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〕 | mouth_name = Koyukuk River | mouth_location = northeast of Bettles |mouth_district= Yukon–Koyukuk Census Area | mouth_state = | mouth_country = | mouth_note = | mouth_lat_d = 66 | mouth_lat_m =54 | mouth_lat_s = 49 | mouth_lat_NS = N | mouth_long_d = 151 | mouth_long_m =39 | mouth_long_s = 13 | mouth_long_EW = W | mouth_coordinates_note = 〔 | mouth_elevation_imperial = 600 | mouth_elevation_note = 〔 | length_imperial =125 | length_round = 0 | length_note = 〔 | watershed_imperial = | watershed_round = 0 | watershed_note = | discharge_location = | discharge_imperial = | discharge_round = 1 | discharge_note = | discharge_max_imperial = | discharge_min_imperial = | discharge1_location = | discharge1_note = | map = | map_size = 300 | map_caption = |map_alt = | map1 = Alaska Locator Map.PNG | map1_size = 300 | map1_caption = Location of the mouth of the John River in Alaska | map1_locator = Alaska |map1_alt = | commons = }} The John River is a tributary of the Koyukuk River in the northern part of the U.S. state of Alaska.〔 It was named after John Bremner, a prospector and explorer who was one of the first non-native persons to go there.〔 It flows south from Anaktuvuk Pass in Alaska's Brooks Range, into the larger river at a point near Bettles,〔 slightly north of the Arctic Circle. In 1980, the segment of the John River within the Gates of the Arctic National Park and Preserve were designated "wild" and added to the National Wild and Scenic Rivers System.〔(【引用サイトリンク】publisher=National Wild and Scenic Rivers System )〕 The designation means that the segment is unpolluted, free-flowing, and generally inaccessible except by trail.〔(【引用サイトリンク】publisher=National Wild and Scenic Rivers System )〕 The John River Valley is an important migration route for Arctic caribou.〔 ==Boating== It is possible to run the John River in canoes, kayaks, and small rafts, though conditions vary from place to place. The upper are rated Class III (difficult) on the International Scale of River Difficulty and "should be attempted only by experienced paddlers with solid wilderness skills." Below this, the river is rated Class II (medium) for the next , then Class I on the lower reaches all the way to the mouth. Dangers on the upper river include sustained whitewater, swift currents, a difficult portage, and the possibility of water too shallow to run.〔 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「John River (Alaska)」の詳細全文を読む スポンサード リンク
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