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Oaks Bottom Habitat Restoration

Photo courtesy of City of Portland Bureau of Environmental Services.

The Oaks Bottom Wildlife Refuge is the largest remaining natural area within the Lower Willamette River floodplain. The complex of meadows, woodlands and wetlands offers a unique opportunity for large-scale, tidally influenced floodplain and wetland area to be restored in the heart of the city, at approximately River Mile 16 just north of the Sellwood Bridge. 

The Corps is undertaking this large-scale habitat enhancement project in partnership with the City of Portland Bureau of Environmental Services and Parks & Recreation. 

Construction Updates

In March 2018, cottonwood and ash trees and other vegetation will be cleared in construction areas. Completing this work before the primary bird nesting season in mid-April, ensures that birds will build nests out of harm’s way. Many large trees will be re-used on-site as large wood in the channels or as snags. A total of 8,500 native trees and shrubs will be planted after construction is complete. 

To do the tree removal work, the contractor will construct a ramp from the railroad side of the Springwater Trail down into the wetland. When this work is complete, activities at the site will be relatively quiet until summer. Most of the construction is scheduled during the in-water work window, between July 1 and October 31. 

Project Details

Map courtesy of City of Portland Bureau of Environmental Services.
The U.S. Army Corps of Engineers is partnering with the city of Portland to restore 75 acres of wetland habitat by:
  • Replacing the existing culvert under the Springwater Corridor and railroad berm with a larger box culvert;
  • Removing a water control structure;
  • Excavating tidal slough channels; and
  • Removing invasive plant species and replanting with native riparian and wetland species.

Funding for the project is provided by Corps and the city’s Bureau of Environmental Services. Portland Parks & Recreation owns the Oaks Bottom Wildlife Refuge, and will continue to be the steward of the property after completion of the project. Project costs are shared between the Corps (65%) and the city (35%). 

The Continuing Authorities Program and Section 206 of the Water Resources Development Act of 1996 allow the Corps to partner with non-federal agencies to accomplish certain water resources development projects.

Short Term Impacts, Long Term Benefits

During construction, the Springwater Corridor Trail will close for up to 120 consecutive days. Directional signage will provide bicyclists and pedestrians with alternative routes around the closure. Walking and biking access to the Oregon Yacht Club floating home community and Oaks Amusement Park will be maintained throughout the project via the Springwater Corridor.

The restoration of Oaks Bottom will provide important habitat for fish and wildlife that are considered "special status," including threatened salmon and over 100 bird species. Improving the connection between Oaks Bottom and the Willamette river will:

  • Facilitate fish passage into Oaks Bottom so that juvenile salmon can access calmer waters to rest and find food;
  • Restore the natural tidal exchange between Oaks Bottom and the Willamette River to improve wetland habitat; and
  • Reduce invasive species and foster growth of native vegetation.

The addition of two wildlife viewing platforms will also increase opportunities for recreational and educational enjoyment of the Oaks Bottom Wildlife Refuge.