Background Jurisdictional wetlands at the Terminal 5 property were filled for development of a bulk-commodities marine terminal facility. The T-5 Powerline site was chosen for mitigation because it offered an opportunity to restore wetlands adjacent to the Willamette River and along a corridor that connected the river with Smith and Bybee Lakes. The mitigation site is located along the Willamette River at approximately river mile 3. Historically, it was part of a large wetland complex in the Ramsey Lake area and was filled with dredge material in the early 1940s.
Mitigation Plan The goals for this site were to 1) restore wetland hydrology; 2) establish emergent, scrub-shrub and forested wetland; and 3) establish a buffer around the wetland area. Target wetland functions and values include 1) diversification of wildlife habitat and enhancement of the wildlife corridor between the Willamette River and the Columbia Slough; 2) increasing the ecological integrity of the mitigation site; and 3) protecting and increasing painted turtle habitat. The regulatory requirements for the site include restoring 10.7 acres of wetland: 7 emergent; 1 open water; 2.7 wetland scrub-shrub.
Status The T-5 Powerline site was initially constructed as a 10.7-acre site in 1995. In 1996 and again in 1997, the section west of Time Oil Road was re-excavated in order to improve wetland hydrology. However, dry conditions during 1999 and 2000 further reduced the wetland footprint. A total of 10 monitoring wells were installed to evaluate groundwater levels on the western portion of the site, and information obtained indicated that adequate hydrology could not easily be achieved in the portion of the property closest to the river without jeopardizing the function of the existing wetlands. A modified design for restoring the wetlands was proposed in 2001, which allowed for the restoration of 2.6 acres east of Time Oil Road, re-excavation of approximately 4.4 acres west of Time Oil Road, and approximately 3.7 acres of restoration at the Vanport Wetlands site. This was accepted by the agencies, and restoration work was completed in 2003.
The performance criteria as specified in the permits for the section of the site located east of Time Oil Road were met in 2003. Monitoring of performance criteria west of Time Oil Road will continue through 2007. Since 2003, wildlife observations on the site include over 60 species of birds; three amphibian species; three species of reptiles (western painted turtle, common garter snake and western terrestrial garter snake); and 11 species of mammals.
A road-over-rail project located in the vicinity of the wildlife corridor facilitated an under-crossing tunnel for animals below Time Oil Road. The tunnel was completed in the spring of 2004 and is currently under surveillance of a digital, infra-red, motion sensor camera. The camera has captured numerous animals utilizing the passage from rodents to coyotes to reptiles. In the spring of 2007 the Port installed approximately 1000 new native shrubs along both sides of Time Oil Road. The plantings will enhance the wetland buffer while providing a natural barrier meant to direct wildlife towards the tunnel entrance and keep them off of the road.