Small infrastructures: Breaking down scales and categories
Small infrastructures have often been viewed as private and individual, but they can be more effective – and allow for a better overall urban ecology – when used collectively, explains Nigel Bertram.
Just as soft infrastructures need to be considered as necessary adjuncts to hard infrastructures, and equally vital to the success of both cities and organizations, small infrastructures are different in nature and complementary to larger ones. Of course, dividing and classifying by size is only one way of sorting things, and small infrastructures can be of both the hard and soft variety. I will discuss aspects of both in terms of their impact and usefulness in enabling the urban environment to function.
Infrastructures can also be categorized by the way they perform.
When thinking about stormwater, for example, there are “trunk” systems such as main drains, which are tree-like hierarchical systems of pipes that increase in diameter as more and more branches join into the flow. Such a system has very definite peak capacity limits that can only be raised by increasing the diameter of the pipes. On the other hand, “closed-loop” systems keep excess stormwater flow in the local area and allow it to be stored temporarily until the peak passes, gradually releasing the water into the soil rather than evacuating it from the site as quickly as possible. There are many benefits of this second type of system, if it is managed well, including passive irrigation of trees, which reduces the need for mechanical irrigation, and a reduction in the velocities of flood waters. Closed-loop systems can also act as buffer-systems that reduce stress on trunk infrastructure that was sized for a previous population and previous climate patterns, both of which are now being recalibrated as our cities infill and densify. To function reliably, cities need good trunk infrastructure, but there is growing awareness that a well considered combination of trunk and closed-loop systems can enable practical and costeffective solutions to contemporary problems of increased peak loads.
Small infrastructures can be understood in a similar way in their relation to larger urban systems. Take, for example, the open-space network of a city. Public parks, river corridors, ecological reserves and coastline reservations would constitute the large elements and are essential to overall city health (for both human and other species) and what is these days known as “livability.” Supporting this, however, is a network of smaller green and/or natural entities – from the carefully considered to the completely unplanned and accidental – that support the actual ecological performance and biodiversity of a city, let alone its use value for residents. To think (hypothetically) from the point of view of a bird, an insect or a drop of water might allow us to consider the ways in which small and large form a connected and holistic system or habitat, irrespective of ownership or maintenance regime.
Every land use and built development also produces open space, even if this is only an afterthought consisting of mostly fragmented leftovers such as unusable enforced minimum side setbacks. If these myriad small open spaces produced as byproducts of development were thought of collectively as an infrastructure, what could be the impacts for the way the city performs?
Deep soil or deep root zones are directly related to tree canopy cover and are becoming an increasingly valuable commodity in an era of shrinking or non-existent backyards. The largest tree canopies can be found along watercourses
or in major parks; however, medium-sized canopies are possible once unbuilt space reaches a certain size, and even pocket-size courtyards play a supporting role by housing smaller trees and shrubs. The critical factor is that as size decreases, frequency increases, so that by the time we get down to pot plants, the numbers become enormous. Experientially, the sense of the visible “green-ness” of a city is the sum total of all of these open-space sizes working in unison. New development and infill densification in Australian cities are usually measured in terms of heights, plot ratios or dwelling yields; however, in other places, unbuilt space has long been considered as a type of infrastructure that can support densification. Courtyards, for example, are an easily understood form of positive open space. A courtyard can be visualized and experienced as a “thing” rather than just a leftover remnant notbuilding. The courtyard I am looking out on now, for example, is approximately 10 by 10 metres in size, and supports 12 apartments looking onto it (one-third of a block of 36 designed by Harry Ernest and Associates in 1964 in the inner-Melbourne suburb of Fitzroy) at a height of three storeys. This space contains one very large tree, the canopy of which is far higher than the flanking buildings, a range of mediumsize trees that are deciduous and flower in the spring, and a lower storey of groundcover plantings. It is a semi-planned garden with many self-seeded plants, but the basic physical infrastructure has been consciously designed. The courtyard and its plantings provide shade, coolness, visual outlook, a habitat for insects and birds (and possums and cats) and, importantly, privacy between dwellings, allowing groundfloor living. All 12 dwellings are entered by walking through the courtyard from the street, and they all share the multifunctional amenity it provides, as does the street outside. When seen from an aerial view, it is clear that the canopies of large trees in this courtyard and its similar neighbours are significantly larger than the canopies in surrounding individual backyards. By coagulating all the open green space of 12 dwellings together, a shared infrastructural unit is created that forms an environmental mid-point between the atomized and frequent private open space, and large and infrequent public reserves.
The “soft” side of this infrastructural equation is equally important. In 2007, at the height of the millennium drought, the body corporate that manages the three courtyards on behalf of the 36 dwellings elected to invest in this shared garden infrastructure by installing centralized large rainwater tanks and connecting them to an irrigation system. Dying lawns and silver birch trees suffering after years of drought were replaced with more climate-tolerant and native species, resulting in a hybrid garden of local and exotic, deciduous and evergreen plants. Body corporates are often derided as annoying, time-consuming and costly; however, the benefits of scale in this case were clear. Each dwelling could achieve much more benefit by pooling their spending on garden infrastructure than they could on their own, and everyone could see the financial sense of investing in the courtyard gardens to support the ongoing financial and amenity value of all individual apartments. Body corporates of this scale are an example of small and soft (organizational) infrastructures that can achieve things that are impractical for either individual landowners or city councils to provide. Other examples of collective organization at this sub-civic scale are emerging in the form of Baugruppen-style intentional communities grouping together to build small apartment buildings. In some ways, this can be interpreted as a formalization of the informal social structures that naturally occurred in suburban cul-de-sacs in the 1950s and 60s, when small groups of neighbours held joint Christmas parties in the street, with Santa Claus arriving in the back of a ute.
A similar way of thinking about a continuous spectrum between small and large, which operates in ways both hard and soft and integrates both centralized (trunk) and decentralized (closed-loop) systems, can be and is being applied to transport, power generation, rubbish collection/recycling/composting and the provision of public services. Parking spaces, for example, are more usefully considered as collective urban infrastructure that supports a suite of urban functions and mobility rather than as a required room type attached to every dwelling. Parking infrastructure ranges from very large shared parking structures to small individual garages and carports, and can be collectively organized in smaller groups for mutual benefit and greater economy, just as is the case with courtyards and water tanks. There is a spectrum of needs, which can all be provided and priced: from secure undercover parking to open street spaces and from multi-level private underground garages to carshare networks. Seeing this collectively as a spatial (hard) infrastructure with a range of service and access (soft) options – similar to the way in which phone and internet services are purchased – would allow for a better overall urban ecology than the current one-size-fits-all approach to planning for and storing vehicles across the city. This thinking could likewise be applied to holiday houses and other high-cost/low-use items such as boats and swimming pools. There are already Airbnb-type services for people who want to experience sailing a boat but can’t own one, provided by people who own one but don’t use it enough.
Thinking about the spaces and services we use as flexible infrastructure for life, rather than as private “possessions,” can shift the way we think about planning, building and using the city. The city is something we all have an interest in maintaining – and the process of thinking of this infrastructure across scales and across categories can increase the quality and the economy of our everyday life.