Mill Creek is located in the South Fork Clearwater River within the Nez Perce Tribe ceded territory of 1855 and within the Nez Perce National Forest. Mill Creek is a long linear watershed encompassing over 23,000 acres. It is of particular importance to steelhead and westslope cutthroat trout and is considered a population stronghold for these species. Chinook salmon are also present within the watershed.
Past land use activities have negatively impacted aquatic processes within this drainage. Encroaching roads and grazing processes have degraded the stream/riparian processes. The upper meadow of Mill Creek has been severely impacted by cattle grazing for several years. Grazing and the trampling of stream banks by cattle were a significant annual disturbance to riparian zones which led to changes in riparian plant communities. Aerial photographs taken in 1927 indicated that 80% of the stream banks were lined with riparian hardwood shrubs. In the same photograph taken in 1990, riparian shrubs lined only 5% of the stream banks. The riparian community consisted mostly of grasses and forbs in the first year of this project, 2000. Roads have been constructed in the Mill Creek watershed, and the majority of these roads were constructed several decades ago. Road/stream crossing assessments revealed that passage for aquatic species through many of the structures is not adequate or not functioning at all.
The Mill Creek Watershed restoration project began in 2000 and is a cooperative effort between the U.S. Forest Service and the Nez Perce Tribe. Since 2000 the Nez Perce Tribal Fisheries/Watershed Program, in cooperation with the Nez Perce National Forest, has accomplished various watershed restoration projects including fence construction and maintenance, riparian planting, culvert inventories, and culvert replacements and removals.