Canal Automation Research Articles

Distributed model predictive control based on the alternating direction method of multipliers for branching open canal irrigation systems

Most studies of open canal automation concentrated on the control of single canal pool or cascaded multiple canal pools, neglecting the hydraulic coupling effects between the main canal and lateral canals. Low transmission efficiency and poor equity of agriculture water delivery may be caused in the practical application of large-scale irrigation networks. Considering the high computation and communication requirements for large-scale operating systems, a distributed model predictive control (DMPC) algorithm based on the alternating direction method of multipliers (ADMM) is developed for the branching open canal irrigation systems (BOCISs). A simplified BOCIS example, originating from Test case 2 proposed by the American Society of Civil Engineers, is used for control tests. Moreover, for control performance comparisons and evaluations, centralized model predictive control (CMPC) is employed by modifying the state space of the integrator delay (ID) model. The results show that the control performance of the proposed DMPC converges to the global optimal solution of the CMPC under the normal scenario, and the degradation is less than 0.35 %. The communication and coordination process of DMPC contributes to more powerful robustness and interference immunity than CMPC. Furthermore, in case of sudden accidents occurring in some subsystems, the proposed DMPC is more convenient and timely to execute fault isolation. The improvements on water level oscillations and overshoots can reach 20.3 % and 52.1 % in the other subsystems which need normal water delivery, respectively. Equipped with outstanding control characteristics, the proposed ADMM-based DMPC framework enables the water authorities of large-scale BOCISs to promote surface water distribution in a practicable, flexible, and secure way, showing great potential in developing intelligent irrigation districts.

The Integrator Dual-Delay model for advanced controller design of the open canal irrigation systems with multiple offtakes

The Integrator Delay (ID) model is widely used for advanced controller design in canal automation projects, assuming that all offtakes are aggregated into one at the most downstream end for each canal pool. However, such an unrealistic assumption differs greatly from the actual location distribution of the offtakes in most open canal irrigation systems (OCIS), leading to increased uncertainties and inaccurate canal operations. For this reason, this study introduced the Integrator Dual-Delay (IDD) model, capable of innovatively considering the lag-effect of the offtake flow changes alongside the irrigation canal. To investigate the effectiveness of the modified control-oriented model in upgrading the canal automatic operating systems, two centralized model predictive controllers were designed with the ID model and the IDD model, respectively. Then the simulation tests were carried out on the Third Main Canal of the Zhanghe Irrigation System in Southern China. Two performance indicators of Non-dimensional Integrated Square of Error (NISE) and Non-dimensional Integrated Square of Discharge Change (NISQ) were adopted to measure the water level control stability and flow control stability. The results show that with the IDD model, the NISE is reduced from 3.53 × 10-5 to 1.88 × 10-5 and the NISQ is reduced from 3.23 × 10-6 to 2.88 × 10-6, indicating that the proposed IDD model can help the control stabilities of water level and flow to be improved by 46.7 % and 10.8 %, respectively. The IDD model constructs a more accurate state-space prediction process for advanced controller design and contributes to more efficient canal automatic operations, showing great potential in precision irrigation for various OCIS.

A parallelized algorithm to speed up 1D free-surface flow simulations in irrigation canals

AbstractA parallel algorithm for 1D free-surface flow simulations in irrigation canals is shown. The model is based on the Hartree method applied to Saint-Venant equations. Due to the close-to-steady flow nature in irrigation canals, external and internal boundary conditions are linearized to preserve the parallel character. Gate trajectories, off-take withdrawals, and external boundary conditions are modeled as piece-wise functions of time, so there are discontinuities. To achieve a fully parallelized algorithm, an explicit version of the Hartree method is chosen, and external and internal boundary conditions are linearized around operation point. This approach is used to build a computer simulator, written in C-CUDA language. Two tests by ASCE Committee on Canal Automation Algorithms have been used to evaluate accuracy and performance of the algorithm. The Maricopa Stanfield benchmark has been used to prove its accuracy, and the Corning Canal benchmark to evaluate performance in terms of processing time. Surprisingly, solving a 12 hr-long prediction horizon with a cell size of about Δx= 10 m is less than 1 s on a Nvidia K40 card. Results were compared with a serial and a multi-CPU version of the same algorithm. The implementation that showed the best performance on different platforms is the one that uses GPU.

Evaluating Optimization Objectives in Linear Quadratic Control Applied to Open Canal Automation

AbstractProportional-integral (PI) control, as one of the most popular classic control methods, has been applied widely to the real-world practice of canal automatic control. The performance of a P...

Decentralized ellipsoidal state estimation for linear model predictive control of an irrigation canal

AbstractA centralized linear MPC is used to stabilize an irrigation system whose operation is represented by an integrator-delay model. Since not all the state variables can be measured, a decentralized ellipsoidal estimation strategy is proposed. This approach keeps the quality of a centralized estimation and reduces significantly the computation time for the systems considered. An adaptation of Test Canal 1, developed by the ASCE Task Committee on Canal Automation Algorithms, is used as a case study to show the performance of the proposed methodology.

Automation of water distribution management during the reconstruction of main irrigation canals

Canal automation allows increasing the efficiency of projects for the reconstruction and construction of irrigation systems. Modern technological and technical advances make it possible to regulate the flow of irrigation water at all levels of the system more accurately. The basic requirements for water accounting and water metering systems implemented on irrigation systems are applicable only to the conditions of water distribution static regulation. This is primarily due to the use of water-accounting and water-measuring devices developed and used in conditions of steady-state water flow, when there is an unequivocal relationship between the depth and water flow on the rise and on the decline of levels. Using world experience in connection with new achievements in the field of management theory research, it is necessary to consider how and when to implement automation of water distribution management in the context of reconstruction and construction of irrigation main canals. In addition, practical recommendations on other aspects of channel automation should be taken into account, including the dynamic nature of the system; irrigation infrastructure survey; use of SCADA-systems; improving the concept of water distribution management using automatic control methods.

Constrained Model Predictive Control Algorithm for Cascaded Irrigation Canals

AbstractAgricultural irrigation accounts for the largest proportion of freshwater use worldwide, and canal automation potentially improves conveyance efficiency in irrigation canal systems. In this...

Operational performance improvements in irrigation canals to overcome groundwater overexploitation

Groundwater overexploitation due to unsustainable agricultural development is a widespread problem in irrigation districts relying on conjunctive use of surface and groundwater resources. Nearly 90% of global groundwater supported irrigated areas have conjunctive use of both surface and groundwater. A major driver behind the use of groundwater in these regions, in addition to surface water scarcity, is the poor operational performance of the irrigation schemes. The lack of reliability of water deliveries at farm gates forces farmers to increasingly turn to groundwater. Therefore, they intensively extract water and continuously deteriorate groundwater aquifers. This case study investigates the potential impact of improved water distribution and delivery through implementing canal automation techniques. These techniques can enhance the reliability of irrigation deliveries to the endpoint, resulting in reduction of groundwater extraction and associated benefits in decreasing energy consumption and CO2 emissions. The current study focuses on six main irrigation districts located in the Zayandeh-Rud River Basin (ZRB) in central Iran, where a total area of 200,000 ha is irrigated using surface water in conjunction with groundwater. To improve the performance of the irrigation networks for each of these districts, three operational model alternatives, including fully automated systems, were considered. Each of these models was designed and run for each of the six districts separately. The results showed a reduction of operational water losses in the range of 15% –25% depending on the implemented operational model. These potential water savings are then available to be used in the agricultural sector and can result in a reduction in groundwater extraction of up to 300 Million Cubic Meters (MCM). The associated reduction in energy consumption and carbon emission was about 450 GWh and 57,500 t each year, respectively. The results of this study can be employed in designing a centralized configuration of automated systems that enable water managers to reduce pressure on groundwater resources.

Canal Automation for Irrigation Systems: American Society of Civil Engineers Manual of Practice Number 131

AbstractRecently, the American Society of Civil Engineers (ASCE) prepared a Manual of Practice (MOP) on canal automation for irrigation systems. Formally referred to as MOP 131 Canal Automation for Irrigation Systems, this book focuses on the technical aspects of modernizing irrigation systems through the use of automated canal control systems. MOP 131 is an essential reference for professionals in agricultural and irrigation engineering, as well as owners, managers, and operators of irrigation water delivery systems.Canal automation saves water and improves the efficiency of irrigation water supply projects or of irrigation district operations. Recent technological and engineering advances now enable more accurate control of water deliveries throughout all parts of an irrigation project. Using information collected from irrigation systems around the world in conjunction with new advances in control theory research, this MOP examines how and when to implement canal automation within the context of canal modernization. In addition, MOP 131 provides practical guidance on other aspects of canal automation, including the modernization process, constraints, and concepts; survey of irrigation physical infrastructure; SCADA systems; control operation concepts; canal hydraulic properties; automatic control methods; verification of controller performance; and implementation of control systems.This paper provides a brief summary of MOP 131 within the context of the history and future of canal automation. Copyright © 2017 John Wiley & Sons, Ltd.

Providing a Reliable Water Level Control in Main Canals under Significant Inflow Fluctuations at Drought Periods within Canal Automation

Supplying agricultural water has recently become more challenging due to increase in drought frequency in semi-arid regions. Unreliable supply water resources lead to inflow fluctuations in irrigation districts locating at the downstream part of the rivers. The conventional operation cannot handle the fluctuations effectively; therefore, water delivery to the off-takes is seriously compromised. In this study, the capability of decentralized Proportional-Integral (PI) and centralized Linear Quadratic Regulators (LQR) controllers were investigated to alleviate the effects of severe inflow fluctuations in the main irrigation canals operation. In this regard, the Roodasht North Branch (RNB) main canal, located in the central Iran, consisting of 24 reaches was selected as a test case. Mathematical operational model of the canal was coupled with the designed PI and LQR controllers. The performance of the controllers were evaluated under the normal and severe unpredictable inflow fluctuations scenarios. The results showed that the PI configuration was able to successfully deal with and handle the normal inflow fluctuations. Water delivery to the upstream and middle canal reaches was regulated reasonably well, while the downstream canal reaches were still slightly suffering from the inflow fluctuation. The LQR controller showed an outstanding performance in dealing with both normal and severe inflow fluctuation test scenarios. The controller optimally adjusted the gates accordingly to manage even the sever inflow fluctuation. The results of this study demonstrate capabilities of the control configurations in managing the inflow fluctuations in main canals which can help moving towards the urgent needs for improving the current canal operational performance.

Special Issue on Canal Automation

Special Issue on Canal Automation

Integration of irrigation district personnel with canal automation projects

Canal companies are adapting automation equipment to assist in the management of their canal systems and provide water to users at a near constant flow rate. Many of these canal companies have been motivated out of need to meet the water demands of their customers while limiting flow rate and depth fluctuations. Several canal automation schemes have been successful, while a few systems have had problems. After studying 179 canal automation projects, key points have been identified that contribute to the success of the automation systems. The most important factor is that the automation system has the support of the board of directors and the management personal. Other factors include a supportive automation company, use of simple, understandable sensors, and reliable equipment.

The Effect of Design Parameters of an Irrigation Canal on Tuning of Coefficients and Performance of a PI Controller

AbstractThe 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.

Case Studies of Innovative Irrigation Management Techniques

Irrigation is a vital input in the agricultural productivity and agricultural growth. More than 80% of available water resources worldwide as well as in India are being presently utilized for irrigation purposes. However, in India, the average water use efficiency of Irrigation Projects is assessed to be only of the order of 30-35%. There is no doubt that modernization of irrigation system like concrete lining to the inner surface of the open channel; canal automation etc. will save water significantly. But these techniques require huge capital investment, hence uneasy to adopt. On this background it is appropriate to know the innovative, simple, low cost, easy to adopt, water conveyance techniques used in the command of few irrigation projects in Maharashtra. The paper discusses the need to increase the Water Use Efficiencies of existing Irrigation Projects and new projects and the success case studies in detail. The findings show that such pioneering techniques shall be implemented in the command areas of other irrigation projects as and where found techno economically feasible to achieve improvement in crop yield and good water management with high water use efficiency.

Development of a fuzzy logic based software for automation of a single pool irrigation canal

A fuzzy logic based software for automation of a single pool irrigation canal is presented. Purpose of the software is to control downstream discharge and water level of the canal, by adjusting discharge release from the upstream end and upstream gate settings. The software is developed on a fuzzy control algorithm proposed by the first author during his doctoral research work and published in literature. Details of the algorithm are given. The algorithm was originally developed using fuzzy logic tool box of MATLAB, which is proprietary software not available freely and hence cannot be adopted for general use. Present study describes development of a canal automation software based on this algorithm using open source tools, which are freely available. The software is transparent and intuitive, which can be easily applied by field engineers. The effort required in tuning the fuzzy model has been reduced by including an optimization technique. Also, a new procedure has been introduced for fuzzy inference based on the Mamdani Implication method. The software is tested by applying it to water level control problem in a canal with a single pool, as reported in literature, and satisfactory results are obtained.

GoRoSo: Feedforward Control Algorithm for Irrigation Canals Based on Sequential Quadratic Programming

AbstractThe feedforward control canal problem is stated as a nonlinear optimization problem with constraints on the gate movements. It is numerically solved with the use of the sequential quadratic problem (SQP) method and the active set. The main objective of the resulting GoRoSo algorithm is the scheduling of the gate openings over a programmed operation scenario, and their calculation relies on the use of the Saint-Venant’s complete model over a prediction horizon. A numerical and analytical procedure is developed to quantify the influence of any gate movement over the canal flow conditions for a prediction time horizon. All these influences are lumped together in a global matrix, which is referred to as the hydraulic influence matrix. The GoRoSo algorithm is validated by means of a series of test developed by the ASCE task committee on canal automation algorithms.

The Research of Canal Fuzzy Self-Adapting P+PR Controller of Long Distance Water Diversion Project and Applications

Canal control algorithm is very import in the process of water delivery. The paper presents a parameters-self-adapting canal flow fuzzy P+PR control according to the merits of fuzzy-control and the features of P+PR control algorithm through fuzzy inference method. The model uses the canal automation history control experiences to realize the optimization of parameters and make the control process always running in the optimal state. The parameters of fuzzy rule-table are built, the solution processes are deduced. The simulation results show that the overshoot is reduced significantly, and the dynamic behaviors are improved by using this adaptive fuzzy P+PR control model.

Automatic Downstream Water-Level Feedback Control of Branching Canal Networks: Simulation Results

Previous research on canal automation has dealt with the control of single, in-line canals, while canal operators typically have to control an entire network of canals. Because the branches in a network are hydraulically coupled with each other, control of a branching canal network based on separate controllers for each branch may not be the most effective control strategy. A methodology by which existing automatic control systems could be modified to control branching canal networks is provided in a companion paper. This paper presents results of hydraulic simulations of the new methodology to estimate the controllability of a large portion of the branching canal network operated by the Salt River Project (SRP). Two types of controllers were used for this study: (1) linear quadratic regulator (LQR) and (2) model predictive control (MPC). Both controllers used the same underlying process model [integrator-delay (ID) model], and both controllers were capable of feedback and feedforward control. Under feedback control alone, both controllers gave similar performance, but were unable to effectively control the overall system because of the long delay times. When feedforward control was added to the feedback controller, both of these control systems were able to effectively control the branching canal network operated by SRP. For the LQR controller, the volume compensation method for routing known demand change was used as the feedforward controller. For the MPC controller, the ID model was used as the feedforward controller. Slight differences were noted between the performance of the two feedforward controllers.

Automation of the East Bench irrigation main canal

Canal automation equipment in the East Bench Irrigation District in Dillon, Montana, was over 30 years old and needed to be replaced. Portions of the old automation system were salvaged in an attempt to reduce rehabilitation costs. Because wiring diagrams were not available for the old control system, time would have been saved if the old control system were completely removed and replaced with a completely new system. Data communication via radio and bubbler water level sensors proved to be troublesome. After three seasons of operation, problems with the new automation system were corrected, but it became evident that a technician was needed to maintain the system. Copyright © 2006 John Wiley & Sons, Ltd.

Volume Compensation Method for Routing Irrigation Canal Demand Changes

This paper examines the problem of routing known water demands through gate-controlled, open-channel irrigation delivery systems. Volume-compensation principles were used to route multiple demands in multiple-pool canal systems. The volume-compensation method schedules each demand change individually under the assumption of a series of steady states and superimposes the individual results. Volume-compensation routing schedules were computed for two of the test cases proposed by the ASCE Task Committee on Canal Automation. Alternative routing schedules were computed with the gate-stroking method, which is an inverse solution of the unsteady-flow equations. Both solutions were tested through unsteady-flow simulation. While not as effective as gate-stroking solutions, volume-compensation solutions performed satisfactorily under ideal flow control conditions. When subjected to realistic operational constraints, specifically constraints on the flow regulation interval, and also to incorrect canal hydraulic roughness information, both methods performed similarly.