Socio-hydrological dynamics in Bangladesh : Understanding the interaction between hydrological and social processes along the Jamuna floodplain

Bangladesh is a large delta, where most people live in the overpopulated floodplains. Flooding is a normal phenomenon, which causes much suffering. How to reduce this suffering through better managing floods is a big societal challenge. To date, societal initiatives to address this challenge mainly consist of the construction of embankments along the river bank, to control hydrological processes and ‘discipline’ the river. Yet, such embankments generate their own hydrological and societal responses in sometimes unexpected ways. The study of these interactions and feedback mechanisms between hydrological and social processes is a new academic field, one that is particularly relevant in a dynamic delta such as Bangladesh. This research sets out to explore the phenomena, opportunities and risks generated by the interactions between physical and societal processes along the Jamuna River in Bangladesh. It conceptualize these interactions as temporally dynamic and spatially diverse combinations of fighting and living with water. The research proposes the concept of “Socio-hydrological spaces (SHSs)” to enrich the study of sociohydrology. A SHS is a geographical area in a landscape. Its particular combination of hydrological and social features gives rise to the emergence of distinct interactions and dynamics (patterns) between society and water. The SHSs concept suggests that the interactions between society and water are place-bound and specific because of differences in social processes, technological choices and opportunities, and hydrological dynamics. Through the concept of SHS, this research does not only contribute to advance the knowledge about sociohydrological dynamics in Bangladesh, but also provides more general insights for flood risk management

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

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

Socio-hydrological spaces in the Jamuna River floodplain in Bangladesh

Socio-hydrology aims to understand the dynamics and co-evolution of coupled human-water systems, with research consisting of generic models as well as specific case studies. In this paper, we propose a concept to help bridge the gap between these two types of socio-hydrological studies: socio-hydrological spaces (SHSs). A socio-hydrological space is a geographical area in a landscape. Its particular combination of hydrological and social features gives rise to the emergence of distinct interactions and dynamics (patterns) between society and water. Socio-hydrological research on human-flood interactions has found two generic responses, "fight" or "adapt". Distilling the patterns resulting from these responses in case studies provides a promising way to relate contextual specificities to the generic patterns described by conceptual models. Through the use of SHSs, different cases can be compared globally without aspiring to capturing them in a formal model. We illustrate the use of SHS for the Jamuna floodplain, Bangladesh. We use narratives and experiences of local experts and inhabitants to empirically describe and delimit SHS. We corroborated the resulting classification through the statistical analysis of primary data collected for the purpose (household surveys and focus group discussions) and secondary data (statistics, maps etc.). Our example of the use of SHSs shows that the concept draws attention to how historical patterns in the co-evolution of social behaviour, natural processes and technological interventions give rise to different landscapes, different styles of living and different ways of organising livelihoods. This provides a texture to the more generic patterns generated by socio-hydrological models, promising to make the resulting analysis more directly useful for decision makers. We propose that the usefulness of this concept in other floodplains, and for other socio-hydrological systems than floodplains, should be explored

The Costs of Living with Floods in the Jamuna Floodplain in Bangladesh

Bangladeshi people use multiple strategies to live with flooding events and associated riverbank erosion. They relocate, evacuate their homes temporarily, change cropping patterns, and supplement their income from migrating household members. In this way, they can reduce the negative impact of floods on their livelihoods. However, these societal responses also have negative outcomes, such as impoverishment. This research collects quantitative household data and analyzes changes of livelihood conditions over recent decades in a large floodplain area in north-west Bangladesh. It is found that while residents cope with flooding events, they do not achieve successful adaptation. With every flooding, people lose income and assets, which they can only partially recover. As such, they are getting poorer, and therefore less able to make structural adjustments that would allow adaptation in the longer term