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The City of Portland, Oregon

Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Ave, Suite 613, Portland, OR 97204

More Contact Info

Multnomah Arts Center Stormwater Swales

Multnomah Arts Center Parking Lot - Before and After

Multnomah Arts Center parking lot before
Multnomah Arts Center parking lot after

Rain falling on the Multnomah Arts Center parking once washed pollutants from the pavement into Tryon Creek. In summer 2013, Environmental Services constructed three parking lot swales that collect and slow stormwater runoff. Vegetation and soil in the swales filter oil, metals and other pollutants then release the water to Tryon Creek.

Native wetland plants grow in the swales. The native and ornamental plants in the surrounding landscape soak up rain and shade paved areas.

Swale Plants

  • Cascara – Rhamnus purshiana
  • Douglas Spirea - Spirea douglasii
  • Common bulrush - Scirpus Lacustrus
  • Sloughsedge - Carex obnupta
  • Common rush - Juncus patens

Native Plants in the Landscape

  • Douglas fir – Psuedotsuga menzesii
  • Vine Maple - Acer circinatum
  • Western Sword Fern - Polystrichum munitum
  • Beach strawberry - Fragaria chiloensis

About the Watershed

About three fourths of the 4,000-acre Tryon Creek Watershed is in th ePortland city limits. Tryon Creek flows southeast for about seven miles from its headwaters in Multnomah Village to its confluence with the Willamette River in Lake Oswego.