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The Clackamas River is an approximately tributary of the Willamette River in northwestern Oregon, in the United States. Draining an area of about , the Clackamas flows through mostly forested and rugged mountainous terrain in its upper reaches, and passes agricultural and urban areas in its lower third. The river rises in eastern Marion County, about east-southeast of Salem. The headwaters are on the slopes of Olallie Butte in the Mount Hood National Forest, about north of Mount Jefferson, at an elevation of in the Cascade Range. The Clackamas flows briefly north and then flows northwest through the mountains, passing through North Fork Reservoir and Estacada. It then emerges from the mountains southeast of Portland. It joins the Willamette near Oregon City and forms the boundary between Oregon City and Gladstone. The Clackamas provides hydroelectric power and drinking water for some of the Portland metropolitan area, and it supports runs of Coho salmon, spring and fall Chinook salmon, and summer and winter steelhead. The river's old-growth forests, its habitat for several species of birds, its healthy fish runs, and the recreational opportunities that it provides—such as fishing and whitewater rafting—led to the designation of more than half of the length of the river into the National Wild and Scenic Rivers System (NWSRS). This environment also allowed Native Americans to settle in the river's basin as early as 10,000 years ago. Regulation of the river began in 1905 with the Cazadero Dam. In 1912, the River Mill Dam intercepted wood and coarse sediment. Later dams at North Fork, Oak Grove, Stone Creek, and Timothy Lake also intercepted wood sediment on the lower river. ==Course== The Clackamas River arises on the western slopes of the Cascade Range near Olallie Butte, between Mount Hood and Mount Jefferson in the Mount Hood National Forest. Flowing generally northwest and then west for about , it joins the Willamette River at Gladstone. The river falls nearly between its source and its mouth.〔(【引用サイトリンク】 publisher = TopoQuest )〕 Originating in Marion County, the Clackamas River receives Squirrel Creek from the left bank and Lemiti Creek from the right bank before entering Clackamas County about from the mouth. Over its next , much of which is in a relatively level stretch known as Big Bottom, the river receives Cub Creek from the left, Sisi Creek from the right, then Hunter, Fawn, Rhododendron, and Lowe creeks, all from the left, followed by Wall, Pinhead, and Campbell creeks, all from the right, Kansas Creek from the left, and Cabin Creek and Lost Creek, both from the right. About from the mouth, Granite Creek enters from the left, and the river flows by Austin Hot Springs and Picnic Area. Shortly thereafter, Switch Creek enters from the right, and at about from the mouth, the Clackamas receives the Collawash River from the left. At the confluence, Two Rivers Picnic Area is on the left and Riverford Campground is on the right. About further downstream, Trout Creek enters from the left, and Riverside Campground is on the right.〔〔 Shortly thereafter, Tag Creek enters from the right, and at about from the mouth, the Clackamas River receives Oak Grove Fork Clackamas River from the right. From its confluence with Oak Grove Fork, the river runs close to Oregon Route 224 for most of the rest of its course. The highway is initially north and east of the river; that is, to its right. Over the next few miles, the river receives Big Creek, Sandstone Creek, and Whale Creek, all from the left, passes under Route 224, receives Cripple Creek, and passes under Route 224 again at the unincorporated community of Three Lynx. It receives Three Lynx Creek and Deer Creek from the right, Cat Creek from the left, and then Dinner Creek from the right as it enters a chute known as The Narrows about from the mouth. Soon Pup Creek enters from the left opposite the Sunstrip Campground before Roaring River enters from the right at about from the mouth. Near this point, Roaring River Campground is on the right. Shortly thereafter, Murphy Creek enters from the right, and Fish Creek enters from the left about from the mouth.〔〔 Over the next few miles, the river flows by Fish Creek Campground and Armstrong Campground, where it passes under Route 224. The river then passes Lockaby Campground and Carter Bridge Campground, where it passes under Route 224 again for the fourth and final time. From here to near Gladstone, the river flows south and west of the highway, which is on its right. Below Carter Bridge, the Clackamas River receives Hellion Creek from the left about from the mouth, passes Big Eddy Campground, receives Moore Creek from the right, and passes Lazy Bend Campground. Around from the mouth, the river receives the South Fork Clackamas River from the left opposite a landform known as Big Cliff. About later, the river enters North Fork Reservoir and soon receives the North Fork Clackamas River from the right. The Clackamas reaches the Faraday Dam, formerly known as the Cazadero Dam, about from the mouth and passes Faraday Lake, which is on the river's left about later. Shortly thereafter, the Clackamas receives Lingleback Creek from the right, passes under Oregon Route 211 at Estacada, receives Dubois Creek from the left, and reaches River Mill Dam. It flows by Milo McIver State Park, south of the river between and from its mouth.〔〔 The river then flows by Bonnie Lure State Recreation Area, which lies to the north, and receives Eagle Creek from the right about from the mouth. It receives Goose Creek from the right before passing Barton County Park, which lies north of the river about downstream of Bonnie Lure. Deep Creek then enters from the right, Foster Creek from the left, and Richardson Creek from the right before the Clackamas River reaches Carver from the mouth. Here it receives Clear Creek from the left. Thereafter, Rock Creek enters from the right and Johnson Creek from the left before the river passes under Interstate 205 and then Oregon Route 99E (McLoughlin Boulevard) between Oregon City to the south and Gladstone to the north. Clackamette Park lies to the left of the river's last stretch as it enters the Willamette above its confluence with 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「Clackamas River」の詳細全文を読む スポンサード リンク
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