Control of Irrigation Channels

Water losses in irrigation channels are large, but they can be substantially reduced by improving the control systems. The flows and water levels are controlled using overshot gates located along the channels, and in this paper we consider decentralized PI control and centralized multivariable LQ control of the flows and water levels. The controller designs are based upon simple system identification models which capture the relevant dynamics and are easy to use for control design. The controllers showed very good performance in field tests. The water levels recovered smoothly from disturbances without excessive oscillations, and the deviations from setpoints were small. As expected the centralized LQ controller showed better performance, attenuating disturbances faster than the PI controllers. However, more effort has to go into the design of an LQ controller.