|
The Dickerson Whitewater Course, on the Potomac River near Dickerson, Maryland, was built for use by canoe and kayak paddlers training for the 1992 Olympic Games in Spain. It was the first pump-powered artificial whitewater course built in North America, and is still the only one anywhere with heated water. It remains an active training center for whitewater slalom racing, swiftwater rescue training, and other whitewater activities. The facility is owned by the NRG Energy company. Except during special events, access requires membership in the Potomac Whitewater Racing Center, a USA Canoe/Kayak National Training Center.〔(Potomac Whitewater Racing Center ) Cards are issued by the (Liquid Adventures Kayak School ).〕 The course was constructed in 1991, inside a pre-existing straight, -long concrete channel, wide. Since 1959, the channel has returned cooling water from the Dickerson Generating Station to the Potomac River, upstream from Washington, D.C. Water is pumped from the river, warmed as much as 35 °F (20 °C) as it cools the power plant's three coal-fired generators, and then emptied into the channel for gravity flow back to the river.〔(Davey Hearn, ''Dickerson Whitewater Course'' )〕 (The plant has three other generators which use a different cooling system.) Streamflow through the course is to , depending on the operation of the plant's three coal-fired generators and their six cooling water pumps. In the summer months, when water temperature in the channel exceeds , the course is closed for health reasons.〔(''Dickerson Workouts'' ). Retrieved 2010-06-11.〕 It is also closed when the Potomac River rises above on the Little Falls gauge〔(USGS Real-Time Water Data for USGS 01646500 POTOMAC RIVER NEAR WASH, DC LITTLE FALLS PUMP STA )〕 , flooding the lower section of the course.〔 ==History== In the 1960s, local canoe and kayak paddlers began conducting winter practice in the heated Potomac River water immediately below the discharge channel. Nearly three decades went by before paddler Scott Wilkinson got the idea of moving the practice up into the concrete-lined channel itself. In 1991, he sold his idea to two of the power plant managers, and, in support of the 1992 Olympics team, the Potomac Electric Power Company, Pepco, which owned the plant at the time, approved the insertion of approximately 75 artificial concrete boulders and two wing dams into the channel. Wilkinson's fellow paddler John Anderson, an architect, built a 1:12 scale model with flow-diversion features similar to those in the Segre Olympic Park artificial course in La Seu d'Urgell, Spain, built for the 1992 games. The model was tested at the Navy's David Taylor Model Basin. Local construction companies donated time and equipment, and the course was opened in December 1991. The first race was held in June 1992. Athletes who trained at the Dickerson course won bronze and gold medals in the 1992 Olympics, and others have continued to win Olympic medals and world championships in subsequent years.〔 The course was redesigned in the fall of 2002, once again by John Anderson. A new scale model was built, this one outdoors and onsite. After testing his new arrangement of flow-diversion features on the model, he specified new locations for some of the artificial boulders. The wing dam on the left side was moved downstream into section four. A crane was deployed for the moving job. In October 2003 a persistent problem at the end of the course was fixed. Whenever the Potomac River level is below on the Little Falls gauge , there is a sheer drop between the end of the concrete channel and the river. In certain conditions of high course flow and low river level, a stream-wide retentive hydraulic, or "sticky hole," posed a hazard to paddlers who failed to correctly "boof stroke" across the drop. It was a worse problem for paddlers who had made a wet exit from an upside-down boat and were swimming the course. This feature was modified by adding a concrete slab under the drop and two trapezoid-shaped diverters on the sides. The hydraulic was converted into a central tongue of water ending in a wave train, with an eddy on each side. 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「Dickerson Whitewater Course」の詳細全文を読む スポンサード リンク
|