There was a time when ‘sustainable development’ was the latest buzzword, but soon the term became overused, and now its meaning has shifted towards climate change and the need for resilient thinking. That brings me to resilience – a trending word that easily rolls off the tongue. But what exactly is it? And how can it be applied to the design and construction industry?
Rethinking resilience
Resilience can be defined as ‘the ability to provide the required capability in the face of adversity.’ Indeed, considering our local situation where load shedding and teetering services are the norm of the day, we are in an excellent position to reflect on our designs to ask: How well are the buildings and landscapes we designed functioning during power outages? Lighting, air conditioning, pumps for boreholes and basements, and irrigation systems all come to a standstill. What about our standby generators? Will they continue to function when there is another 25% to 30% increase in fuel cost? These points make a strong case for designing buildings with natural light and passive cooling, as well as unirrigated landscapes that are sustained by the careful infiltration of rain. But how will buildings and landscapes be affected by disruptions in water supply, another drought, or flooding event?
Wondering ‘what if?’
While these questions may seem pessimistic, it is worth noting that engineers are trained to think and design in this way. The profession is proactive rather than reactive. It considers the threats (e.g., a system failure) before there is an event. Asking ‘what if?’ is an inherent part of the design process. What if a bridge collapses or a skyscraper falls down? While this can happen during an earthquake or extreme event, it is remarkable how seldom and unlikely it is to occur during normal conditions. But engineers are always prepared for the possibility of abnormal loads or stressors, while staying conservative in their designs, allowing for large margins. They deliberately build in redundancy, so that when one system or machine part fails, there are others that can perform the same function.
Whether you are an architect, landscape architect, or contractor, we can all learn from this proactive approach, and make resilient thinking a routine part of our practice. Instead of ignoring the threat of climate change, the wild day-to-day temperature fluctuations, the potential risk of floods, wildfires, or the impact of social upheaval; we need to contemplate these possibilities upfront and plan for mitigating factors. I have found the principles listed by the Resilient Design Institute to be invaluable and would like to encourage you to read more at www.resilientdesign.org/the-resilient-design-principles.
Building with backup plans: a case study in Mossel Bay
Since I started applying the ‘what if?’ question to our landscape design work, I came to both a surprising and obvious realisation: the simpler the design, the better. By this, I do not mean ‘simple’ in a one-dimensional way; it is more like going back to basics by including flexibility, diversity, and natural processes in your design approach.
To provide a real-life example, we are currently working on the landscape of a low-cost housing development in Mossel Bay. Considering the budget and potential for vandalism, our first response was that it should have an unirrigated landscape. However, the annual rainfall in the region is low (455 mmPY) and the remaining fragments of fynbos and dune thicket vegetation on site indicate that the coastal conditions are tough – really tough. We knew that regular watering during the establishment phase would make a big difference. When seen in this light, irrigation is regarded as an asset that expands the possibility of planting. But it is also a liability: there are the concerns of vandalism or theft, and the extensive management and maintenance such a system requires, not to mention the impact of load shedding.
The Environmental Management Plan (EMP) for this development requires the planting of at least 500 trees and 850 linear metres of screen planting. The decision was made to invest in a borehole, but the landscape’s water supply remained a major concern to me. What if the borehole pump fails? How can we build in redundancy?
Fortunately, JSA Architects designed two 5000-litre rainwater tanks within the housing units that can be used for watering trees and plants in the courtyards. But what if the tap is left open, or all the rainwater is used and the tanks are empty? One can hardly expect residents to use their tank water for watering a berm. What is our Plan B and Plan C? First off, Plan B is the local municipality: they have committed themselves for two years to water 500 trees by hand, using treated wastewater. Next up, Plan C is the new borehole installation for the project. Great! But what if the pump fails, trips, or gets stolen? That brings me to our final backup plan, Plan D, which is connecting to the water mains.
However, after the borehole was finally drilled and the yield test was good, we were hit by a major curveball: the water tested saline (EC = 450). It was like diluted seawater – not even suitable for growing date palms! At that point, the landscape contract and installation of hard landscaping had commenced, but we went back to the drawing board, facing a true test of resilience. In fact, how designers have to adapt and change their designs during a project due to unforeseen events and budget cuts, is an unacknowledged aspect of resilience that deserves just as much emphasis.
Thankfully, our resilient design-thinking paid dividends. We did not have any borehole water, but at least we still had Plan A, B, and D. In terms of water supply, the trees and courtyards were provided for with rain and wastewater, using a manual system that had nothing to do with borehole water and irrigation. What a relief! This left the berm and screen planting – an extensive area of planting where we had planned thousands of fynbos and thicket plants to create a haven of biodiversity. Obviously, we could not use municipal mains water to irrigate it all, so the berm planting was reduced to the bare minimum: a double row of planting with drip lines. Aside from drip irrigation being the most efficient method of watering, its minimal evaporative water loss (the drip lines will be partially buried) makes it very easy to calculate water usage. This enabled us to determine a water budget and get the municipality on board to allocate 41 kilolitres per week for two years. (In the greater scheme of things, this is not a lot of water, especially when one considers the amenity and biodiversity benefits). Of course, thinking about ‘what if? does not stop there. Municipal water is not guaranteed, and the region could be faced with another drought.
We have adapted the planting strategy to include more legumes and pioneer species, carpets of sour fig, and the sowing of green manure seed as a soil conditioner for future planting. In the future, local seed can be collected from the site and used for increasing biodiversity.
Working in a low-cost housing environment has been an excellent exercise in designing for resilience. We would dream up the possibilities of vibrant urban spaces, beautiful green parks, and climber-covered pergolas and then wonder: What if the raised planters are turned into braai pits? What if the pergolas are turned into shacks? What if the planting on the berm fails, or is trampled, or gets smashed by soccer balls, or goats come in? What would be left over?
From this perspective, the less planting and irrigation, the better. Instead, we should focus on allowing weeds and indigenous plants from the soil-stored seedbank to sprout and create a self-sustaining, unirrigated landscape to develop over time. Additionally, we can establish mini-swales and depressions so that water and organic matter can be collected, making conditions favourable for germination. And we can provide perches for birds to sit on, so that seed can be brought in a natural way, for free.
In retrospect, the saline borehole water has been a blessing in disguise. It forced us to simplify the design and reduce the planting, which in turn reduces the maintenance and watering. The Berm Park has a strong design: even if the berm is covered with weeds, the long slide down the embankment, curved seat walls, natural rocks and boulders in the grass (serving as seats, stepping stones, and giant bollards to keep cars out), jungle gym, and tyre embankment will all provide amenity value. One of our primary underlying goals is to activate the public spaces with social activity so that they are safe and used by the community. We envision it to be a place where people can sit and watch while kids are playing and having a ball.
“Real resilience begins by understanding what you have.”
Materiality matters
Without a doubt the choice of material plays a considerable role in designing resilient buildings that will last and age gracefully through the centuries. We can learn from the past by looking at structures and landscapes that have withstood the test of time. While travelling through Denmark, it struck me how timeless and durable the houses are: they are made of stone or brick, and their rooves are covered with mossy thatch or clay tiles with a steep pitch for snow. There were very few ‘designer’ landscapes or fancy gardens using plants from all over the world. The Danes seem content to work with whatever is growing locally in the area – whether that be dune grass and beach roses by the coast, or simply mowing the prevailing meadow mix. By using the local materials at hand (e.g., timber and stone), they display a sense of design and style that is both sophisticated and understated.
In the built environment and landscape industry, I think we are quick to turn to concrete and composite materials for a ‘designer’ look. While concrete may last long, and even acquire a patina, it has a massive carbon footprint and does not lend itself to redesign and reuse by the next user. Why not use a natural material that is timeless, like stone? It can be rough, carefully hewn by hand, machine cut, polished, and everything in between. While broken or used concrete pavers become landfill, stone cobbles and flagstones are invariably recycled and reused on a site. We all know concrete products do not include the environmental damage and impacts of their production. So, suggesting that natural stone is ‘too expensive’ is not a good enough excuse. If the client cannot afford it, then just reduce the extent of its use.
Biomimicry and beyond
Finally, we can draw inspiration from nature for many wonderful examples of resilience. Think of how fynbos and grasslands bounce back after a fire, the plants literally growing from the ashes. Biomimicry is essentially innovation inspired by nature; when people use ideas from the natural world to solve modern problems. The website www.asknature.org features an extensive library of biological strategies, grouped into collections for solving different challenges; whether it is solutions for mitigating and adapting to climate change, producing clean energy, or the making of lightweight structures or high-performance materials. After millions of years of evolution, the solutions are right there – we just need to know how to look for them.
Marijke wanted a picture that demonstrates biomimicry. Please use the coral reef pic somewhere on the spread (see folder) with the caption: Biomimicry helps us to learn from marine ecosystems to develop concrete alternatives
Marijke Honig
Landscape Designer, Environmentalist, and Author of Indigenous Plant Palettes
@marijke_honig
