Design & Construction Standards Update

News and Updates

District staff held a kickoff meeting at the Hillsboro Civic Center on August 8, 2017. Partners and members of the public attended the event to get context on the hydromodification requirement and reviewed the process for this phase of the Design & Construction Standards update. View the slides (PDF, 3.3MB) from this presentation to learn more. Sign up to be informed of future meetings.

Commonly Asked Questions

Why is CWS updating the Design and Construction Standards?

Clean Water Services works with our community and partners to provide cost-effective and environmentally sensitive management of water resources for the Tualatin River Watershed. Part of that work is to provide Design & Construction Standards for sanitary sewer and surface water management that are periodically revised. The update process is necessary to incorporate changes in the watershed-based permit, and to reflect new technologies, approaches and development patterns.

What is included in this update?

This update process will:

  • Implement a hydromodification strategy to meet Oregon Department of Environmental Quality permitting requirements
  • Refine stormwater treatment and erosion control standards adopted by the 2017 update (Chapters 4 & 6)
  • Revise pump station standards (Chapter 9)
  • Make housekeeping edits to administrative and submittal requirements (Chapters 1 and 2)

These updates will be developed with stakeholder input and proposed for Board adoption in spring 2019.

What is the timeline for the update process?

What is hydromodification?

When rain falls on traditional parking lots, sidewalks or driveways, it flows across the surface to the nearest storm drain, and immediately to the nearest stream or river. After all, the drainage system was designed to concentrate surface water flows and efficiently send them downstream.

Nearly every time it rains, urban streams rise rapidly, flowing faster and faster. This “flashiness” cuts away stream banks and disrupts the physical and biological systems that support fish and other aquatic organisms. Preventing stream flashiness is an important strategy to protect and restore our urban streams and wetland systems. 


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Send questions or comments to

Damon Reische
Planning & Development Division Manager

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