Cedar Mill Creek and its tributary, North Johnson Creek, drains 5,300 acres from the West Hills into Beaverton Creek in the Tualatin Hills Nature Park. These creeks pass through neighborhoods and parks, around businesses and under roadways, and join at the intersection of Walker Road and Murray Boulevard in Beaverton.


Streams have been impacted by rain patterns and human activities including:

  • Draining of wetlands for early logging, farming and other development.

  • Homes construction in historic floodplains before regulation was in place.

  • Urban growth, roadway construction and reduced natural space limiting absorption of rainfall.

These changes cause flooding, especially at lower elevations.

The Cedar Mill Creek Flood Remediation Collaborative, comprised of agencies, businesses and other interested organizations in Washington County, formed a project team to mitigate flooding and provide high-quality natural habitat within the Cedar Mill Creek/North Johnson Creek Basin. Oregon Solutions guided this effort by bringing stakeholders together to better understand local flooding and to reach agreement on working together to address these issues. The result included the signing of a Declaration of Cooperation, which included the formation of the Tualatin Watershed Enhancement Collaborative (TWEC). Learn more


The Cedar Mill/North Johnson Creek basin has been TWEC’s first priority. Using public comments and experiences shared at several open houses, technical experts developed potential strategies to both mitigate flooding and to improve the health of the watershed. Those strategies fall into two categories:


Structural projects:

Strategies that help manage flooding by building or enhancing public infrastructure along stream corridors.

Policies and Programs:

Strategies that increase the community’s flood resiliency.