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Berthoud Pass ( ; el. 11,307 ft./3446 m.) is a high mountain pass in the Rocky Mountains of central Colorado in the United States. The pass is located west of Denver, and provides a high route between upper Clear Creek Canyon to the upper valley of the Fraser River in Middle Park to the north. The pass traverses the continental divide at the Front Range, on the border between Clear Creek County and Grand County. The pass is named for Edward L. Berthoud, the chief surveyor of the Colorado Central Railroad during the 1870s. Accompanied by Jim Bridger, Berthoud discovered the pass in July 1861 while surveying a possible route for the railroad. Berthoud concluded that the pass was suitable as a wagon road, but not as a railroad, and was then hired by the Central Overland California and Pikes Peak Express Company to survey a route over the pass to Salt Lake. The pass is currently the route of U.S. Highway 40, north of its junction with Interstate 70 in Clear Creek Canyon. It provides the fastest road access to Winter Park and a secondary route to Steamboat Springs from Denver and the Colorado Front Range. However, the pass is one of the most notoriously difficult passes in Colorado for motorists, based on its height as well as the steep grades on both sides (6.3%) and the large number of switchbacks on the southern side of the pass. ==Berthoud Pass Ditch== In 1902, the 3.5 mile (5.6Km) Berthoud Pass Ditch began diverting water from the headwaters of the Fraser River over the continental divide into the basin of Clear Creek. Initially, this water was used for irrigation, but the cities of Northglenn and Golden purchased the ditch in the mid-1980s. The ditch has a capacity of 53.4 cubic feet per second (1.51m3/s), 〔John N. Winchester, (A Historical View: Transmountain Development in Colorado ), 2000; retrieved July, 2015.〕 The ditch was blocked in 1999 by the collapse of the tunnel under the parking lot at the summit of the pass, but it was repaired the next year. 〔PAW, (“The Ditch” on Berthoud Pass ), Clear Creek County Document Center, 2012, retrieved Aug. 2015.〕 In the decade since the repairs, the ditch has typically diverted on the order of 500 acre-feet (600,000m3) per year.〔(Appendix IX. Transbasin Diversions ), (HB 1278 Final Report: The South Platte River Alluvial Aquifer ), Colorado State University, Dec. 31, 2013; retrieved Aug. 2015.〕 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「Berthoud Pass」の詳細全文を読む スポンサード リンク
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