Abstract
Water quality of dam reservoirs controlled by the ministry of construction of Japan is basically good, according to the investigation of water quality for them. But, the high level of nutrient salt in inflow river water and high turbid water of flood are represent the possibility of occurrence of temporary water quality problems in many reservoirs. The most important things for the water quality of dam reservoirs are pollutant loads running into water basin, and pollutant load control measures in the watershed that is realized step by step for a long time is the fundamental measures as well as the temporary measures with an immediate effect. We discuss the water quality control system based on the actual condition of water quality of dam reservoirs in this report. And we summarized by the present situation of water quality problems that artificial current control of dam reservoirs and environmental control of the surface layer for algae growth are very effective for preserving water quality in reservoirs.
