A Rational Approach to Scheduling Main-System Maintenance

Rational methods for setting priorities formaintenance of irrigation systems aredeveloped. The methods, which are aimed foruse by irrigation system managers, describethe link between maintenance activities andthe consequent improvement in theperformance of an irrigation system.Hydraulic analysis methods are developedfor assessing potential `restorativemaintenance' tasks, which are usuallyundertaken to increase the deliveries ofwater to the outlets. The new methods useinputs that have been limited to thoseeasily available from scheme records, theknowledge of irrigation agency staff andfrom infrastructure inspections. Twoalternative methods are developed, onebased on Fuzzy Logic and one on numericalmodelling. Risk analysis methods are alsodeveloped for assessing `preventativemaintenance', to reduce the probability ofsupply failures. Benefit-cost ratios arederived that allow direct comparisonbetween maintenance tasks of each type. Themethods are tested at two irrigationsystems in Tamil Nadu, India.