Abandoned Mining Pits Become Valuable Habitat: Willamette Confluence Preserve


LANE COUNTY — Rivers are more than just water.

When you think of the ways a river benefits people, your first thought is almost certainly related to water. But the fine gravel that forms the riverbed is nearly as important in the establishment of permanent settlements.

It’s a key ingredient in concrete and other mixes used to build roads, sidewalks, foundations and other structures. People have been mining such gravel from pits at the edges of the Willamette River for decades—a practice that often leaves behind step-sided holes of stagnant water cut off from the healthy flow of the river itself.

Environmental Damage

This has certainly been the case near Eugene-Springfield at the confluence of the Middle and Coast Forks of the Willamette River. There a levee had been built to protect pits mines that pockmarked the riverbank for several miles, keeping them dry to accommodate mining equipment.

After mining at this location ceased in the 1980s, these holes filled up with ground water and rain. Their steep sides made access difficult for land animals, and many were choked off with blackberries and other invasive growth. The flooded pits provided little benefit for wildlife and were potentially dangerous to humans. They had been fenced off from public access ever since.

Conservancy Takes Action

In 2010, however, The Nature Conservancy acquired 1,400 acres of the former mining site and its associated floodplain. Their goal was to restore the area and eventually turn it over to public ownership. Under the leadership of the Oregon Watershed Enhancement Board and partially funded by grants from the Oregon Lottery, they have worked to lower the top of the levee so that the river can overflow it and reach the pits during all but the driest part of the year.

New side channels allow the water to escape back to the river, providing fish with access to these valuable, protected pools. The sides have been smoothed so that land animals can better reach these deep waterholes. Invasive vegetation was removed and replaced with native plantings. Thousands of trees and shrubs were added after the heavy construction was complete.

Today, some six miles of riverfront have been restored, allowing the Willamette to meander into side channels as it had historically. The mine pits have been transformed into sanctuaries for pond turtles, Osprey and juvenile salmon. Beaver and geese have been spotted, and even black bear and cougar could return to roam the area. After giving so much to the people of Oregon, this neglected section of the Willamette River is finally fully restored.

The Oregon Watershed Enhancement Board (OWEB) is celebrating its 20th anniversary this year. OWEB is a leader in the conservation of Oregon’s natural resources and enjoys strong public support for its contributions to community-based conservation, watershed health, and local economies.

About Author

The Oregon Lottery was created through the initiative petition process. In November 1984 voters approved an amendment to the Oregon Constitution requiring the establishment and operation of a state lottery. Since then, the Oregon Lottery has become a critical funding source for important Oregon programs.

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