Reclaimed Water Program

Carnation (Chinook Bend)

When it comes online in 2008, the new Carnation treatment plant will use an advanced treatment technology called a membrane bioreactor or MBR. The plant will produce reclaimed water that can be used safely as a drought-proof water source for wetland enhancement and other beneficial uses. Reclaimed water will be discharged to a wetland in the county’s Chinook Bend Natural Area, next to the plant’s river outfall site at the Carnation Farm Road Bridge.

Project Design

King County is partnering with Ducks Unlimited (external link) to design the wetland discharge project. Ducks Unlimited is a nonprofit group dedicated to wetland conservation. This partnership will help reduce costs and expedite implementation of the project. Last summer, the county and Ducks Unlimited worked with the Snoqualmie tribe and other interested stakeholders to develop a design for the wetland.

The wetland design focuses on enhancing native plantings and controlling reed canary grass through the use of a water control structure, which allows for moist soil management as well as fish passage. The design includes removing an existing culvert and pipe system that currently drains the existing degraded wetland, installing a new water control structure and “daylighting” the water flowing out of the wetland. The design will increase the size of the wetland to nearly four acres, benefiting wildlife and enhancing opportunities for passive recreation at Chinook Bend.

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Schedule

Construction of the wetland is scheduled to begin in the second half of 2007. The treatment plant is expected to come online in the first half of 2008. During start-up, treated water from the plant will be discharged via the river outfall. After start-up is complete in later 2008, the wetland will become the primary discharge location for reclaimed water. The river outfall will remain operational and serve as a backup to the wetland, but only used when maintenance or equipment problems prevent the facility from producing reclaimed water. When the outfall is in use, the plant is still expected to produce highly treated water that meets or exceeds river discharge standards.

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More information

• For information on the wetland enhancement of Chinook Bend Natural Area or the Carnation Wastewater Treatment Plant, call 206-296-8361, or e-mail us.
• This page is also available as a PDF file (375KB).
• Advanced treatment technology at the Carnation Wastewater Treatment Plant

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For more information about King County's Reclaimed Water Program, contact Jo Sullivan at 206-296-8361 or by e-mail.

Jo Sullivan
King County Water Reuse Program
201 S. Jackson St., Suite 505
Seattle, WA 98104-3855

Updated: July 2, 2007

Also of interest

Snoqualmie - Skykomish Watershed

Regional Wastewater Services Plan

Water Conservation Program

Water Supply in King County

Biosolids Recycling