Using biomimicry to make our landscape sustainable

By on June 16, 2015

Since the Industrial Revolution, a general approach of human culture has been directed by the question: what can we extract from nature? Using this culture as an analogy with urban landscape design, the results can culminate in static designs that create a “domestic” look and cater to our visual needs while promoting unsustainable landscape maintenance practices: supplemental landscape irrigation, removal of organic matter such as raking leaves, frequent mowing and the over-use of chemical pesticides and fertilizers, etc. Maintaining high input, domesticated landscapes can be a daunting task just to keep up appearances. More importantly, these high input practices are exhausting our water supply and polluting our air and water.

npsot_news_spring_2015 (1)-11Let’s step back and look at nature. Does she have all these problems? No, because nature’s approach focuses on low energy input with maximum output, with form, function and systems that change and evolve over time. In short, natural ecosystems are the perfect model of sustainability. From the knowledge we collect by observing natural systems, we can produce ecologically sound landscape designs that can enhance the quality and quantity of soil, air, water and wildlife habitats, as well as reduce the effects of erosion and flooding. Using nature to guide designs like this is called biomimicry. Examples of biomimicry can be seen in suspension bridges, velcro, solar panels and even Nikola Tesla’s Wardenclyffe Tower.

I know there is a trend (mostly urban) to limit the use of vegetation and use rocks as mulch to produce a “clean look” – that to me is the equivalent of a lunar surface. That is the opposite of biomimicry. Those that favor such designs claim these landscapes are sustainable because they do not require supplemental irrigation, maintenance mulching and little to no plant care. Such an approach implies that a natural system does not need these services either.

It is my observation that natural systems give back because they are functional. For instance, a bioswale running alongside an urban street can be used to collect and purify rainwater, to reduce storm drainage volumes and to direct water to street trees or vertical trellises grown to mitigate a harsh microclimate and shade buildings.

When biomimicry is applied to landscape design, we find ourselves learning to really see the form and function of individual plants and plant combinations, soil microbes and water flows. We begin to think of inventive ways to produce green infrastructure such as green roofs, climate mitigation, and biofiltration. We find ourselves paying close attention to proper plant selections and placements, to protecting soils during construction. Ultimately, we end up producing landscape designs that function first as ecological systems, designs where human function and aesthetics come second.

Another question: if the use of biomimicry is about making ecology the priority, can we ego-based humans truly allow such designs to be?

I believe the answer is “yes”, because a sustainable design based on biomimicry can still fulfill the functional needs of humans and be visually satisfying. A design solution that uses biomimicry can be as highly stylized as you want. However, the aesthetics will always be dictated by the ecological function of your landscape.

Let’s look at a design solution I produced for an Austin gully washer. A development upslope from one of my clients had increased the impervious cover and cleared the slope of its Ashe junipers. The result was a massive gully washer formed downslope between my client’s home and their neighbor’s. During a flood, waters would rush down this gully that had eroded down to hardpan caliche and straight into another neighbor’s front door. A typical engineered solution would have been to pipe the water under the driveway to the downslope concrete drainage inlet. This would have diverted the problem, but it would not have solved it.

I wanted to design a sustainable system that would solve the problem and utilize biomimicry. So I looked at what I already knew. I know that the stair-stepped terrain present in Hill Country geology helps to slow overland water flows from our frequent flash floods. At the smaller scale, I know the dense canopies of trees such as Ashe junipers and Live Oaks break the impact of rain on slopes, and that a dense cover of grasses and matted leaf litter slows overland flows. Looking deeper, I also know a large percent of water captured by the tree canopies flows down the trunks, enters the soil and travels deep along larger tree roots.

I then applied my knowledge to solve the problem. Having only a narrow space between the two homes, I had to go more vertical than horizontal. I duplicated the function of tree roots with a downward sloping perforated pipe and I added terraces, deep organic soil and dense, native Muhly grass and sedges to slow overland flows and allow for deep infiltration; see diagram the illustration below.

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As luck would have it and after installation, Austin was hit with the 2013 October floods. I drove to the site a few days later and it was as if no flooding had occurred. Not one piece of mulch…not one rock…nothing…had been washed away. After several severe floods, the design still serves as a functional, sustainable system that appears to be growing stronger with time.

This is just one example of using biomimicry to guide a landscape design. I believe it is time to rethink our approach and societal views of what defines a good landscape design. We need to put an end to design that serve as a static stage for plants that serve no other purpose than “icing on the cake.” Instead, I see the potential as a landscape designer to develop designs, installation and maintenance processes that work with and evolve with nature.

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