Tumwater committee backs HDR consultant agreement to design Somerset Hill culvert replacement

The Tumwater Public Works Committee on June 18 voted to place a consultant agreement with HDR Engineering for the Somerset Hill Culvert Replacement (fish-passage) Project on the city council’s July 7 consent calendar with staff’s recommendation to approve.

Ryan Blazer, an engineer in the city’s transportation and engineering department, presented the project background and design scope. Blazer said the site contains a small culvert that creates a high-velocity "fire-hose" effect that prevents fish from passing at higher flows and destabilizes the stream bank. The design will evaluate realigning the stream, replacing the culvert with an appropriately sized bridge structure, stabilize banks and protect utilities.

Blazer described the consultant selection process: the city issued a request for qualifications, a five-person city-staff panel evaluated submissions, interviewed candidates, and recommended HDR Engineering. The design scope presented includes survey, geotechnical work, environmental permitting, plans and specifications, right-of-way services, construction support and estimates. Blazer said the design schedule aims for completion by the end of 2027, with construction advertised around that time and construction estimated for summer 2028.

Staff stated a rough total-project estimate of about $68 million. The transcript records a design consultant fee presented as "$1,151,62" (appears truncated in the transcript and requires confirmation from staff); staff said this figure is slightly higher than the number in the staff report because updated overhead rates were included after coordination with partner agencies. Staff also said the city has secured $4 million in federal PROTECT funding for design and construction and is pursuing additional grant opportunities.

Committee members asked about the status of a notable tree on the bank; staff said the tree remains standing but its stability is uncertain and that geotechnical and forestry analyses during design will determine whether it can be preserved or reused in-stream as habitat. Staff also said the city works with tribal partners and watershed biologists on project design and habitat outcomes.

A council member moved to place the consultant agreement on the July 7 consent calendar in substantially the form approved by the city attorney and to authorize the mayor to sign; the committee approved the motion by voice vote.

Next steps: if the council places and approves the agreement, HDR will begin design work; staff will return with refined cost estimates and design deliverables as the project progresses.