Alex Johnson, the city's surface water engineer, briefed the committee on several surface-water capital projects, including a 2,000-foot replacement of aged corrugated metal pipe on Fifth Avenue and 212th Street, the estuary project and a recently revised 16th Avenue pipe project.

On the Fifth Avenue/212th project, Johnson said the existing corrugated metal pipe will likely be replaced with polyethylene and that design work is planned for 2026 with construction anticipated in 2027. "They're made out of corrugated metal right now, which is part of, it'll probably be, polyethylene, plastic," Johnson said. He said modern buried pipe can have an expected service life "70 to a hundred years."

Johnson said the estuary project is progressing toward 30% design and that staff expect to present a more substantive update in the first quarter of next year. "We are currently funded through about 900,000 of the 1,030,000 that we anticipate for design," he said, and described construction as a conservative placeholder at $16,500,000 that staff intend to fund with a package of grants (flood reduction, salmon recovery, recreation and watershed funds were mentioned as likely contributors).

The 16th Avenue pipe project recently changed scope after a feasibility study indicated the city could divert flows into the existing system rather than construct a new alignment across private parcels; the project now focuses on upsizing and upgrading existing pipes with design and construction targeted for 2026.