identify any 5 ecological problems caused by building large dams.
Answers
Answer:
Soil erosion, Species extinction, Spread of diseases, Changes to Earth's Rotation, Sedimentation.
Explanation:
(i) Soil Erosion:
One of the first problems with dams is the erosion of land. Dams hold back the sediment load normally found in a river flow, depriving the downstream of this. In order to make up for the sediments, the downstream water erodes its channels and banks. This lowering of the riverbed threatens vegetation and river wildlife.
One of the reason dams are built is to prevent flooding. However, most ecosystems which experience flooding are adopted and many animal species depend on the floods for various life cycle stages, such as reproduction and hatching. Annual floods also deposit nutrients and replenish wetlands. A major example of soil erosion problems is the Aswan Dam.
(ii) Species Extinction:
Fisheries become an increasingly important source of food supply more attention is being paid to the harmful effects of dams on many fish and marine mammal populations. The vast majority of large dams do not include proper bypass systems for these animals, interfering with their life cycles and sometimes even forcing species to extinction.
(iii) Spread of Disease:
Dam reservoirs in tropical areas, due to their slow-movement, are literally breeding grounds for mosquitoes, snails and flies, the vectors that carry malaria, Schistosomiasis and river blindness
(iv) Changes to Earth’s Rotation:
Nasa geophysicist Dr. Benjamin Fong Chao found evidence that large dams cause changes to the earth’s rotation, because of the shift of water weight from oceans to reservoirs. Because of the number of dams which have been built, the Earth’s daily rotation has apparently sped up eight-millionths of a second since the 1950s. Chao said it is the first time human activity has been shown to have a measurable effect on the Earth’s motion.
(v) Sedimentation:
It is the process by which larger sediments in water entering a reservoir are deposited as its upper end forming a delta and steadily raising the level of the upper reaches of the reservoir. This causes flooding due to its bank water effect, and in the case of the Sardar Sarovar Dam, this process shortens the utility of the dam.
Answer:
The three ecological problems caused by building large dams could be soil erosion, extinction of species, loss of forests and wildlife, etc. Explanation: ... As a result, many aquatic species are getting extinct.
Explanation:
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