Mukilteo Ferry Terminal Replacement Project Environmental and Tribal Services

  • Locations of submerged aquatic vegetation mapped by Confluence in 2017.
  • Proposed construction site during 2017 survey.

In 2020, Washington State Department of Transportation completed construction on the new Mukilteo Ferry Terminal, part of the State Route 525 transportation corridor connecting the Seattle-Everett metropolitan area to Whidbey Island. The project involved removal of a 3,000-foot-long pier supported by 4,000 creosote-treated piles, and dredging of potentially contaminated sediments beneath the existing pier, followed by construction of the new facility in a nearby location. Confluence Environmental Company staff supported environmental permitting, Endangered Species Act (ESA) compliance, and tribal strategy for the project.


During Phase 1 of the project, Confluence’s Sasha Visconty, while working as Axis Environmental, led tribal strategy and provided ESA strategic oversight and permit direction for the project. The property being considered for the new terminal had significant cultural resources on the site, and was an area used by 4 tribes for treaty fishing activities. The Tribal Team led by Ms. Visconty developed a project approach to resolve the tribes’ issues and obtained permits for the project. Four separate tribal agreements and operations protocols were drafted.

Ms. Visconty also managed eelgrass and macroalgae vegetation surveys conducted by Confluence scientists at the site for 3 separate alternatives under consideration. Confluence scientists designed and implemented the eelgrass and macroalgae surveys for both the first and final phases of the project. The first effort in 2011 supported the National Environmental Policy Act (NEPA) environmental impact statement (EIS) alternative analyses for the planned replacement of the Mukilteo Ferry Terminal. Three alternative locations were surveyed by SCUBA and underwater video to document existing conditions and determine benthic habitat including eelgrass and macroalgae presence. The 2017 surveys were conducted to support the final design phase and were conducted by underwater video. Maps were produced for the construction contractor to facilitate avoidance of potential impacts to eelgrass and macroalgae during construction. For each phase, reports were prepared detailing the study results to satisfy Washington Department of Fish and Wildlife eelgrass/macroalgae survey guidelines and summaries were prepared for inclusion in the NEPA EIS and supporting discipline reports and permitting documents.


Early engagement and coordination between the Tribal Team, mitigation program, and NEPA lead ensured successful and on-time resolution of tribal issues, ESA consultation, and permitting. The 2011 aquatic vegetation surveys helped identify a preferred alternative for the project and documented avoidance and minimization of potential impacts to eelgrass and macroalgae. Additional surveys in 2017, confirmed areas to be avoided during construction and areas mapped by Confluence were provided to the construction contractor ensure successful avoidance and minimization and to fulfill permitting requirements.

Project Location
Mukilteo, Washington

Washington State Department of Transportation Ferries Division

Project Timeline