Evaluation of Water Delivery Performance in Doroodzan Irrigation Network under Two Different Water Requirement

he subject of this study was to evaluate the water delivery and find solution for increasing water productivity in Doroodzan irrigation and drainage network. Five water delivery indices such as water delivery adequacy, water delivery efficiency, water delivery equity, water delivery dependability, and delivery performance ratio were measured. The indices were measured in 12 selected third grade tertiary canals for at two irrigation intervals during spring season. Evaluations were accomplished for two water requirement scenarios based on the primary design condition (based on hydromedol) and current condition (based on Penman Montieth evapotranspiration model and efficiencies). Statistical analysis was performed using Chi-squared test and standard and average errors. Results showed that the water delivery equity and water delivery dependability values were equal to 0.31 and 0.12, which can be categorized as poor and fair, respectively, based on the standard values. The average of water delivery performance ratio based on the primary and current condition approaches were 1.41 and 0.61, which indicates that the exess and deficit delivered water were about 41% and 39%, respectively. Water delivery efficiency index for the two approached were about 0.79 and 0.97, while the water delivery adequacy were about 0.93 and 0.56, respectively. Generally, the differences between the water delivery adequacy, water delivery efficiency and delivery performance ratio in the two studied water requirement approaches were considerable. Therefore, the approach based on Penman Montieth evapotranspiration model and efficiencies should be considered instead of hydromedol approach for water requirement assessment in Doroodzan irrigation network.