BACKGROUND |
Many of the developmental projects in the past have been implemented with little environmental concern in India. The assessment of the projects was based on only technical, economic and political criteria, mainly due to the fact that knowledge of environmental impacts and impact assessment technology were not fully developed at that time. As a result, a number of large-scale development projects led to adverse impacts on the environment. Environmental Impact Assessment (EIA) has gained tremendous importance in nineties and is mandatory for any major developing work in India. An EIA is an effective tool in identifying and evaluating the potential impacts of the project, related to physical, chemical, biological and socio-economic components of the environment and in-turn reducing the likely adverse consequences, by proper mitigation measures, appropriate monitoring as well as auditing programmes. Normally, EIA is vastly implemented prior to project initiation. In absence of such investigations, the scope is expanded to include larger issues, such as biodiversity changes, sustainable development, economic valuation of natural resources and impacts etc., to assess the cumulative impacts. The projects that have not undertaken EIA, during the construction phase can be valued using Cumulative Impact Assessment studies. The Cumulative Impact Assessment or Cumulative Effects Assessment (CEA) considers systematically multiple impact sources, pathways between sources and impact receptors, and direct and indirect, additive and non-additive interactions.
The practice of Environmental Impact Assessment (EIA) was nonexistent at the time of execution of the Linganamakki and Talakalale reservoirs. Naturally these projects had telling consequences on the fragile ecosystems of which no documentation, whatsoever, was ever made. The area affected had substantial tracts of species rich tropical forests with their varied kinds of habitats. These included climax forests, Myristica swamps, gallery forests, grasslands, and ecosystems of varied kinds. Also were lost large tracts of traditional agricultural systems, which harboured priceless heritage of domesticated biodiversity. The submersion of lands and consequent resettlements of the affected people as well as the influx of migrant population brought in for the various developmental activities in the region had tumultuous effects on the entire ecosystems. These included fragmentation of natural habitats, forest encroachments, poaching of wildlife, excessive extraction of forest biomass, disruption of wildlife corridors, diversion of streams for agriculture, over grazing, etc. After the passage of four decades, the need was felt to assess the cumulative impact of the Sharavathi river valley hydroelectric projects on the environment. In this connection, the Karnataka Power Corporation Limited approached the Centre for Ecological Sciences, Indian Institute of Science, Bangalore, which is one of the centres of excellence under the Ministry of Environment and Forests, Government of India, to undertake such a study.
