Abstract
When deciding the priority of possible countermeasures, it is important to understand the conditions and factors of water shortage in irrigation canal system both objectively and quantitatively. In this study, we organized information on irrigation canal system, including regulating reservoir according to the spaces and times, which are in turn divided by spatial and temporal aspects, namely, (1) satisfaction of users on the adequacy of supplied irrigation water and (2) indicator values for 3 assessment items, adequacy, reliability, and vulnerability. As a result, we have reached three important conclusions. (1) In sections where the satisfaction was low, 1) the amount of intake flow of lateral canals was less and 2) there was a day which the flow was less. (2) The shortage of intake flow was considered to be because of a shortage in the reliability of the main canal water flow according to the increasing demand. (3) The use of vulnerability together with reliability was considered important for deciding the priority of possible countermeasures. Further, we consider that a combination of diagnoses that could aid in identifying the sections having usage issues regarding the main canal water flow and detailed diagnoses of these sections would result in effective cost reduction.
