Coastal sediment dynamics: recent advances and future research needs

This vision paper discusses the advances made over the last three decades in coastal sand transport and morphodynamics, and the research needs for the coming decades. The prime focus of the paper is on the relationship between the transport of sand particles and fluid motions in the coastal environment based on laboratory and field experiments as well as mathematical modelling. The paper mainly focuses on two main issues: (1) better understanding of sediment transport processes in the coastal zone and (2) the development of improved practical engineering sand transport formulae and morphodynamic models

Suspended and bedload transport in the surfzone : implications for sand transport models

ACKNOWLEDGMENTS The research presented in this paper is conducted within the SINBAD project, funded by STW (12058) and EPSRC (EP/J00507X/1, EP/J005541/1), and received additional funding through the European Community’s FP7 project Hydralab IV (contract no. 261520).Publisher PD

Modeling biogeomorphological interactions in underwater nourishments

To prevent sandy coastlines from further erosion, nourishments are executed in which sand is usually put underwater at the foreshore. Waves and currents transport the sand on the beach and in this way stabilize the coastal profile. Little is known about the interactions of these so-called shoreface nourishments with the benthic populations inhabiting the coastal strip. Benthos is affected by the nourishments, but benthic populations could in turn affect the morphological evolution of the nourished coast. Monitoring has shown that the benthic community will mainly recovery after ca. 1 year. However, the impact of benthos on the sediment dynamics and hydrodynamics is unknown. In this paper we focus on tube building worms, which have a large abundance in the foreshore, live in patches of several square meters in diameter and protrude several centimeters from the sediment in the water column. Tube building worms are included in a numerical modeling tool (Delft3D), by explicitly accounting for the influence of cylindrical structures on drag and turbulence by an extra source term of friction force in the momentum equation and an extra source term of Total Kinetic Energy (TKE) and turbulent energy dissipation in the k-ε equations respectively. The model is validated against field and flume experiments and it shows a significant influence on flow velocities near the bed, bed shear stress and bed-load transport rates. Moreover, model results reveal that tube building worms are able to stabilize nourishments and slow down the migration of the outer breaker bar. Present model explorations indicate that future research should focus on the measurement of the patchy distribution of bio-engineers in the foreshore and their impact on the sediment dynamics and hydrodynamics. Such knowledge will enable process based modeling of the spatial and temporal variation in biological activity on the morphological development of the coastal profile and also it will lead to validation of the proposed model with field measurements.</jats:p

Practical sand transport formula for non-breaking waves and currents

Open Access funded by Engineering and Physical Sciences Research Council Under a Creative Commons license Acknowledgements This work is part of the SANTOSS project (‘SANd Transport in OScillatory flows in the Sheet-flow regime’) funded by the UK's EPSRC (GR/T28089/01) and STW in The Netherlands (TCB.6586). JW acknowledges Deltares strategic research funding under project number 1202359.09. Richard Soulsby is gratefully acknowledged for valuable discussions and feedback on the formula during the SANTOSS project.Peer reviewedPostprin

Sediment transport in non-linear skewed oscillatory flows : the TRANSKEW experiments

Peer reviewedPreprin