Background The Port of Portland's Marine and Industrial Development (MID) section manages a wide variety of constructed and natural riverbanks, and has initiated a Riparian Zone Management Program to address conditions along the Willamette and Columbia Rivers in association with its other programs. A number of these projects involve vegetation enhancements or stabilization improvements and do not have mitigation permit requirements. These projects are managed entirely by MID and are not incorporated into the mitigation program. Mitigation staff become involved in riparian zone projects that have mitigation permit obligations, and these projects are included in the Mitigation Management Program.
Mitigation Plan Bank stabilization at Berth 503 was undertaken to repair damage caused by the flood of 1996 to the Willamette River frontage at Terminal 5. The total mitigation area, including the slope and greenway, is approximately 34,000 square feet.
Mitigation at Berth 607 was a result of impacts to surrounding habitat as a result of repairing two outfalls on the Columbia River that were heavily eroded. The permit required that approximately 23,200 square feet (0.5 acre) be planted with 1690 woody plants.
The Berth 607 Honda Dock Improvements included widening of the access ramp to Berth 607, repair of deteriorated pilings, removal of creosote-treated dolphins, installation of new steel dolphins and adjustment of the ballast from the floating dock. Native planting was required due to construction-related disturbance to the bank. The project at Berth 408 involved stabilizing and replanting approximately 3,200 square feet (0.07) of the Willamette riverbank at Terminal 4. The permits required that 53 (ACOE, DSL, DEQ) and 121 (COP) plants be installed.
Status The Berth 503 bankline was reconstructed in 1997 using sand fill, rock and riprap, and stabilized with mechanically stabilized earth which was then planted with native plants. The upland area adjacent to the slope is located in the City of Portland's Greenway and was planted with native species by the property developer. The final monitoring report for the Berth 503 bank stabilization was sent to the Department of State Lands in 2001. As of 2006, willows are well-established on the stabilized bank and much of the Greenway has reached 100% cover of trees and shrubs. The Port continues to manage and maintain the site for invasive species and native plant establishment.
Berth 607 was repaired and planted by April 2001. Planting consisted of 2560 native trees and shrubs to provide stabilization of the outfalls and riverbank. These included black hawthorn, Oregon ash, red alder, Indian plum, pacific crab apple, red flowering current, salmonberry, common snowberry, red-osier dogwood and pacific willow. Invasive vegetation was removed, silt loam was spread over the sand and mechanically stabilized earth, and a piped irrigation system was installed. Vegetation monitoring in 2004, during the final monitoring year, indicated that plant survival exceeded the 80% required by permit with less than 20% cover by invasive species. The Port continues to manage and maintain the site for invasive species and native plant establishment. Berth 607 Honda Dock Improvements occurred in the winter and early spring of 2007. Plantings were installed by March and will be monitored for three years as required by the Corps of Engineers and the Department of State Lands. The initial vegetation monitoring will occur during the fall of 2007.
Planting at Berth 408 was completed by February 2001. In total, 123 trees and shrubs were planted including black hawthorn, red alder, red-flowering current, common snowberry, Nootka rose and live cuttings of local willow species below 17´ elevation. A piped irrigation system was also installed. Vegetation monitoring in 2004, during the final monitoring year, indicated that plant survival exceeded the 80% required by permit. The Port continues to manage and maintain the site for invasive species and native plant establishment.