Identification of Coastal Defence Measures Best Adapted to Mitigate Hazards in Specific Coastal Systems: Development of a Dynamic Literature Meta-Analysis Methodology

Philippe Sauvé,Pascal Bernatchez,Mathias Glaus

doi:10.3390/jmse10030394

Abstract

The decision-making process of the coastal defence measures (CDMs) is complex and filled with uncertainties due to site-specific interactions between hydrodynamic and geomorphological conditions, which have repercussions on the ecological and social aspects of coastal communities. Scientific knowledge of the effects of CDMs contributes to the reduction in inherent uncertainties and facilitates the decision-making and design processes. The goal of this article is to present an algorithm designed to evaluate and hierarchize CDMs in relation to different coastal environments. Drawn from 411 published scientific case studies, a total of 1709 authors’ observation statements regarding the effects of CDMs on the study sites’ environmental features (type of coast, type of substrate, tidal range, and wave climate) were entered in a database, categorized, and weighted according to a qualitative scale. The algorithm processes the information by establishing a correspondence between user-selected environment features and those stocked in the database, and it evaluates user-selected CDMs in relation to the specified coastal characteristics by identifying, collating, and rating the effects as observed in similar contexts. The result is a tool able to process, structure, and concretize scientific knowledge regarding CDMs and their effects on coastal systems. It is complementary to existing tools currently used in the decision-making and design processes of the CDMs. The results present the hierarchization of CDMs according to a multilevel aggregated structure, which can be used in different ways by coastal managers, decision-makers, and engineers. The algorithm, based on standardized coastal characteristics, can be applied to any shoreline worldwide.

Highlights

Coastal systems are affected by coastal hazards such as erosion, flooding, and landslides
Based on a literature review of case study publications regarding the effects of coastal defence measures (CDMs) on coastal systems, the purpose of this article is to present the development of an algorithm capable of conducting a dynamic meta-analysis of relevant publications and forming a qualitative synthesis to be used in the CDM decision-making process
The coastal defence measure identification algorithm (CDMIA) is developed to (1) conduct a dynamic meta-analysis of the effects of CDMs on coastal systems, (2) centralize and structure the existing scientific knowledge drawn from published studies, (3) evaluate, compare, and rank CDMs in different environmental contexts, and (4) yield useful information to support the decision-making process

Summary

Introduction

Coastal systems are affected by coastal hazards such as erosion, flooding, and landslides. Coastal erosion and flooding have been exacerbated in recent decades by the effects of climate change, sea-level rise [2–5], and anthropogenic activities [6–8], which have led to an increase in shoreline armouring worldwide [9–12]. Hard reflective coastal defence structures have been implemented on shorelines without consideration for coastal dynamics and with potentially negative environmental impacts [9,15–18]. The selection of this type of CDM can be explained by a lack of knowledge regarding coastal dynamics and a lack of tools available to make sound decisions [12,19–23]. Given the unpredictability brought on by climate change, such knowledge is becoming more and more critical and can greatly contribute to the integrality of the CDM decision-making process by reducing inherent uncertainties [14]

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Discussion

Conclusion