Slough outruns poison past
Urban waterway, once foul, continues its rebound
In the very place where Lewis and Clark once camped, majestic blue herons still take flight and otters litter the water's edge with pearly shells after feasting on freshwater mussels.
Not that you would know it from nearby Airport Way or the endless string of business parks along it.
This is where the Columbia Slough - a meandering, misunderstood and often-misused waterway - approaches the end of its 18-mile length.
The real surprise is that it hasn't ended altogether. The channel once ran so red with the blood and offal of slaughterhouses that mill workers downstream refused to pull logs from it.
But last fall, the city added 114 acres to its Big Four Corners Natural Area in outer Northeast Portland, which contains significant stretches of the upper slough. The move created the fourth largest natural area in the city at 165 acres, and extended a firewall against the 'corporate sanctuary' that surrounds it, where industry-ready land can go for $200,000 an acre.
'It's a core wildlife habitat,' says Ry Thompson, an environmental planner with the city's Bureau of Environmental Services and a member of the Columbia Slough Watershed Council. 'It's an acquisition we've been looking at for nearly a dozen years.'
Educating the public about the slough - an almost motionless backwater that stretches from Kelley Point Park, near the confluence of the Columbia and Willamette rivers, to Fairview Lake in east Multnomah County - is a big reason for the 12th annual Columbia Slough Small Craft Regatta, which takes place this weekend. Thompson says the event has drawn more than 500 participants annually in recent years.
The regatta is not a race at all. It offers short canoe and kayak trips for anyone with an interest in nature, history, activism or all three.
And it showcases the quiet, surprising beauty of a waterway that stubbornly struggles to overcome a history of abuse.
Taking a closer look
At the point where Sunday's regatta will begin - which is also the trailhead to a 40-mile walking loop - the slough does not look inviting. The waterway is narrow and still, like a small, stagnant pond, and clumps of dirt-colored algae tempt one to imagine the worst.
But a short distance east, the slough widens and splits in a spot where towering black cottonwoods and Oregon ash shade waters that ripple in a light breeze. The only sounds come from songbirds and young wood ducks that skitter away frantically.
Along the length of the slough are bald eagles, great horned owls, deer, beaver and white sturgeon as long as a small boat.
'It's such a great waterway,' says Bonnie Shoffner, an outreach coordinator for the Bureau of Environmental Services and a Watershed Council member. 'It's a very nice beginning paddler experience.'
More important, Shoffner says, the slough offers an invaluable educational resource. 'It reflects the complexity of the culture and mixed use and how we can do that well,' she says.
Developments on and around the slough have mirrored the area's evolution. Chinook longhouses gave way to trapping, logging and farming with the arrival of European settlers in the 19th century. Sawmills sprang up along the slough, and the waterway was used to ship milled lumber to Portland. Truck farms, many run by Italian immigrants, came later.
But in time, industrial wastes and pesticides fouled the slough's waters, leaving a toxic legacy that remains a vexation today.
'I'm not saying that the slough is pristine by any means,' Thompson says, combing through a small, unappealing clump of algae with his fingers. 'There's just low-level pollutants throughout the system.'
Thompson says most of the long-lived poisons in the slough reside in the sediment beneath it. But swimming is not advisable, nor is eating any of the dozens of species of fish that inhabit the slough's wandering channels.
Still, Thompson says, environmental regulations and a heightened awareness of the value of natural areas have brought the slough back.
'There's a lot less algae than there used to be,' he says. 'It's not a mountain stream. It heats up in the summer. It's shallow. It's a different kind of system.'
Salmon run and trees grow
It's also, Thompson says, a heavily managed system. The Multnomah County Drainage District, a nongovernmental agency formed at the behest of farmers in 1917, still controls flooding in the area, which was once inundated each spring by the rising waters of the Columbia River. One pumping station can pull a million gallons a minute from the slough, Thompson says.
But water also is pumped from the slough in the dryer months, he says, part of a 'low flow' strategy that allows cooler groundwater into the mix.
Vegetation is planted on the banks of the slough to help shade its waters. 'We've planted about 1.2 million trees and shrubs,' Thompson says. 'Temperature is kind of the main issue we're trying to address as far as water quality goes.'
And the city builds 'created wetlands,' catchments around sewer outfalls to filter runoff from impermeable surfaces like roads and parking lots.
Efforts like these can pay tangible dividends, Thompson says. Within Big Four Corners, the Bureau of Environmental Services has established special management units to restore stands of Oregon white oak and western red cedar.
And studies done along the lower nine miles of the slough reveal that the waterway is an important stopover for juvenile salmon.
'They're rearing, feeding, resting,' Thompson says. 'Some of the fish are growing as much as 30 to 40 percent while they're here. To see Columbia River salmon using Portland habitat on their way to the ocean, it was a pretty big 'aha' moment for federal agencies.'
Economics and the environment have come to an understanding along the Columbia Slough, Thompson says.
'It's quite a juxtaposition, industry and nature on the slough,' he says. 'They can coexist. They must coexist.
'Why do people move to Oregon? They love the natural areas, even in the city. If you want to help the economy, you also require a healthy ecology.'
From the back of a canoe, Thompson points out enormous boulders, carried into the area thousands of years ago by the cataclysmic Missoula Floods.
He points to where beavers have gnawed at the base of a willow tree and says the great blue herons policing the slough from nearby treetops may one day establish a rookery at Big Four Corners.
'I think this is one of the most spectacular resources we have in the city,' Thompson says. 'It's a hidden gem. People don't know about it.'
Small Craft Regatta
When: 9 a.m. Sunday, July 30
Where: Portland Water Bureau Canoe Launch, 16550 N.E. Airport Way, 503-823-2831, www.columbiaslough.org
Cost: $5 suggested donation, free 45-minute canoe or kayak rental, reservations are necessary and space is limited