Approach to the Evaluation of Undependable Delivery of Water in Irrigation Schemes

The method developed in thisstudy quantifies the undependable deliveryof water with respect to the overallirrigation efficiency in irrigationschemes. It shows how well operationperformance matches required water deliveryand reflects the combined effect ofreliability and predictability. Theapproach has the possibility to take intoaccount deficit and excess water, both asresults of undependable delivery.Appropriate weighting factors can beconsidered for deficit and excess in eachscheme. The method has the flexibility touse available data for crop waterrequirement and supply water according tothe time base in which the scheme isscheduled. The approach reveals that,without taking into consideration the jointeffects of delivery schedule and operationperformance and without improving thedelivery schedule, any increase inefficiency is not worthwhile.