Urban anti-fragility: the water sector beyond resilience

© LioNgeR / iStock.com

As water professionals face climate chaos, infrastructure solutions must go beyond resilience, argues Kala Vairavamoorthy. They must become anti-fragile, with systems growing cleaner and stronger with each climate shock. And developing countries are positioned to lead the way towards a new low carbon economy.

From Geneva, the UN’s recent IPCC report provides unequivocal evidence that climate change is manmade, widespread, and rapidly escalating.

Whether as drought or deluge, water is the medium through which we experience climate impacts. In response, IWA members act on two fronts: mitigation and adaptation. Globally, water professionals take measures to reduce greenhouse gas emissions. Locally, we prepare for extreme weather and escalating shocks.

Climate shocks touch us all. But they fall hardest on society’s most exposed families, those who lack access to the basic water and sanitation services that provide a foundation for safe, healthy and secure life. By targeting these vulnerable populations, water adaptation will serve to benefit us all.

IWA emphasises urban water adaptation in two overlapping contexts: cities and utilities. The city remains the visible nexus of innovation, knowledge and sharing. But within cities, less visible but equally essential, IWA has launched the Climate Smart Utilities Vision, seeking to catalyse the cultural shift we need to face the climate and water emergency, united as one.

Mitigation is a must

It isn’t enough to mop up when a pipe is leaking. The pipe must be fixed. Similarly, the water sector can’t just adapt; it must mitigate greenhouse gas emissions. While not initially a primary target, energy-intensive utilities and wastewater treatment plants have, on a closer look, revealed themselves as sources of carbon dioxide, as well as methane and nitrous oxide.

We mitigate best by accelerating and scaling up efforts to reuse, reduce, and recycle. The water sector’s use of biogas is hardly new, for example, but there is increasing recognition of the potential to push the boundaries of what is possible and achieve an energy transformation. Consider the Danish success story, where sewage is now a primary renewable energy source, even supplying district heating systems. Consider also how the UK’s Anglian Water produces biofuel for use in vehicles, helping displace fossil fuel.

Beyond reuse of waste resources, digital technologies can unlock efficiencies that dramatically ramp down energy use. Renewables like solar can replace traditional dirty sources of energy. Fixing leakage and loss not only reduce demand for water – such efforts pay dividends in terms of our sector’s carbon footprint.

Indeed, there is so much tremendous mitigation potential in our water and waste systems that the “net energy positive utility” is already here.

In light of ongoing efforts to achieve climate progress, the UK water sector can trumpet its commitment to achieve a net zero emissions goal by 2030. This milestone connects with progress and enthusiasm in the wider world and exemplifies how the UN-supported Race to Zero can mobilise the global community.

Advancing adaptation

Yet adaptation can’t wait for mitigation. Both efforts can, and must, work together – in some cases as two sides of the same coin. As noted, efficient usage and lower demand does more than slash emissions, it also creates a buffer against the new normal of longer, drier droughts.

Even as we push boundaries as we, for example, extract energy from wastewater, we also ramp up water reuse as one way to boost supplies. This edition of The Source, explores how Australia is framing its water resources thinking in terms of Rainfall Independent Supplies. In the US, California is the latest state to embrace direct potable reuse. China, which already leads in reuse, will expand its efforts in scope, scale and advanced design much further.

It’s not just industrialised nations. Reuse is also spreading, from Senegal to the multi-sector approach in India of Chennai Metro Water, and from Colombia, where they’ve launched a new national policy on water with the circular economy at its heart, to the World Bank’s Water in the Circular Economy and Resilience (WICER) initiative.

Anticipating extremes

Such pioneering efforts to mitigate and adapt will soon become the norm. They won’t seem outliers, but standard and mainstream – the obvious way utilities will work.

This is especially the case in developed countries looking to bolt on to established infrastructures. But when setting out to adapt, let’s take stock of what exactly we are trying to achieve. These tools seem like natural and necessary measures, but in pursuing them, we are beginning to embed an entirely new paradigm, and must consider whether this paradigm is indeed fit for purpose.

Our infrastructure was never built to be infallible (even if we tend to forget this reality). Rather, it has been built with return periods of extremes in mind – a once in x year chance that a given event (flood, drought, hurricane, wildfire etc.) will occur. And we have treated these extremes with certainty. As climate change breaks down the expected range of extremes – the loss of stationarity – our infrastructure reveals just how fallible it may be.

Chronic and acute concerns

That revelation comes through two kinds of stressors: chronic and acute.

The water sector is used to responding to chronic stresses, which have the potential to create ‘slow-moving disasters’ over long periods.

The second is more troubling. As our sector suffers periodic acute stresses – as dam failures, flooding from storm surges, crippling droughts – which take time, often years, from which to recover. If the frequency of the extremes behind these stresses overtakes urban recovery efforts, we may confront what Paul Brown describes as “the slow death of the city”.

The resilience response

Our physical assets, be it dams, dikes, levees, or treatment plants, have traditionally been built to resist extremes – to reject disturbance. Yet we know that major infrastructure such as the Thames Barrier in the UK and the Dutch Delta Works ultimately face the prospect of failure against some future unprecedented event, and so will need to be rebuilt.

We have moved beyond such ‘all-or-nothing’ thinking. Faced with urgent pressure to adapt, we now seek the go-to response of resilience. Resilience appreciates how, where and why water infrastructure has the potential to be overwhelmed, crippled, weak, and found wanting.

In anticipating failure, resilience looks beyond impacts toward the recovery phase, bouncing back, getting things running again. It applies a human trait to inorganic systems. Again, Paul Brown sees resilience as “based on the humility and wisdom to provide for survival and rapid recovery, instead of bold promises of protection that may be unattainable”. Essentially, building water resilience means creating, supporting, and expanding the capacity of communities to respond to the impacts of extreme events.

Resilience is essential. But is it enough? Or does the concept of mere resilience limit our reach, and hold back an opportunity to do better?

Adding anti-fragility

Resilience allows systems to return to their previous state. But what if those systems built in the ability to absorb shocks and risk and then recover faster, better, stronger – back to a higher threshold?

For that outcome, we need not just resilience, but resilience+, entering the realm of anti-fragility.

Nassim Taleb coined this term in his book Antifragile – Things that gain from disorder: “Wind extinguishes a candle and energizes fire,” he writes. “Likewise with randomness, uncertainty, chaos: you want to use them, not hide from them. You want to be the fire and wish for the wind.”

Anti-fragility is used in areas such as IT and organisational theory. But it is too new and rare in the context of urban water infrastructure. So let us try. If our cities and utilities try merely to avoid extreme climate shocks, we will continue to become fragile. Instead, if we plan for and allow exposure to stress these systems, we will bounce back stronger with each impact.

Rob Roggema’s paper, “Design for Disruption: Creating Anti-Fragile Urban Delta Landscapes”, has applied the concept to river delta projects for coastal protection. His examples include the Double Defence, the Floodable Eemsdelta, and the Sydney Barrier Reef.

The idea of Double Defence is to create a second row of barrier islands in the northern part of the Netherlands. Doing so creates a region between the two, where sedimentation will create more sandbanks and in time enhance the wetland ecosystem of the Wadden Sea. The new coastal defences set up a natural and dynamic process that improves and grows stronger as storm surges continue to escalate over time.

Roggema noted the link of these examples to anti-fragility, describing their characteristics as spanning an abundance of network connections, an ability to adapt, and also that often the interventions were counterintuitive.

There are other examples of anti-fragile planning for flood resilience. In The Source in 2018, Bruce Beck highlighted the work of systems ecologist H-K Liao in the city of Kent, Washington State, USA. “For cities, how about allowing modest floods in – even welcoming them,” Beck writes, “as opportunities for learning, for forearming the city and its water infrastructure, hence coping all the better with the ‘big one’, when it comes, as it will.”

The ecological dimension of Liao’s example is that recreated flood refugia benefit salmon fry. The important human dimension is that citizens get reacquainted with flood risk and the associated governance needs. More broadly, this shows the need for our knowledge of flood adaptation to advance.

Thus, we find that anti-fragility can be incorporated into urban spatial planning, for healthy deltas and cities facing disruptive storms. Or that allowing modest urban flooding helps cities prepare for severe events.

“Low- and middle-income countries can take the lead and show how water can be the cornerstone of our low carbon economy”

Creating resilient, anti-fragile systems

Both resilience and the resilience+ of anti-fragility still anticipate failure. But rather than catastrophic, crushing, overwhelming failures that come from relying solely and utterly on large infrastructure, we want a different, softer, kind of failure. If (and when) a system fails, we want it to fail gracefully.

Given this desire, decentralised systems can serve us better. Like cell phones, start-ups, restaurants, or the internet, failure of one part does not bring down the whole. Decentralised, distributed, modular systems contain any failures, without propagating them. They also allow for incremental growth and improvements as new elements are added – drawing in lessons from past disruptions.

Centralised systems have their place. Many evolved into highly complex, hierarchical and internally connected systems that prove highly efficient. But that very interconnectedness built around a single source or a single point of treatment means any shocks reach further and travel faster through the system as a whole, elevating risk of collapse.

As set out above, reuse helps water resources adapt to climate shocks. So too does desalination. But as noted by Filip Babovic, Vladan Babovic and Ana Mijic in their paper ‘Antifragility and the development of urban water infrastructure’, adopting a diverse portfolio of sources, at different scales, bring us closer to the resilience+ of anti-fragile water systems.

Chennai has developed just such a portfolio approach, with each component contributing to the redundancy that we would wish to see in an anti-fragile system. The use of multi-barrier approaches and the concepts embodied in Water Safety Plans make similar contributions to a resilience+ future.

Similarly, decentralised approaches to urban drainage – think green roofs, bioswales, buffers, rainwater harvesting, permeable pavement – ensures risks are diffuse because the parts are less connected. Runoff does not speed up in flow and compound in force. It slows, spreads, and sinks through countless levels and layers of protection. •

A change of mindset

In the developed world, with infrastructure already in place, a resilience+ outlook requires a new mindset about how to tinker with, add to, and refine waterworks with familiar tools and options. But in the developing world, where water infrastructure is lacking, it means grasping a new and home-grown paradigm. By baking in new approaches, technologies, and systems, low- and middle-income countries can take the lead and show how water can be the cornerstone of our low carbon economy.

The climate change emergency is not coming. It’s already arrived. As recent years remind us, water professionals cannot use the same methods to build ourselves out of extreme events, hoping simply to prevent droughts or banish floods.

Yet nor should we seek to. Rather, we can prepare for these in new ways and with approaches so the shocks make cities stronger. We can, again quoting Paul Brown, “encourage the acceleration of our evolution as cities and embrace the challenge of needing systems that are multi-purpose, durable, flexible, regenerative, and possibly ‘anti-fragile’”.

Dr Kala Vairavamoorthy is CEO of the International Water Association