Disruptions from small hydropower dams

Hydropower has been used as a clean energy source because it does not emit any greenhouse gases during electricity generation, thus helping to mitigate climate change. In particular, small hydropower (SHP) can be used in rural areas to increase the electrification of local communities. Unfortunately, the use of small hydro is not without side effects. Environmental impact assessments for these projects are often lacking, as their socio-economic or environmental impacts are considered negligible due to their small size. However, some scientists argue that the negative impacts of SHP could be even worse than those of large hydropower plants, given the cumulative effects of the construction of several small dams. By disrupting the flow of small rivers, fish populations are isolated and genetic diversity is reduced, leading to an overall decrease in biodiversity. From a socio-economic perspective, SHPs can lead to habitat degradation and landscape-scale changes that negatively affect the provision of cultural services by the river itself.

Nº 81

Nu River Basin

some attempts made
past case
Region-1
Region-2
Region-3
Region-4
ongoing case
no attempts made

Disruptions from small hydropower dams

Hydropower has been used as a clean energy source because it does not emit any greenhouse gases during electricity generation, thus helping to mitigate climate change. In particular, small hydropower (SHP) can be used in rural areas to increase the electrification of local communities. Unfortunately, the use of small hydro is not without side effects. Environmental impact assessments for these projects are often lacking, as their socio-economic or environmental impacts are considered negligible due to their small size. However, some scientists argue that the negative impacts of SHP could be even worse than those of large hydropower plants, given the cumulative effects of the construction of several small dams. By disrupting the flow of small rivers, fish populations are isolated and genetic diversity is reduced, leading to an overall decrease in biodiversity. From a socio-economic perspective, SHPs can lead to habitat degradation and landscape-scale changes that negatively affect the provision of cultural services by the river itself.

In China, there has been an increase in energy and development policies aimed at promoting the expansion of small hydropower (SHP) projects. However, research has revealed environmental impacts in the Nu River basin attributed to these SHPs. These include unanticipated changes in the length of the affected river channel, impacts on diverse habitats, impacts on designated nature reserves and biodiversity hotspots, and the potential to disrupt hydrological patterns and water quality.

Kibler, K. M., & Tullos, D. D. (2013). Cumulative biophysical impact of small and large hydropower development in Nu River, China. WATER RESOURCES RESEARCH, 49, 3104-3118. doi:10.1002/wrcr.20243.

Lange, K., Wehrli, B., Brodersen, U. Å., Fischer, M., Liermann, V. H., Schmid, M., . . . Weber, C. (2019). Small hydropower goes unchecked. Frontiers in Ecology and the Environment, 17 (5), 256-258. https://www.jstor.org/stable/10.2307/26675020.


Lange, K., Wehrli, B., Åberg, U., Bätz, N., Brodersen, J., Fischer, M. & Weber, C. (2019). Small hydropower goes unchecked. Frontiers in Ecology and the Environment, 17(5), 256-258.