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〕 | length_imperial = 110 | length_note = 〔(【引用サイトリンク】publisher = National Oceanic and Atmospheric Administration )〕 | width_imperial = | width_orientation = | depth_imperial = | volume_imperial = | watershed_imperial = 1373 |watershed_note= | discharge_imperial = 3687 | discharge_note = | discharge_location = Winchester | discharge_max_imperial =150000 | discharge_min_imperial =235 | free = | free_type = | map1 = Oregon Locator Map.PNG | map1_size = 300 | map1_caption = Location of the mouth of the North Umpqua River in Oregon | map1_alt = | map1_locator = Oregon | website = | commons = North Umpqua River | footnotes = }} The North Umpqua River is a tributary of the Umpqua River, about long, in southwestern Oregon in the United States. It drains a scenic and rugged area of the Cascade Range southeast of Eugene, flowing through steep canyons and surrounded by large Douglas-fir forests. Renowned for its emerald green waters, it is considered one of the best fly fishing streams in the Pacific Northwest for anadromous fish. ==Description== It rises in the high Cascades, issuing from Maidu Lake at elevation of in the Mount Thielsen Wilderness, along the Douglas-Klamath county line approximately east of Roseburg. It follows a serpentine course down from the Cascades, westward along the southern side of the Calapooya Mountains. Its upper course passes through the Umpqua National Forest, past Toketee Falls and Steamboat, where it receives Steamboat Creek from the north. It receives the Little River from the south at Glide (the confluence is known as the Colliding Rivers) and joins the South Umpqua from the east approximately northwest of Roseburg to form the Umpqua. It is impounded in its upper reaches in the Cascades to form Lemolo Lake for hydroelectricity. It is also impounded for hydroelectricity at Soda Springs Dam, forming a small reservoir on the upper river. The river's reputation as a world-class steelhead stream and its famous emerald waters are a result of the fact the river source is high enough in the Cascades to derive from snowmelt during the entire year. The melting snow is trapped in volcanic soil and pumice and released during the summer months, providing an even cool-temperature flow. During the summer the flow of the river is approximately 20 times that of the nearby South Umpqua. In its lower reaches, the river's flow becomes increasingly erratic, in a manner typical of mountain streams of the region. The region around the river has long been a timber-producing area. Starting in 1955, the watershed of the river was extensively clear cut, a practice which continued until 1969 when forestry management practices were changed. During this period many tributary streambeds were used as impromptu logging roads. The recovery of the river from these practices has been closely monitored by state and federal agencies. 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「North Umpqua River」の詳細全文を読む スポンサード リンク
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