|
〕 | mouth_name = Lewis River | mouth_location = slightly upstream of Swift Reservoir | mouth_district = | mouth_region = | mouth_state = | mouth_country = | mouth_note = | mouth_lat_d = 46 | mouth_lat_m = 04 | mouth_lat_s = 11 | mouth_lat_NS = N | mouth_long_d = 122 | mouth_long_m = 00 | mouth_long_s = 25 | mouth_long_EW = W | mouth_coordinates_note = 〔 | mouth_elevation_imperial =1040 | mouth_elevation_note = 〔 | length_imperial = 29.8 | length_note = | length_round = 0 | watershed_imperial = 351 | watershed_round = 0 | watershed_note = 〔 | discharge_location = from the mouth | discharge_round = 0 | discharge_imperial = 865 | discharge_note = | discharge_min_imperial = 153 | discharge_max_imperial = 25000 | map = | map_size = | map_caption = |map_alt = | map1 = Washington Locator Map.PNG | map1_size = 300 | map1_caption = Location of the mouth of Muddy River in Washington | map1_alt = | map1_locator = Washington | commons = }} The Muddy River is a stream, about long, southeast of Mount St. Helens in the U.S. state of Washington.〔 The Muddy River flows south–southeast and joins the Lewis River just above the Swift Reservoir. The Lewis River flows west and is a tributary to the Columbia River. The east flank of Mount St. Helens is within the watershed of Muddy Creek. During the 1980 eruption of Mount St. Helens, lahars (volcanically-induced mud and debris flows) swept through its channel. About of stream channels around the volcano were affected by lahars.〔 The United States Forest Service maintains the Muddy River Picnic Site, next to the river and to Forest Road 25 in the Gifford Pinchot National Forest.〔(【引用サイトリンク】publisher=United States Forest Service )〕 Trails cross the river on its upper reaches.〔 ==Course== Muddy River originates at about the level on the southeast side of Mount St. Helens in the Cascade Range.〔 The river source is within Mount St. Helens National Volcanic Monument and Gifford Pinchot National Forest. Shoestring Glacier is to the right and East Dome is to the left. Flowing southeast down steep slopes, the river curves sharply to the northeast just beyond the level of the volcano.〔 Here the river crosses Forest Road 83 and passes the Ape Canyon Trailhead and the Lava Canyon Interpretive Site, both on the left,〔(【引用サイトリンク】url=http://www.fs.usda.gov/recarea/mountsthelens/recarea/?recid=47014 )〕 before entering Muddy River Gorge.〔 River miles are marked on the map quadrangles for the lower Muddy River and the Lewis River.〕 Flowing northeast through the gorge, the stream plunges over three waterfalls before emerging from the narrows and curving sharply again to the southeast.〔 Here Crane Lake is on the left, Smith Creek enters from the left, and Smith Creek Trailhead is on the right.〔 Slightly downstream of the trailhead, the river leaves the national volcanic monument but remains in the national forest.〔 At about the level, Clearwater Creek enters from the left.〔 Turning south, the river descends less rapidly, passing under Forest Road 25 and then receiving Clear Creek from the left about from the mouth.〔 At the road crossing, Muddy Creek Picnic Site is on the left.〔 Below the confluence with Clear Creek, the river meanders through Cedar Flats, leaves the national forest slightly more than a mile from the mouth,〔 and passes a United States Geological Survey (USGS) stream gauge, on the left from the mouth.〔 Muddy River enters the Lewis River about from the larger stream's mouth on the Columbia River.〔 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「Muddy River (Washington)」の詳細全文を読む スポンサード リンク
|