Risk Assessment of Agricultural Water Conveyance and Delivery Systems by Fuzzy Fault Tree Analysis Method

Improving the efficiency of main Agricultural Water Conveyance and Delivery Systems (AWCDS) has a significant impact on improving water productivity in agriculture. Therefore, risk assessment of mentioned systems is necessary to increase reliability of operational performance. Accordingly, this study for the first time presents a unique framework to assess the adequacy, equity, and efficiency of agricultural water distribution and delivery risk assessment within AWCDS. In this way, the Fault Tree Analysis (FTA) technique is employed for risk assessment of “undesirability of supply and delivery”. The west Dez main irrigation canal in Khuzestan province of Iran was determined as the case study of the research. A set of questionnaires filled up by managers and experts of this irrigation district, the failure probabilities of the basic events are gathered in the form of linguistic terms. Due to the uncertainty in these terms, the system’s risk assessment to determine the failure probability of the top event was performed based on Fuzzy Fault Tree Analysis method (FFTA). The results of the study showed that the failure probability in the fuzzy approach is 0.55 which is roughly 0.15 more than crisp approach. Also, the rating of the basic events based on their contribution to the occurrence of the top event was carried out using importance measures. Five major events were identified with an emphasis on operational and socio-economic issues related to distribution and delivery of water. Comparing the results of risk assessment with the mathematical model reveals that the latter’s failure probability will be less than the system’s FTA due to non-consideration of some important factors.