Large-scale hydrologic engineering, such as dam building, can offer many benefits. This form of clean energy can provide electricity for many homes, for example, in the 1980’s, approximately 15 million people received power from the Hoover Dam (McNeill 2000, 178). Another important benefit is the ability to have water where and when it is needed. There are also many negative effects that dam construction can cause, including both environmental and social. The environmental effects often include habitat loss and alteration. The dams create barriers for the wildlife that depend on the rivers for spawning, migrating, and much more. They also affect the land both upstream and downstream by changing the amount of water in those locations.
The social effects caused by dams can be much more difficult to measure than the environmental effects. A tool that is used to measure the social effects is called a social impact analysis (SIA). The impacts felt by dam construction can result “…in a wide array of subsequent social impacts, including changes in household size and structure; changes in employment and income-generating opportunities; alteration of access and use of land and water resources; changes in social networks and community integrity; changes in the nature and magnitude of various health risks; and often a disruption of the psycho-social wellbeing of displaced individuals” (Tilt, Braun, and He 2009). A more specific example of the types of social effects a dam can cause are those that resulted from the Manwan Dam which was built on the upper Mekong River in China. “The economy of the rural areas adjacent to the Manwan Dam experienced significant impacts, including a decline in productivity in agriculture and animal husbandry, shortages of water for irrigation, increasing costs for electricity, and depletion of forest resources” (Tilt, Braun, and He 2009).
When considering the construction of something as large as a dam, all of the impacts need to be taken into account along with the benefits. In the past this was not done, instead the dams were built hastily without much thought of the consequences. “During the 1960s, more than one large dam was completed per day on average” (McNeill 2000, 159). For future hydrologic engineering projects like dams, we need to look at the past and learn from those mistakes.
McNeil., J.R., 2000: An Environmental History of the Twentieth-Century World: Something New Under the Sun. Norton & Company, Inc., New York.
Tilt, Bryan, Yvonne Braun, and Daming He. 2009. Social Impacts of Large Dam Projects: A Comparison of International Case Studies and Implications for Best Practice. Journal of Environmental Management 90, S3 (July): S249-S257.
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I agree with your point on potential impacts needing to be taken into account by dam building. It is not enough to only think about the benefits as as McNeil demonstrated, hastily built dams or dams built with only certain objectives in mind can prove to be highly disastrous. In the instance with the USSR and the Aral Sea, the country indeed did become "cotton independent" but they produced large exports of the world's lowest quality cotton. Not even going into how much biodiversity in the environment was effected, I was surprised to learn that the Aral Sea has now become two smaller seas with a land bridge in the middle due to such rapid shrinkage.
ReplyDeleteHowever, it was mentioned in the beginning of the chapter that most people see water as a resource, a tool that needs to be exploited. Just like air pollution, our thinking in regards to water pollution and water usage needs to be changed so that effects are not so greatly felt in such a short amount of time. We indeed need to remember our past mistakes to cooperate best with one another in creating a more thoughtful future.
I definitely agree that the building of dams is or was done without much regard for any other effects other than the control of the water. There seems to be more negative effects than positive ones. Dams have been useful, and have saved many humans from starvation, however we also must wonder if it is way past due that humans come up with alternate methods of water control. Instead of seeing water as a resource, we need to think of it a need that most animals on the planet depend on for survival. by taking it away from some people to provide it more regularly to other people is along the lines of murder. We have to come up with better ways of helping each other instead of saving some and killing others. We need to work together not against each other!
ReplyDeletewww.hetchhetchy.org.
ReplyDeleteCheck out this website to see what hetchhetchy looked like before dam construction. These twelve pictures speak of beauty only compared to Yosemite. (One picture looks like the mate to half dome.) The Sierra Club is trying for a "compromise" in bringing back the hetchhetchy. "What beauty lies beneath."