The McKenzie River Sub-basin is known for outstanding water quality and steady flows due to its unique hydrogeology. It is one of the last remaining strongholds for threatened Willamette River spring Chinook salmon and bull trout. McKenzie rainbow trout are a prized target for recreational fisheries and the businesses that depend on them. Many strong partnerships exist among local organizations, and the Sub-basin is a hub for innovative programs. Despite these excellent features, the Sub-basin is showing signs of degradation in water quality and habitat quality, loss of riparian forest, and disconnection from its floodplain. These downward trends are largely a result of a variety of anthropogenic impacts including dam and hydroelectric project construction, rural and urban development pressures, and land-use practices. Conservation and restoration in the McKenzie River Sub-basin is essential to providing the foundation from which ecological uplift in the entire Willamette River Basin can occur.
Deer Creek flows into the upper McKenzie River downstream of Olallie Campground near river mile 80. Until recently, lower Deer Creek was significantly degraded. Large wood had been removed, berms were built to channelize the creek, and the stream bed consisted of large cobble and boulders with little spawning gravel and few large deep pools. In 2016, the US Forest Service and the watershed council partnered to implement a restoration project on the lower portion of Deer Creek.
The Lower Deer Creek Floodplain Enhancement Project enhanced habitat conditions within the lower 3/4 mile of the creek through the placement of large wood structures. The creation of these log jams within the creek and along stream banks will help create places for fish to spawn, and create cover for all life stages of salmonoids in the area.
The lower South Fork floodplain has been significantly impacted by the presence of Cougar dam. Similar to the smaller-scale Deer Creek Project, the intent of the South Fork Project is to restore natural processes which will create and maintain habitat over time by removing berms, placing fill within incised channels, adding large wood throughout the floodplain, upgrading culverts, and decommissioning roads.