LP Operation Model for On‐Demand Canal Systems

Abstract

A computer model was developed to assist watermasters in making the daily operating decisions required for irrigation water delivery systems which operate under flexible scheduling regimes. The objective of the model, which was formulated for micro computer use, was to calculate gate discharge rates which would: (1) Maintain stable flows in canal reaches; (2) prevent excessive shortages and waste; (3) respond to changes in demand in a timely manner; and (4) supply users with water as close to when they want it as possible. A linear programming approach was chosen as‐the optimization technique to minimize the differences between the water order demands of the users and the gate releases. Projected water order demands in each canal reach are input to the model. Water volume balance and physical limitations of the system were used as constraints in the model. The gate releases specified by the model were compared with actual gate releases for a 24,000 hectare irrigation project. Some of the water level fluctuations which occurred in actual operation, when flow rate adjustments were made in response to water level changes, could have been eliminated by using release rates predicted by the model.