Hydrological Sciences

Why social inequalities matter for hydrologists?

Why social inequalities matter for hydrologists?

After a few years spent at an Earth Science department researching social inequalities and hydrological extremes — i.e. floods and droughts — I have often been asked these rhetorical questions: “Isn’t it obvious that the weakest individuals or social groups suffer the most in case of extreme hydrological events? So, why should we study these inequalities?” Driven by these questions, and the years of research ahead, I have decided to write this blog post in order to engage with my fellow hydrologists. With them, I wish to discuss the reasons why it is important to retrace social power and the resulting inequalities that intersect with the production and distribution of hydrological extremes.

Thanks to decades of studies about human-water system dynamics, I can easily assert that water and human systems are interconnected. Over the past decade more and more hydrologists have stressed the importance of considering the mutual interactions between social and physical processes in order to better describe hydrological flows and avoid unintended consequences in water management. The theory of water and society coevolution has been advanced by many hydrologists involved in Panta Rhei, the current research decade (2013-2022) of the International Association of Hydrological Sciences (IAHS). It elegantly describes the way in which human and water systems shape and reshape each other over time and space. On the one hand, society alters the hydrological regime and eventually modifies the frequency and occurrence of floods and droughts. This takes place via urbanization processes, water abstraction, dams and reservoirs construction, flood protection measures, and other interventions. In turn, hydrological extremes can also shape societies, which spontaneously or not, react, respond, and adapt to the impacts of floods and droughts.

Yet, we must add to the complexity of this theory to do it justice. Society is by nature heterogenous and as such, is characterized by power imbalances between different individuals and social groups. Thus, if society is unequally structured, every social relationship is mediated by societal differences and power imbalances. These unequal relations of power determine who gets what, when, and how, and in turn, all too often result in an uneven distribution of privileges and burdens.

Thus, the first implication that social heterogeneity has for hydrology is that society interacts with water systems as a result of these power imbalances. In other words, it is not society as a whole that directly reshapes hydrology, and not every individual or social group is able to alter water flows in the same way. Most commonly, the most powerful social groups, through their prevailing ideas and actions, determine human interactions with the water systems and possibly exacerbate extreme hydrological conditions.

In a rural community, for instance, it is often the demand of farmers and their agricultural production that is able to produce (often through imposition) the need for a new dam or reservoir. Indeed, because farming activities, in this instance — through their surface or groundwater abstractions — are the main interventions that substantially alter the hydrological regime, they eventually make hydrological or agricultural droughts far more severe than would have otherwise been the case. Thus, this example shows that it is the unequal power of the farmers relative to other societal groups, that initiates and materializes the major human interactions with the local hydrology and eventually influences extreme hydrological conditions.

While studying Cape Town 2015-17 drought and the consequent Day Zero crisis1, my research came across a similar phenomenon. Before that crisis, the unsustainable water consumption of elites and upper middle classes2 transformed the most recent drought into an extreme water crisis. It was these privileged groups — by washing their cars, filling up their swimming pools, and/or watering their gardens — that made the hydrological drought far more extreme. Conversely, the remaining Capetonians living in townships or in informal settlements, had little effect on the City’s water balance. In fact, for most of these urban dwellers ‘every day is a Day Zero’. Thus, without accounting for these social inequalities whilst treating society as a unified whole, we risk overlooking the real drivers and rationale behind societal interactions with the water systems which produced extreme hydrological conditions in Cape Town.

Another hydrological implication of human inequality relates to the way in which hydrology and hydrological extremes interact with or affect society. As the theory of coevolution teaches us, hydrology reshapes society because, directly or indirectly, spontaneously or not, society reacts, responds, and adapts to the impacts of floods and droughts. Yet, every social group or individual have different capacities and resources to recover from, and adapt to extreme hydrological events. Thus, as a result of floods or droughts, society will engender different resilience trajectories that cannot be generalized nor merged as a common societal response. In turn, each trajectory will diversely affect or interact with water systems.

Cape Town’s Day Zero crisis once again provides compelling evidence for this. During the crisis, most of the townships’ dwellers could not consistently access alternative water sources, nor pay higher tariffs imposed during the drought. As a result, they faced even more water shortages and lower levels of water security relative to the pre-drought period. Yet elites and upper middle class households were able to increase their level of water security by paying for higher tariffs, enjoying easy access to alternative sources and, eventually, going off the grid3. In turn, because this privileged group is now more water secure, in all likelihood they will continue to (over)consume the same water they were able to use before the crisis. Without considering such differences, we fail to fully appreciate that these differences exacerbate unequal vulnerabilities, but we also fail to accurately capture societal interactions with hydrological systems.

To fully comprehend hydrological extremes and thus avoid unintended consequences in water management, hydrologists will need to open up to a more nuanced understandings of society, particularly with regard to power relations. Thus, deeper interdisciplinary conversations between social science and hydrology are needed to help capture inequalities that reshape water systems, and all too often exacerbate extreme hydrological events. In turn, an integrated understanding will provide space to produce more just and sustainable solutions that address floods and droughts well into the future.


Elisa Savelli is a PhD Candidate in Environmental Analysis at the Department of Earth Sciences, Air, Water and Landscape Science at Uppsala University, and Centre of Natural Hazards and Disaster Science (CNDS) in Sweden. Elisa studies the politics that intersect with the production and distribution of hydrological extremes — i.e. floods and droughts. For more information see http://hydrosocialextremes.org or email Elisa elisa.savelli@geo.uu.se.


Edited by Sina Khatami



1 Day Zero Crisis took his name from the Day Zero Campaign, a communication strategy adopted by Cape Town’s Authorities to prevent the occurrence of water shortages across the City, “Day Zero” would herald the start of Level 7 water restrictions, when municipal water supplies would largely be switched off and residents would have to queue for their daily ration of water, making the City of Cape Town the first major city in the world to potentially run out of water. See also COCT 2017.

2 According to the Socio-Economic Index (SEI) developed by the City of Cape Town, elite and upper middle classes are citizens who benefit of “very good” socioeconomic conditions.  Lower middle classes have good or average socio-economic index, whereas township dwellers and informal settlers are very needy and needy citizens COCT 2014.

3 Going off the grid means to install an additional domestic water system completely independent from the municipal water grid.

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