The use of Delft3D to simulate the deposition of cohesive and non-cohesive sediments in irrigation systems

Abstract

There are many people who were involved and gave lots of assistance and cooperation in this research. The author would like to deliver the gratefulness for their contribution.Firstly, I would like to thank my Promoter and supervisor, Prof. Charlotte de Fraiture PhD, MSc who gave opportunity, ideas and support to this study, also I would like to thank Dr. Bert Jagers from Deltares for always sharing the ideas, knowledge and encouragement, the technical support and guiding me during this research and for his kind brotherly support. Also many thanks to my co-promotor Dr. F.X. Suryadi, PhD, MSc for sharing the ideas and guiding during my research. I would like to thanks would like to thank the Iraqi Ministry of Higher Education and ScientificResearch and the Ministry of Water Resources as well for funding my scholarship. Additionally, I would like to thank Deltares in Delft, the Netherlands for their technical support in providing the new version of the Delft3D and all modelling courses and workshops, it really appreciated especially Bert Jagers and Edward Melger. I also express my gratitude for other staff of Hydraulic Engineering -Land and Water Development, I also express my gratitude for other staff of Hydraulic Engineering in Wageningen University and all guest lecturers who have taught me during my study in IHE-Delft.Thanks to all my family of IHE who shared time together and did support each other and I would like to thank Prof. Bart Schultz, PhD, MSc for his help from the beginning, and my best friends Marielle Van Ervan, Mireia Lopez Royo, Zaki Shubber and Tonneke Morgenstond for their kind support. Many thanks to Professor Dano Roelvink, Roel Noorman, Loes Westerveen, Gordon de Wit, Jaap Kleijn and Lennard Teileman for their brotherly help. I would show their appreciation Dr. K.P. Paudel and SMIS for their field data and reports that have other data helpful for this study. Above all, I would like to express my gratefulness for my husband Naser A. Kadhim and my son Ali, I dedicate this thesis as an insignificant gift for your endless love and sacrifices. Finally yet importantly, for others who were not mentioned but contributed to this thesis, I express my gratitude.

Can Mud Deposits Indicate Inundation Extent of Paleotsunamis? Insights From Sediment‐Transport Simulations for Sand and Mud

“…Sediments can be classified into cohesive and non‐cohesive. Cohesive sediments are composed primarily of clay‐sized material with strong inter‐particle forces due to their surface ionic charge and are usually found flocculated in suspension mode (Theol, 2020). On the other hand, non‐cohesive sediments are composed primarily of sand material with weak interparticle forces (Theol, 2020).…”

“…Cohesive sediments are composed primarily of clay‐sized material with strong inter‐particle forces due to their surface ionic charge and are usually found flocculated in suspension mode (Theol, 2020). On the other hand, non‐cohesive sediments are composed primarily of sand material with weak interparticle forces (Theol, 2020). They are usually transported by bedload and suspended load during tsunamis (e.g., Sugawara et al., 2014).…”

“…For M , 1.0 × 10 −5 to 5.0 × 10 −4 kg m −2 s −1 have been considered as typical values (e.g., Winterwerp et al., 2012), while 4.0 × 10 −7 to 5.0 × 10 −6 kg m −2 s −1 has been used for the simulation of cohesive sediment transport (e.g., Grasmeijer et al., 2011; Santoro et al., 2017; Xie et al., 2009). In this study, we assumed as M is 1.0 × 10 −4 kg m −2 s −1 as in Theol (2020), but we ran the simulation when the values of M were 1.0 × 10 −5 and 5.0 × 10 −4 kg m −2 s −1 . Both τ ce and τ cd are also determined by sediment properties.…”

Challenges and prospects to reduce sedimentation in small-scale irrigation schemes in the Great Rift Valley Basin, Ethiopia

“…In a study of factors underlying the dysfunctionality of SSI in sub-Saharan Africa, Pittock et al, (2020) argued that SSI had failed due to the disruption of traditional water management practices experienced in the colonial period, when local crops were replaced by export-based crops and farmers were excluded from decision making. Indeed, Bjornlund et al (2020a;2020b) argued that concerns related to Africa's biophysical environment and people are secondary, with the major causes of SSI underperformance being related to policy instruments, mode of donor engagement, the farming systems in use and the technologies that were introduced during the colonial period and which African governments continued to promote after independence. During the postcolonial period, expansion of irrigated agriculture was driven largely by the political interests of governments, with keen encouragement and backing by donors, contributing to the poor performance of SSI up to today (Bjornlund et al, 2020a).…”

“…This is especially true in river diversion irrigation schemes with a longer feeder canal. Some previous studies have investigated the role of sediment in the design and operation of irrigation schemes (Munir, 2011;Nestore et al, 1998;Osman, 2015;Paudel et al, 2010;Theol et al, 2020b); however, these studies only focused on sediment influx from a river. The overarching objective of the current research was therefore to assess the extent of sedimentation challenges, estimate their magnitude, and analyse how sedimentation problems might be overcome through the in-depth study of two SSI schemes in Ethiopia, using a sociotechnical approach.…”