The interplay between structural flood protection, population density, and flood mortality along the Jamuna River, Bangladesh

Giuliano Di Baldassarre,Md Ruknul Ferdous,Luigia Brandimarte,Anna Wesselink

doi:10.1007/s10113-020-01600-1

Abstract

Levees protect floodplain areas from frequent flooding, but they can paradoxically contribute to more severe flood losses. The construction or reinforcement of levees can attract more assets and people in flood-prone area, thereby increasing the potential flood damage when levees eventually fail. Moreover, structural protection measures can generate a sense of complacency, which can reduce preparedness, thereby increasing flood mortality rates. We explore these phenomena in the Jamuna River floodplain in Bangladesh. In this study area, different levels of flood protection have co-existed alongside each other since the 1960s, with a levee being constructed only on the right bank and its maintenance being assured only in certain places. Primary and secondary data on population density, human settlements, and flood fatalities were collected to carry out a comparative analysis of two urban areas and two rural areas with different flood protection levels. We found that the higher the level of flood protection, the higher the increase of population density over the past decades as well as the number of assets exposed to flooding. Our results also show that flood mortality rates associated with the 2017 flooding in Bangladesh were lower in the areas with lower protection level. This empirical analysis of the unintended consequences of structural flood protection is relevant for the making of sustainable policies of disaster risk reduction and adaptation to climate change in rapidly changing environments.

Highlights

In the year 1964, new levees were built to prevent flooding in the village of Char Jabbar, Bangladesh
Numerous scholars have shown that structural flood protection tends to be associated with increasing flood exposure, defined here as the population and assets located in flood hazard-prone areas (Jongman et al 2015), and flood vulnerability, defined here as the susceptibility of the exposed elements to flooding (Jongman et al 2015)
To better understand the interplay between structural protection levels and flood exposure/mortality, we explore the effects of structural flood protection in four different types of human settlements along the Jamuna River floodplain

Summary

Introduction

In the year 1964, new levees were built to prevent flooding in the village of Char Jabbar, Bangladesh. The presence of this structural protection measure encouraged more human settlements and numerous people moved into this flood-protected area (Burton et al 1993). Numerous scholars have shown that structural flood protection tends to be associated with increasing flood exposure, defined here as the population and assets located in flood hazard-prone areas (Jongman et al 2015), and flood vulnerability, defined here as the susceptibility of the exposed elements to flooding (Jongman et al 2015). This tendency is typically described as the ‘safe development paradox’, ‘levee effect’, ‘residual risk’, or ‘safety dilemma’ and it was shown to potentially offset the intended benefits of structural flood

Results

Discussion

Conclusion