Considering all the harmful environmental effects that hydropower dams have, many countries in the world are now fighting the construction and maintenance of large dams by prohibiting their funding. Even though dams are supposed to bring particular economic benefits, many people argue that they do “more economic harm than good” (“Social, environmental impacts of dams can be reduced” 10).
To start with, dams are expected to assist in mitigating floods, generating electricity, and supplying water for various industries and agriculture (Rosenberg, Mccully, and Pringle 747). Finally, the least they do is improve the navigation of rivers. However, the practice shows that all of those advantages are arguable and can hardly compensate for the harm that dams, especially the large ones, are fraught with.
First of all, any hydrological alteration disrupts the natural river flows, and as Rosenberg, Mccully, and Pringle state in their article, dams are “a major cause of these disruptions” (747). For example, dams usually become the reason for the loss of river deltas and dewatering of rivers and contribute to water pollution. When there are too many dams on the same river, its waters can even stop reaching the sea, although they are supposed to. As Rosenberg, Mccully, and Pringle write, the Colorado Rivers rarely discharge any freshwater to the sea (749).
Secondly, because of water stored in reservoirs, the worldwide sea level has significantly reduced (Rosenberg, Mccully and Pringle 747). Since the middle of the twentieth century, the approximate volume of water impounded in reservoirs has reached the point of 10,000 cubic kilometers, which equals the amount of water in all rivers around the world (Rosenberg, Mccully and Pringle 747). Additionally, dams and reservoirs contribute to greenhouse gas emissions.
Another significant harm that large dams cause is that regarding river inhabitants. Dams usually become the reason for habitat fragmentation and changes; they block the migration of fish, hinder spawning, and so forth. As proof, after four dams were constructed on the Snake River, people faced a significant deterioration in salmon fishing (Rundle 138).
To conclude, the construction, funding, and maintenance of hydropower dams have numerous adverse consequences, including the disruption of the natural river flows, decrease in the water level in the seas, the contribution to the greenhouse emissions, etc. The possible advantages that those constructions can bring can not compensate for all the negative consequences, which is why the use of large hydropower dams should be terminated.
Works Cited
Rosenberg, David M., Patrick Mccully and Catherine M. Pringle. “Global-Scale Environmental Effects of Hydrological Alterations: Introduction.” BioScience 50.9 (2000): 746-751. Print.
Rundle, Simon D. “Threats to the Running Water Ecosystems of the World.” Environmental Conversations 29.2 (2002): 134-153. Print.
“Social, environmental impacts of dams can be reduced: IIED.” Ecos 195 (2014): 10-11. Print.
Burton, Tony, David Sharpe, Nick Jenkins and Ervin Bossanyi. Wind Energy Handbook, West Sussex, England: John Wiley & Sons, 2001. Print.