Modeling Storm Surge Attenuation by an Integrated Nature-Based and Engineered Flood Defense System in the Scheldt Estuary (Belgium)

Sven Smolders,Patrick Meire,Tatiana Maximova,Maria João Teles,Agnès Leroy,Stijn Temmerman

doi:10.3390/jmse8010027

Abstract

There is increasing interest in the use of nature-based approaches for mitigation of storm surges along coasts, deltas, and estuaries. However, very few studies have quantified the effectiveness of storm surge height reduction by a real-existing, estuarine-scale, nature-based, and engineered flood defense system, under specific storm surge conditions. Here, we present data and modelling results from a specific storm surge in the Scheldt estuary (Belgium), where a hybrid flood defense system is implemented, consisting of flood control areas, of which some are restored into tidal marsh ecosystems, by use of culvert constructions that allow daily reduced tidal in- and outflow. We present a hindcast simulation of the storm surge of 6 December 2013, using a TELEMAC-3D model of the Scheldt estuary, and model scenarios showing that the hybrid flood defense system resulted in a storm surge height reduction of up to half a meter in the estuary. An important aspect of the work was the implementation of model formulations for calculating flow through culverts of restored marshes. The latter was validated comparing simulated and measured discharges through a physical scale model of a culvert, and through a real-scale culvert of an existing restored marsh during the storm surge.

Highlights

Storm surges, caused by low atmospheric pressure and strong winds, are the main mechanism responsible for coastal flooding around the world [1]
We present a hydrodynamic modelling study, aiming to assess the effectiveness of storm surge height reduction that is caused by the presence of constructed flood control areas (FCAs) with and without controlled reduced tide (CRT) during the 2013 ‘Sinterklaas’ storm in the Scheldt estuary (Belgium)
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Summary

Introduction

Storm surges, caused by low atmospheric pressure and strong winds, are the main mechanism responsible for coastal flooding around the world [1]. In addition to traditional engineering approaches, such as dikes and flood barriers, there is an increasing interest in so-called nature-based and hybrid (i.e., combined nature-based and engineered) approaches for mitigating storm surge flood risks [10,11,12,13]. These include studies identifying the impact of naturally existing intertidal ecosystems (marshes, mangroves) on attenuation of storm surge water levels, when storm surges propagate through such intertidal wetlands or through estuarine or deltaic channels with adjacent wetlands [14,15,16,17,18,19]. Very few studies have quantified the effectiveness of storm surge reduction by a real-existing, estuarine-scale, nature-based or hybrid flood defense scheme, under specific storm surge conditions

Methods

Results

Conclusion