Modelling the effects of coastal vegetation
JBPacific is modelling wave and storm surge interaction through coastal mangrove forests. Mangrove forests are complex coastal ecosystems that occupy a critical niche as coastal defence and natural marine habitat. Their intricate root and trunk systems trap incoming wave energy and bind soil to prevent erosion. Field studies have shown that mangroves can reduce incoming wave height by as much as 45% across 100m of forest. Globally, the health and density of coastal mangrove forests is a key predictor of reduced flooding of low-lying coastal regions.
The XBeach coastal hydro-morphology model, developed by Deltares, allows for the inclusion of short-wave dissipation and flow interaction through coastal vegetation. This is an important inclusion for estimating the reduction in wave height, runup, and overtopping across mangrove fields. The drag coefficient, stem diameter, and density can be varied with height throughout the field, allowing for the simulation of plant roots, trunks and canopies. The inclusion of vegetation in the XBeach model is the focus of ongoing research and validation and will be an important consideration in simulating. This is important development for coastal engineers looking to design nature-based coastal defences. With the threat of sea level rise and increasing population density in coastal areas, the preservation and expansion of mangrove forests will be critical factor in reducing coastal flood risk.