King County outlines Coal Creek sewer upgrade, warns of traffic and trail impacts

King County wastewater officials briefed the Newcastle City Council on July 15 on a multi‑year plan to replace an aging sewer trunk that runs adjacent to and in places inside Coal Creek.

The project will replace a pipe built in the 1960s, relocate most of the line away from the creek, add a tunneled segment through the Red Cedar Trailhead and construct open‑cut sections where needed. King County said the work advances two goals: meet 20‑year peak flow capacity and reduce environmental vulnerability by moving the pipe away from the stream.

King County Wastewater Treatment Division Director Cameron Gural called the work “a very important project.” Project manager Scott Dingus said most of the existing alignment (the presenter showed it in red) will be removed and replaced with new pipe and a tunnel (shown in orange on project maps). Dingus said the tunnel reduces surface impacts in neighborhoods…