McKenzie Watershed Council

This , the McKenzie Watershed Council and EWEB are back with more ! We’re exploring one answer to the question: “Why reconnect the floodplain?” It's also – so we’re focusing on how reconnecting the floodplain can improve water quality!

The McKenzie River in particular is the sole source of drinking water for 200,000 people in the Eugene area – and it is an excellent source. It’s exceptionally clear most of the time – but during storms, rains can pull sediments down from the hillsides and into the waterways.

Land management practices over the last 150 years have changed the shape of our river valleys. Rivers should naturally flood the valley floor, forming braided wetland complexes with cool, slow-moving waters. But by confining rivers into single-thread river systems to protect roads, bridges, homes and other infrastructure, rivers become more like fire hoses that transport sediments downstream. When water is no longer allowed to connect to its floodplains, it loses the chance to slow down and let sediments to drop out or get filtered through downed wood and plants.

By reconnecting the river to its floodplain, we’re helping the river spread out and dissipate its energy across the floodplain. By slowing water down, sediment drops out and settles into the riverbed, protecting the McKenzie’s crystal-clear waters and reducing the need for EWEB to add as many chemicals to remove sediments as part of the drinking water filtration process.

In other words, by reconnecting the river to its floodplain, we’re restoring its natural filtration processes! Not only do we lower the cost for drinking water treatment, but we support water quality for all the people, fish, plants, birds, and bugs that we share the McKenzie with!

The image shows an in-stream photo from Phase 1 of the South Fork Floodplain Reconnection Project, completed in 2018. Wood crisscrosses the river, whose waters are clear enough to see aquatic plants growing below the surface.

Follow along throughout the summer for project updates and every !
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Please be advised: The U.S. Army Corps of Engineers (USACE) is planning to release flow pulses from Cougar Dam on the South Fork McKenzie River as soon as Friday, March 6th for up to five days. The release will result in higher and faster-moving water for up to five days, which will create potentially hazardous conditions for recreational users and may cause minor inundation in low-lying areas downstream of the dam to the confluence of the South Fork McKenzie and the mainstem McKenzie Rivers.

The increased flows will help move juvenile spring Chinook salmon and bull trout downstream, supporting ongoing fish passage efforts in the McKenzie River Basin. The water releases are also intended to activate recently restored side channels and floodplain areas, which improves the ecosystem and creates better rearing habitat for fish.

While these releases are within the dam's standard operational range, they do not coincide with naturally occurring higher inflows. Recreators who are used to a lower river and no significant rain may be surprised by the rapid increase in flow.