Our Projects

Railway Culvert Assessment to Advance Restoration Efforts along Puget Sound Nearshore

As part of a multi-entity team, Confluence has completed the first 2 phases of this grant-funded project – managed by the Tulalip Tribes – to restore nearshore habitat in Puget Sound along 73 miles of Burlington Northern and Sante Fe (BNSF) rail line between Olympia and Blaine, Washington. The latest deliverables included preliminary restoration designs […]

Log Boom Park Improvements

The improved Log Boom Park on the shore of Lake Washington in Kenmore, Washington, opened on June 30, 2022. Confluence was part of a multidisciplinary team led by engineering firm Mott Macdonald and including J.A. Brennan Associates landscape architects and Davido Consulting Group civil engineers. The citizens of Kenmore had been seeking better waterfront access […]

Copper Mine Remediation Project

Holden Mine was a copper mine active from 1938 to 1957. Through acquisition of former operators, Rio Tinto took over remediation of the relic copper mine as required by the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Phase 1 of the Remedial Action (RA) encompassed 170 acres and caused both temporary and permanent impacts […]

Critical Areas Mitigation Site Monitoring Services

King County Department of Natural Resources and Parks (DNRP) has constructed multiple critical areas mitigation sites as required by the local jurisdictional code to offset impacts from DNRP projects across King County. Confluence managed consecutive contracts from 2015-2020 to perform post-construction mitigation site monitoring and reporting for numerous such mitigation sites. Monitoring efforts typically included […]

McSorley Creek Pocket Estuary Restoration Project at Saltwater State Park

Confluence managed the first phase of this project to enhance habitat for salmon. Key goals of the project included realigning McSorley Creek to restore stream and estuary habitat and removing marine shoreline armoring to create a dynamic and natural beach front and nearshore area, as well as redesign of the park recreational facilities. Approach Confluence […]

Confluence delineated wetlands on this 16.75-acre site.

Ovenell Farm Proposed Park Critical Areas Study and Master Planning

The City of Stanwood’s Community Development Department is developing a master plan to convert a former dairy farm, the “Ovenell Farm,” into a park and historical site. Confluence has conducted several tasks to support the master planning process and future permitting for this project, including completing a wetland and ordinary high water mark delineation, Shoreline […]

Culvert Replacement Corps Permitting and Engineering Review

Snohomish County Surface Water Management (SWM) proposed 29 culverts and 2 water quality facilities for replacement as part of a program to improve fish passage and habitat conditions. Confluence managed the effort to determine applicable U.S Army Corps of Engineers (Corps) regulatory requirements for the proposed projects. Confluence worked with design engineers to assess field […]

Mukilteo Ferry Terminal Replacement Project Environmental and Tribal Services

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 […]

Aberdeen Mill Wetlands Restoration/Mitigation & Mitigation Monitoring

Confluence provided permitting assistance for the construction of an expanded wood-manufacturing facility in Aberdeen, WA. Work included field surveys on over 100 acres of the project site to delineate wetlands, identify mitigation opportunities, and evaluate fish and wildlife habitat. Confluence staff developed detailed plans to rehabilitate wetlands along the Chehalis River and in Elliott Slough […]

Environmental Permitting for Industrial Property Development

Sierra Pacific Industries (SPI) developed industrial land in Frederickson, Washington. Confluence Environmental Company served as the lead consultant for critical areas studies; wetland mitigation design and planning; environmental review; and local, state, and federal environmental permitting for the property. Confluence led the multi-disciplinary team from design of site development through design of on-site and off-site […]