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〕 | length_imperial = 15 | length_round = 0 | length_note = 〔 Approximate length determined by map scale and ruler.〕 | watershed_imperial = 22.3 | watershed_round = 0 | watershed_note = 〔 Stated watershed size includes only that part of the watershed above river mile 1.95 (river kilometer 3.14).〕 | discharge_location = from the mouth | discharge_round = 0 | discharge_imperial = 143 | discharge_note = 〔 | discharge_min_imperial = 8 | discharge_max_imperial = 5320 | discharge1_location = | discharge1_imperial = | discharge1_note = | map = Bull run river oregon watershed map.png | map_size = 300 | map_caption = Bull Run River watershed | map1 = Oregon Locator Map.PNG | map1_size = 300 | map1_caption = Location of the mouth of the Little Sandy River in Oregon | map1_locator = Oregon | commons = }} The Little Sandy River is a tributary, roughly long, of the Bull Run River in the U.S. state of Oregon.〔 Forming west of Mount Hood in the Mount Hood National Forest, it flows generally west, roughly parallel to the Sandy River to the south.〔 Its entire course lies in Clackamas County, and most of its main stem and tributaries are within the Bull Run Watershed Management Unit (BRWMU), a restricted zone that protects Portland's main water supply. In 2008, Portland General Electric (PGE) removed the Little Sandy Dam, the only dam on the river, while decommissioning its Bull Run Hydroelectric Project. This made possible, for the first time in nearly a century, the return of migratory salmon and steelhead to the river. In 2009, both types of fish were reported spawning above the former dam site. ==Course== Arising southeast of Hickman Butte in the Mount Hood National Forest, the river flows northwest between North Mountain on the left and Goodfellow Lakes on the right. Turning west, it passes south of Aschoff Buttes before receiving its only named tributaries, Bow Creek and Arrow Creek, both from the right. As the river nears a United States Geological Survey (USGS) stream gauge at river mile (RM) 1.95 or river kilometer (RK) 3.14, a ridge, the Devil's Backbone, separates the Little Sandy from the Sandy River to the south. Just below the stream gauge, the Little Sandy passes the former Little Sandy Dam. The river enters the Bull Run River about from the larger stream's confluence with the Sandy River.〔 Falling between source and mouth, the river's average loss of elevation is about .〔〔〔 Most of the course of the river lies within the BRWMU,〔(【引用サイトリンク】 publisher = Portland Water Bureau )〕 a federally protected area of surrounding the main drinking water supply for Portland. Access to the BRWMU is generally limited to government employees and guests on official business, and security guards keep watch on its three gated entrances. In 1996, the U.S. Congress banned commercial logging on all federal lands in the Bull Run River watershed and, through the Little Sandy Act of 2001, extended the ban to include all federal lands draining into the Little Sandy River and the lower Bull Run River.〔(【引用サイトリンク】 publisher = Portland Water Bureau )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Little Sandy River (Oregon)」の詳細全文を読む スポンサード リンク
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