Role Of Sediment Transport In Operation And Maintenance Of Supply And Demand Based Irrigation Canals

This work describes the role of sediment transport in the operation and maintenance of demand-based downstream controlled irrigation canals. Sediment deposition in these irrigation canals severely affects the operation of the automatic flow control system. The book also discusses sediment transport modelling in irrigation canals. A simplified 1-D mathematical model SETRIC (SEdiment TRansport in Irrigation Canals) has been improved with the inclusion of downstream control component for the downstream controlled irrigation canals. Based on field measurements and sediment transport modelling, a number of approaches have been proposed for sediment management in such irrigation canals by improvement in their design and operation. This book will be of interest to Irrigation Engineers and Managers, Hydraulic Engineers, Water Resources Engineers and Managers, Civil Engineers, and Agricultural Engineers.

Sediment transport in irrigation canals influences to a great extent the sustainability of an irrigation system. Unwanted erosion or deposition will not only increase maintenance costs, but may also lead to unfair, unreliable and unequitable distribution of irrigation water to the end users. Proper knowledge of the characteristics, including behaviour and transport of sediment will help to design irrigation systems, plan effi cient and reliable water delivery schedules, to have a controlled deposition of sediments, to estimate and arrange maintenance activities, etc. The main aim of these lecture notes is to present a detailed analysis and physical and mathematical descriptions of sediment transport in irrigation canals and to describe the mathematical model SETRIC that predicts the sediment transport, deposition and entrainment rate as function of time and place for various flow conditions and sediment inputs. The model is typically suited for the simulation of sediment transport under the particular conditions of non-wide irrigation canals where the flow and sediment transport are strongly determined by the operation of the flow control structures. The lecture notes will contribute to an improved understanding of the behaviour of sediments in irrigation canals. They will also help to decide on the appropriate design of the system, the water delivery plans, to evaluate design alternatives and to achieve an adequate and reliable water supply to the farmers.

The transport of sediment greatly influences the sustainability of an irrigation system. Erosion and deposition not only increase maintenance costs, but may result in an inequitable and inadequate distribution of irrigation water. Understanding the behaviour and transport of sediment allows efficient planning and reliable water delivery schedules,

Sediment deposition threatens the performance of many irrigation systems. Because of the high impact on irrigation performance and crop production, many studies have been done on how to deal with sediment deposition. In this research, the Delft3D model, originally developed for hydro-morphologic modeling of rivers and estuaries, was adapted for the use in irrigation systems simulations and applied to different case studies. This research addresses two shortcomings of previous studies of sediments in irrigation systems. Firstly, while previous studies primarily used 1D models, this research uses a 2D/3D model. The use of 2D/3D models in irrigation systems is significant because the non-uniform flow around structures such as offtakes, weirs and gates, leads to asymmetric sedimentation patterns that are missed by 1D simulations. Secondly, whereas previous studies mostly considered non-cohesive sediments, this research simulates cohesive, non-cohesive and a mix of both sediment types. This is important for irrigation systems that draw water from natural rivers that carry a mix of cohesive and non-cohesive sediments. The findings of this research are important for irrigation system maintenance and gate operation. It is also essential for the development of canal operating plans that meet crop water requirements and at the same time minimizes sediment deposition by alternating gates.

After publishing the famous “Fluvial Processes in Geomorphology” in the early 1960s, the work of Luna Leopold, Gordon Wolman, and John Miller became a key for opening the door to understanding rivers and streams. They first illustrated the problem to geomorphologists and geographers. Later, Chang, in his “Fluvial Processes in River Engineering”, provided a basis for engineers, showing this group of professionals how to deal with rivers and how to understand them. Since then, more informative studies have been published. Many of the authors started to combine fluvial geomorphology knowledge and river engineering needs, such as “Tools in Fluvial Geomorphology” by G. Mathias Kondolf and Hervé Piégay, or focused more on river engineering tasks, such as “Stream Restoration in Dynamic Fluvial Systems: Scientific Approaches” by Andrew Simon, Sean Bennett, and Janine Castro. Finally, Luna Leopold summarized river and stream morphologies in the beautiful “A view of the river”. It appears that we continue to explore this subject in the right direction. We better understand rivers and streams, and as engineers and fluvial geomorphologists, we can establish tools to help bring rivers alive. However, there is still a hunger for more scientific tools that we could use to further understand rivers and to support the development of healthy streams and rivers with high biodiversity in the present world, which has started to face water scarcity.

Ever-increasing population growth has caused a proportional increased demand for water, and existing water sources are depleting day by day. Moreover, with the impact of climate change, the rates of rainfall in many regions have experienced a higher degree of variability. In many cities, government utilities have been struggling to maintain sufficient water for the residents and other users. The Handbook of Irrigation Hydrology and Management examines and analyzes irrigated ecosystems in which water storage, applications, or drainage volumes are artificially controlled in the landscape and the spatial domain of processes varies from micrometers to tens of kilometers, while the temporal domain spans from seconds to centuries. The continuum science of irrigation hydrology includes the surface, subsurface (unsaturated and groundwater systems), atmospheric, and plant subsystems. Further, the book includes coverage of environmental and economic impacts, water quality issues, water harvesting, satellite measurements for irrigation, and more. Features: Offers water-saving strategies to increase the judicious use of scarce water resources Presents strategies to maximize agricultural yield per unit of water used for different regions Compares irrigation methods to offset changing weather patterns and impacts of climate change

This study focuses on sediment transport in irrigation canals which may have a serious impact on design, operation and maintenance activities. Using a mathematical model, and examing ways in which this model can be applied to real-world situations, this text is highly useful for theoreticians and students alike.