determining the optimum values of the design parameters for furrow irrigation with winsrfr3.1 model (case study: sugarcane fields of southern ahvaz)

low level of efficiency is a main problem of surface irrigation systems that is due to their poordesign and management. furrow inflow rate and cut off time are the most important design parametersthat affect the efficiency of furrow irrigation. in this study, furrow irrigation condition of amir kabiragro-industry sugarcane fields was simulated with winsrfr3.1 model. then, irrigation performancesof the relevant fields for different cut-off times and inflow rates were evaluated. water flow wassimulated for the both open and block-ends furrow positions. selected furrows for flow simulation hada length of 250 m, with a slope of 0.04 percent and 1.83 m spacing between the furrows. the input dataof the model were measured in these furrows for an inflow rate of 1.5 ls-1. four performanceevaluation indices namely, the application efficiency (ea), distribution uniformity (du), deeppercolation ratio (dpr) and tail water ratio (twr) were computed for evaluating the irrigationperformance in the selected furrows. prior to simulations, the model was calibrated for local conditionsby using measured and simulated flow advance time. the results showed that the best option for furrowirrigation of amir kabir agro-industry fields is the use of end-blocked system with inflow rate of 1.8ls-1 and irrigation duration time of 5 hr.