By Alexandra Gorbatova Hydroelectric dams create differences in water level by blocking river’s stream. During the times when energy consumption is the highest, water is allowed to pass through the dam, spinning the turbine and converting energy from mechanical to electrical. Production of electricity using hydroelectric power stations is one of the most environmentally sustainable approaches, but it has its disadvantages. A paper published by Quintero J. D. and Ledec G. in November 2003 discusses potential advantages and disadvantages of dams. According to the research, the advantages include flexibility – regulated generation of power only when it is needed, lower costs compared to the other ways of generating “green” energy, low level of carbon dioxide emissions compared to combustion of fossil fuels and industrial applications – a hydroelectric dam can generate electricity not only to power populated regions, but also industrial structures. Despite all the advantages of large dams mentioned above, there are some serious disadvantages to consider. Some of the most serious issues to consider are the following: methane emission from reservoirs, risks of failure, siltation, altering natural flow regimes, water temperatures and alternation of fish migration pathways. In a way, the negative aspects of hydroelectric dams are interconnected. Sediments might overfill the reservoir making it useless and increase a risk of flood and failure. Methane emissions, siltation and effects on river’s ecosystem are the issues directly related to the environmental sciences and are not to be overlooked. So why, considering all the risks and disadvantages, do companies decide to continue dam construction? On “China Three Gorges Corporation” website it is possible to find only the benefits of the project, not the drawbacks. The benefits of the Three Gorges dam are very significant for the area: clean cheap energy, improving water and weather conditions, flood control and improvement of navigation capacity between cities connected by Yangtze River. The main disadvantages include harmful impacts on river ecosystem, but according to the data provided by the company, there is a significant technology advance helping to decrease sedimentation. Also the company takes into account environmental aspects, such as protection of valuable and rare species and improving water quality. Thus a conclusion can be made that not all hydroelectric dams are equally harmful to the environment and river ecosystems. Some of them are of a great importance. Hydroelectric dams: the way of the future or the road to damnation? So which one is it? There are some general approaches suggested in Hydropower Reform Coalition of how the current and potential negative impacts of dams can be minimized, such as changing the times of power production, so that the water flow will be as close to the natural flow as possible, maintenance of water level to prevent shoreline erosion and vegetation from flooding, advancement in technology, providing pathways for fish migration and other alternative habitats for growth and artificial maintenance of oxygen and nutrient level in a river. By taking such measures and considering all the harm that a hydroelectric dam can cause to the environment, it is possible to create a very efficient and clean power source with minimized risks and harm to ecosystems. Sources:
Bangqi Hu et al. Hydrology and Earth System Science: Sedimentation in the Three Gorges Dam and the future trend of Changjiang (Yangtze River) sediment flux to the sea. 2009. Barnes an Hays. Dams: Impacts, Stability and Design. April 2009. China Three Gorges Corporation. Three Gorges Project. Last read 21.02.2015. http://www.ctgpc.com/introduction/introduction_a.php FWEE (Foundation of Water and Energy Education). How a hydro project affects a river: changes to the ecosystem. 2015. Last read 21.02.2015. http://fwee.org/environment/how-a-hydroelectric-project-can-affect-a-river/changes-to-the-ecosystem/ Hydropower Reform Coalition. Modernizing hydropower. 2015. Last read 22.02.2015. http://www.hydroreform.org/abouthydro/modernizing-hydropower International Rivers. Environmental Effects of Dams. 2054 University Ave, Suite 300, Berkeley, CA 94704-2644, USA. Last read 20.02.2015. http://www.internationalrivers.org/environmental-impacts-of-dams |
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May 2019
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