River water is a domestic resource which, unlike fuel or natural gas, is not subject to market fluctuations. Hydroelectricity helps fight climate changes. The hydroelectric life cycle produces very small amounts of greenhouse gasses. Hydroelectricity improves the air we breathe. Cons of Hydropower Hydroelectric power is not perfect, however, and does have some significant disadvantages: Hydropower is non-polluting, but does have environmental impacts.
Hydropower facilities can affect land use, homes, and natural habitats in the dam area. The construction of surface reservoirs has slowed considerably in recent years. Building a dam and reservoir to support hydroelectric power takes a lot of money, time, and construction, and most of the suitable sports to locate hydro plants have already been taken.
Hydroelectricity is hydrology dependent. The system depends on precipitation levels, which can fluctuate from year to year, causing instability. In some cases, hydroelectricity can disrupt wildlife habitat. Hydroelectric power plants can cause a loss or modification of fish habitat, and lead to the entrapment of fish and the restriction of their passages. To cope with this demand Vietnam has built many dams on its rivers. These dams have had a significant impact on the environment as well as on the lives of those people who were dependent on the river for their livelihood.
Many people and communities have been forcibly moved due to the construction of dams. These people were poor but had sustainable lives along the river, growing their own food and fishing in the river. They were moved to areas where they had insufficient land to grow their own food and provide for their families, no access to employment and often no access to water.
In Central Vietnam over the past 20 years, many hydropower projects of different sizes and capacities have been planned and constructed, especially from Quang Binh to Phu Yen and Provinces in Central Highlands.
Overall, hydropower is now contributing about 35 per cent to 40 per cent of national energy production. However, the rapidly increasing number of hydropower plants in Central Vietnam has already raised many environmental and social concerns and we are facing adverse consequences for the sustainable development of the whole area.
Hydropower requires vast quantities of water from the rivers and destroys the river ecology. We found that fishing activity at the mouth of the free-flowing San Pedro River was much higher than around the mouth of the dammed Fuerte River.
Reduced sediment flow also deprives coastal estuaries of nutrients. Lucrative shrimp and oyster fisheries in the region we studied rely heavily on nutrient inputs from rivers. Coastal mangrove wetlands also protect shorelines from hurricanes and tropical storms, and serve as recreational areas and conservation habitat for wildlife. But when coastlines recede and mangroves are destroyed, this carbon is released. Because sediments are so essential to areas around river mouths, reducing sediment trapping behind dams could mitigate some harmful impacts on coastal areas.
There are several ways to do this — notably, sediment bypassing, or diverting a portion of the sediments flowing from upriver around dams and allowing it to rejoin the river downstream. This strategy can be included in new construction or incorporated into existing dams. Hydropower dams can contribute to global warming pollution : When a forest is cut down to make way for a dam and reservoir, those trees are no longer available to absorb the carbon dioxide added by fossil fuels. Further, decaying vegetation beneath the reservoirs can generate emissions, which can contribute to global warming.
Reservoirs slow and broaden rivers, making them warmer. The environmental, economic, and societal footprint of a dam and reservoir may extend well beyond the immediate area, impacting drinking water, recreation, fisheries, wildlife, and wastewater disposal. Solutions For The 21st Century American Rivers supports the continued operation of most hydropower projects.
Many of these dams use antiquated, inefficient generating equipment. Dam owners should be required to bring their plants up to modern standards in order to ensure that they are generating the maximum amount of power from every drop of water that they use.
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