Columbia Slough Outfall 57 Stormwater Project

Sewer and Stormwater
Environmental Services is designing a stormwater management project in the Portsmouth neighborhood to reduce the amount of pollution entering the Columbia Slough. This project is part of a larger effort to improve water and sediment quality in the Columbia Slough.
Construction is expected to begin in January 2025 and take about one year to complete.
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When it rains, stormwater may pick up and carry pollutants from the street – metals (such as copper and lead), oil, and dirt – into the storm drains.  The polluted stormwater then travels through underground pipes into the Columbia Slough. This is one of several Columbia Slough stormwater projects with the goal to remove pollutants from stormwater before they reach the slough. 

Engineers are designing infrastructure to capture and clean polluted stormwater in your neighborhood, including above ground green street planters and underground stormwater facilities, such as filter vaults and sedimentation structures. These facilities are specially designed to filter stormwater and reduce the amount of pollution entering underground pipes and reaching the slough. These improvements will protect water quality, the community, and the health of the Columbia Slough watershed.

In addition, we will be partnering with the Portland Bureau of Transportation (PBOT) to install or upgrade several sidewalk corner ramps to current Americans with Disabilities Act (ADA) standards.

Project Area

The Columbia Slough Outfall 57 Stormwater Project will build underground stormwater facilities in multiple locations between N Columbia Boulevard to the north and N Newark Street to the south, and between N Geneva Avenue to the west and N Fisk Avenue to the east.  Green Street planters will be built along N Columbia Boulevard to manage stormwater in the public right-of-way on the north and south sides of Columbia Boulevard between N Columbia Court and N Fiske Avenue.

What's Happening Now

Over the next several months, work crews will be in the study area to perform investigative activities. Activities include site visits and evaluation, survey, utility locates, and soil sampling.

Some investigative activities will require restricting parking and closing travel lanes. The traveling public should expect minor traffic delays.

Information gathered will help determine the repair locations, stormwater management methods, and how to minimize construction impacts on residents and businesses.

We Want to Hear from You

Environmental Services would like to hear from you about special events, school activities, and community services in your neighborhood you think might be affected by this project. Also, we want to know if you have any concerns related to business operations, disability or mobility issues, or medical or business deliveries. Your input will help us design a successful project that minimizes the impact to your neighborhood during construction.

We will inform residents and businesses about project activities and respond to questions and concerns in a timely manner. We encourage you to:

  • Visit this project webpage regularly for updates. 
  • With questions or comments, please contact Matt Gough by email or phone 503-823-5352.
  • If you have a question or concern, please be sure to include your name, property address, and project name (Outfall 57) in your voicemail and email so we can provide you more details about what to expect in front of your property.
  • If your basement sewer backs up or your property or street floods, please report it immediately to the City’s Maintenance Operations hotline at 503-823-1700. It is staffed 24/7, all hours and all days.

Project Background

Since 1993, Environmental Services and the Oregon Department of Environmental Quality (DEQ) have studied the Columbia Slough Watershed and worked together to improve sediment quality. Studies show widespread, low-level contamination throughout the slough's sediments with a few isolated areas of higher contamination. The City's cleanup approach includes controlling the source of the contaminants, cleaning up the most contaminated areas, and long-term monitoring. Environmental Services and DEQ are working together to improve water and sediment quality in the Columbia Slough. By identifying the sources of pollutants and controlling them, less pollution will reach the waterway. The Columbia Slough Stormwater Projects will help with this goal.

Additionally, this project was formerly known as the Portsmouth Stormwater Project and included many green streets planters in the neighborhood. After community feedback and more site investigation and research, underground stormwater facilities were deemed the most effective and appropriate way to manage and treat stormwater in most locations throughout the neighborhood. 

Get Support for your Green Project

Do you have an idea for a green project that will improve your community and the environment. Environmental Services has resources to help keep our watersheds healthy and our rivers and streams clean.  

Project ideas include, but are not limited to: 

  • Planting trees in your yard and encouraging neighbors to join you 
  • Installing a rain garden or native plants at a place of worship, business, non-profit or school 
  • Removing pavement and replacing it with trees or plants 
  • Engaging your community group in watershed education opportunities 

To learn more about how we can fund your project, contact: or 503-823-5729

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This project will help protect the health of the Columbia Slough Watershed