CERCLA Response Action: Diablo Dry Dock Site
The NPS is in the planning stages of preparing an Engineering Evaluation and Cost Analysis in consideration of a non-time-critical removal action (TCRA) for the Diablo Dry Dock (Site) located within Ross Lake National Recreation Area, Washington, in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act, as amended, (CERCLA), 42 U.S.C. §§ 9601 et seq. The President has delegated response authority under CERCLA Section 104 to the Secretary of the United States Department of the Interior (DOI) by Executive Order 12580, 52 Fed. Reg. 2923 (1987), as amended by Executive Order 13016, 61 Fed. Reg.45871 (1996), to respond to the release or threat of release of hazardous substances on or from land under the jurisdiction, custody, or control of DOI. The National Park Service (NPS) Pacific West Regional Director, through delegations of authority, retains CERCLA Section 104 authority for the Site.
This Engineering Evaluation and Cost Analysis (EE/CA) will provide site characterization data, assesses site-specific ecological and human health risks and identify ecological-based cleanup levels, evaluate various response alternatives, recommend a preferred response alternative, and provide a vehicle for public involvement. Once drafted, this EE/CA will be published to the public and made available for a 30-day public comment period. Once this EE/CA is finalized, the NPS will develop and prepare an action memorandum to authorize a non-time-critical removal action on Site.
The Diablo Dry Dock Site is located on the north shores of Diablo Reservoir, Whatcom County, WA along the Skagit River in Ross Lake National Recreation Area, immediately adjacent to the North Cascades Environmental Learning Center. The Diablo Dry Dock Site itself is located within Deer Creek Cove on Diablo Reservoir.
As the first development on Diablo Reservoir, the Seattle City Light (SCL) Diablo Marine Railway and Shelter (referred to as the Diablo Dry Dock) was built in the early 1930s after Diablo Dam was completed in late 1929. This building was constructed to provide shelter for a marine railway used to build and maintain vessels operating on Diablo Lake, including the construction of the Alice Ross, SCL's first tour boat used to provide Seattle City Light Skagit Tours, in 1936 and 1937. The railway and building have been used in this capacity ever since. The dry dock building was constructed of sheet metal on a wood framework, supported by treated logs on concrete bases, and was built on the native soils. It is open to the weather on two sides, and is surrounded by a chain‐link fence. A concrete and metal railway extends from the boathouse into the lake to haul boats out of the water of Diablo Reservoir.
A Site investigation completed in September 2014 found that soils on Site (both in and outside of the building, below OHWM, and up to one foot deep) include elevated levels of arsenic and lead above MTCA Method A cleanup levels, and levels of carcinogenic PAH (cPAHs) above MTCA Method A and B cleanup levels. These contaminants are understood to be the result of sandblasting operations that were conducted onsite over the years.
Elizabeth Boerke, Environmental Protection Specialist, 360-854-7328