Digging in, at the Oaks Bottom rehab project
Major work was underway in August at the "Oaks Bottom Tidal Restoration Project", designed to improve the movement, distribution, and quality of water in the Oaks Bottom Wildlife Refuge and lagoon, and to enhance the habitat for protected wildlife species, including amphibians, reptiles, birds, bats, and salmon.
The most dramatic change is that the dike between the Oaks Bottom and the Willamette River – upon which both the Springwater Trail and the Oregon Pacific Railroad tracks rest – has now been excavated to below water level, removing about 4,000 cubic yards of rock and soil.
This project involves the U.S. Army Corps of Engineers and "the Oaks Bottom Habitat Enhancement Project" of the City of Portland's Bureau of Environmental Services in association with Portland Parks and Recreation.
A contractor on the project is LKE Corporation, whose President and Lead Ecologist Kim Erion pointed out to THE BEE where the new excavation had revealed the remains of ancient Oregon Electric Railway Trolley pilings, long buried under the weir.
"We've excavated the culvert out of the cut, and much of the material removed isn't suitable for fill material, and so is being taken away from the site by Richard Samuel's Oregon Pacific Railroad, to an area where can be safely disposed of," Erion remarked at the site on August 12.
She pointed out vertical pipes around the perimeter of the cut, and explained that they are all part of their de-watering system. "The white pipes remove water pumped out of the work area, into a pond holding area, where some of the sediments can settle out.
"Then, that water is pumped into the new channel, and from there, it's pumped to water the upper areas of the natural area. So, all the water coming out of the construction site is being recycled and naturally filtered."
But, this project goes far beyond just removing and replacing the old, small culvert and the companion dam-like water control structure, explained Erion, whose company has specialized in land restoration and rehabilitation projects since 1993.
"Historically, this area was not good terrain for a wetland," Erion said, walking east into the former bog. "The small culvert choked off fresh water from flowing in and out as the Willamette River rises and falls with the tides backed up the Columbia River.
"When it's finished, the area will flood during high water periods; and, in low-water times, the new channel we're digging – it snakes through the area – will still provide a stream flowing through here," Erion made clear.
"We're working with a local company, Westlake Consultants – it's another woman-owned business – which created a computer-aided design model of the new wetland area, and we're using that digital information in our GPS-controlled excavating and contouring machines, allowing us to perfectly follow the topographical computer model!"
As part of the wetland contouring project, they'll remove about 4,000 yards of material from the area.
"The project is coming along well, and it's on schedule," Erion told us. That schedule calls for the Springwater Trail through Oaks Bottom to reopen no later than October 31st.