Fish are an essential resource in Washington, but dams, culverts, bridges, and other infrastructure block certain fish species from going upstream. Municipalities, counties, and the Washington Department of Transportation (WSDOT) are replacing this infrastructure with fish-friendly bridges and culverts, and TKDA is helping them preserve this important resource. 

TKDA acquired Sáez Consulting Engineers (SCE), a Seattle and Kitsap County-based civil and structural engineering firm, to expand our capabilities for Pacific Northwest municipalities, counties, and other government agencies. Our integrated team of engineers, surveyors, and other specialized technicians have the experience and expertise to work on fish passage projects. Our expertise spans across structures, civil roadway, hydrology, survey, utility coordination, and MicroStation. Overall, we are a uniquely positioned team with diverse technical abilities and a dedication to implementing proven strategies to create durable and reliable fish passages. 

Advanced PHDS for Olympic Region Fish Passages | Olympic Peninsula Region, WA

TKDA worked with HDR, Jacobs, and a hydraulics subconsultant to develop the creek’s vertical and horizontal realignments and establish surface models of existing and proposed CAD surfaces to develop plans, critical sections, details, and the culvert geometry for insertion into the Preliminary Hydraulic Design document deliverables. Our team supplemented the topographical survey with LiDAR technology to get the most accurate grading model. Additionally, we assisted the PHDS team with other figures such as LWM (Large Woody Material) exhibits for their reports. We provided services related to fish passage hydraulic crossings for Lunch Creek, Crane Creek, and Wayne Creek. Learn more about this project.

SR 3 Chico Creek Fish Barriers | Kitsap County, WA

TKDA performed a topographical survey and mapping to illustrate all existing on-site pipe inverts and drainage ditch locations, show all existing culvert crossing inverts, verify the WSDOT-provided survey along SR 3, provide Chico Creek stream channel survey sections, and provide SR 3 and Chico Way alignment survey. Read more about this project.

Culvert Replacement at Railroad MP 28 | Bremerton, WA

TKDA established horizontal and vertical control, completed property line surveys, and implemented the entire three-dimensional manual deformation monitoring program. The project entailed replacing an existing 48-inch diameter RCP culvert on this salmon-bearing stream with a 20-foot diameter fish passage crossing a 120-foot-high railroad embankment.

I-90 Soderman Creek Fish Passage | King County, WA

As part of the WSDOT Fish Passage Program, TKDA is currently replacing one existing culvert with three new single-span bridges to help with fish passage beneath I-90. Working with COWI, our services include the structural design of the new bridges, the load rating of the new bridges, calculating bridge item quantities, preparing bridge contract plans, and supporting the project through the advertisement period.

Learn more about our Surface Water and Transportation service offerings