Hydro-electric power is the conversion of the kinetic energy of falling water into electricity. Of the world's electricity, 15% is produced in this fashion (Baird, Stuart. http://www.iclei.org/efacts/hydroele.htm, 07/09/00). In 1996 the demand for electricity in developing Asia was rising at 8% a year and the region has enormous potential for hydro-electric power (The Economist (US), Oct 12, 1996 v341 n7987 p66(1).). In order to produce hydropower, dams must be built. From an economic viewpoint, unless a river is dammed for industrial or commercial purposes it is useless.
However, ecologically all river water is used. The dilemma remains one of whether the benefits of industrialisation outweigh the costs to the environment. Most Asian countries are willing to tread the path of industrialisation at all costs. This essay will examine the advantages and disadvantages of dam construction, then look at China's Three Gorges Project as a case study.
The main advantage of dams can be seen when hydro-electric power is compared to other energy sources such as coal, oil, wood and nuclear power.
Dams are renewable and emit no air or water polluting by-products as well as no waste heat as thermal pollution (Kraushaar & Ristinen, 1993, p186). China's Three Gorges Project is expected to produce 84 billion kilowatt hours which is equal to a coal mine that extracts 40 – 50 million tons of coal per year. China presently uses coal to generate three quarters of its energy which releases carbon dioxide and other gases into the atmosphere (Three Dams Project, http://www.dur.ac.uk/ desOwww4/cal/dams/othe/3dams.htm, 15/09/00). These emissions contribute to global warming, so dam construction can help reduce this threat to the environment.
While dams are generally viewed as being environmentally unsound, they can also be seen as preventing environmental degradation. Nine out of ten Nepalese still use firewood for cooking. Deforestation was also a major problem in the United States and Europe before the advent of electricity (Asia Week, 7/19/96, p14). Hydro-electric power helps minimise deforestation by providing an alternative to wood and charcoal as fuel.
Dams reduce peak flows downstream during storms and heavy rain periods. While this is not advantageous for pristine watersheds, it can prevent erosion of riverbanks if the watershed has been heavily logged or overdeveloped. Reducing peak flows in overlogged areas also prevents heavy silt deposits from moving downstream. Dams also slow the river preventing pollutants from damaging fish stocks and other fauna as well as flora downstream. Much depends on what has taken place in an area before the construction of a dam (CDA's "Ask an Expert" Archive…, http://www.cda.ca/cda/main/faq/faq6.htm, 05/09/00).
In 1954 flood killed 30,000 people and left 1 million homeless in the Chang Jing River Valley. The damming of the Chang Jing River has prevented such natural disasters from occurring since its construction (Three Dams Project, http://www.dur.ac.uk/ desOwww4/cal/dams/othe/3dams.htm, 15/09/00). The multipurpose nature of dams can be seen in that they not only provide flood control, but also store water for irrigation as well as municipal drinking water. In addition, dams also provide areas for aquaculture and recreation (Hydro-electricity, http://www.pgeedsvcs.com/clackamas/hydro2.html, 05/09/00). Dams have the potential to increase food production and health in these ways.
Asia has emerged in recent decades as a world economic power. This has been the result of a commitment to industrialisation. Modernisation requires electricity to keep pace with economic growth and a dam's main purpose is to generate electricity. It is estimated that China's power output must rise 8% annually if they are to keep pace with a 6% annual rise in Gross National Product (Three Dams Project, http://www.dur.ac.uk/ desOwww4/cal/dams/othe/3dams.htm, 15/09/00). Dams construction has the potential to raise standards of living by powering local industry, thus creating employment opportunities (Asia Week. 7/19/96, p14). Spin off industries are then created and, as claimed with the proposed Bakun Dam in Malaysia, local infrastructure is created where tourism has the potential to bring in money and create more jobs locally (The resettlement of indigenous people affected by the Bakun Hydro-electric Project, Sarawak, Malaysia.http://www.rengah.c2o.org/announce/19990600.htm, 19/09/00).
Attention will now be turned to the disadvantages of dam building. Those who suffer most in the wake of dam construction are the local residents who are forced into resettlement programs. Worldwide, 30 – 60 million people have become "reservoir refugees" as a result (Major Problems Found in Three Gorges Dam Resettlement Program. http://www.hrichina.org/reports/3gorges.html, 05/09/00). They are more often than not rural, poor and politically powerless, and are generally left worse off after their homes and land are flooded. For instance, four out of five resettlers surveyed after the Khao Laem Dam project in Thailand considered themselves economically worse off (McCully, Patrick. http://www.irn.org/programs/finance/critique.shtml, 05/09/00).
Chinese farmers traditionally have a deep attachment to the land they work. The massive Three Gorges Project will displace more than 1 million people from, not only their homes, but from the roots of their culture (Three Dams Project, http://www.dur.ac.uk/ desOwww4/cal/dams/othe/3dams.htm, 15/09/00). This is also illustrated by the proposed Bakun Hydro-electric Project that affected fifteen indigenous communities of Sarawak. The common cultural belief of these communities is landbased. It is their spiritual home that was taken from them when they were forced to relocate despite the project now being on hold (The resettlement of indigenous people affected by the Bakun Hydroelectric Project, Sarawak, Malaysia. http://www.rengah.c2o.org/announce/19990600.htm, 19/09/00).
Dam construction alters the natural course of rivers and affects those who depend on it for their food and income (Asia Week, 7/19/96, p14). They are responsible for reducing fish production and ruining seasonal farming that depends on regular flooding leaving silt fertiliser on the floodplain (Baird, Stuart. http://www.iclei.org/efacts/hydroele.htm, 07/09/00). Dams are the main reason why one fifth of the world's freshwater fish species are now endangered or extinct (McCully, Patrick. http://www.irn.org/programs/finance/critique.shtml, 05/09/00). It is estimated that the Nam Theun Hinboun Dam project will block the migration routes of 100 species of fish (Parnwell and Bryant, 1996, p126). The World Bank claims that new fisheries in the dam reservoir make up for these losses, but fewer species are suited to reservoirs, lowering diversity. Also, locals generally have less access to the reservoir because reservoir fishing is different to river fishing and requires different skills and equipment (McCully, Patrick. http://www.irn.org/programs/finance/critique.shtml, 05/09/00). Dam construction separates people from their economic and social networks.
In addition to the negative impacts on fish production downstream, dams adversely affect other animals as well as flora. The influx of 20,000 people, including construction workers, on the Pali Falls Dam resulted in the illegal hunting of protected animals (Parnwell and Bryant, 1996, p232). Silent Valley was one of the few remaining untouched rainforest areas of India, filled with rare species of plants, ferns and endangered fauna (Karan, 1994, p37). Plants and animals rely on the river's natural variation for reproduction, migration, etc. (McCully, Patrick http://www.irn.org/programs/finance/critique.shtml, 05/09/00). Ecosystems are dependent on the delicate balance around them in order to survive. Once a dam has altered this balance it is difficult to predict the outcomes.
Many tribal groups in remote parts of Asia rely on the forest and jungle to hunt and forage for food (Karan, 1994, p36) as well as gather plants for medicinal use (Parnwell and Bryant, 1996, p126). Dams are a threat to forests both directly and indirectly. The Hoa Binh Dam in north Vietnam displaced 58,000 people and flooded 11,000 hectares of productive agricultural land. The displaced people cleared the hillside along the top of the reservoir for land to cultivate. The local farmers were skilled at farming the fertile valley soil but had no knowledge of upland development and conservation practices. This led to deforestation and, consequently, soil erosion (Parnwell and Bryant, 1996, p231). New roads associated with dam building also cause deforestation undermining local people's source of food, medicine and income.
In some cases locals do not gain any developmental benefits from the electricity generated through hydro-electric power. The electricity is consumed by industry outside the region or it is sold abroad as is the case with the Nam Theun Hinboun Dam in Laos. The electricity will be mostly sold to Thailand so the only benefit to Laos is foreign exchange earnings (Parnwell and Bryant, 1996, p123). The costs are borne by the Laotian people and environment while the benefits are exported to Thailand.
Land and water are ecologically linked to form a watershed. Dams slow the river's flow and hold back sediments. The river seeks to recapture these sediments by eroding riverbanks. It is not uncommon for river beds to erode several metres after the river has been dammed (McCully, Patrick. http://www.irn.org/programs/finance/critique.shtml, 05/09/00). This can render structures like bridges and houses downstream unsafe.
Health issues associated with dam construction cannot be ignored. The sudden influx of construction workers can bring the risk of disease to remote areas. These include tuberculosis, measles, diarrhoeal infections, syphilis and AIDS (McCully, Patrick. http://www.irn.org/programs/finance/critique.shtml, 05/09/00). Waterborne tropical diseases can devastate local ecosystems, endangering animals and humans (Asia Week, 7/19/96, p14). Bacteria in the submerged, decaying vegetation also has the potential to transform the mercury in rocks into a soluble form (Baird, Stuart. http://www.iclei.org/efacts/hydroele.htm, 07/09/00). This affects fish in the dam and those who are dependents on them. Studies have also suggested that when the submerged vegetation in large dams decays it emits greenhouse gases that are equal to those released by other sources of electricity (Baird, Stuart. http://www.iclei.org/efacts/hydroele.htm, 07/09/00).
Now a brief summary of the benefits and costs associated with the Three Gorges Project will be examined. This Chinese endeavour will be the largest hydro-electric project in history. It will displace more than a million people and flood 32,000 hectares of prime farmland. It will leave 13 cities, 140 towns, 1352 villages and 657 factories submerged (Environment-China: Banned Voices speak on Three Gorges Dam. http://www.members.aol.com/cmwwrc/marmamnews/97121202.html, 05/09/00).
The dams success depends on avoiding a massive build up of sediment behind the dam which will damage the turbines and adversely affect power output (Environment-China: Banned Voices speak on Three Gorges Dam. http://www.members.aol.com/cmwwrc/marmamnews/97121202.html, 05/09/00). If successful, the Three Gorges Dam will power industry helping keep pace with China's modernisation program. In doing so, the dam will also spare the Earth's atmosphere of carbon dioxide and acid rain causing sulfur dioxide produced by fossil fuel alternatives (Three Dams Project, http://www.dur.ac.uk/ desOwww4/cal/dams/othe/3dams.htm, 15/09/00).
Despite these obvious benefits, China's historic pattern of discrimination against rural dwellers may well bring social unrest as many peasants are forced from fertile land to other undesirable areas (Major Problems Found in Three Gorges Dam Resettlement Program. http://www.hrichina.org/reports/3gorges.html, 05/09/00). This relocation will increase deforestation and soil erosion by forcing people onto overused lands (Environment-China: Banned Voices speak on Three Gorges Dam. http://www.members.aol.com/cmwwrc/marmamnews/97121202.html, 05/09/00). It may also increase regional conflict as Sichuan Province, which is upstream, will only receive a small amount of energy but must bear the greater burden of resettling people. While downstream Hubei will not only benefit from improved flood control but of greater electricity (Three Dams Project, http://www.dur.ac.uk/ desOwww4/cal/dams/othe/3dams.htm, 15/09/00).
The Yangtze River's wildlife may be the greatest loser, especially the Yangtze Dolphin which only has a population of around 200. It is on the World Wildlife Fund's short list as one of the most endangered animals on Earth. Other animals to suffer include the Chinese Sturgeon, Chinese Tiger, Chinese Alligator, Siberian Crane and the Giant Panda (Three Dams Project, http://www.dur.ac.uk/ desOwww4/cal/dams/othe/3dams.htm, 15/09/00).
The Three Gorges Dam will be built over several seismic faults which indicates a danger of earthquakes and landslides occurring. It will also submerge 6,000 year old historical artefacts and some fear it will turn the Yangtze into a cesspool by slowing the river causing a build up of pollutants. Other's fear the escalating cost may wreck the Chinese economy as even the World Bank does not see the project as economically viable (Environment-China: Banned Voices speak on Three Gorges Dam. http://www.members.aol.com/cmwwrc/marmamnews/97121202.html, 05/09/00).
While the economic benefits of dam construction are far reaching, it remains difficult to weigh Gross National Product against environmental destruction. How does one put a price on a species of fish or plant? Dams have been a contentious issue for decades and will remain so into the future until methods to minimise the negative impacts are formulated. At the same time, fossil fuels will not last forever so other alternative sources of energy must eventually be utilised, such as nuclear, solar, wind, and hydro power. Dams are cheap, renewable and non-polluting. It seems that you are "dammed if you do and dammed if you don't."