Print Email Facebook Twitter Coastal Aeolian Sediment Transport in an Active Bed Surface Layer Title Coastal Aeolian Sediment Transport in an Active Bed Surface Layer: Tracer Study and Conceptual Model Author Uphues, Charlotte (TU Delft Civil Engineering and Geosciences) Contributor de Vries, S. (mentor) van IJzendoorn, C.O. (mentor) van Prooijen, Bram (mentor) Pearson, S.G. (mentor) Hallin, E.C. (mentor) Miot da Silva, G. (mentor) Degree granting institution Delft University of Technology Programme Civil Engineering | Hydraulic Engineering Date 2021-10-07 Abstract Coastal aeolian sediment transport is influenced by supply-limiting factors such as sediment sorting by grain size. Sorting processes can cause a coarsening of the bed surface and influence the formation of aeolian ripples. However, it is not fully understood what influence sorting processes have on the magnitude of this transport. In this study, sorting processes of different grain sizes when interacting with wind and their influence on the magnitude of aeolian transport are investigated by performing a tracer study and developing a conceptual model. Sand grains were painted in different colors according to particle size and placed on Noordwijk beach, Netherlands. Several experiments were conducted with varying wind speeds. Surface sampling and cameras tracked the sand color movement on the bed surface, and wind speed and direction were measured. The tracer experiments show that for moderate wind conditions, ripples developed. Once the ripples have formed, the supply of finer tracer grains in downwind direction decreased over time, while the supply of coarser grains remained constant. A strong linear relationship between ripple speed and wind speed was found. For higher wind velocities, no ripples or differences in transport of grain size fractions were observed. Alternating phases of erosion and deposition of upwind sand were observed which could not be related to local variations in wind speed. Based on these results and literature, a conceptual model for an Active Bed Surface Layer (ABSL) with two regimes corresponding to moderate (I), and high (II) wind speeds was developed. The concept enables to estimate the magnitude of aeolian sediment transport as a function of wind speed, bed characteristics, and upwind sediment supply. For Regime I, a linear relationship between sediment transport and wind speed is suggested and for Regime II a third power relationship in combination with a process-based model accounting for supply limitations is suggested. Subject Aeolian sediment transportSupply limitedSediment sortingArmoringAeolian ripplesTracersField measurementsConceptual modelBeach To reference this document use: http://resolver.tudelft.nl/uuid:11fc3463-9bea-4638-b782-169abe398934 Embargo date 2022-10-07 Coordinates 52.25556,4.43611 Bibliographical note The main body of this thesis (Part I: Paper) is provided in paper format with the aim to publish it in the Special Issue in Earth Surface Processes and Landforms “Coastal dunes: links between aeolian processes and landform dynamics”. Therefore, the Embargo option with end date October, 7 2022 (1 year after graduation) is chosen. Part of collection Student theses Document type master thesis Rights © 2021 Charlotte Uphues Files PDF Master_Thesis_Charlotte_Uphues.pdf 39.64 MB Close viewer /islandora/object/uuid:11fc3463-9bea-4638-b782-169abe398934/datastream/OBJ/view