ABSTRACT
The continued performance of national irrigation systems (NIS) below the expected levels despite rehabilitation and improvement efforts have been a subject of discussions by concerned government policy- and decision-makers. The planning and formulation process for system improvement projects in the Philippines does not include a diagnostic assessment. This chapter explores the utility of coupled diagnostic assessment techniques deemed relevant in the formulation of a modernisation strategy for many NIS in the Philippines. A combination of concrete pipe farm turnout, concrete pipe bifurcating canal intake and cross regulator or water level control were originally constructed at major bifurcation points in Balanac River Irrigation System. It focuses on the discussion on the systems components whose current state deviates significantly from their design or newly-constructed state and, hence, are no longer functioning as intended. The chapter presents a comparison of the design, actual and required capacities of irrigation structures to perform their functions that are relevant to system operations.
