Status quo and perspectives in integrated management of water resource facilities for agricultural water use in the upper Tone River basin [Japan]

Problems on changes of water cycles, of which solutions are required to be watershed ranges, have much interests from only urban perspectives, so that there are few analyses from the viewpoint of agriculture and/or rural regions. In addition, just modeling of water cycles keeps its popularity, then quite a few analyses from regional-scale aspects have been done in irrigation and water management or in the assessment of impact on water cycles. Especially dam operation is one of the keen human activities in that dams are operated by humans and in that their operation/maintenance affects people downstream. However, while concerns on droughts and floods for dam controls ebbed away easily due to irregular occurrence (not every year), it is anticipated that, because of global warming, extreme events occur constantly in the respect of the decrease of week rainfalls and the increment of drought events as wall as the increase of record heavy rainfalls. In this report, therefore, status quo of reservoir management and control for agricultural use are summarized and present situation and perspectives in integrated management of water resource facilities for agricultural use in the Tone River Basin are analyzed. The final target is to set up technologies of integrated family control for a series of water resource facilities and to stabilize and/or secure agricultural water use in future. As a result, the following outcomes and suggestions are obtained: 1) In order to perform rational management for complex facilities, decision-support frameworks such as various AI technologies and/or game theory are of great promise. 2) It is necessary to carry out the proposal of essential modification to the operation rule curves for reservoirs and detail analyses for those for performing effective agricultural use. 3) Taking facilities in the upper-stream of the Tone River Basin as an example, problems to be resolved for integrated management of water resource facilities are extracted and a basin-wide watershed management of a series of water resource facilities by utilizing low-lying paddy areas as retarding areas (water storage) was proposed.