Wave transmission and drag coefficients through dense cylinder arrays: Implications for designing structures for mangrove restoration

Mangrove vegetation constitutes a natural coastal defence against waves and erosion. Despite their protective role, mangrove ecosystems have experienced continuous degradation over the last decades due to human causes. At retreating mangrove coastlines, bamboo structures are built to create new habitat for mangrove colonization. Existing...

A laboratory and numerical study of transverse momentum exchange in vegetated channels

Transverse exchange processes of mass and momentum in floodplain regions of channels are of primary importance regarding the sediment transport and riverbank stability. The presence of large horizontal coherent structures (LHCSs) at the interface of the floodplain and main channel regions may contribute up to 90% the amount of transverse...

Estimating the stability of a bed protection of a weir-mounted tidal turbine

Coastal infrastructure, such as bridges and storm surge barriers with weirs, provides an attractive location for harvesting renewable energy using tidal turbines. Often stone layers are applied downstream of coastal infrastructure to protect the sea bed from erosion. However, little is known about the potential effect of tidal energy...

Estimating the stability of a bed protection of a weir-mounted tidal turbine

Coastal infrastructure, such as bridges and storm surge barriers with weirs, provides an attractive location for harvesting renewable energy using tidal turbines. Often stone layers are applied downstream of coastal infrastructure to protect the sea bed from erosion. However, little is known about the potential effect of tidal energy extraction...

Morphological Adaptation of River Channels to Vegetation Establishment: A Laboratory Study

While the scientific community has long recognized that alluvial rivers are the product of interactions between flowing water and bed material transport, it is increasingly evident that vegetation mediates these interactions and influences the stream channel characteristics. In a novel set of mobile bed laboratory experiments with variable...

Deriving vegetation drag coefficients in combined wave-current flows by calibration and direct measurement methods

Coastal vegetation is efficient in damping incident waves even in storm events, thus providing valuable protections to coastal communities. However, large uncertainties lie in determining vegetation drag coefficients (C_D), which are directly related to the wave damping capacity of a certain vegetated area. One major uncertainty is...

Impact of flow variability and sediment characteristics on channel width evolution in laboratory streams

Alluvial rivers are shaped by sequences of water flows excavating their channels. Observations show that besides the magnitude, the frequency and duration of streamflow oscillations might also be important for the river channel formation. In addition, the river morphology appears influenced by both size and degree of uniformity of the...

Sediment Transport of Fine Sand to Fine Gravel on Transverse Bed Slopes in Rotating Annular Flume Experiments

Large-scale morphology, in particular meander bend depth, bar dimensions, and bifurcation dynamics, are greatly affected by the deflection of sediment transport on transverse bed slopes due to gravity and by secondary flows. Overestimating the transverse bed slope effect in morphodynamic models leads to flattening of the morphology, while...

Long-term morphological developments of river channels separated by a longitudinal training wall

Rivers have been trained for centuries by channel narrowing and straightening. This caused important damages to their ecosystems, particularly around the bank areas. We analyse here the possibility to train rivers in a new way by subdividing their channel in main and ecological channel with a longitudinal training wall. The effectiveness of...