This story appeared in the Winter 2015 edition of Our Big Backyard, a quarterly magazine about parks and nature. Read more stories, plan an outing with a field guide, and find out more about fun nature events and classes.
As winter storms replenish the region’s waterways, juvenile salmon will find one more place to grow and thrive.
A years-long project is restoring native wetlands at Metro’s Multnomah Channel Marsh, a narrow area of more than 300 acres wedged between Highway 30 and the channel, just across from Sauvie Island.
As part of that project, work this fall made it easier for juvenile Chinook and coho salmon, steelhead and cutthroat trout, and Pacific and brook lamprey to swim into the marsh. The improved connections are important because the marsh’s slower waters provide crucial habitat with abundant food and fewer predators, boosting the health of young salmon before their journey to the ocean.
In October, crews breached two 100-foot-wide sections of the earthen berm along the channel, creating openings that will allow salmon to enter the marsh when the water level rises.
Workers also removed three culverts under the property’s sole road, replacing them with a 27-foot-wide bridge to allow fish and wildlife easier passage through the wetlands.
“A lot of the work we’ve done out here is to get water back to some semblance of what it used to be here,” Curt Zonick, a senior natural resources scientist at Metro who is leading restoration efforts at the site. “What we’ve done is to try to get water back onto the site, and then get it moving through the site.”
The project is a partnership between Metro and Ducks Unlimited. The restoration work is possible in part thanks to voters, who passed a regional parks and natural areas levy in 2013. The project also received $240,000 in grants from the U.S. Fish and Wildlife Service, the Oregon Watershed Enhancement Board and Ducks Unlimited.
On a recent autumn morning, bald eagles perched on trees across the channel as egrets, blue herons and other birds soared across the quiet landscape, occasionally landing in the wetlands to fish.
It all could have looked much different today.
A previous property owner drained large portions of the wetlands, re-aligned Crabtree Creek into a ditch and graded much of the land in preparation for potential residential development.
But floodwaters in 1996 left the site under about a dozen feet of water, and Metro started to acquire parcels at the site with money from the natural areas bond measure that voters approved in 1995.
In 2000, Metro partnered with Ducks Unlimited to install two water control structures to help restore more natural, seasonal flooding to about 150 acres.
Six years later, crews returned Crabtree Creek to its historic streambed, connecting two large wetland basins at the site and restoring flooding to the site’s large north basin.
The results of the work are evident in the land’s inhabitants. Northern red-legged frogs, which previously crowded into two small beaver ponds, now lay their egg through more than 100 acres of the restored wetland.
Many new beaver ponds have helped create habitat for turtles, which did not inhabit the site before the wetland restoration. Blue herons breed at a new rookery that they built the year after the water control structures were installed.
Metro is also partnering with fish biologists from Oregon Department of Fish and Wildlife and the National Oceanic and Atmospheric Administration to monitor fish populations and gauge how much they use the restored wetlands and the new breaches.
Later this winter, biologists hope to capture and tag several thousand juvenile Chinook salmon from Willamette Falls and release them just upstream of Multnomah Channel Marsh. Scientists hope that these marked salmon will find their way into the restored wetlands to grow and to someday return to the region’s rivers and streams to spawn.