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Building habitat for the next century
Restoration bodes well for salmon in Oneonta and Horsetail creeks
A battered coho salmon swirls to safety under a root ball as Chris Collins makes his way down a rocky bank of Oneonta Creek.
A spawned Chinook salmon lies in a pool nearby. Fifty yards downstream several more coho patiently fin at the edge of a massive culvert under Interstate 84.
On a fall day when hundreds of thousands of salmon are finishing their life cycle in tributaries up and down the Columbia River, Collins is happy to see the fish return to tiny Oneonta and Horsetail creeks. Its another sign that a $1 million project to restore 190 acres of wetlands for migrating salmon is working.
Two summers ago the Lower Columbia Estuary Partnership and Collins oversaw the rebuilding of a slough that 50 years earlier had been virtually cut off from the Columbia by the construction of Interstate 84.
As state and federal agencies look for ways to rebuild runs of endangered Columbia River salmon and steelhead, they turn to Portland-based nonprofit groups like the Columbia Partnership, which specializes in finding and restoring wetlands. Habitat restoration in the Columbia basin is one of four areas of emphasis to rebuilding salmon runs.
The U.S. Environmental Protection Agencies and the states of Oregon and Washington created the Lower Columbia Estuary Partnership 20 years ago to tackle habitat projects along the 140 miles of river from Bonneville Dam to Astoria. Although it gets private contributions or state and local help for projects, the bulk of its funding comes from the Bonneville Power Administration as mitigation for environmental harm caused by Columbia River dams.
Which led LCEP and Collins to Horsetail and Oneonta creeks back in 2010.
The two creeks feed the 190-acre wetland tucked between the gorges steep basalt cliffs and I-84. But when engineers built the freeway they cut off four outlets to the Columbia and channeled all the water through one massive 230-foot long culvert.
In the spring, juvenile fish heading downstream like to use wetlands to rest, escape predators and grow. In the summer and fall, adult fish returning upstream use sloughs to cool off until temperatures drop in the Columbia.
Because of the culverts design the Oneonta/Horsetail wetland was barely accessible to migrating fish. If fish made it past the culvert they found the floodplain inhospitable long straight channels without good shelter that got too warm in the summer. A three-acre pond fed by Oneonta Creek in the winter would get cut off from flows once the stream receded in the summer.
The U.S. Forest Service owns the land and identified the area as a good one to restore. It contacted LCEP and in 2010 the two began collecting data on water flow and temperature, fish and plants.
In 2013 crews used a two-month summer construction window to carve twists and turns into straight channels, place logs and root balls for shelter, shrink and make the pond better for fish, and plant thousands of trees and native plants to provide shade.
Now two years into four years of post-construction monitoring, Collins and LCEP are pleased with what they are finding.
Changes to the culvert have improved passage, water temperatures have dropped significantly, and logs, root balls and plantings have taken hold.
Were very happy with passage and temperature results, says Collins, LCEPs principal restoration ecologist. These sites are dynamic so its always interesting to see how they evolve.
In the culvert, 18-inch high baffles were notched to 6 inches so juvenile fish in the spring and summer and adult fish in the fall can more easily reach the creeks. A wide, flat concrete slab that funneled water into four of the culverts five tunnels was replaced with gravel and rocks to aid fish travel into the slough.
An array of electronic monitors at both ends of the culvert now tells researchers when specially tagged fish move in or out of the wetlands.
We get lots of hits of juveniles tucking into the site, says Collins. Were seeing them in the summer and fall.
Significantly cooler water temperatures are attracting the fish. Before restoration began, the highest summertime temperature in the pond reached 75 degrees the lethal threshold for salmon and steelhead. This summer, after one of the warmest and driest spring and summer on record, the ponds highest temperature was 65 degrees.
As the Columbia River heats up in the summer and in the future, its important to help create pockets of cool water for migrating fish, Collins says. This year we saw that temperatures in the project remained in a suitable range throughout the summer.
This is especially important for juvenile fall Chinook which complete their journey to the ocean in June, July and August.
They are the most estuary-dependent fish because they migrate during the harshest conditions, Collins says.
Anne Creason, project manager for BPA-funded estuary projects, said the restoration is doing what the agency hoped providing colder water habitat for upriver stocks of juvenile coho, chinook, sockeye and steelhead to rest and recover.
These cold water refuges are important for salmon growth and survival, Creason said. This restoration site also proves that estuary habitat in the Columbia River Gorge can be very important to fish migrating out to sea.
The changes are also attracting beavers, whose dams create more shelter for fish.
Now they can build dams and they dont blow out year after year in high water, he said.
When it started, the Oneonta/Horsetail creek project was LCEPs largest. Since then it has embarked on one twice that size near LaCenter, Wash. and the biggest yet is in the planning stages a 900-acre, $15 million to $20 million project just east of Washougal.
We spend a lot of time on projects in the gorge, Collins says. The gorge is really important and the Oneonta/Horsetail project was one chance to do something quite big in a really valuable area.
And, he says, the results found during this record-dry, hot spring and summer bode well for the future.
Were trying to make the Columbia and this wetland suitable for salmon in the next century, Collins says.