SMALL HYDROPOWER PROJECTS: ENVIRONMENTAL AND HYDRO·GEOLOGICAL PERSPECTIVES

Abstract

Small hydropower projects are those that generate less than 10 MW of electricity usingsmall run-of-the-river hydropower systems. They usually consist of water conveyance.(headrace channel, forebay and penstock), powerhouse unit, tailrace and transmissionline. It is considered as a renewable resource of energy. It does not contribute to globalwarming and does not contribute to acid rains etc. Therefore, there is no question ofpollution or degradation of land, waterways or other water bodies. However, large-scaledam hydropower projects are often criticized for their impacts on environment,particularly on wildlife habitat, fish migration, and water flow and quality. It is usuallyassumed that small, run-of-the-river projects are free from many of the environmentalproblems associated with their large-scale counterparts because of the use of the naturalflow of the river, and thus producing relatively little change in the stream channel andflow. This paper addresses the feasibility of small hydropower projects in Sri Lanka withrespect to environmental issues, geological stability and hydrological feasibility usingcase studies. The results of the study revealed that environmental impacts of smallhydropower projects are location sensitive and also case dependant. In most cases,proper planning and implementation of the project and relevant mitigatory measures canminimize significant impacts of projects. Problems related to implementation andmonitoring of impacts and possible solutions are also discussed.