Adjacent to Sauvie Island and a short walk from the traffic of U.S. 30, a quiet, undistinguished marsh is testament to conservation efforts that have restored the historic function of an important wetland.
Like turning back the environmental clock, Metro and its partners have returned the Multnomah Channel natural area wetlands to much like it was when it first was mapped more than 150 years ago.
The 300-acre natural area is part of another 600 acres of restored floodplain – owned by the Bonneville Power Administration and others – that is sandwiched between Multnomah Channel and U.S. 30. Once graded and drained for a dairy farm, the natural area has been transformed over a dozen years.
The Multnomah Channel wetlands flood in winter and spring, and slowly dry through the summer. Streams from the Tualatin Mountains to the east bring cold water, which eventually flows in to cool the Willamette and Columbia rivers. The wetlands filter out sediment and toxins, and reduce the risk of flooding in developed areas. They are home to native wildlife, a refuge for young salmon and the state-listed northern red-legged frog.
"We're not trying to turn back time magically," said Jonathan Soll, science and stewardship manager for Metro. "We're trying to take cues from what was here before and mimic the function."
But nature still needs a helping human hand.
Crews regularly visit the wetland, cutting weeds or spot-spraying invasive reed canary grass and other pests. New trees and shrubs need attention for several years until they can out-grow grasses and fend for themselves. And sometimes a planting must be replaced.
Metro voters will decide in May whether to continue the work of restoration through Measure 26-152, which would establish a five-year, $53 million levy to help sustain and protect the agency's 13,000 acres of natural areas, care for its regional parks, improve public access and conservation education and fund community project grants.
Bond measures in 1995 and 2006 established Metro's Natural Areas program, with the goal of protecting water quality, wildlife habitat and outdoor recreation opportunities for future generations.
Since 1995, Metro has invested a total $360 million into more than 16,000 acres of environmentally significant natural areas and parks – properties that include more than 100 miles of river and stream banks, wetlands, rare prairies, oak woodlands and uplands forests.
Bond funding paid for the initial stabilization of the lands – the large-scale removal of invasive species, replanting, selective logging and other work to give nature a boost – but not the regular upkeep and other needs, or to manage accessibility if the property is open to the public.
The levy would cost the owner of a $200,000 home approximately $20 yearly for five years.
"We knew going into the bonds that we would have a huge portfolio of natural areas," Soll said. "The levy would allow resources to get to trouble spots, to patch holes in the matrix."
Wildlife at work
The beaver had been working on its perfect arc of a dam just steps from the old farm road when the human visitors arrived. Startled, the beaver froze in plain view. Its mate watched, similarly motionless, from a nearby tussock.
Wintering water fowl, including a pair of tundra swans, paddled on the marsh behind the beaver dam. Spring was still just a hint in the misty rain.
"When we bought the place, it was all graded out to be a golf course," Soll said. "It had been a dairy farm. It had undergone draining and diking. People don't find wetlands too beneficial when they're trying to farm."
For millennia, flood plains like those along the Multnomah Channel had held and filtered flood waters in a natural seasonal rhythm. Native species thrived.
But the low lands were prized for farming. Without flood plains, high winter waters flooded developed areas. As wetlands were captured for development, the threat of flooding grew, whether it was from Johnson Creek in suburban Portland or from the Willamette River.
"The big problem is what used to be just a winter storm becomes a flood storm," Soll said. "We're catching up. We are realizing a place like Multnomah Channel can help us solve this problem.
"We need to make these investments in Multnomah Channel and these little flood plains in Gresham and Beaverton that keeps the water from just rushing down," he added. "We need to restore the flood plains on Johnson Creek so that people's houses aren't flooded by just a winter storm."
More than a decade
Work at the Multnomah Channel natural area began in about 2001, with the installation of two water control devices that mimic the annual cycle of flood and drying. The results were almost immediate. Young salmon, particularly Chinook, used the refuge.
"Fish were getting in, they were using the habitat and their growth rate was pretty staggering," said Curt Mykut, a regional biologist with Ducks Unlimited, which is a partner in the wetlands restoration.
When surveys of northern red-legged frogs' egg masses showed that holding the flood water just a little longer would help survival, the extended wet time not only caused a population explosion of frogs, it also drowned out stands of reed canary grass. In its place grew native plants like wapato and sedges.
"The more we learn about green infrastructure, the more we realize it's a really good investment, a really good investment over time," Soll said. "Just get out of the way of nature."
An ongoing story
The Multnomah Channel success story isn't done.
Ducks Unlimited, Metro and its partners hope to further improve the wetlands for young salmon and other fish by installing two broad breaches in the natural berm to better connect the wetlands to the Multnomah Channel during high water events. The project, which is planned for 2014, also would remove three undersized culverts between the two main basins.
"During peak high water movement, these young fish depend on these slower moving areas, to conserve energy and to forage," Mykut said. "With dams and developments, we've lost function and conductivity to the flood plains.
"A 300-acre site is no insignificant piece of habitat," he said. "It's not often that you find pieces that large that have an impact on a real population of fish."