Mega dams have the multipurpose applications and considered as the greener energy source than most alternatives. But as compensation to this development it may result a wide range of environmental degradation.
This study aims to search the fact of environmental impacts due to the existing and proposed mega dams of the Himalayas and also to investigate the sustainability of the dams. Being the youngest and fastest changing mountain, the Himalayas and it mighty glaciers, sources of important rivers, are highly susceptible to global warming. Recently, there are plans to transform the Himalayan Rivers into the powerhouse of South Asia by building hundred of mega dams to generate 150,000-megawatt electricity in the next 20 years. These dams pose severe environmental risks in the Himalayan region and mostly in the downstream and the climate change associated with the global warming threatens the safety and viability of these hydropower projects.
Dams and their associated reservoirs impact freshwater biodiversity and hydrogeology; changing turbidity, sediment levels, nutrient levels; causing flash flood and prolonged submergence; severe drought in dry season; affecting local ecology and habitat; contribute greenhouse gases and the resulting global warming; dry up the rivers for even longer lengths; impact traditional livelihoods, agriculture, irrigation and fisheries; threat political, regional and geo-strategic stability; increase the rate of disaster associated with the dam failure, land sliding, earthquake in the downstream.
The study investigates the fact that the forthcoming hydrological projects in the Himalayas need proper EIA and information sharing to decrease the environmental impacts, to ensure water distribution of rivers, the riparian countries, to make the projects sustainable and to ensure benefits for all with proper negotiations and commitment.
In the Himalayas the threat from the concrete works that would include huge walls damming the rivers, underground tunnels that could go scores of kilometer long, that could completely bypass and dry up the rivers for even longer lengths, the massive blasting that would be required for the same, the power houses, the roads, the townships, the mining that would be necessary to procure the materials for the projects, the hundreds of kilometer long transmission lines meant for the power promised to be generated, threats from all this is indeed of Himalayan proportions. And even if it cannot dwarf the mountain itself, certainly it has the potential to destroy large parts of it permanently.
Dams are a principal threat to environment mostly in freshwater diversity and that threat is largely mediated through loss of habitat frequently involving modifications to the natural flow regime and to blockage of migrations. Putting aside the enormous cost involved in constructing nearly 80 dams in the four countries stated above, it would not be wrong to question the wisdom of constructing them in fragile, erosion prone, landslides prone, active seismic zone.
In view of the above the prudent course would be for the Himalayan countries to develop water resources in a way that helps people of the region adapt to the changing climate as well as hydro-geologic characteristics and reduces their risks. The concerned countries of this region, therefore, should work together to forge a common platform for water resource management planning vis-à-vis river basin management that should be above opportunistic short term political interests but dedicated to a longer term regional socioeconomic development of the people with a common goal to safeguarding and ensuring a sustainable regional environment.
Authors: K. Maudood. Elahi, Department of Environmental Science, Stamford University Bangladesh. And: M. Tajuddin Sikder, Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan email: email@example.com
Started in year 2010, ‘Climate Himalaya’ initiative has been working on the mountain and climate related issues in the Himalayan region of South Asia. In the last two years this knowledge sharing portal has become one of the important references for the governments, research institutions, civil society groups and international agencies, those have work and interest in Himalayas. The Climate Himalaya team innovates on knowledge sharing, capacity building and climatic adaptation aspects in its focus countries like Bhutan, India, Nepal and Pakistan. Climate Himalaya’s thematic areas of work are mountain ecosystem, water, forest and livelihood. Read>>