Observations and Modelling of Shoreface Nourishment Behaviour

Journal of Marine Science and Engineering

Dirk-Jan Walstra¹  Matthieu de Schipper²  Bastiaan Huisman²  Gerben Ruessink³  Max Radermacher⁴ 

[1] Department of Applied Morphology, Deltares, P.O. Box 177, 2600MH Delft, The Netherlands;Department of Hydraulic Engineering, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600GA Delft, The Netherlands;Department of Physical Geography, Faculty of Geosciences, Utrecht University, P.O. Box 80115, 3508TC Utrecht, The Netherlands;H-max, Rijswijk, The Netherlands;

关键词: morphology;    shoreface nourishment;    sand bar;    erosion;    modelling;   

DOI  :  10.3390/jmse7030059

来源: DOAJ

【 摘 要 】

Shoreface nourishments are commonly applied for coastal maintenance, but their behaviour is not well understood. Bathymetric data of 19 shoreface nourishments located at alongshore uniform sections of the Dutch coast were therefore analyzed and used to validate an efficient method for predicting the erosion of shoreface nourishments. Data shows that considerable cross-shore profile change takes place at a shoreface nourishment, while an impact at the adjacent coast is hard to distinguish. The considered shoreface nourishments provide a long-term (3 to ∼30 years) cross-shore supply of sediment to the beach, but with small impact on the local shoreline shape. An efficient modelling approach is presented using a lookup table filled with computed initial erosion–sedimentation rates for a range of potential environmental conditions at a single post-construction bathymetry. Cross-shore transport contributed the majority of the losses from the initial nourishment region. This transport was driven partly by water-level setup driven currents (e.g., rip currents) and increased velocity asymmetry of the waves due to the geometrical change at the shoreface nourishment. Most erosion of the nourishment takes place during energetic wave conditions ( Hm 0 ≥ 3 m) as milder waves are propagated over the nourishment without breaking. A data-model comparison shows that this approach can be used to accurately assess the erosion rates of shoreface nourishments in the first years after construction.

【 授权许可】

Unknown