Applicability of satellite radar imaging to monitor the conditions of levees

Işıl E. Özer,Ramon F. Hanssen,Freek J. van Leijen,Sebastiaan N. Jonkman

doi:10.1111/jfr3.12509

Işıl E. Özer, Ramon F. Hanssen + Show 2 more

Open Access

https://doi.org/10.1111/jfr3.12509

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Abstract

Levees are critical systems in safeguarding an area against catastrophic flooding events with potential fatalities and economic losses. Current monitoring methods of levees highly rely on expert judgement, resulting in infrequent and subjective assessments of their status. Satellite radar imaging, in particular using interferometry (InSAR), holds a large potential to monitor the condition of levees with millimetre‐level precision, anywhere on the planet. However, for levee management, the usability of the technique requires significant radar expert knowledge. Here, we provide a comprehensive overview of the state of the art in using time‐series InSAR for systematic levee deformation monitoring. We explore its use to complement existing approaches for assessing levee deformation and failure investigations in a fast, systematic, and cost‐effective way. The applicability of imaging radar satellites is discussed, supported by case studies on levee monitoring in the Netherlands. We elaborate on the technical aspects with respect to levee monitoring using SAR technology, such as estimating deformation in different directions, satellite characteristics, precision, and reliability. We conclude that InSAR is becoming an operational deformation monitoring system, which allows for the detection, tracking, and analysis of irregularities on levee sections with increased efficiency and quality, thus contributing to improved risk management.

Highlights

Levees are critical systems that provide flood protection
We provide a comprehensive overview of the state of the art in using time-series Interferometric Synthetic Aperture Radar (InSAR) for systematic levee deformation monitoring, aiming to assess its usability and applicability as a way of complementing existing monitoring approaches and failure investigation methods
The most suitable approach depends on the surface cover, the number of available radar images, the orientation of the structures and the expected deformation signal

Summary

| INTRODUCTION

Levees are critical systems that provide flood protection. Rapid economic and demographic growth, in combination with natural changes such as sea level rise, extreme weather conditions, and land subsidence, increase the potential impact of a levee failure. Conventional levee monitoring methods mainly consist of visual inspections (Cundill, van der Meijde, & Hack, 2014; Mériaux & Royet, 2007; Sharp et al, 2013), restricted to a typical frequency of twice a year in the Netherlands (Bakkenist, van Dam, van der Nat, Thijs, & de Vries, 2012). During these inspections, the integrity of the structures is assessed using qualitative inspection parameters (Bakkenist, 2012), for example, by checking the presence of any damage, crack, animal burrows, or irregular vegetation on the levees. We discuss the potential of using satellite radar imaging for levee monitoring, and analyse the links between levee deformations and various failure mechanisms

Findings

| METHODOLOGY

| CONCLUSIONS