Liquid flow controller for ancillary span zones

Aspects of the disclosure provide systems and methods for controlling the flow of water through zones of an ancillary span of an irrigation system to achieve optimal water distribution for each of a plurality of sections of a field-of-interest to be irrigated by the ancillary span. The disclosed systems and methods optimally turn control zones on and off to minimize the flow variability of water supplied to the ancillary span. The technology described herein runs a series of simulations to determine an optimal irrigation plan for the ancillary span. The instantaneous average flow at different points within a simulation may be calculated. The plurality of instantaneous average flows are used to determine a variance statistic for the plurality, which is used to determine the optimal plan.