Lake Washington Dry Docks Removal

Floyd|Snider began this fast-paced project by leading a preliminary design evaluation that developed several deconstruction and removal alternatives for two derelict wooden dry dock structures that were sunk on contaminated sediment on the Quendall Terminals Superfund site within Lake Washington. This work was conducted for the Washington State Department of Natural Resources (WDNR) as part of their Derelict Vessels Program. After the evaluation was completed, WDNR selected their preferred alternative for removal of the dry docks, which was in-water deconstruction of the dry docks. Based on this selection, Floyd|Snider then developed bid documents and assisted WDNR in the selection of the deconstruction contractor. All regulatory permits were obtained by Floyd|Snider to complete the project work within a narrow time frame. Prior to deconstruction of the dry docks, an investigation was performed on the sediment contained within the dry docks ballast tanks and this contaminated sediment was removed. Deconstruction was accomplished primarily using a long-reach excavator with a grapple attachment. Water quality during deconstruction was protected by installing a full-depth, anchored, impervious turbidity curtain around the work area perimeter to contain suspended lake bed sediment and construction debris. Floyd|Snider provided oversight services for all construction activities, and coordinated with the Washington State Department of Ecology, the U.S. Environmental Protection Agency, and other regulatory agencies to ensure the project was completed in accordance with the permits. After deconstruction activities were completed at the site, a clean layer of sand was placed over the dry dock deconstruction area.


  • Preliminary Design Evaluation
  • Permitting 
  • Agency Coordination and Negotiation
  • Design and Bid Package Preparation
  • Sand Blast Grit Investigation
  • Construction Management

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