Council ratifies emergency declaration after King County finds leaking Eastside interceptor that could discharge into Lake Washington

Kirkland City Council on Sept. 16 ratified a city manager emergency proclamation after King County engineers identified a structural problem and leakage in the Eastside interceptor — an 84‑inch wastewater interceptor that runs beneath the Cross Kirkland Corridor (CKC) and conveys wastewater to Renton.

City Manager Kurt Triplett told council he had signed the emergency declaration late the night before so response work could proceed. “I also, late last night, signed a declaration of emergency for the city,” Triplett said during the meeting.

Why it matters: The Eastside interceptor handles millions of gallons per day for multiple jurisdictions. County and city engineers said a pipe failure could cause uncontrolled wastewater overflow into the Houghton B‑1 Stream and then to Lake Washington, with high environmental and public‑health consequences.

What King County and city staff said: Deputy Public Works Director Sarah Olson led the presentation. City water‑quality sampling had revealed elevated bacteria in Houghton B‑1 Stream; follow‑up tracing identified a leakage location in segment 14 of the interceptor and related instability in a city stormwater pipe beneath the interceptor. “City water quality testing revealed elevated bacteria levels in Houghton B 1 stream,” Olson said.

King County engineers told the city the surrounding soils appear unstable and the failure risk increases in wet weather. Olson summarized flows and the potential scope: the interceptor conveys “between 2 to 10,000,000 gallons of wastewater per day during dry season flows and up to 20,000,000 gallons a day during wet season flows.” She said the county is preparing an above‑ground bypass to divert flow while crews make repairs.

Planned mitigation and impacts: King County plans to construct an approximately 3,000‑foot above‑ground bypass using 18‑inch high‑density polyethylene (HDPE) pipe secured between geology blocks, then plug and dewater the interceptor for joint repairs. Assembly of the bypass is expected to take two weeks and will require a full CKC trail closure between NE 50th Street and 108th Avenue NE; once the bypass is in place the county anticipates the trail will reopen at a reduced width (about five feet) while the repair continues for an estimated 6–8 weeks. Eight pumps will be staged at the site with two to three operating at any time; staff cautioned that nearby residents should expect increased noise and lighting.

Council action: Deputy Mayor Arnold moved and Council Member Sweet seconded a motion to ratify Resolution R‑56‑95, the city manager’s proclamation of emergency; council approved the resolution 7–0. Olson said the city issued a notice to proceed that conditions the county’s work on communications, traffic control, and an after‑the‑fact land‑surface modification permit and other mitigation measures.

Communications and detours: City and county staff said they would coordinate weekly on communications, traffic control and mitigation. The county will notify residents within 500 feet of the bypass site and King County and the city posted project pages and temporary signage; a detour using Lake Washington Boulevard has been planned for pedestrians and cyclists while the CKC is closed.

Council concerns: Council members pressed staff for clear, proactive communications and additional advance notice for intermittent full closures related to material deliveries. Mayor Kelly Curtis emphasized outreach given the steep nature of detour routes and the likelihood of noise impacts to adjacent properties.

Ending: Council approved the emergency proclamation for immediate repair work and asked staff to keep the council informed through weekly coordination updates and the planned October study‑session briefings on related public‑works impacts and trail access. The county’s immediate bypass and repair plan aims to prevent an uncontrolled discharge while permanent repairs are completed.