Abstract
Following periods of heavy rain and flooding, large amounts of water with high turbi01dity may flow into reservoirs. The larger the reservoir, the longer high turbidity levels may persist, which may disrupt water supplies. In this paper, we estimate the retention period of suspended matter in rivers that flow into Ogouchi Reservoir. The estimated retention period becomes the basic data to rapidly exhaust high turbidity water at an early stage. The retention period was obtained by assuming the complex flow of water into the reservoir as a "black box." By using cross-correlation analysis, the I/O response relation was calculated. We set the river water quality as the input and the effluent water quality as the output. We then estimated the retention period of the suspended matter to be almost 250 hours. The analysis method used in this paper does not use diffusion equations which require complex factors that influence the flow of water, such as wind, density, water temperature, topography, etc. Moreover, this analysis method is readily applicable to other reservoirs.
