New publication on dune erosion

23/07/2021
Sun rise over dune Copyright: © IWW

Extension of the open-source XBeach model to account for the effect of belowground biomass (roots) on wave-induced erosion.

 

Dunes as a part of coastal protection

Dunes are used worldwide as a natural barrier to protect coastal regions from marine hydrodynamic forcing. In this context, especially dune vegetation has a positive effect on the resilience of a dune to storm surge-induced erosion, with both the above- (stem leaves) and belowground (roots) vegetation structures influencing the erosion processes. However, in numerical coastal erosion models such as XBeach, the effect of vegetation has so far mostly been considered by locally increasing the bed friction, which is equivalent to the effect of aboveground vegetation structures.

Increasing the precision of dune modelling

The paper “Considering the effect of belowground biomass on dune erosion volumes in coastal numerical modelling” presents an approach to account for the effect of vegetation roots on wave-induced erosion in the XBeach model. The basic principle is a local increase of the critical erosion velocity due to additional root cohesion that decreases with the rooting depth. Validation of the novel approach based on small-scale physical model tests, where belowground vegetation at the dune was represented by coir fibers, showed improved model accuracy in the area of the dune.

Published in:

Coastal Engineering, Volume 168, 2021

“Considering the effect of belowground biomass on dune erosion volumes in coastal numerical modeling” von Constantin Schweiger and Holger Schüttrumpf, September 2021, https://doi.org/10.1016/j.coastaleng.2021.103927