Abstract
In recent years, a technique for the functional diagnosis of various structures and a verification approach have been developed in order to increase the life-span of agricultural irrigation facilities. This permits visual inspections to understand structural conditions of deteriorated hydraulic structures and to assess their soundness indices. To update or upgrade an agricultural irrigation canal on the other hand, it is necessary to establish performance-based design of the system. In addition to structural performance, this performance-based design system should include the evaluation of hydraulic performance and water serviceability. This report targets the irrigation canal system in an irrigation district consisting of paddy fields. It provides examples of the generation of a diagnosis chart for irrigation canal systems that can be effective as an investigation method involving functional diagnosis. This report also discusses a diagnosis example to evaluate the problem examination priority.