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Le Touquet – Paris-Plage, France

Lemperiere F.,Hydro Coop | Vigny J.-P.,Hydro Coop | Ouamane A.,University Mohamed Khider of Biskra
International Journal on Hydropower and Dams | Year: 2012

Experts review several research efforts and discuss various applications, outlining the associated advantages of P.K. Weirs. P.K. Weirs is being operated in various parts of the world and offers a number of technical and economic advantages as compared with traditional labyrinth spillways. The principle of these models is to obtain the best ratio of cost per saving in nappe depth, or per specific flow increase. Designs without overhangs, keeping a rectangular shape, have been studied to facilitate the construction of vertical walls and to obtain a better hydraulic performance and cost saving, as compared with traditional labyrinths. The P.K. Weirs can have four or five times the discharge capacity, as compared with a traditional Creager spillway. The main possible applications of labyrinths and P.K. Weirs include free-flow spillways for new dams, free-flow spillway added to a gated spillway, and upgrading of existing free-flow spillways.

Lemperiere F.,Hydro Coop | De Savignac X.,Hydro Coop
International Journal on Hydropower and Dams | Year: 2010

The major roles to be played by some of Africa's large river systems in meeting water and energy needs were discussed at HYDRO 2010, held in Lisbon, Portugal, in September 2010. Potential hydropower development and the need of water were analyzed during the event, with specific focus on the four most important rivers, such as the Congo, Zambezi, Niger, and Nile. It was observed that hydropower accounted for 15 per of African electricity generation and it was more useful for energy storage linked with wind and solar energy, while having additional impact on the design of many of the existing hydroelectric schemes that were designed only for generation. The hydropower potential of 5 TWh per year had the capacity to meet most of the needs of Mali within the next 15 years, at low cost by the construction of run-of-river plants along the River Niger.

Lemperiere F.,Hydro Coop | Vigny J.-P.,Hydro Coop | Deroo L.,ISL
International Journal on Hydropower and Dams | Year: 2012

Present methods for designing spillways are generally based on traditional criteria, which are not well adapted to present knowledge of actual risks. A review of facts and costs suggests that better adapted criteria and methods of design could reduce risks and costs. Most failures have been caused by floods which exceeded the spillway capacity, but a significant number of gated dams have failed as a result of total jamming of the gates for various reasons, such as mechanical or electrical problems, lack of operators or operational errors. The data for masonry and concrete dams are quite different. The rate of flood failures has been quite high for masonry gravity darns, either at the foundation level or in the dam body. This may be caused by a lower density than expected, uplift in upstream cracks or low mechanical strength, especially for very old dams. The breach may be instantaneous and its length be about five times the dam height.

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