Sandy River

Oregon

Designated Reach: October 28, 1988. From the headwaters to the Mt. Hood National Forest boundary. From the east boundary of Section 25 and 36, T1S, R4E downstream to the west line of the east 1/2 of northeast 1/4 Section 6, T1S, R4E.

Classification/Mileage: Wild — 4.5 miles; Scenic — 3.8 miles; Recreational — 16.6 miles; Total — 24.9 miles.

The River

The designation includes two separate segments. From the river's headwaters within the Mt. Hood Wilderness to the Mt. Hood National Forest boundary, a 12.4-mile segment is administered by the USDA Forest Service. A n additional 12.5 miles, between Dodge Park and Dabney Park, is administered by the Bureau of Land Management.

The upper Sandy originates from the high glaciers of Mt. Hood; riverside trails offer spectacular scenery, easily observed geologic features, unique plant communities and a variety of recreational opportunities. Just outside Portland, the lower Sandy flows through a deep, winding, forested gorge known for its anadromous fish runs, botanical diversity, recreational boating and beautiful parks.

The upper Sandy begins at Reid Glacier at an elevation of 6,200 feet on the steep, rugged slopes of Mt. Hood. The river falls 4,600 feet in the 13 miles to its confluence with the Zigzag River. The uppermost 4.5-mile segment is characterized by steep canyons, waterfalls, cascades and narrow boulder-choked chutes. The lower, 7.9-mile segment is characterized by moderately steep gradients and somewhat wider cobble and gravel-dominated channels.

The shape and character of the upper Sandy River Valley are products of the glaciation and the volcanic activity of Mt. Hood. Glaciers widened and deepened the Sandy River Valley, exposing volcanic rocks of many different ages in the valley walls. The valley has been partially filled in by mudflows and pyroclastic flows from two recent significant eruptive periods at Mt. Hood. The Old Maid Flats area is an excellent example of a multiple debris flow deposit that provides unique interpretive opportunities. In this area there are buried snags and tree cases or wells that are some of the best examples of a buried forest found in the Pacific Northwest.

The lower Sandy flows through a distinctive canyon landscape, characterized by steep topographic relief and varied and diverse vegetation. The river flows by rushing rapids and still pools with occasional riverside cliffs and waterfalls. Its complex geologic history includes incised oxbows from the Pliocene river channel, volcanic deposits from the Old Maid Eruptive period and buried forests from volcanic activity 200 years ago.

Annual precipitation in the Sandy River watershed ranges from around 110 inches in the upper elevations to about 70 inches near the mouth. Mt. Hood sustains a snowpack year-round in its higher elevations, which provides water storage over the winter and supplemental flows in the summer. The water quality of the Sandy River varies seasonally depending on climatic events and human influences within the watershed. Particularly noteworthy is the presence of fine suspended sediment known as "glacial flour," formed by the grinding of rock under the tremendous weight of the glaciers. The glacial flour gives the Sandy a pale green opacity or milky-gray color, which is most apparent in middle to late summer during the peak of glacial melt. The Sandy River has one of the highest percentages of glacial melt of all major Oregon rivers.

Recreation Opportunities

The upper Sandy River provides a wide variety of recreational opportunities, ranging from hiking, fishing and backpacking to a more developed recreation experience in one of the three campgrounds in and adjacent to the river corridor. The Ramona Falls Trail is the most popular trail in the river corridor, providing a relatively easy hike to see this well-known and very scenic waterfall. The upper Sandy River provides a unique kayaking opportunity for experienced kayakers. Nordic skiing is popular during winter months when the snow level drops to a low enough elevation.

The lower Sandy River provides an outstanding sport fishery and exceptional recreation opportunities for nature study, day-use activities and nonmotorized boating or floating.