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Lakes of Ounianga are a series of lakes in the Sahara Desert, in North-Eastern Chad, occupying a basin in the mountains of West Tibesti and Ennedi East. It was added as a UNESCO World Heritage site in 2012. According to the UNESCO description, the lakes are in a hot and hyperarid desert that features a rainfall of less than a year. The lakes exhibit a variety of sizes, depths, chemical compositions and colorations. There is a total of 18 lakes in groups as follows: * Ounianga Kébir group: Lake Yoa, Lake Katam, Lake Oma (or Ouma), Lake Béver, Lake Midji, Lake Forodom; * Lake Motro, about southeast of Ounianga Kébir; * Ounianga Sérir group about southeast of Ounianga Kébir: Lake Melekui, Lake Dirke, Lake Ardjou, Lake Téli, Lake Obrom, Lake Élimé, Lake Hogo, Lake Djiara, Lake Ahoita, Lake Daléyala, and Lake Boukkou. The total surface area of the lakes is about . The largest of the lakes, Lake Yoa, has about a area and attains in depth. The names of the lake groups are derived from the name of a village nearby (literally, Ounianga Kébir = "the great Ounianga" and Ounianga Serir = "little Ounianga"). ==Geography== These lakes form a hydrological system that is unique in Earth’s deserts. Ordinarily when water is exposed at the surface in highly arid environments it becomes saline due to a high rate of evaporation. In this case, even though the rate of evaporation from Lake Yoa is equivalent to a year, the total lake depth is , unique physical factors combine to keep all of the lakes, except the central Lake Teli, fresh. First, water accumulated in an underground aquifer during the wet millennia is supplied to the lakes. Second, wind blown sand separates the basin into 10 lakes with Lake Teli occupying a lower position than the lakes around it. Third, thick mats of reeds cover the surface of the fresh water lakes where they slow evaporation, but are absent from the saline waters of Lake Teli. As a result, greater evaporation takes place from the surface of Lake Teli, keeping its water level low. This allows water from the adjacent lakes to flow through the permeable dune barriers into Lake Teli keeping their waters fresh. 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「Lakes of Ounianga」の詳細全文を読む スポンサード リンク
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