A Regional Application of Bayesian Modeling for Coastal Erosion and Sand Nourishment Management

Alessio Giardino,Giorgio Santinelli,Kees Den Heijer,Eleni Diamantidou,Stuart Pearson

doi:10.3390/w11010061

Alessio Giardino, Giorgio Santinelli + Show 3 more

Open Access

https://doi.org/10.3390/w11010061

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Journal: Water	Publication Date: Jan 1, 2019
Citations: 15	License type: CC BY 4.0

Affiliation: Deltares, Delft University of Technology

Abstract

This paper presents an application of the Bayesian belief network for coastal erosion management at the regional scale. A “Bayesian ERosion Management Network” (BERM-N) is developed and trained based on yearly cross-shore profile data available along the Holland coast. Profiles collected for over 50 years and at 604 locations were combined with information on different sand nourishment types (i.e., beach, dune, and shoreface) and volumes implemented during the analyzed time period. The network was used to assess the effectiveness of nourishments in mitigating coastal erosion. The effectiveness of nourishments was verified using two coastal state indicators, namely the momentary coastline position and the dune foot position. The network shows how the current nourishment policy is effective in mitigating the past erosive trends. While the effect of beach nourishment was immediately visible after implementation, the effect of shoreface nourishment reached its maximum only 5–10 years after implementation of the nourishments. The network can also be used as a predictive tool to estimate the required nourishment volume in order to achieve a predefined coastal erosion management objective. The network is interactive and flexible and can be trained with any data type derived from measurements as well as numerical models.

Highlights

Coastline retreat is a worldwide phenomenon caused by an imbalance between sediment supply and demand
A tool based on the use of a Bayesian network (BERM-N) was constructed using measured data collected along the entire Holland coast for a period of over 50 years at
A first application was used to quantify the issue of coastal erosion along the Holland coast region

Summary

Introduction

Coastline retreat is a worldwide phenomenon caused by an imbalance between sediment supply and demand. Causes of erosion may be either anthropogenic (e.g., construction of river dams, ports or coastal protection works, sediment mining) or natural (e.g., natural gradients in alongshore sediment transport, storms, presence of submarine canyons near the coastline) [2]. The Holland coast is a typical example of an erosive coastline, along which coastal erosion is managed by applying sand nourishments. The management of coastal erosion relies on the continuous development of new and flexible solutions and tools, which can account for changes in natural hazard conditions and anthropogenic interventions and which are based on long-term observations [3,4]. Several examples are available of small-scale data or numerical modeling studies with long-term datasets (e.g., [5,6,7]). The use of data analysis or numerical modeling at the local scale often provides information which is

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