Scientists from Wildlife Conservation Society – India Program (WCS-India Program), National Centre for Biological Sciences (Bengaluru), University of Florida, Ashoka Trust for Research in Ecology and the Environment, and Foundation for Ecological Research Advocacy and Learning (FERAL), jointly conducted a study in the upper reaches of river Nethravathi, which is part of the Western Ghats biodiversity hotspot.
A first-of-its-kind holistic study in India, which has evaluated the environmental impacts of Small hydropower projects (SHPs) in the biodiversity hub of Western Ghats found out that SHP’s have not only altered the composition of freshwater fish communities but also reduced the number of species.
The study titled ‘Fish community responses to stream flow alterations and habitat modifications by small hydropower projects in the Western Ghats biodiversity hotspot, India’ showed that SHPs reduced the water flow immediately downstream of the dam and caused flow fluctuation when water is released back into the river after power generation, both of which impact fish assemblages (variety and abundance).
SHPs are a classic case of good intentions leading to terrible consequences. Since SHPs result in diverting water for long distances, vast stretches of the river are almost completely devoid of water flow in the dry season. Water in these stretches had lower oxygen levels and higher water temperature.
Not surprisingly, these habitat alterations strongly affected freshwater fish assemblages. They also had reduced numbers of migratory fish such as Mahseer. Native species were strongly affected and were being driven to extinction, the study added.