Designing buildings to cope with extreme climate events: Part 1
The planet is becoming evermore hostile to human life – how can building design help us to adapt? Today: high winds, high waters.
Cities must leverage their influence to ensure water, the most precious of all resources, is used responsibly and shared equitably.
World Built Environment Forum
8 April 2020
The constant stream of people into urban areas has created a concentrated and focused demand for water. This has brought about the development of new, risky, and oftentimes socially inequitable water supply channels. Cities are thirsty places, and naturally become thirstier as their populations grow, but they also wield an immense and growing political influence with which rural areas can rarely compete. Accordingly, water reallocation schemes often prioritise the needs of the city over those of the countryside.
Moreover, the question of urbanisation and water security is not simply one of increased demand. The natural capacity of the land to accommodate rainfall is also significantly lessened in heavily built upon areas. Whereas ordinarily, we might expect to see 10% of rainwaters run off into adjacent rivers in rural regions, in heavily urbanised areas that figure can be as high as 55%. This causes the dual problem of parched aquifers (subterranean layers of permeable rock that retain vital groundwater) and greatly increased vulnerability to flooding events.
The risk is intensified by locational factors. Proximity to water is a common feature of many of the most successful and long-established human settlements. As far back as the third millennium BCE, the earth’s waters provided the means by which otherwise disparate peoples could exchange materials and ideas. One upshot of this has been the gradual creep of cities onto flood plains. Over the past two hundred years, the development of land and air transport has served to dampen the situational advantages of closeness to water. The attendant jeopardy, meanwhile, has remained undiluted.
Cities, then, face an unenviable triple bind; rarely can simple fixes be found for such complex problems.
Scientific consensus states that an uplift in global temperature of 1.5 degrees will cause a 1 meter rise in sea levels by the end of the century, threatening catastrophic floods in low lying regions, and at the same time usher in an age of frequent drought events in areas prone to hydro-shortages. Clearly, our ability to manage water in times of both inundation and scarcity will be key to global economic prosperity and wellbeing.
“One of the things that governments, particularly at the city-level, get wrong is to think about this as a problem that can be solved,” says Jessica Lamond, Professor in Real Estate and Climate Risk at the University of the West of England. “There is less strength of purpose in adapting the built environment; we're still focusing on hard engineered defences and not focusing so much on the smaller scale water management techniques that are needed.”
Large scale capital projects are attractive to policymakers for a variety of reasons: in places where flooding events are a recurring and devastating feature of life, they serve to clearly signpost the fact that action is being taken by public officials to protect homes and businesses. But such projects are expensive, take time to realise, and aren’t always effective.
From the numerous available examples, Dr Lamond points to Venice, where the acqua alta floods of 2019 were among the worst in the frequently deluged city’s modern history. A flood protection system that has been in the works for over 15 years remains unfinished. “According to the Mayor of Venice, the recent flooding would have been prevented by the defences,” says Lamond. “Engineers, on the other hand, argue that it is untried, and that it has been pursued in favour of other, tested methods.”
Venice is, of course, a unique example – particularly by European standards; the specific nature of the water security challenge changes from country to country and continent to continent. Mandakini Surie is an international development consultant, specialising in water governance. She notes: “From an infrastructure perspective, it's necessary to understand how the built environment coexists with the natural environment – to understand how they work together. In South Asia, there's a sense that you can just build exponentially and there's very little concern for the role of lakes and wetland, or mangroves and urban forests.” The depletion of such natural assets may be an ecological disaster, but the consequences are all too human. Water shortages in the global south inordinately affect the rural poor, as well as women.
Water shortages in the global south inordinately affect the rural poor, as well as women.
Surie also notes how well-intentioned agricultural policy in the region has had the unforeseen consequence of exacerbating the situation. “Since Indian independence, a big focus for successive governments has been achieving food security. That has actually resulted in very wasteful irrigation practices and crops being grown in areas to which they are not suited…often you see articles which say South Asia is running out of water. A lot of that is to do with structures that have been in place for decades, which have actually fostered a system which incentivises wasteful practices.”
The climate emergency has brought the scale of the problem into sharp focus. Alfred Lee, Past President (Hong Kong) of the Chartered Institution of Water and Environmental Management admits that vital ground has been surrendered over previous decades: “I don’t think that governments have actually placed water issues at the very highest level of priority in past decades. Perhaps only in the past 10 or 15 years did they start realising that they can no longer take water for granted.”
I don’t think that governments have actually placed water issues at the very highest level of priority in past decades. Perhaps only in the past 10 or 15 years did they start realising that they can no longer take water for granted.
Alfred Lee, Past-President (Hong Kong)
Chartered Institution of Water and Environmental Management
However belated the realisation may have been, it has yielded a series of innovations that could yet become common practice. Speaking specifically of Hong Kong, Lee says, “We have actually used a risk modelling system to predict forthcoming weather situations in order to anticipate how much rainfall we are going to have. In doing so, we are able to fully utilise our rainwater harvesting methods. And we should be able to adapt more, using up to date technology to install sensors and monitoring equipment to create an intelligent water network.”
On the theme of predictive mitigation, Lamond is cautiously optimistic: “There are ideas about how to deal with uncertainty in our future that need to be brought to bear here, because we don't want maladaptation: adapting for something that we expect to happen that then doesn’t happen. We must make sure that whatever we do is robust to uncertainty and that we’re not going to make things worse in the future by making bad investments…we're looking for solutions that are more flexible and incremental.”
Surie credits the government of Punjab for attempting to roll back a legacy of bad policy. The district is “experimenting with a very unique scheme, rewarding farmers for using less electricity to pump water, giving them cash incentives to make a kind of ‘save water, save money’ scheme. So the question becomes: ‘how do you take these small innovations to scale?’”
Ultimately, she believes a key weapon in the fight will be broader public awareness of water scarcity: “How do you move from a culture that sees water as an abundant and limitless resource, to one that recognises it as finite?"
In 2008, Goldman Sachs described water as “the petroleum for the next century.” The comparison has always seemed inexact: the transition from petroleum to alternatives is the preponderant social, ethical and scientific challenge of the recent past and near future; we can make no such transition away from water. Cities must develop better processes for managing the twin hydrological dangers of scarcity and inundation. There are no alternatives.