Fifteenmile Creek originates at Senecal Springs on Lookout Mountain in Oregon's Cascade Range and flows northeast, eventually joining the Columbia River just below the Dalles Dam. Where the river flows through the Badger Creek Wilderness, it is classified as wild, descending from Senecal Springs, which is a series of large springs with unconfined braided stream channels in a sub-alpine forest. At 5,900 feet in elevation, Lookout Mountain is the highest point in the Badger Creek Wilderness. The braided channels soon come together as one confined channel flowing in a high gradient stream through a dense mixed conifer forest prior to ending at Badger Creek Wilderness boundary. The next stretch of river is classified as scenic and flows downriver from the Badger Creek Wilderness boundary near Fifteenmile Creek Campground to a location downriver of the confluence with Fret Creek. Multiple waterfalls are present in the river with the highest estimated at 51 feet high. Below the waterfalls Fifteenmile Creek flows through a floodplain located in a box canyon with mixed conifer and pine/oak forests. The last designated stretch of Fifteenmile Creek continues descending toward the Columbia River and is classified as scenic.
March 30, 2009. From its source at Senecal Spring to the southern edge of the northwest quarter of the northwest quarter of Section 20, Township 2 South, Range 12 East.
The upper part of Fifteenmile Creek, above Forest Service Road 2730 and within the Badger Wilderness, provides high-quality riparian habitat. The area has not been well-explored botanically or ecologically, but it does not seem remarkably different than adjoining drainages. Rhizomnium nudum, naked rhizomnium moss, and schistostega moss, were found along the edge of Fifteenmile Creek. Both are likely present in the adjacent Dog River Drainage. The schistostega moss was also found just outside the boundary of the Fifteenmile Creek Wild and Scenic River corridor in a wetland associated with Fret Creek. Both species are found around Mt. Hood at higher elevations, typically in westside drainages. It is unusual to find either of these species in eastside drainages of the Cascade Range.
The naked rhizomnium moss is a Forest Service Region 6 sensitive plant and a "survey and manage" species. It is found in moist to wet areas on rocks or soil in the splash zone along the river. Schistostega moss is also a Forest Service Region 6 sensitive plant and a "survey and manage" species. It is an Oregon Natural Heritage Program list 2 species, threatened and endangered in Oregon, but stable and more common elsewhere. It is found on mineral soil almost exclusively in the area, on upturned root wads in moist to wet areas, usually near water, and often in low light circumstances. Both species can be found in upland habitats where the moisture regime is wetter, but in this drier environment, they are more associated with standing or running water.
Below Forest Service 2730, the riparian habitat is also high quality. Naked rhizomnium was found along Fifteenmile Creek just below the road but has not been found any further downstream. The upper part of the corridor is either subalpine or borders on subalpine and is not very incised. The lower part of the corridor is much more incised and runs due east. The north facing slopes are timbered all the way to the end of the corridor while the south facing slopes become dramatically different, grading to a much drier open, pine, oak, and bitterbrush savannah on the east end. This is typical of drainages in this area.
The river sustains multiple fish species, including steelhead, redband trout, and Pacific lamprey. All known year-round human-created barriers to fish passage have been removed up to the middle-designated segment in Fifteenmile Creek. Multiple impassable waterfalls (10-to-51-foot height) are present higher in the river corridor. The headwaters of Fifteenmile Creek are some of the best fishery's habitat within the subwatershed for the mid-Columbia steelhead, one of the few remaining wild runs with little hatchery introgression. The steelhead in this subbasin are the easternmost run of wild winter steelhead in the Columbia Basin.
Cultural history in the area is connected to past Forest Service administration, homesteading, agriculture, timber harvest, transportation, and recreation. The corridor includes transportation routes that owe their location to the creek and may be spurs of the Historic Barlow Road. The Dufur to Lookout Mountain Trail played a prominent role in the early history and settlement of Wasco County. The drainage was first documented as Nansene Creek prior to the large immigration waves of the mid-nineteenth century, and archaeological evidence suggests the headwaters and travel corridor have been in use for more than 2,000 years.
In 1852, the first permanent settlers, primarily stockmen, arrived in the Fifteenmile Creek drainage, homesteading near the current site of Dufur. By 1872, the Dufur brothers and others were grazing large herds of sheep and other livestock along this travel corridor and at High Prairie, near the Headwaters of Fifteenmile Creek. Several small sawmills operated along the upper extent of Fifteenmile Creek during this period to support the area’s fledgling communities and homesteads, the trail and waterway essential to growth. In 1893, the upper extent of Fifteenmile Creek became part of the Cascade Range Reserve. Fire prevention was a priority, and an extensive and well-maintained trail system was considered vital to that effort. During this period, the first fire lookout on the eastern side of the forest was constructed on Lookout Mountain, the peak considered one of the best vantage points in Oregon. Sometime prior to 1901, the Dufur to Lookout Mountain Trail was extended to the southwest over Bennett Pass to link with the Barlow Road near Summit Creek. This would become an important cutoff from the Barlow Road, linking the communities from east and west. Much of this work was spearheaded by J.B. Senecal, the first ranger in the northeastern portion of the reserve.
Within a decade, recreational use of the trail increased greatly. To the east, the trail provided a grand view of eastern Oregon and the Blue Mountains. The unobstructed view of Mt. Hood, several miles to the west, was considered the best on the forest. Planning was under way for the Mt. Hood Loop Highway during this period, and the Lookout Mountain Trail was a strong candidate for improvement as this scenic travel route. An alternate route prevailed; however, efforts to convert the trail to a road persisted. In 1933, Roy T. Johnson and a crew of sixty Civilian Conservation Corp men were charged with creation of the Bennett Pass Road. This road followed the trail alignment from High Prairie to the Barlow Road in the west and Fifteenmile Campground in the east. The men camped at High Prairie, using the cabin built nearly three decades earlier by Senecal as a main office. The Dufur to Lookout Mountain Trail is associated with nearly every activity occurring in the drainage including grazing, timber harvest, recreation, and Forest Service administration. Fifteenmile Creek played a prominent role in each.
The river flows through the Fifteenmile National Recreation Area (part of the Mount Hood National Recreation Area), which was designated to provide protection, preservation, and enhancement of recreational, ecological, scenic, cultural, watershed, and fish and wildlife values, and is popular with mountain bikers. Visitors experience a variety of scenery along the river, from an alpine fir forest along the upper segment to a ponderosa pine and Oregon white oak forest as they move east. The Fifteenmile Creek Trail parallels Fifteenmile Creek for 5.7 miles, while the Fret Creek and Cedar Creek Trails intersect this main primitive travel route. Prominent exposures of columnar basalt along the Fifteenmile corridor add to the scenery. There are places where long distance views of eastern Oregon’s Blue Mountains, the Columbia River Corridor, and Deschutes River corridor can be seen. Most recreational use in the river corridor occurs in the summer and includes camping, hiking, mountain biking, climbing, horseback riding, mushrooming, hunting, berry picking, and paddling, while winter attracts Nordic skiers and snowmobilers. There is one campground in the corridor, and the lack of development is a draw to this area. Fifteenmile Creek provides an opportunity to enjoy a quieter recreation experience than can be found along many river corridors on the Mt. Hood National Forest.
Fifteenmile Creek is confined in a high-gradient stream channel, which flows through a mixed conifer forest type in a transition zone between the High Cascades and the Columbia Plateau with a diversity of vegetative types. The wild and scenic river corridor provides diverse wildlife habitat for American marten in the high elevations to gray squirrel in the pine/oak forests. Migratory birds are supported along the corridor because of the varied habitat types, although some bird populations, such as blue grouse, olive-sided flycatcher, and brown creeper, are declining. Beaver colonies are present in the watershed, which create even more habitat diversity within the river corridor.
The eastern five miles of the river corridor provides winter range for deer and elk while the western 2.5 miles provide high-quality calving/fawning habitat, and the entire corridor serves as an important migration route. The pine/oak portions of the corridor provide habitat for species including Lewis’ woodpecker, white-headed woodpecker, western bumblebee, deer, elk, wild turkey, and western gray squirrel. Most of the river corridor, aside from the pine/oak, provides habitat for northern spotted owl.