1st Edition
The Use of Delft3D to Simulate the Deposition of Cohesive and Non-Cohesive Sediments in Irrigation Systems
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.
1 Introduction
1.1 Importance of irrigated agriculture
1.2 Sediments problems in irrigation canals
1.3 Operation of canals
1.4 Mathematical models
1.5 Previous studies & research gap
1.6 Research objective
1.7 Methods
1.8 Structures of the thesis & Scope of the study
2 The use of DELFT3D for irrigation systems simulations
2.1 Introduction
2.2 Methods
2.3 Results
2.4 Discussion
2.5 Conclusions
3 The use of 2D/3D models to show the differences between cohesive and non-cohesive sediments in irrigation canals
3.1 Introduction
3.2 Methods
3.3 Model setup
3.4 Results
3.5 Discussion
3.6 Conclusion
4 What is the effect of gate selection on the non-cohesive sedimentation in irrigation schemes? – A case study from Nepal
4.1 Introduction
4.2 Methods
4.3 Results
4.4 Discusison
4.5 Conclusions
5 The role of gate operation in reducing problems with cohesive and non-cohesive sediments in irrigation canals
5.1 Introduction
5.2 Materials and Methods
5.3 Results
5.4 Discussion
5.5 Conclusions
6 Conclusions and Recommendations
6.1 Conclusions
6.2 Reflection
6.3 Recommendation
6.4 Research contributions
6.5 Further studies
References
Biography
Shaimaa Abd Al-AMear Theol is a Ph.D. fellow in the Water Science and Engineering Department/ Land and Water Development for Food Security in IHE Delft, and Wageningen University & research in the Netherlands. She obtained MSc in Hydraulic Engineering from IHE-Delft (was named UNESCO-IHE), Delft, the Netherlands in the year 2011. Her study abroad is fully supported by the Iraqi Ministry of Higher Education and Scientific Research. She has a background in engineering. Her primary research interests are the cohesive and non-cohesive impacts on the irrigation systems, and the 2D/3D modelling in irrigation systems.
