EVALUATION OF WATER ABSTRACTION IMPACT ON MOUNTAIN ECOSYSTEM CAUSED BY MICRO HYDRO POWER PLANTS

Abstract

 Micro-hydropower, as a hopeful decentralised renewable energy, is expected to be introduced in various parts of Japan. Micro-hydropower has been considered to have a small environmental load, but since a water abstraction reach exists, it is necessary to evaluate the impact on the river ecosystem correctly. In this study, the influence of water abstraction by micro hydropower was quantitatively evaluated for each habitat type of mountain streams using benthos as a sensitive index. As a result of field investigation, in the Kaji River, the influence on the benthic animal population, the number of taxonomic groups, and the community structure by water abstraction were not statistically recognised in all mountain stream habitats. In the Kamo River, the number of benthic animals and the number of taxonomic groups decreased in the water abstraction reach in some habitats, including step, cascade, rapid and stagnation.