"With an average annual rainfall of 1,170 mm, India is one of the wettest countries in the world. Still, even with its rich natural water resources, with more than 300,000 square meters of bodies of water, the country is plagued by environmental issues such as water pollution from raw sewage and runoff of agricultural pesticides (Sharma, 2005). Another major problem is that tap water is not potable throughout the country. This implies that people, especially those from the lower income bracket, cannot avail of clean drinking water, since these have to be bought. Repugnant as it may sound, it is a reality that millions of Indians queue up everyday at public taps for one of life's most precious commodity — water." -ADB

Thursday 26 November 2009

The emission of Green House Gases(GHG) from its reservoir

Will complete this issue on next few days..pls give yr inputs

some thoughts

  1. HOW?--->Large hydroelectric dams release methane into the atmosphere because trees and other plants settle to the bottom when the reservoir is first flooded. This plant material decomposes without oxygen and dissolved methane builds up. When water passes through the dam's turbines, this methane is released.
  2. Dr. Ivan Lima and his colleagues(Brazil) used a theoretical model, bootstrap resampling and data provided by the International Commission On Large Dams World register of dams to demonstrate that global large dams annually release about 104 million metric tons of methane to the atmosphere through reservoir surfaces, turbines and spillways.
  3. The International Hydropower Association, IHA, says considering only total greenhouse gases measured at the surface of reservoirs can be misleading; these measurements should be considered as "gross" emissions. "Net" emissions for which dams are responsible must consider the emissions from ecosystems before the creation of a reservoir when the land was in its natural state.
  4. Interesting paper suggesting " the hydro-power plants studied generally posted lower emissions than their equivalent thermo-based counterparts.(http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2W-4F1J8N1-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1111131857&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=5e14d12ab4f0bf2b69ec81d74fa44dad)"
  5. http://www.adb.org/Water/topics/dams/dams0535.asp    suggests WCD recommends that GHG emissions from reservoirs need to be assessed and compared with emissions from other generations sources. The effect is highly location specific and may change significantly over time.
  6. In response, the industry coordinated by the International Hydropower Association (IHA) prepared a fact sheet Greenhouse Gas Emissions from Reservoirs that countered the claims of hydropower opponents, concluding that 'relative to typical values for hydro, coal fired generation emits about 100 times more GHG and natural gas combined cycle turbines about 40 times more'.
  7. The NGO, International Rivers Network (IRN), published a paper Flooding the Land, Warming the Earth; Greenhouse Gas Emissions from dams that documents the growing evidence for the global significance of greenhouse gas emissions from dams and reservoirs
  8. Recently I attended a symposium on Climate Change at NIH Roorkee. Some technical papers were presented. I will post the Gist. In short, More studies are needed in our tropical Zone before we arrive at any conclusion . Dams Located in  Boreal climate cant replicate our (India,Brazil's) cases.



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Disclaimer: This Blog is a small step towards building a knowledge-based platform for Professionals interested in "water resources management(WRM)". One of the objective is knowledge dissemination. Please note that VIEWs expressed here are purely personal.