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Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Avenue, Suite 1000, Portland, OR 97204

Watershed Facts

Columbia Slough Watershed Facts 

The Columbia Slough watershed contains:

  • 32,700 acres

  • Largest urban wetland in the USA (Smith and Bybee Lakes Wildlife Area )

  • Salmon refugia in the Lower Slough

  • 175 bird species

  • 26 fish species

  • 6 lakes, 3 ponds, 50 miles of waterway

  • 30 miles of flood control levees

  • 158,000 residents (1/20 of Oregon's population)

  • 54 schools, 2 universities, 1 community college

  • Critical wildlife corridors

  • Portland International Airport

  • Port of Portland marine terminals

  • 3,900 businesses

  • 57,000 jobs

  • 54% impervious surface

  • Columbia South Shore Well Field (drinking water)

  • One of Portland's "industrial sanctuaries"

  • Critical transportation corridors (I-5, I-205, I-84)

  • 250,000 railroad cars per year use its railroad tracks

  • The Slough is 303(d) water quality listed

  • 6 Golf Courses

  • 40 Mile Loop Trail

  • Canoe and kayak launches

  • 426 acres without sewers

  • Whitaker Ponds Environmental Learning Center

  • Lewis and Clark expedition sites

  • Historic Native American settlement sites

Heartbleed Security Notice

A serious security vulnerability known as "Heartbleed" was recently discovered in OpenSSL, a popular software library commonly used by many websites on the internet to encrypt communication between a user's computer and a web server.

PortlandOregon.gov is NOT affected by this vulnerability as it does not use the OpenSSL software library. Please rest assured we are dedicated to protecting your security on this website.