Skip to main content
King County logo

Newsroom

Natural Resources and Parks
Public Affairs


King County completes new study of Cedar River channel migration zone

Summary

King County has completed a study of the Cedar River’s channel migration zone (CMZ), which extends from the river’s mouth in the City of Renton upstream to Landsburg.

Story

King County has completed a study of the Cedar River’s channel migration zone (CMZ), which extends from the river’s mouth in the City of Renton2015_cedar_river_rsz upstream to Landsburg.

Channel migration is when bank erosion occurs and a river channel shifts location, and channel migration zones are mapped and regulated by King County as flood hazard areas.

The CMZ study and accompanying map are in draft form while they undergo a public review and comment period that ends March 6. The newly identified channel migration areas illustrated in the draft mapping are hazards areas where existing county regulations will apply for land development proposals.

King County hosts a public meeting to present the study and map from 6-8 p.m. on Wednesday, Feb. 4, at the Lake Wilderness Lodge, 22500 SE 248th St., Maple Valley.

The first half-hour of the meeting will be an open house to review maps and meet with project employees, followed by a presentation at 6:30 p.m., then a second open house starting at 7:30 p.m., to review maps and ask questions.

The CMZ maps are adopted by amendment to the King County channel migration public rule, and are used to regulate land use within affected areas. Existing regulations are not being changed.

The draft study and map, the draft amendment to the channel migration public rule, and general information about channel migration in King County can be viewed at kingcounty.gov/rivers. Paper copies are available for review during business hours at the following locations:

• King County Department of Development and Environmental Review, 35030 SE Douglas St., Suite 210, Snoqualmie;
• Fairwood Library, 17009 140th Ave. SE, Renton;
• Maple Valley Library, 21844 SE 248th St., Maple Valley.

Written and oral comments can be provided during the public meeting. Written comments can also be sent to terry.butler@kingcounty.gov, or Attn: Terry Butler, King County Department of Natural Resources and Parks, 201 S. Jackson St., Suite 600, Seattle, WA 98104. The deadline for comments is March 6.

The draft CMZ report and map could be revised based on comments received.  A final Cedar River CMZ map will be adopted by the DPER and the Department of Natural Resources and Parks, consistent with provisions of the public rule. In addition to regulating land use within affected areas, the Cedar CMZ map and study will inform the Cedar River Corridor Planning process which can also be viewed at kingcounty.gov/rivers.

For more information about the draft Cedar River CMZ study, map or public meeting, contact Terry Butler at 206-477-4660, or terry.butler@kingcounty.gov. If you have questions about the King County channel migration public rule or CMZ regulations, contact Steve Bottheim at 206-477-0372 or steve.bottheim@kingcounty.gov.