Human-made lakes or reservoirs are usually created as a result of dams constructed over a river. The water behind the dam accumulates to fill up the created artificial basin. Dams could also be made on an outlet channel of a naturally occurring lake to provide better control of the water level in the lake.Such types of constructions typically maintain the natural characteristics of the lake, and examples of such constructions include Lake Tahoe in the US and Lake Victoria in East Africa. Human-made lakes are found mainly in regions having limited natural lakes or where the lakes are not suitable for human water needs.
The Largest Artificial Lakes In The World
Kariba dam is the largest humanmade lake in the world. Located in Zambia and Zimbabwe, it can hold up to 180.6 cubic kilometers of water. It was constructed in 1959 on river Zambezi and has a height of 420 feet and a width of 1900 feet. Lake Kariba extends for 170 miles. The primary purpose of the dam is to generate electricity and supplies about 1626 megawatts of electricity to Zambia and Zimbabwe. When the dam was constructed there was resettlement or approximately 57,000 people who were living in the area on both countries of Zambia and Zimbabwe. Lake Kariba controls about 90% of the total runoff of river Zambezi and has directly affected the ecology significantly in the downstream. Between 1958 and 1961 the wildlife rescue operation on river Zambezi captured about 6,000 large animals and several other small animals that were facing a threat from the rising water on the lake. In 2008 it was reported that the heavy rains could force the release of water from the dam which would affect at least 50,000 people who were living downstream. In 2010, the floodgates of the dam were opened because of the rising water on the reservoir, and this forced evacuation of about 130,000 people who were living in the floodplains. In 2014 engineers from the Zambezi river authority warned the foundation of the dam had weakened and needed repairs.
The Akosombo dam is also known as Volta Dam, and it is a hydro-electric generating plant on Volta River in Ghana. The Akosombo dam is the largest human-made lake in the world by surface area which is approximately 3,283 square miles and accounts for 3.6% of the land area of the whole of Ghana. However, by volume size, it is the third largest after Bratsk reservoir in Russia. Akosombo dam has a volume of 150 cubic kilometers, and the main purpose of the dam is to provide electricity, and its original output was 912 megawatts, which was later upgraded in 2006 to 1020 megawatts.The flooding that created Lake Volta reservoir had a substantial environmental impact and displaced many people. The Akosombo dam supplies electricity to Ghana and other neighboring countries in West Africa like Benin and Togo. At the time of commissioning 20% output of the dam was serving 70% of the country's demand, while the 80% was reserved for Volta Aluminium Company (VALCO).
Manicouagan Reservoir in Canada is multiple buttress dam, and it was constructed on Manicouagan River stretching 133 miles. The construction of the dam began in 1959 and by 1970, and the primary purpose for the dam is to generate electricity and supplying water to the powerhouses. It has the capacity of 2,596 megawatts. The dam is the fourth largest in volume holding capacity of 141.8 cubic kilometers. The project is owned and operated by Hydro Quebec.
Importance Of Dams
The human-made lakes are purposely constructed to address specific requirements.The purpose they serve may include commercial fisheries, power generation, Supplying drinking water, irrigation, industrial and cooling water supplies, commercial sports, and other recreational activities. Some of the earliest reservoirs were constructed about 4000 years ago in Egypt, China, and Mesopotamia and their primary purposes were irrigation and supply of drinking water.