GROBAL EVALUATION AND UTILIZATION OF ENVIRONMENTAL EFFECTS INCLUDED IN AGRICULTURAL WATER-USE -DEVELOPMENT OF THEIR STANDARD METHODS-

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This study group supposed that agricultual water-use systems spread widely in rural areas were useful for environmental conservation. Therefore the group tried to evaluate environmental effects of canal and farm land, and to get fundamental indexes for their utilization from 1994 to 1996. In addition, regional environment analysis by processing images from earth observation satellite was also tried in the same years.The results are as follows :1. Evaluation of environmental effects of canal and fundamental indexes for its utilization.(1) Aeration effect in hydraulic jump is theoretically high. But exposed jet flow has some theoretical problems in aeration effect.(2) If paddy field accounts for 40% of catchment basin, water quality of canal must be estimated by both L-Q eqation of irrigation period and non-irrigation period.(3) A method to infer influence of plants on velocity distribution and water level variation in canal was found for planning of canals to conserve ecosystem.2. Evaluation of environmental effects of farm land and fundamental indexes for its utilization.Quantitative measurement of denitrification in paddy field was done and Quantitative index of denitrification was found to evaluate environmental effects of paddy field.3. Regional environment analysis by processing images from earth observation satellite.By processing images from NOAA satellite, it was possible to globally classify vegetation, to globally find movement and existence of land cover due to climatic change and to roughly find quantitative change of carbon dioxide fixation due to its movement and existence.