Big dams have a serious record of social and environmental destruction, and there are many alternatives. So why are they still being built?
Big dams have frequently imposed high social and environmental costs and long term economic trade offs, such as lost fisheries and tourism potential and flooded agricultural and forest land. According to the independent World Commission on Dams, most projects have failed to compensate affected people for their losses and adequately mitigate environmental impacts. Local people have rarely had a meaningful say in whether or how a dam is implemented, or received their fair share of project benefits.
The dam building industry is ‘greenwashing’ hydropower with a public relations offensive designed to convince the world that the next generation of dams will provide additional sources of clean energy and help to ease the effects of climate change. In some of the world’s last great free-flowing-river basins, such as the Amazon, the Mekong, the Congo, and the rivers of Patagonia, governments and industry are pushing forward with cascades of massive dams, all under the guise of clean energy.
Chinese banks and companies are involved in constructing some 216 large dams (“large” means at least 15meters high, or between 5 and 15meters and with a reservoir capacity of at least 3million cubic meters) in 49 different countries, particularly in Africa and Southeast Asia, many with poor human rights records. A look at the heavy dam-building activity in China, the Amazon basin, and Africa illustrates the risks involved.
New African dams are being built with no examination of how climate change will affect them, even though many existing dams are already plagued by drought-caused power shortages. Climate change is expected to dramatically alter the dynamics of many African rivers, worsening both droughts and floods. In this climate, the proposed frenzy of African dam building could be literally disastrous. Unprecedented flooding will cause more dams to collapse and hasten the rate at which their reservoirs fill with sediment. Meanwhile,worsening droughts will mean dams will fail to meet their power production targets.
Dams are not inexpensive investments: Just developing one of these dams, the Mphanda Nkuwa in Mozambique, is
expected to cost at least $2 billion (not including the necessary transmission lines). Yet these huge projects are doing little to bridge the electricity divide in Africa. With the majority of the continent’s population living far from existing electricity grids, what is needed is a major decentralized-power roll out of renewables and small power plants to build local economies from the ground up, not the top down. But that’s not where the money is right now.
Big dams can contribute to development, but that progress often comes at staggering cost, in displaced and impoverished refugees, ecologically fragmented and damaged rivers, and downstream victims of destroyed fisheries and impounded sediments. Big dams also expand the habitat of waterborne disease vectors such as malaria, dengue fever, schistosomiasis, and liver fluke, and can trigger devastating earthquakes by increasing seismic stresses. Dams frequently fail to deliver their projected benefits and usually wind up costing more than predicted. And although hydropower is touted as a solution to climate change, many dams actually emit huge quantities of greenhouse gases.
Environmental impact assessments (EIAs) that should anticipate problems have served as a rubber-stamping device rather than a real planning tool. Impact assessments should follow European Union and other global EIA standards. By definition, an effective EIA“ensures that environmental consequences of projects are identified and assessed before authorization is given”—something that almost never occurs in today’s world.
Developing countries often have vast, unexploited renewable energy potential, such as wind, solar, geothermal, and modern biomass energy, as well as low-impact, non-dam hydro power. Such technologies are much more suited to meeting the energy needs of the rural poor, as they can be developed where people need the power and do not require the construction of transmission lines.
Source: Excerpts from Jan/Feb 2010 World Watch magazine
Hydro power generation from many existing dams is an important source of electricity. However, we tend to forget (within a generation or two) what environmental and social impacts the dams had when they were built. Once a dam is built, upstream and downstream ecology is changed forever. Downstream water supply may be diminished causing water shortages to communities and wildlife. Dammed water often has water quality issues and may become unsafe to drink. It is sad that often, Environmental Impact Assessments (EIA’s) are merely formalities and their findings are often ignored. Apart from hydro power, dams do provide many benefits such as water storage and irrigation but their construction must be weighed up against the potential damage to the environment and the cost to society. The proposed Mphanda Nkuwa Dam on the Zambezi River (Mozambique) is a case in point. Water Rhapsody would like your comments on the Mphanda Nkuwa Dam project, especially if you live in Mozambique.
Water Rhapsody supplies and installs high quality, World Wildlife Fund Award-winning water conservation systems that include rainwater harvesting systems, grey water recycling systems, gray water irrigation and grey water for toilet flushing (see product demo for our other water systems). Water tanks are integral to many of our water systems and thus we supply Atlas Plastics water tanks and JoJo water tanks at excellent prices (we are authorized JoJo Tank dealers in Mpumalanga & Limpopo). Water and energy are so closely linked that we have incorporated Yes Solar Mpumalanga to offer high quality solar energy solutions to the Lowveld. Our solar energy systems are made by Solsquare (Germany); the solar water heaters are both SABS- and Eskom-approved. Solsquare solar geysers are eligible for Eskom’s renewable energy rebate and are installed by qualified solar installers.
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