Astari 
The Lakes of Ounianga are a series of lakes in the heart of the Sahara Desert in northern Chad.
UNESCO emphasizes the Lakes of Ounianga, located in Ennedi Plateau, renowned for aridity and vast dunes, receiving under 2 mm rainfall annually.
Aquifers from the Tibesti Mountains sustain the lakes, ensuring a stable water source underground.
With a combined surface area of around 20 km2, the lakes vary in size, depth, chemical composition, and coloration.
These lakes, totaling 18, are categorized into two groups: the Ounianga Kebir (Greater Ouniang), including Lake Yoa, Lake Katam, Lake Oma, Lake Béver, Lake Midji, and Lake Forodom, and Lake Motro located southeast of Ounianga Kébir.
The Ounianga Serir (Lesser Ounianga), situated 45 to 60 km southeast, featuring lakes Melekui, Dirke, Ardjou, Téli, Obrom, Élimé, Hogo, Djiara, Ahoita, Daléyala, and Boukkou.
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Contents
Enchanting Hues and Submerged Landscapes of the Lakes of Ounianga
One striking feature is the mesmerizing hues that adorn these lakes, ranging from deep blues and greens to shimmering browns.
The colors are a result of factors such as mineral content, sedimentation, and the interplay of sunlight with the lake’s surface.
The clarity of the water in certain lakes allows for visibility of the submerged landscape, revealing submerged features such as sand dunes beneath the water’s surface.
Hydrological System of Lakes of Ounianga
The hydrological system of the Lakes of Ounianga is intriguing and unique.
Additionally, the water in these lakes is derived from underground aquifers that are replenished by the rains in the Tibesti Mountains.
This underground water source maintains stable lake levels, even amidst the Sahara Desert.
Furthermore, the lakes are interconnected through a network of channels, enabling the water to flow between them.
Despite these interconnected channels, arid conditions in the Lakes of Ounianga Kebir cause salinity, as water rapidly evaporates upon exposure.
For instance, Lake Yoa’s yearly evaporation, at 20 ft, leaves it with a total depth of 82 ft.
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Human Migrations and Environmental Challenges
Influenced by climatic history, human migrations took place around 11,000 years ago.
Following a monsoon period, the desert reclaimed the area about 5,000 years ago.
A drilling core analysis of Lake Yoa’s sediments, spanning 52 feet, revealed 10,940 layers, corresponding to each year.
Early settlers combated desertification by erecting barriers with distinctive “V” shapes in Ounianga Kebir and Serir.
Despite substantial community collaboration, these efforts were unfortunately unsuccessful.
Consequently, relentless desert winds and sand deposition led to the abandonment of lakeside settlements between 7,500-5,000 years ago.
This marks a significant chapter in the enduring impact of climate change on this ancient landscape.