Environmental and social impact of a mini-hydropower plant based on Sudu Ganga in Sri Lanka

H. M. K. A. Herath, R. A. Ranga Prabodanie, M. T. M. Tharanga Wijewicrama


Hydropower plants are generally considered as economical and sustainable sources of energy, yet they can create unintended disruptions to sensitive ecosystems. The objective of this study was to assess the environmental and social impact of a proposed mini-hydropower plant based on Sudu Ganga (Matale district) in Sri Lanka. Data for the environmental impact assessment were obtained via species observation and from secondary sources. Data for social impact assessment were obtained through the views of the residents and other stakeholders in the area. The regulation degree was 0.052% which indicated minor impact on the hydrological flow regime. In the project area, the study identified 28 flora species and 30 fauna species including five flora and fauna species at high risk of disappearance, and another five species at the risk of falling into a threatened category. The estimated value of the Shannon biodiversity index for flora species was 1.71 and was lower compared to other ecologically sensitive areas in surrounding districts. The environmental impact values for the physical and biological environment, and the social environment were -0.65 and 1.4, respectively, on a scale of [-5, 5]. These values indicate a slight negative impact on the physical and biological environment but a positive impact on the social environment. The proposed reforestation project and fish bypass gate were recognized as significant mitigation measures. We recommend further precautionary measures, particularly, during the construction phase to minimize disturbance to wildlife and damages to plant species, proper management of site excavation and construction waste, careful use of machinery and vehicles, environmental awareness of employees, and involvement of community and stakeholders to reduce adverse impacts.

Keywords: Environmental assessment, hydropower, impact mitigation, Mahaweli project, Shannon-biodiversity index

Full Text:



CEB. 2019. Long term generation expansion plan 2020-2039. Ceylon Electricity Board, Colombo.

De Faria FAM, Davis A, Severnini E, Jaramillo P. 2017. The local socio-economic impacts of large hydropower plant development in a developing country. Energy Economics 67: 533-544.

De Silva MT, Hornberger GM. 2019. Assessing water management alternatives in a multipurpose reservoir cascade system in Sri Lanka. Journal of Hydrology: Regional Studies 25:100624.

Dittus WPJ. 1977. The ecology of a semi-evergreen forest community in Sri Lanka. Biotropica 9(4): 268-286.

DWC. 2007. Biodiversity baseline survey: Horton Plains National Park. Consultancy Services. Report prepared by Green MJB (ed.), De Alwis SMDAU, Dayawansa PN, How R, Singhakumara BMP, Weerakoon D, Wijesinghe MR. ARD Inc in association with Infotech IDEAS and GREENTECH Consultants. Department of Wildlife Conservation, Ministry of Environment and Natural Resources, Colombo.

Edenhofer OPM. 2011. Renewable energy sources and climate change mitigation: Special report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge.

Eriyagama N, Smakhtin V, Udamulla L. 2020. How much artificial surface storage is acceptable in a river basin and where should it be located: a review. Earth-Science Reviews 208: 103294.

Gyamfi S, Derkyi NSA, Asuamah EY. 2018. Chapter 7 - The potential and the economics of hydropower investment in West Africa. In Sustainable hydropower in West Africa: Planning, operation, and challenges, Eds: Kabo-Bah A, Chukweumeka JD. 95-107 pp.

Gunatillake PMPC, Thiruchelvam S. 2003. An evaluation of a small scale hydropower development project in Sri Lanka: a case study in Sripadagama. Tropical Agricultural Research 15: 288-298.

Iglesias-Rios R, Mazzoni R. 2014. Measuring diversity: looking for processes that generate diversity. Natureza & Conservação 12(2): 156-161.

Kibler KK, Tullos DD. 2013. Cumulative biophysical impact of small and large hydropower development in Nu River, China. Water Resources Research 49: 3104–3118.

Mahaweli Consultancy Bureau (Private) Limited. 2014. EIA study of the proposed north western province canal project. Asian Development Bank, Colombo.

Mendis R. 2019. Mini hydros killing many species. Ceylon Today, 18 August 2019. Available at: https://archive.ceylontoday.lk/features-more/3410. Accessed on 25/06/2020.

MOE 2012. The National Red List 2012 of Sri Lanka: conservation status of the fauna and flora. Ministry of Environment, Colombo.

Rupasinghe BWHA, De Silva SN. 2007. Environmental impacts of mini hydropower projects in Sri Lanka. Proceedings of the International Conference on Small Hydropower. Hydro Sri Lanka, Kandy, 373-382pp.

Safont E, Vegas-Vilarrúbia T, Rull V. 2012. Use of environmental impact assessment (EIA) tools to set priorities and optimize strategies in biodiversity conservation. Biological Conservation 149:113–121.

SLSEA. 2017. Sri Lanka energy balance 2017: an analysis of the energy sector performance. Sri Lanka Sustainable Energy Authority, Colombo.

Silva EIL, Silva ENS. 2016. Handbook on small hydropower development and environment: a case study on Sri Lanka. Water Resources Science and Technology, Ragama.

Steinmetz M, Sundqvist N. 2014. Environmental impacts of small hydropower plants-a case study of Borås Energi och Miljö’s hydropower plants. Master of Science thesis. Chalmers University of Technology, Gothenburg, Sweden.

Suratissa DM, Rathnayake US. 2016. Diversity and distribution of fauna of the Nasese Shore, Suva, Fiji Islands with reference to existing threats to the biota. Journal of Asia-Pacific Biodiversity 9(1):11-16.

Thoradeniya B, Ranasinghe M, Wijesekara NTS. 2007. Social and environmental impacts of a mini hydropower project on the Ma Oya basin in Sri Lanka. Proceedings of the International Conference on Small Hydropower. Hydro Sri Lanka, Kandy, 363-372pp.

Ummalla M, Samal A. 2018. The impact of hydropower energy consumption on economic growth and CO2 emissions in China. Environmental Science and Pollution Research 25: 35725–35737.

Wijenayake T. 2016. Mini hydro-power projects and human issues. Daily News, Wednesday May 2016. Available at: http://www.dailynews.lk/2016/05/25/features/82707. Accessed on 25/06/2020.

World Commission on Dams. 2000. Dams and development: a new

framework for decision-making. Earthscan Publications Ltd, London.

Zelenáková M, Fijko R, Diaconu DC, Remenáková I. 2018. Environmental impact of a small hydro power plant – a case study. Environments 5(12): 1-10.


  • There are currently no refbacks.

Creative Commons Licence
Ruhuna Journal of Science by University of Ruhuna is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

eISSN: 2536-8400

Print ISSN: 1800-279X (Before 2014)