeur d’Alene Basin Commission’s Recreational Areas Project Focus Team visited the Thompson Lake Boat Launch. The conclusion of the site visit was that the facility was functioning as intended, and that no additional cleanup is warranted.
During EPA’s Five-Year Review in 2005, the agency checked up on the overall cleanup of the Bunker Hill Mining and Metallurgical Superfund Site. EPA found that the remedy at Thompson Lake continued to protect human health.