Coal Creek sewer upgrade
June 16, 2021
Crews will carry out surveys in the Coal Creek Natural Area beginning June 18
King County’s Coal Creek Sewer Upgrade Project is in final design. The project team is continuing to collect information in the field to inform design. Beginning June 18, crews will be working within the Natural Area to conduct soil and groundwater surveys.
Read more on what to expect here .
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King County Wastewater Treatment Division (WTD) will upgrade a regional sewer line that serves Bellevue and Newcastle. The existing pipeline was built between 1966 and 1991 in an area that looked different from today, with a smaller population. The pipeline is nearing its maximum capacity and needs to be upgraded to carry more wastewater and meet the growing needs of your community.
Once installed, the new sewer pipe is designed to serve your community for another 50 years or more.
Protecting the Coal Creek Natural Area
The existing Coal Creek Trunk is approximately 2.5 miles long and primarily follows the banks of Coal Creek in the Coal Creek Natural Area between Newcastle and I-405. The new pipeline alignment will move the active pipeline away from Coal Creek offering better protection to this sensitive environmental area.
The selected pipeline alignment also aims to decrease impacts to both the Natural Area and Coal Creek Parkway SE during construction.
This map shows the project work areas and the construction methods King County’s contractor will use in each area. The contractor will install about 10,800 feet of pipe to build the new Coal Creek Trunk Sewer and re-establish connections to the City of Bellevue’s sewer collection system.
King County’s designers work to reduce community impacts and inconveniences where possible. But on large projects like this one, inconveniences are unavoidable. People can expect up to 3-years closure at the Red Cedar trailhead, with a trail detour around the construction site. There will be traffic impacts during work close to the Parkway.
Keep up to date to make sure you have the latest news and information as final design continues.
Contact Monica Van der Vieren at:
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If you are just learning about the Coal Creek project, you can visit two online resources to learn more:
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