Humans have been building dams as irrigation systems for centuries. In 1950, there were a total of 5,000 dams worldwide, in 2000 this number increased to over 45,000 dams. This exponential increase has affects countless numbers of ecosystems. The changing of the water directionality and movement, along with the disruption of an ecosystem, has caused a lot of damage for both terrestrial and aquatic creatures. In the study published in the journal Conservation Biology, Maharaj K. Pandit and R. Edward Grumbine look specifically at a project proposal for India. India has the most people living without electricity in the world. To address this problem, an immense hydropower project has been proposed. This project entails the building of 292 dams in the Indian Himalayas that would generate 50,000 MW (megawatts) of electricity to India’s growing population. To put this in perspective, the annual amount of electricity that 400-900 US families will use per year is 1 MW. Pandit and Grumbine predict and examine possible changes that can occur in the land, species loss, seek to quantify the affects on forests and finally analyze environmental policies that the Government of India (GOI) plans to implement.
To find out more information about the land, scientists focused on three main river basins in the Indian Himalayas: the Ganga, Indus and Brahmaputra. They collected data about the proposed dams such as location, elevation, megawatt capacity, size, water storage, river directionality and further details concerning forested versus non-forested plans.
Ecologists also focused on the spatial and geographic location of the dams, species richness, and fauna richness and how these factors would affect land loss and change. The individuals conducting the study also considered a relationship between species diversity and dam sites.
According to the proposal, close to 90% of the dams would be constructed in species rich subtropical and temperate zones, 27% of these dams would affect dense forests. According to the SAR model, as many as 22 angiosperm and 7 vertebrate taxa could become extinct. The study shows that dam disturbance in dense forests is predicted to reduce tree species richness by 35%, tree density by 42%, and forest floor fauna by 30%. With the dam construction, many species will be submerged, causing either immediate wipeout or obstacles to survive. Moreover, dams will transform land cover and therefore impede species from adapting to the changes.
So why use hydropower? Many developing countries use hydropower because of the amount of energy it provides and because of its reduced carbon emission. Furthermore, dams facilitate flood control as well as water irrigation for drinking. This study is the first to examine the potential effects of this immense project. The Environmental Impact Association (EIA) does have regulations considering biological diversity for these types of projects, however in India these regulations have not been effectively carried out. Also, the EIA’s regulations are not legally imbedded, which affects motivation to execute these rules.
There has been civil discontent with the dam proposal, however citizens are concerned about its social consequences, not environmental. They are strongly against losing traditional lands and the irreversibility of the project.
This study was conducted in hopes that people could use the data presented to consider environmental concerns over a developmental agenda. The data will hopefully reveal to the public that the placement of dams should be ecologically and socially studied before plans are finalized.
1. Pandit, M. K. and Grumbine, R. E., Potential Effects of Ongoing and Proposed Hydropower Development on Terrestrial Biological Diversity in the Indian Himalaya. Conservation Biology, 2012. DOI: 10.1111/j.1523-1739.2012.01918.