Review of Canal Automation for Irrigation Systems Edited by Brian Wahlin and Darell Zimbelman

The Manual of Practice (MOP) No. 131 was prepared by the ASCE Task Committee on recent advances in canal automation of the irrigation delivery and drainage systems, which is part of the Irrigation and Drainage Council of the Environmental and Water Resources Institute of the ASCE. More than 40 different professionals from eight different countries (Australia, China, France, Portugal, Mexico, Netherlands, Spain, and United States) participated in the development of the manual. The development of the manuscript was kicked off by a series of video conferences in 2009. The great achievement in preparing this manuscript is bringing together a large group of worldwide experts, without unnecessary travel. The book’s preface provides more details on the development of the manuscript.

Canal automation is a key component in effective water management systems, optimizing water delivery in complex canal networks. Although the ASCE Journal of Irrigation and Drainage Engineering has recently published a special issue on canal automation (Volume 143, Issue 3, March 2017), a practical, comprehensive document on this subject is lacking. The attempt started four decades ago with a symposium on planning, operation, rehabilitation, and automation of irrigation water delivery systems (Zimbelman 1987), followed by the MOP 57 (Johnston and Robertson 1991), and further improved by the current MOP 131. Authors of MOP 131 made a great attempt to end the lack of a comprehensive manual by gathering information on canal automation research and practice from around the world.

The book is divided into eight chapters: (1) “Modernization Process, Constraints, and Concepts”; (2) “Physical Infrastructure”; (3) “SCADA Systems”; (4) “Control Operation and Control Concepts”; (5) “Canal Hydraulic Properties”; (6) “Control Methods”; (7) “Verification of Controller Performance”; and (8) “Implementation of Control Systems.” A glossary of canal automation terminology is also included in the book. Lead chapter authors are as follows: Charles Burt (Irrigation and Training Research Center, San Luis Obispo, California)—Chapters 1 and 2; Robert Strand (LemnaTec Corporation, Aachen, Germany)—Chapter 3; Peter-Jules van Overloop (Delft University of Technology, Delft, Netherlands)—Chapters 4 and 6; Bert Clemmens (WEST Consultants, Tempe, Arizona)—Chapters 5 and 7; and Sumith Choy (Rubicon Water, Hawthorn East, Victoria, Australia)—Chapter 8. Sadly, a few months after publication of the MOP 131, Professor Peter-Jules van Overloop passed away in February 2015.

Chapter 1 provides a general overview and potential benefits of canal automation, including operational constraints and typical modernization steps. Chapter 2 discusses instrumentation and types of water control structures (for flow and water level) used in conveyance systems. Different types of hydraulic structures and their use in different projects are presented. Instrumentation and sensor characteristics, which are an important subject on canal automation, are also discussed in Chapter 2.

Chapter 3, which is probably the most important one, describes the supervisory control and data acquisition (SCADA). The SCADA is a backbone of every automated canal network and provides real-time monitoring and control capabilities. A reliable network-wide SCADA system is critical in providing operators with the data and level of control necessary to meet their strategic cost goal, while maintaining their core mission and regulatory compliance. For example, the South Florida Water Management District (SFWMD) operates and maintains a complex water control network using a centralized SCADA system that includes approximately 3,380 km (2,100 mi) of canals, more than 750 major water control structures (spillways, pumps, culverts, and weirs), approximately 3,500 hydrological monitoring stations (including approximately 650 flow monitoring sites), over 2,000 water levels sensors, approximately 300 rain gauges, and 30 full weather stations. The uniqueness of the SFWMD SCADA system is that, because of its vulnerability to hurricanes landfall, it has its own backbone telemetry microwave towers looped network (over 30 towers). The towers can withstand Category 4 Hurricane force winds, and each water control structure communicates with a primary and a secondary tower (redundancy). This telemetry system was developed in the mid-1980s. It started with home-built remote terminal units (remote access control units or RACUs). Today, it uses state-of-the art command and control technology including Campbell Scientific data loggers (CR1000, Logan, Utah) for data logging, and a Motorola SCADA automated control engine (MOSCAD-ACE) (Chicago, Illinois) for data logging, command, and control. This SCADA system also includes operation decision support tools, including automated alarms/warning and automated structure operations algorithms [e.g., gate control program (GCP)]. The GCP in its current state allows operators to set constant headwater/tailwater elevations, or constant discharge at a gated structure, based on preset rules that specify an operational stage range and a target stage. Although the automation of the structure is fully at the structure level (structure-centric), it does not account for the flow dynamics between the structures.

Chapter 4 presents canal control methods and different configuration for operating a network of canals as supply and demand–oriented. The authors stress that the concepts are only typical, as different concepts can often be used on different parts of the same canal network. Chapter 5 discusses the hydraulic response of canal pools, in addition to the canals’ hydraulic properties and structures. The hydraulic response is important, as water level responses to changes in flow rate in extensive water control structures networks, with various ranges of operations and ground water interactions, is not well understood (Belaud et al. 2013; Soler et al. 2016). This book does not address canal automation for canals in which surface/groundwater interactions are significant, as is the case in South Florida.

Chapter 6 presents how the methodologies presented in Chapters 2 and 4 can be implemented automatically using command and control field devices such as programmable logic controllers or remote terminal units. Routing water through a canal (feedforward control) and a routing schedule example are presented in this chapter. There is also a discussion on combining feedforward and feedback control, as these are explained as follows: “A common approach to canal automation is to make gate adjustments at each site successively and then return to each gate to make corrections depending on the observed situation. These initial changes and the later corrections can be interpreted as feedforward and feedback control actions, respectively.”

Chapter 7 describes the verification of controller performance, and raises and attempts to answer two essential questions: (1) Are the right processes being controlled? and (2) Is the automatic control functioning in an acceptable manner? This chapter also discusses performance testing issues with unsteady-flow simulation models. If flow changes are gradually varied, canal flow can be assumed to be under a succession of steady states. However, when significant fluctuations occur, steady-state assumptions break down and unsteady flow must be considered. Chapter 8 elaborates on the sequence of required tasks for a control system’s implementation.

Overall, this is an excellent reference book on irrigation canal automation, and the techniques presented by this manuscript can potentially be expanded for the automation of canals with broader uses and applications such as flood control, water quality enhancement (e.g., stormwater treatment areas), and navigation. The book is recommended to practicing hydraulic/electronic engineers involved with water control systems, as a design guideline. The authors of this MOP have a strong background in this subject and have presented the material in a logical manner, still keeping the presented information engaging and relevant.