SR 202 - Evans & Patterson Creek - Fish Passage - Fish-friendly structures

What type of fish passage structures will replace the existing culverts?

WSDOT is using a design-build project method for this work. Design-build is a method used around the nation where a single contractor is hired to be responsible for both the design and construction of a project. As a result, the contractor will decide what to install in each stream while still meeting WSDOT requirements. Among the requirements, the structures will need to have minimum span widths.

  • Evans Creek - the structure must have a minimum span of 25 feet for a creek that is located approximately 40 feet below the roadway.
  • Patterson Creek – the structure must have a minimum span of 16 feet. The creek is located approximately 7 feet below the road.
  • The west tributary to Patterson Creek – the structure must have a minimum span of 12 feet. The stream is located approximately 7 feet below the road.
  • The east tributary to Patterson Creek – the structure must have a minimum span of 23 feet. The tributary is located approximately 9 feet below the road.

How much of each streambed will be rebuilt and replanted with native shrubs and trees?

  • Evans Creek: Approximately 100 feet upstream and 300 feet downstream will be rebuilt.
  • Patterson Creek: Approximately 100 feet upstream and 50 feet downstream will be rebuilt.
  • Patterson Creek west tributary: Approximately 150 feet upstream and 100 feet downstream will be rebuilt.