Study shows big ecological impact of small hydro-power projects

Small hydro-power projects are often promoted as a cleaner alternative to large projects as they are assumed to have little or no environmental impact.  

The first-ever scientific study in India of small hydro-power projects (SHPs) has revealed that despite their being promoted as generating clean energy, the plants have a significant ecological impact and there is a correlation between the rise in SHPs and the increase in human-elephant conflict.

According to a release issued by the Wildlife Conservation Society–India Program, SHPs also cause alterations in stream geometry and affect the water quality and freshwater fish communities in the Western Ghats.

SHPs are often promoted as a cleaner alternative to large hydro-power projects as they are assumed to have little or no environmental impact. In India, they are defined as plants generating up to 25 MW of power.

The study area of the WCS and others was in the upper reaches of the river Nethravathi, which is part of the Western Ghats biodiversity hotspot, and was conducted from February to May 2014. The release said the scientific work, recently published in the journal Aquatic Conservation, was conducted by WCS-India Program, National Centre for Biological Sciences, Bengaluru, the University of Florida, Ashoka Trust for Research in Ecology and the Environment, and the Foundation for Ecological Research Advocacy and Learning.

The study found that SHPs affect the river flow by reducing it immediately below the dam and causing fluctuation when the water is released back into the river after power generation — both of which have consequences on fish assemblages. The dammed streams studied had altered fish composition and reduced the number of species, the release said.

Explaining the results, Suman Jumani, the lead author, said their study was one of the first to holistically assess the impact of SHPs in the forested regions of the Western Ghats.

The study also found that there was a reduction in the number of fish such as the Mahseer, which are found only in the Western Ghats.

Rise in conflict

The study has also revealed a correlation between the proliferation of SHPs and the corresponding increase in human-elephant conflicts in those areas.

This is an issue of significance for the State, which has seen a spurt in human-elephant conflict in recent years. The research showed that such conflicts increased in the regions where new SHPs were being constructed, said Shishir Rao of WCS-India, who is a co-author of the paper.

“In 2005, the number of claims filed for elephant conflict compensation increased by 173% from the previous year. That was the same year the first SHP was commissioned in this area. Thereafter, the number of claims rose every time a new SHP was commissioned. This is a concern as the reserve forests of Sakleshpur are a critical elephant corridor connecting Pushpagiri wildlife sanctuary in the south and Kudremukh national park in the north,” he said.

The researchers said that given the importance of the region as a watershed and a part of the Western Ghats biodiversity hotspot, there is an urgent need to monitor, regulate, and evaluate the impact of large-scale infrastructure development.

Mr. Suman said that most of these planned dams are located within the biodiversity hotspots of the Western Ghats and the Himalayas, and hence it is imperative that the policy concerning these projects is revised to include mandatory minimum flow requirements and individual and cumulative environmental impact studies.

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Printable version | Jun 17, 2021 12:03:51 AM | https://www.thehindu.com/news/national/karnataka/study-shows-big-ecological-impact-of-small-hydro-power-projects/article24053425.ece

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