Port of Seattle Terminal 10

Floyd|Snider assisted the Port of Seattle (Port) with stormwater infrastructure upgrades at Terminal 10 (T-10) on Harbor Island. Construction activities at the site were complicated by the fact that the T-10 property includes two U.S. Environmental Protection Agency-managed Operable Units of the Harbor Island Superfund site that are currently undergoing long-term monitoring. The Port intends to ultimately return T-10 to active use, and stormwater upgrades were required at the terminal to make the site operational. Site redevelopment consisted of abandonment of the existing partial stormwater collection and conveyance system, installation of a new stormwater collection and conveyance system, installation of a stormwater treatment system, and construction of a new outfall discharging to the surface of the constructed sediment cap in the Duwamish West Waterway. System improvements required excavation and reconstruction of the existing soil cap in order to install the new stormwater conveyance system, and excavation into the existing sediment cap and bulkhead for installation of the new outfall structure.


  • Engineering and Uplands Stormwater Management
  • Agency Negotiation