Uncertainty Analysis of Irrigation Canals Operation

Mostly, the amount of water delivered to the downstream areas of each turnout gate does not meet its actual (demanded) needs in irrigation canals. In practice, the actual openings of the gates applied in an irrigation canal differ from their planned values due to existing uncertainties, causing poor performance. The main objective of this study is to analyze the uncertainty of input parameters (turnout gate opening) in the east Aghili irrigation canal, as a case study, using Monte Carlo Simulation (MCS) and evaluate the canal performance. To this end, the gate opening available data received from the water authority was statistically analyzed with graphical and statistical methods in EasyFit, and the best-fit distribution was found. Next, random gate openings were generated using the R software. They were accordingly introduced to Irrigation Conveyance System Simulation (ICSS) to simulate the canal under several operational timings. Then, the Coefficient of Variations (CVs) of flow, and adequacy and dependability indicators were calculated to analyze their uncertainties. The more the CV, the more uncertainty. The results showed that CVs of flow, adequacy, and dependability were respectively found up to 12.04%, 12%, and 34.2% as gate opening’s CV was up to 12.9%, showing high uncertainty and low performance.