Recently, structures with the flowing water have been constructed to create places for recreation and relaxation for citizens. On the other hand, the scattering light reflected from water surface might play harmful effects on visual handicapped persons. In order to deal with this problem, the handicapped persons only receive advises to stay away from water front areas by medical professions. The fundamental solutions of this problems on the basis of the engineering have not been clarified yet. In this study, we have investigated the characteristics of the scattering light reflected from the water surfaces, and have showed the consideration of visual effect to construct waterside spaces.

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 Real-time rainfall-runoff prediction systems using a particle filter are developed. The systems update state variables (storage variables and model parameters) using observed variables and predict future river discharge on a real-time basis under a parallel computing environment. The systems are applied to the Sonohara River basin (492km²) in the upper part of the Tone River basin and three different prediction systems, a model parameter update system, a storage variable update system, and a parameter and storage variable update system are compared in terms of prediction accuracy. Results obtained are as follows: a storage variable update system provides stable prediction results; it is applicable for floods with different magnitudes; the variance of the system noise influences prediction results and the standard deviation as 10 percent of the storage variable gave appropriate prediction results.

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 This work proposed a method by which disaster prevention weather information standards based on rain gauges can be constructed. First, we compared the difference between rain gauge and radar rain gauge analyzed precipitation, and confirmed that there was a significant difference between them. These results showed that disaster prevention weather information using rain gauges requires modification based on the radar rain gauge analyzed precipitation. Second, we proposed a method to set a rain gauge correction standard based on the disaster prevention weather information. The proposed correction standard agreed almost fully with the number of times that the disaster prevention weather information standard was exceeded. Third, we installed a new rain gauge and obtained a disaster prevention weather information standard using the proposed method described. Through reproduction analysis, we obtained the same results as the disaster prevention weather information that was used and were able to detect disaster cases during the data collection period of the newly installed rain gauge.

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