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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

Carolina-Terwilliger Subwatershed Facts

  • The Carolina-Terwilliger subwatershed covers about 854 acres of southwest Portland.
  • About 500 feet of natural riverbank remain on the Willamette River in this subwatershed.
  • Cottonwood Bay is used as stop-over habitat for osprey, hawks, herons, and other birds.
  • The subwatershed has 28,770 (5.4 miles) feet of open stream channels.
  • Parks and open space make up 234 acres of the subwatershed; 190 acres of land are in public ownership.
  • The central portion is extremely steep and has not been developed.
  • 420 acres of the subwatershed are forested.
  • 31 acres of the subwatershed have woodland type tree canopy.
  • Three streams that originate in Marquam Nature Park and Terwilliger Wildlands flow to a combined sanitary and stormwater pipe near Barbur Boulevard.
  • About half of this subwatershed is impervious area, mostly streets.
  • The forested areas and streams of the subwatershed provide an important link between the West Hills and the Ross Island-Oaks Bottom ecosystem complex to the east, and between Marquam Nature Park to the north and Tryon Creek State Natural Area to the south.

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.