Diagnostic Assessment Approach for Formulating a Modernization Strategy for Small‐Scale National Irrigation Systems in the Philippines

The utility of a logic design framework and the diagnostic tools of the mapping system and services for canal operation techniques (MASSCOTE) were tested in two small-scale national irrigation systems (NIS) with an end view of developing a diagnostic assessment methodology that would be relevant to planning for small-scale irrigation systems modernization. The applicability of the water-related rapid appraisal procedure (RAP) external indicators and structures sensitivity assessment as diagnostic tools was limited by the lack of flow data and the infeasibility of field experiments due to tight rotational irrigation schedules and laissez-faire direct offtakes. The discharge–head relations, the hydraulic flexibility concept and the findings from walkthroughs and interviews were pragmatic alternatives. The results of the study show that inconsistency in the system designs and lack of, or poorly performing, flow control structures are the main factors contributing to mediocre irrigation service. The combination of diagnostic techniques and analytical tools used in this study present a useful framework for system diagnosis in small and ungauged irrigation systems. Copyright © 2017 John Wiley & Sons, Ltd.