TY - JOUR
T1 - Bedforms and sediment dynamics under reduced sediment input and estuarine engineering
T2 - the case of the Bou Regreg estuary, Morocco
AU - Jemily, Linda
AU - Raki, Amine
AU - Trakadas, Athena
AU - Al-Hamdani, Zyad
AU - Jensen, Jørn B.
AU - Huff, Lloyd
AU - Mhammdi, Nadia
N1 - Publisher Copyright:
© 2024 Rosenstiel School of Marine and Atmospheric Science. All rights reserved.
PY - 2024/1
Y1 - 2024/1
N2 - The Bou Regreg riverine estuary constitutes a microtidal environment located within an urban region and characterized by limited sediment inflow from its catch basin hinterlands. The construction of the Sidi Mohamed Ben Abdellah (SMBA) dam has notably diminished sediment supply,especiallycoarserfractions.Inlightoftheseconditions, this study aimed to classify sediment types according to the Folk and Ward classification, stratify morphometric parameters and temporal fluctuations based on dune types, and ultimately evaluate the sediment dynamics driving observed bedform variations. Using an integrated approach, data collection involved various techniques, including CTD profiling, bottom videography, side-scan sonar imaging, sub-bottom profiling, and Van Veen bottom grab sampling. The bed morphology includes segments of smooth bed, erosional and dredged bottom, localized scour features, and submarine dune fields, displaying notable heterogeneity. Acoustic seabed reflections indicated two bedform clusters with maximum lengths of 42.6 m and heights of 1 m. Flow velocities were linked to the presence of 2D and 3D dune forms. Morphological variations encompassed straight, sinuous, and barchan dune configurations, mainly asymmetric with NNW–SSE seaward orientation. Sediment mean size fluctuations spanned from muddy to medium sand deposition. The findings revealed the intricate interplay of dynamics shaping dune field configurations and the heterogeneous dispersion of bedforms throughout the estuary likely due to a sharp decline of sediment discharge caused by the dam upstream and coastal engineering. The study emphasizes the dynamic nature of dunes, highlighting their sensitivity to shifting hydrodynamic conditions and sediment availability, leading to morphological fluctuations over time.
AB - The Bou Regreg riverine estuary constitutes a microtidal environment located within an urban region and characterized by limited sediment inflow from its catch basin hinterlands. The construction of the Sidi Mohamed Ben Abdellah (SMBA) dam has notably diminished sediment supply,especiallycoarserfractions.Inlightoftheseconditions, this study aimed to classify sediment types according to the Folk and Ward classification, stratify morphometric parameters and temporal fluctuations based on dune types, and ultimately evaluate the sediment dynamics driving observed bedform variations. Using an integrated approach, data collection involved various techniques, including CTD profiling, bottom videography, side-scan sonar imaging, sub-bottom profiling, and Van Veen bottom grab sampling. The bed morphology includes segments of smooth bed, erosional and dredged bottom, localized scour features, and submarine dune fields, displaying notable heterogeneity. Acoustic seabed reflections indicated two bedform clusters with maximum lengths of 42.6 m and heights of 1 m. Flow velocities were linked to the presence of 2D and 3D dune forms. Morphological variations encompassed straight, sinuous, and barchan dune configurations, mainly asymmetric with NNW–SSE seaward orientation. Sediment mean size fluctuations spanned from muddy to medium sand deposition. The findings revealed the intricate interplay of dynamics shaping dune field configurations and the heterogeneous dispersion of bedforms throughout the estuary likely due to a sharp decline of sediment discharge caused by the dam upstream and coastal engineering. The study emphasizes the dynamic nature of dunes, highlighting their sensitivity to shifting hydrodynamic conditions and sediment availability, leading to morphological fluctuations over time.
UR - http://www.scopus.com/inward/record.url?scp=85186240049&partnerID=8YFLogxK
U2 - 10.5343/bms.2022.0043
DO - 10.5343/bms.2022.0043
M3 - Article
AN - SCOPUS:85186240049
SN - 0007-4977
VL - 100
SP - 3
EP - 22
JO - Bulletin of Marine Science
JF - Bulletin of Marine Science
IS - 1
ER -