Cedar Mill Creek Flooding

What does Cedar Hills have to do with flooding?

On February 26 at 6:30pm, the Washington County Board of Commissioners (also acting as the Clean Water Services Board of Commissioners) will decide whether to ask the Tualatin Watershed Enhancement Collaborative (TWEC) to adopt a Three-Year Workplan that will guide efforts to better manage flood-related issues in the Cedar Mill and North Johnson Creek basin.

Why it matters


Cedar Hills includes the headwaters of Cedar Mill Creek, which rushes downhill, finding its way along the bottom of ravines before carving out narrow channels that – toward the bottom of its watershed – erode adjacent yards and flood properties. Over the decades, human activities have made the creek and its adjacent wetlands less able to manage heavy runoff impacts. In turn more, and faster, water travels downstream where persistent flooding of parks, roads, and neighborhoods is increasing. Even homes at the top of its reach are threatened with unsupported foundations and destabilized hillsides.

Cedar Mill Creek Headwaters

Devonshire and Walker Road

Downstream creekside neighbor’s eroding bank (between Rita and Evergreen)

Homes atop steep ravines near Mill Pond

Over the past two years – under guidance from the Governor’s Office – agencies, businesses and interested organizations worked collaboratively to identify ways to reduce the frequency and severity of the flooding. After signing an agreement in October 2018 committing to working toward solutions, a new collaborative team called the Tualatin Watershed Enhancement Collaborative (TWEC) was formed to take action on that commitment.

What can you do?

You and your neighbors can review the Three-Year Workplan, see what actions your community can take on, and provide your thoughts/ideas about the plan to the Board of Commissioners. Just as we’re all part of the history of this complicated basin, we can all be part of the solution.

The Board meets Tuesday, February 26, 6:30 p.m., Washington County Public Services Building, 155 N. First Avenue, Hillsboro. Public comment is welcomed. You also may mail your input to this address or email to: CAO@co.washington.or.us.

The Board’s decisions directly affect your community. The more you help inform their decisions, the better the outcomes. To learn more about the background of this effort, visit www.cedarmillcreek.org.


Dark orange outline indicates Cedar Mill / North Johnson Creek basin




Cedar Mill Creek
Flood Remediation
Collaborative Strategy

The Oregon Solutions Project – Cedar Mill Creek and North Johnson Creek Flood Remediation effort would like your input! The project team has drafted some initial strategies to mitigate future flooding events and invite you on a self-guided tour!

More information available at http://cedarmillcreek.org. Have a Nextdoor community? Please share this with your friends and neighbors.