Abstract
Since the water flowing into the Agigawa Dam has a relatively high concentration of nutrient salts and eutrophication of the reservoir is worried about, the several measures are investigated for conserving the water quality in the reservoir. In the catchment area, efforts to reduce the nutrient load are made through measures such as construction of public sewage systems implemented by the cooperation of the local governmental agencies.
As regards the water flowing into the reservoir, the suspended nutrient salts are removed by precipitation using a storage dam, and a pipeline was installed between the point of inflow and the intake tower to reduce the duration of time the nutrient level of the reservoir. In the reservoir, the fountain has been installed with the aim of deactivation, and hypolimnetic aeration equipment has been installed to prevent the generation of hydrogen sulphide and the elution of minerals. The implementation of these measures is expected to have a considerable eff ect in improving the water quality of the Agigawa Dam Reservoir, where the operations started in April 1991, We will conduct verification and evaluation of these measures.
