In the present study, a distant downstream proportional integral (PI) feedback control with decouplers and a local upstream PI feedback control were applied to the West main canal of the Dez irrigation system in Iran. The model of the proposed canal was formulated in the SOBEK simulation package. The control system was programmed in MATLAB. To evaluate the control system potential, simulations were done for two months of the real offtake schedule. The performance criteria of the maximum absolute error (MAE), the integral of absolute magnitude of error (IAE), and the steady state error (StE) were determined for each pool of the canal. The results indicated that the applied controllers have considerable potential to closely match the discharge at the downstream check structures with those ordered by water users while maintaining the water level throughout the length of the canal. The performance indicator values showed that the distant downstream feedback (FB) control as a centralized control with decouplers is a satisfactory controller for the Dez main canal. Hence, operational water management in the canal may be improved if a centralized controller is used rather than individual local controllers. It is strongly recommended to implement the distant downstream FB control with decouplers as a control system in the proposed canal. Copyright RÉ SUMÉDans la présente étude, un contrôleur aval distant avec rétroaction proportionnelle intégrale (PI) et avec DECOUPLEURS et un contrôleur amont avec rétroaction PI ont été appliqués au canal principal ouest du système d'irrigation Dez en Iran. Le canal a été modélisé avec le logiciel de simulation SOBEK. Le système de contrôle a été programmé en MATLAB. Pour évaluer le potentiel du système de contrôle, des simulations ont été effectuées pendant deux mois de tour d'eau réel. Les critères de performance -l'erreur maximale absolue, l'intégrale de la magnitude absolue de l'erreur, et l'erreur de l'état d'équilibre -ont été déterminés pour chacun des biefs du canal. Les résultats ont indiqué que les contrôleurs utilisés ont un potentiel considérable pour faire précisément correspondre le débit aux points de contrôle aval avec ceux demandés par les utilisateurs tout en maintenant le niveau de l'eau sur toute la longueur du canal. Les valeurs des indicateurs de performance ont montré que le contrôleur aval distant comme un contrôleur centralisé avec DECOUPLEURS est un contrôleur satisfaisant pour le canal principal Dez. Ainsi la gestion opérationnelle de l'eau dans le canal peut être améliorée si un contrôleur centralisé est utilisé plutôt que des contrôleurs locaux. Il est fortement recommandé de mettre en oeuvre le contrôleur aval distant avec DECOUPLEURS comme un système de contrôle pour ce canal.

The performance and operation of irrigation networks can be improved using canal automation. This process requires the application of control systems. At the same time, the PI controller has been employed in different areas of the world. However, its adjustment for the different geometric and hydraulic conditions of canals is still considered a major problem for design. The design parameters of a canal such as bottom slope, roughness coefficient and side slope are among the determining factors of water flow dynamic behaviour. In this study, a distant downstream proportional integral feedback control with decouplers is designed for a base canal. By changing the value of design parameters in this canal, their effects on water flow behaviour and controller tuning were investigated. Canal characteristics were determined through a system identification process, and were also used to tune the controller. To simulate the control algorithms and evaluate their performance, a link of the SOBEK model and MATLAB software were used. To evaluate the performance of a well‐tuned controller during a given operation period, the maximum absolute error, integral of absolute magnitude of error and steady‐state error indicators were used. Generally, the result showed the bottom slope to have the most effect on water flow behaviour and tuning of the control algorithm. The effect of the roughness coefficient on the control algorithm and its performance is also more noticeable than the side slope. Copyright © 2015 John Wiley & Sons, Ltd.

In this study an in‐line storage strategy is applied to improve the existing operational performance of an upstream‐controlled 13‐pool irrigation canal. Three pools in the upstream, middle and downstream sections of the main canal are considered as in‐line reservoirs. Decentralized proportional‐integral (PI) controllers are designed to regulate their upstream water levels based on a mixed control method. Each regulator is coupled to its upstream in‐line reservoir. The objectives of the controlled system are keeping the upstream water level of each regulator at the target levels; reducing delay times of flow travelling in the canal and compensating for mismatches between upstream supply and downstream demands. Existing and proposed operational methods are compared, using the hydrodynamic modelling package Sobek, considering a severe and sudden increasing– decreasing flow condition. In this case study, the water level profiles and controller performance indicators imply that in‐line storage in the main canal decreases water level deviations in most of the pools in the range of 24–57 % in comparison with the current operation. Moreover, using in‐line reservoirs decreases the delay times especially in the downstream part of the canal. Copyright © 2013 John Wiley & Sons, Ltd.