Watershed Plan Areas

Portland is part of the Willamette River Basin, and the city is divided into watershed plan areas for its largest urban streams. 

• Columbia Slough
  The Columbia Slough flows from Fairview Lake about 18 miles into the Willamette River near Kelley Point Park.
• Johnson Creek
  Johnson Creek crosses several jurisdictions before entering the river near Milwaukie.
• Fanno Creek
  Only part of Fanno Creek is in Portland, and the stream flows west and south before entering the Tualatin River.
• Tryon Creek
  Tryon Creek flows through parts of southwest Portland before entering the Willamette near Lake Oswego.
• Willamette Watershed
  The Willamette Watershed plan area includes Forest Park, downtown's commercial core, industrial districts on both sides of the river, and Portland's most densely populated residential neighborhoods. 

Since it's a large and diverse area, the plan area is divided into smaller drainage areas called subwatersheds.