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Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

MAILING ADDRESS: 1120 SW 5th Ave, Room 1000, Portland, OR 97204

More Contact Info

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