Contemporary Aspects of Irrigation Tanks, and Management and Conservation Strategies for their Wise-use

Contemporary aspects of irrigation tanks in Japan were investigated mainly through fieldobservations in order to build management and conservation strategies for their wise-use. Mainfruits of the research are summarized as follows.开发一个novel methodology for estimatingdynamic properties of the food runoff这是关于irriga-tion tanks could mitigate flood even when they have no vacancy forstoring flood. Using the modem control theoryoptimal control/management model for interconnected irrigation tanks system wasdeveloped. Reproducing seismic vibrations at a few real irrigation tanks，the seismic behaviors of the embankment ana-lyzed using spectral and model approaches. and，一个attempt to find a transaction of major leaky-path was made at an overage irrigation tank. astatistical approach to confined seepage problem also was developed with generation of randompermeability filed. Using the percolation theory, furthermore，an attempt was made to reproduce spatial spanning that forms "impervious wall" or "flowpath". in situ observations of water quality and biology in irrigation tanks were made，and based on the data obtained，一个attempt was made to categorize the tanks from a viewpoint of water quality/algae facets. Through环境field investigationscauses that generate the water bloom were brought into light Structure of multi-functionsirrigation tanks被分析了，它可以解释the entire function could be structured withmajor four核心功能and detailed description for each核心功能was made in relation to sustainable wis -use andexistence of the tanks. Finally effective strategies for management and conservation of the tankswere proposed in terms of multi-functioning tanks。

Contemporary aspects of irrigation tanks in Japan were investigated mainly through field observations in order to build management and conservation strategies for their wise-use. Main fruits of the research are summarized as follows.・Developing a novel methodology for estimating dynamic properties of the food runoff, it was verified that irriga-tion tanks could mitigate flood even when they have no vacancy for storing flood.・Using the modem control theory, an optimal control/management model for interconnected irrigation tanks system was developed.・Reproducing seismic vibrations at a few real irrigation tanks, the seismic behaviors of the embankment were ana-lyzed using spectral and model approaches. And, an attempt to find a transaction of major leaky-path was made at an overage irrigation tank. A statistical approach to confined seepage problem also was developed with generation of random permeability filed. Using the percolation theory, furthermore, an attempt was made to reproduce spatial spanning that forms "impervious wall" or "flow path".・In-situ observations of water quality and biology in irrigation tanks were made, and based on the data obtained, an attempt was made to categorize the tanks from a viewpoint of water quality/algae facets. Through environmental field investigations, causes that generate the water bloom were brought into light.・Structure of multi-functions of irrigation tanks was analyzed. It was demonstrated that the entire function could be structured with major four core functions, and detailed description for each core function was made in relation to sustainable wise-use and existence of the tanks. Finally effective strategies for management and conservation of the tanks were proposed in terms of multi-functioning tanks.