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Pits to Ponds

River restoration brings back habitat
Wildish Construction creates  a new side channel at CARP. Photo courtesy River Design Group.
Wildish Construction creates  a new side channel at CARP. Photo courtesy River Design Group.

Oregon’s rivers aren’t meant to flow in straight lines. They are meant to meander and twist under the shade of native trees, giving fish like threatened upper Willamette spring Chinook a safe route to the ocean and back. Humans haven’t just dammed and straightened the Willamette — we’ve boxed it in with construction and with the gravel mines fueling that construction. 

McKenzie River Trust’s Coburg Aggregate Reclamation Project (CARP) at Green Island is one effort to give salmon and other species their habitat back. Right now the former gravel pit looks like a construction site, with huge trucks and earthmoving equipment from Wildish Construction rumbling around its quiet pools. But Chris Vogel, the project manager for the site, envisions flowing water, plants and wildlife.

Liz Lawrence, MRT’s director of resources, says CARP’s three steep-sided gravel pits will become sloping ponds that are connected to the floodplain at the confluence of the McKenzie and Willamette rivers through a 2,200-foot-long side channel west of the ponds.

In 2010, MRT used money from the Bonneville Power Administration’s Willamette Wildlife Mitigation Program, created to mitigate the effects of the Willamette’s dams, to purchase the shallow gravel mine located on the southeast edge of its Green Island restoration project and begin restoring it. The 1,000-acre Green Island and its 56-acre CARP project are just north of Eugene/Springfield.

After mining is completed in Oregon, the land must be reclaimed and put to some sort of beneficial use. Vogel says when high water came into the pits, fish were trapped there when the water went down. “The fish have no place to go, except swim or be eaten,” he says, gesturing at the pits on a hot, late summer day. The pits also harbored nonnative fish, such as the invasive carp the project is named for. 

The cost of the project, funded by BPA, Oregon Watershed Enhancement Board and Meyer Memorial Trust, is about $1 million. River Design Group out of Corvallis did analysis and restoration design. Most of what was needed for restoration, including gravel, was already on the site, and Vogel says mounds of rock and gravel that had been mined but not yet sold were included in the purchase.

CARP will go above and beyond the usual standards for gravel pit restoration. Vogel asks, “Why not make it the best we can?” and see if that helps drive others to do the same in removing manmade impediments to the river’s natural flow. The expense, he says, is in the equipment, so why not use that equipment to make the restoration as close to natural as possible.

Making CARP the best restoration MRT can achieve means changing the steep sides of the pit to a more natural grade as well as adding large woody debris such as root wads to create shade and habitat. The standard restoration for a gravel pit, Vogel laughs, is sloping the sides enough so someone could crawl out if he fell in.

In addition to trees and shrubs being planted at Green Island, as the water begins to flow during fall and winter rains native grasses will take root through “passive restoration” and the growing ecosystem will provide food and shelter for western pond turtles, mergansers, green herons, great blue herons and more.