Open canal dynamics in which a constant water level is kept at the bottom end of each canal pools by the upstream control structure of the pool are characterized by a time-varying delay associated with water transport. Predictive control, based on the output prediction over a long time horizon and the minimization of a quadratic cost function is slightly sensitive to the magnitude and variation of the delay. The predictive control performance is tested on the lateral canal MW of the Maricopa Stanfield Irrigation and Drainage District. The simulation results illustrate the capacity of predictive control to improve canal operation.