Depeweg / Méndez V A New Approach to Sediment Transport in the Design and Operation of Irrigation Canals

UNESCO-IHE Lecture Note Series
Erscheinungsjahr 2007
ISBN: 978-0-203-94581-0
Verlag: Taylor & Francis
Format: PDF
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)

E-Book, Englisch, 240 Seiten

Reihe: UNESCO-IHE Delft Lecture Note Series

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, and ensures the controlled deposition of sediments, making maintenance activities more manageable. These lecture notes present a detailed analysis of sediment transport in irrigation canals, together with physical and mathematical descriptions of the behaviour. A mathematical model predicts the sediment transport, deposition and entrainment rate for various flow conditions and sediment inputs. The model is particularly suitable for the simulation of sediment transport in irrigation canals where flow and sediment transport are largely determined by the operation of flow control structures.

Autoren/Hrsg.

Depeweg, Herman

Méndez V, Néstor

Fachgebiete

• Technische Wissenschaften Maschinenbau | Werkstoffkunde Technische Mechanik | Werkstoffkunde Hydraulik, Pneumatik
• Technische Wissenschaften Bauingenieurwesen Bauingenieurwesen
• Geowissenschaften Umweltwissenschaften Wasserversorgung

Inhaltsverzeichnis

Table of Contents
LIST OF FIGURES
LIST OF TABLES
1. INTRODUCTION
2. OPEN CHANNEL FLOW
2.1 Introduction
2.2 Flow types and characteristics
2.3 Geometry
2.4 Basic hydraulic principles
2.5 Velocity distribution
2.6 Uniform flow
2.7 Non-uniform steady flow
2.8 Some general aspects of unsteady flow
2.9 Basic differential equations for gradually varied unsteady flow
2.10 Solution of the de St. Venant equations
2.11 Rectangular channels and the method of characteristics
3. SEDIMENT PROPERTIES
3.1 Introduction
3.2 Density and porosity
3.3 Size and size distribution
3.4 Shape
3.5 Fall velocity
3.6 Characteristic dimensionless parameters
4. DESIGN CRITERIA FOR IRRIGATION CANALS
4.1 Introduction
4.2 The role of sediment transport in the design of irrigation canals
4.2.1 Regime method
4.2.2 Tractive force method
4.2.3 Permissible velocity method
4.2.4 Rational method
4.3 Final comments
5. SEDIMENT TRANSPORT CONCEPTS
5.1 Introduction
5.2 Friction factor predictors
5.2.1 Bed form development
5.2.2 Effect of bed forms on the flow resistance
5.2.3 Determination of the friction factor
5.2.4 Composite roughness for non-wide irrigation canals
5.2.5 A recommended method for the prediction of composite roughness in trapezoidal canals
5.2.6 Comparison of the composite roughness predictors in trapezoidal canal
5.2.7 Prediction of composite roughness in a rectangular canal
5.3 Governing equations for sediment transport
5.3.1 Sediment transport capacity
5.3.2 Comparison of sediment transport capacity
5.3.3 Sediment transport computation in non-wide canals
5.3.4 Comparison of the procedures for computing the total sediment transport
5.3.5 Sediment transport in non-equilibrium conditions
5.4 Morphological changes of the bottom level
5.5 Conclusions
6. SETRIC, A MATHEMATICAL MODEL FOR SEDIMENT TRANSPORT IN IRRIGATION CANALS 120
6.1 Introduction
6.2 Water flow equations
6.3 Sediment transport equations
6.4 General description of the mathematical model
6.5 Input and output data
6.6 Conclusions
7. THE SEDIMENT TRANSPORT MODEL AND ITS APPLICATIONS
7.1 Introduction
7.2 Case 1 – Changes in the discharges
7.3 Case 2 – Changes in the incoming sediment load
7.4 Case 3 – Controlled sediment deposition
7.5 Case 4 – Flow control structures
7.6 Conclusions
REFERENCES
LIST OF SYMBOLS
APPENDIX A: METHODS TO ESTIMATE THE TOTAL SEDIMENT TRANSPORT CAPACITY IN IRRIGATION CANALS
A.1 Introduction
A.2 Ackers and White method
A.3 Brownlie method
A.4 Engelund and Hansen method
A.5 Van Rijn method
A.5.1 The suspended load transport
A.6 Yang method
APPENDIX B: METHODS TO PREDICT THE FRICTION FACTOR
B.1 Van Rijn
B.2 Brownlie
B.3 White, Paris and Bettess
B.4 Engelund
APPENDIX C: HYDRAULIC DESIGN OF IRRIGATION CANALS
C.1 Introduction
C.2 Alignment of an irrigation canal
C.3 Water levels
C.4 Earthwork
C.5 Design of irrigation canals
C.6 Boundary shear stresses
C.7 Sediment transport criteria
C.8 Transport of the bed material
C.9 Final remarks
C.10 Computer aided design of canals
APPENDIX D: DESCRIPTION OF THE MAIN ASPECTS OF THE REGIME THEORY
D.1 Some regime considerations
D.1.1 Sediments
D.1.2 Maturing of canals
D.1.3 Slope adjustments
D.1.4 Diversion of the sediment
D.1.5 Maintenance aspects
D.1.6 Flow capacity
D.1.7 Design considerations
APPENDIX E: GLOSSARY
INDEX

Über Autor(innen)

After graduating in irrigation and hydropower at the Technical University of Delft in 1967 and before joining IHE at the end of 1986, Herman Depeweg was involved in hydraulic research at Delft Hydraulics, the main research topics were related to hydraulic structures, sediment transport, local scour and erosion. He has deepened his knowledge in irrigation by various assignments with Dutch consulting firms, especially as project manager for long-term irrigation projects in the Far East (Indonesia) and the Middle East (Iraq, Saudi Arabia and Yemen) for more than a decade. Herman Depeweg joined IHE to become co-mentor and lecturer at the postgraduate course in irrigation in Bandung, Indonesia. After his return to Delft he has lectured at IHE in hydraulics and irrigation, the latter has been focussed on all aspects related to irrigation at main, tertiary and field level. During the past years he has been mentor of a number of participants who were doing research for their MSc and/or PhD. He has been guestlecturer for IHE around the world, namely in Indonesia, Malaysia, Yemen, Egypt, Libya, Colombia, Bolivia and Venezuela.
Néstor Méndez is associate professor of Hydraulics and Sediment Transport at the Universidad Centro Occidental "Lisandro Alvarado" at Barquisimeto, Venezuela. After his graduation in 1977 and before joining the University in 1981, he has worked for the Ministry of Environment and Renewable Resources (MARNR) in the operation and maintenance of hydraulic works and in the design and construction of large drainage systems in the Western Plains of Venezuela. In 1998 he obtained his PhD degree at IHE, Delft. His research topic has been the behaviour of sediment transport in irrigation canals. Since 1999, he is guestlecturer at the UNESCO-IHE Institute for Water Education in Delft, the Netherlands and at several universities in Colombia, Mexico, Guatemala and Bolivia. Next to his lecturing and research activities, the author guides several undergraduate students and supervises MSc research. At present, he is also active as consultant in the field of Land and Water Development in Venezuela.