This blog post is written by Joseph Hook, a PhD researcher in the Department of Civil and Structural Engineering at the University of Sheffield, and it discusses the potential problems associated with developing countries modelling their water management on a ‘western ideal’.
The lack of a well-developed infrastructure is a serious obstacle to prosperity in areas of the world such as the Asian subcontinent and sub-Saharan Africa. Nevertheless, attitudes towards the future prosperity of economies and individual wealth generation in these regions are too often considered through the lens of an assumed progression towards a western ideal. This is never more true, and possibly never more hypocritical than in the case of the water sector. Although consistent potable water supplies and improved sanitation shouldn’t be taken for granted, a water crisis based on the unsustainability of legacy systems in OECD countries is real. Why then, should these systems be considered as a template for the rest of the world to follow? This article will argue that lower-income countries should be developing their own models, and that these should not always involve centralised networks.
The future impacts of climate change are not fully known; but it is certain that the most severe effects will take place in lower-income countries, and will result in increased incidence of extreme weather events, loss of habitable land due to sea level rises and desertification, and increased local water scarcity (Figure 1).
Figure 1 Global change in average annual precipitation based on “business as usual scenario”. Image courtesy of NOAA Geophysical Fluid Dynamics Laboratory.
Of these consequences, more extreme weather and changes in land use will result in shorter lifespans for existing and forthcoming infrastructure, increasing the importance of resilience and flexibility when designing future systems. Otherwise investment will be wasted and development will need to begin from scratch. For example, if surface water flooding is managed at an individual property level then a natural disaster can only reduce capacity in areas it directly affects. And if wastewater is treated at a community level rather than a city-wide level then failures are localised and can be controlled more easily. Instances such as the flooding in Houston caused by tropical storm Harvey illustrate how fragile safe water access can be. Houston is a post-industrial city with stringent codes and facilities for water distribution, treatment and flood protection, laid low and with water access compromised for months by an extreme weather event. Figure 2 shows a typical layout for a medium sized modern city. The branching structure of the piped networks makes treatment highly efficient and reliable, as economies of scale and safeguards can be implemented in the system hubs (treatment works). However, this structure is more vulnerable to shocks: the entire network can be compromised by a single contaminant, or by central failures. Considering the recent deadly floods that have ravaged south Asia, at current estimates killing over 1200 people, building up highly centralised networks in such areas could be inefficient at best and calamitous at worst.
With increased water scarcity comes an increasing onus to use it efficiently. In tropical and equatorial regions where evaporation causes rivers, lakes and reservoirs to deplete faster it isn’t enough just to limit individual water usage: to begin with in countries where agriculture is still a major part of the economic output a minimum quantity of water is needed for crop irrigation. Cities in these climates therefore need to reuse the water they have to maintain a balance.
An example of this is Windhoek, the capital city of Namibia, which has been recycling sewage since 1968 for municipal irrigation, and since 2002 have treated sewage to drinking water quality for 25% of the city’s needs. Windhoek receives very little water annually from rainfall; including four months with no rain at all, in addition to being hundreds of kilometres from the nearest reliable water source. These challenges make good solutions to water provision in Namibia very different from the paradigms we are used to.
A contrasting case is the “One Million Cisterns Programme” in north-eastern Brazil. As a country Brazil has access to an abundance of surface water sources, but the region around the city of Juazeiro, in the state of Bahia is semi-arid due to its latitude, and the regional government doesn’t have the resources to provide piped water to its rural citizens. To meet this challenge in 1999 a collective of NGOs in the area committed to providing 1 million cisterns to provide 5 million families with drinking water through harvesting rainwater. At the time of the last survey 220,000 had been completed.
These examples differ in their demographic and climactic contexts, but they both involve a departure from the established norm of what a water system is traditionally expected to be. In the case of Windhoek, the municipal government solved an issue of extreme water scarcity by adopting radical blackwater treatment. In the case of Bahia, the non-governmental organisations stepped in to provide a resilient and practical alternative to piped infrastructure in a rural area. In both cases, the presence of pre-existing infrastructure would have made these interventions economically and politically impossible. This situation is seen in countries such as the UK, where innovation in the water sector is becoming increasingly necessary, but where it is of course completely unthinkable to write off existing assets and start again. The expense, and any perceived service decline make certain of this. In such situations legacy infrastructure becomes a burden rather than an asset.
Another reason why moving towards a more decentralised development model can be beneficial is that it allows incremental improvements to be put in place without requiring continued structural remodelling. For illustration, consider a sewer network in a small city of 100,000 residents, with a trunk sewer taking daily flows and surface runoff from rainfall to a single treatment plant before being released into a local river. The treatment works can fully treat a fixed multiple of the average flow, after which it discharges raw sewage directly into the river. This happens approximately once per year. The sewer itself is sized based on the population and expected rainfall such that it should only fail once every hundred years. Now consider the urban population doubling in half a generation, and more extreme rainfall events becoming the norm. The sewer may still be usable most days, but it’s likely to cause flooding every five years instead of every hundred, and the treatment works be overloaded fifty times per year instead of once. This is indeed the situation found in many lower-income countries where urbanisation is outpacing the development of infrastructure, particularly where informal settlements (sometimes called shanty towns) proliferate. Instead of facing the challenge of finding the sums of money required for installing and upgrading centralised infrastructure, local or neighbourhood based solutions to problems such as flooding, sanitation and water provision seem to represent a more sustainable model for development in many cases. This is especially true where growth is happening quickly and the future is uncertain.
It’s important to mention a couple of caveats to this argument. The first is that having decentralised infrastructure doesn’t and shouldn’t mean having decentralised planning. Water networks are vast, interconnected systems that produce complex behaviour, and should be analysed as a whole if their performance is to be maximised.
The second is that a decentralised approach allows individual users to be charged for the quality of service they are provided with. This may result in increased foreign investment, because returns on investment can be realised more easily when selling individual products to consumers than by investing in public infrastructure. For-profit foreign investment in lower-income countries has historically been the cause of much of the poverty we are still trying to alleviate. So although not bad per se, the implementation of this business model needs to be considered very carefully to prevent exploitation, and there is an argument that preventing exploitation in this manner is just impossible. In any case, it should be implemented only when local governance is strong enough to protect the rights of individuals, or the commodification of water resources may lead to still greater inequality.
Despite these objections, the future of water resources in lower-income countries can present an opportunity to design more flexible and resilient systems. The challenges associated with providing sustainable water resources in different geographical and cultural contexts are diverse, and assuming the existence of a universal solution is a mistake. In fact, there are examples throughout the world of non-traditional solutions being successful. It is important to see these as equally valid as centralised piped networks, and to consider that they may represent a more viable future strategy in an increasingly uncertain world.