We normally associate lack of rain leading to decertification. But, did you know it affects lakes too? The two famous lakes in history which have literally shrunk to more than half of its size is the Aral Sea and Lake Chad.

Lake Chad has diminished for various reasons stated below:

• 1)   Overgrazing by cattle around the area of Lake Chad that resulted to a high demand for water for cattle and famers drew out a lot of the water for irrigation.
• 2)   Due to air pollution, the region used to receive 800 millimeters of rain, but now it receives 400 millimeters of rain. Alongside this with the repeatedly failed summer rains, the lake was not replenished.
• 3)   Small rivers do not feed enough water into the rivers due to construction of dams upstream which minimize the amount of water flowing into the Lake.
• 4)   Climate change has resulted to excessive evaporation from the lake and the lack of rain to replenish the water in the lake poses a problem.
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The environmental consequences of lake Chad?s decline are:

• 1)   Due to the shallow waters, the number of fish in the Lake has decreased which has upset the eco-system balance and negatively affected locals who depended on fish for their livelihood.
• 2)   The receding water has left behind sand dunes and unfortunately they cannot be farmed on due to lack of water.

On the other hand, the Aral Sea greatly diminished since 1960. The river canals that once flowed into the lake were diverted to irrigate crops and help in the rapid growth of cotton. The amount of water flowing into the lake decreased. The lake dried up as there was excessive evaporation and the lake was not being replenished. As a result the amount of dissolved minerals increased and the area of the land covered by the water decreased. This has caused several environmental problems such as:

 

• 1.     The increase in salinity in the water that killed the fish.
• 2.     The large decline in fish negatively affected the fishing industry
• 3.     The sediments in the lake- bed are exposed to the wind hence they can easily blow away causing dust storms.