Backyards and spare blocks are gradually disappearing in our major cities and this uncontrolled piecemeal development is having a massive impact on urban water systems.
Infill development is necessary to house Australia’s growing urban population without sprawl, but according to research from the CRC for Water Sensitive Cities (CRCWSC), very little thought has been given to its effect on urban water systems.
What happens, according to director of NMBW Architecture Studio and Monash University Professor Nigel Bertram, is that when permeable vegetation is replaced with impenetrable manmade materials such as homes and pavements, it creates runoff and puts pressure on stormwater systems.
That’s not the only downside of conventional infill development – Professor Bertram told The Fifth Estate it also exacerbates the urban heat island effect and the liveability of a suburb.
Instead of a garden, people living in poorly designed infill developments are just “looking into a fence”. A lack of canopy can also create privacy issues with neighbours able to peer straight into people’s homes.
Professor Bertram is part of a CRCWCS research project trying to determine if it’s possible to design infill development that addresses this big set of challenges.
It won’t be easy, but the research findings so far suggest water sensitive infill development is doable.
“We’re finding that as you densify the middle suburbs, it’s possible to not make them worse, but also better.”
The team, which consists of architects and planners as well as urban heat and hydrology experts, has managed to come up with a range of housing typologies that allow for densification without giving up on green space.
At its core is clawing back more space on each block for greenery by shifting design priorities and using space more economically.
At the moment, outdoor spaces such as strips down the sides of homes are considered “leftover and useless”. Instead, these areas should be considered for greening potential – especially if the soil is deep enough to plant a tree.
It’s also about using space better. For example, car spots and garages take up a lot of space and are typically considered for just one use. If there’s somewhere on the street to park a car then perhaps that spot reserved for a garage can become garden instead.
Other options are communal gardens and other shared amenities that are more economical in their use of space. More flexible home designs, where rooms are multi-functional, can also help.
The researchers also looked at the issue on a precinct scale. The trick is forging a better relationship between the private and public realm.
For example, a treetop canopy on the public street can improve the amenity of homes. Conversely, a tree canopy in private courtyards at scale can provide coolness and privacy.
Professor Bertram says although a more coordinated approach would be “mutually beneficial,” it’s not common practice. “It’s very much site by site.”
Cities should aim for a mix of dwelling types so that retirees don’t end up stuck in giant homes because that’s the only option.
Driving change will require plausible options
A lot of these ideas are really just best practice design in Australia and around the world but the problem is many in the industry aren’t thinking this way.
“The challenge is making these ideas plausible in Australia.”
That’s why the research has used real life case studies all around Australia to prove that it’s possible on real sites.
There needs to be an attitudinal shift across all built environment disciplines, including planning. At the moment, urban planning is “broad brush” and focused on zoning and height limits.
“It should be ‘can you make a good liveable house at that density and at that scale?’”
Planning deep root zones for trees should also be a priority.
Resistance is to be expected
Professor Bertram says it will not be easy for the industry to change when it’s “always more efficient to do what’s always been done”.
“As you can imagine, there’s a lot of resistance to change in this space.”
The goal of developers is often to get the most floor space on each site, which regularly starts with wiping the slate clean of foliage and trees and making the site dead flat.
But thanks to the multi-beneficial nature of the researchers’ suggested typologies, Bertram says it could be an opportunity to build a more favourable perceptions of infill development.
“There’s lots of community resistance to infill development and that’s because it’s usually done poorly.
“But if it’s done well, it can be a net benefit – better quality of life for inhabitants, reduce heat stress of urban locations and have huge benefits for the environment.”