Researchers question dense approach to residential development

Sydney apartments 

High-density city living does not guarantee improved environmental outcomes, according to University of Western Sydney research on the sustainable behavior of households across different urban areas in Sydney.

As a sustainable way to manage Sydney's projected growth, state metropolitan planning strategies have previously promoted density increases, categorised by an increase in the number of dwellings per hectare.  

Yet new research shows this fixation with density is misplaced, and other variables such as belief in human-induced climate change and level of education play a key role, according to Dr Michael Grosvenor.

"Density calculations are commonly used in urban research as a way of representing differences in urban structure and form, yet they typically do little more than represent an area as either high density or low density," he says.

"They do not accurately represent the different mix of dwelling type that can exist in a neighbourhood, the different levels of available transport, and the different levels of access to local community services and facilities."

The research, summarised in the Geographical Research journal, takes an alternative typology approach to representing differences in urban structure and form across the Sydney metropolitan area. Rather than simply relying on density calculations to map variations in the way Sydney has developed, the authors divide the city into seven urban structure categories, each representing different accessibility and built or urban form characteristics. The research then examines markers such as water and electricity consumption and car ownership rates to test the differences that exist across Sydney.

The research found strong statistical associations between the urban structure categories and car ownership, and potential associations with water and energy consumption. To further interrogate why these statistical associations may exist, the researchers surveyed households in case study areas with different urban structure and form characteristics to better understand their attitudes to sustainability and household consumption, and to collect survey data to enable further statistical testing.

The case study analysis confirmed that there are indeed strong associations between urban structure and transport. However, the analysis also found levels of statistical associations previously measured between urban structure and form and water and electricity consumption are much weaker when interrogated further.

"Our case study results suggest other variables such as belief in human-induced climate change and level of education may manifest as geopolitical differences across the metropolitan area, which may better explain why there are large differences in electricity and water consumption across varying urban structures," says Dr Grosvenor, the lead author of the research.

"Such understandings would not be possible by using density calculations alone to represent urban structure and form difference."

Dr Grosvenor says it's clear the continued flawed application of density measures in urban research is resulting in the continuing crude urban consolidation policy response in Australia's largest cities, typically involving a saturation of multi-level apartment construction.

"In order to build the sustainable cities we need, planners need to move beyond the now disproven idea that density is the sole criteria needed to achieve improved environmental outcomes," he says.

Dr Grosvener is currently an Associate Director with urban and social research firm Urbis.

About the study

To better illustrate the relationship between where people live (urban structure) and what they live in (urban form) with environmental outcomes, the researchers developed and tested a typological approach to more accurately represent Sydney's urban structure and form, as compared to current density measures.

Under the model, Sydney was categorized into seven distinct areas:

Compact: Areas located within Sydney's inner urban LGAs – City of Sydney, Leichhardt, Waverley, Marrickville, and Randwick (north of Gardener's Road). These LGAs are generally highly accessible to public transport, employment, retail and essential services, with a mixture of housing choice, with a relatively high percentage of multi-level apartments, walk-up apartments, terraces and semi-detached dwellings, and a relatively low percentage of detached dwellings

Multinode: Areas beyond the compact category located within 800 m of railway stations located within designated high-order centres: Chatswood, Parramatta, Hornsby and Liverpool. Similarly accessible to public transport, employment, retail and essential services as the Compact category but dominated by multi-level apartments.

Subregional: Areas located within 800 m of railway stations (proxy for centroid) located within designated secondary centres: Bankstown, Ashfield, Burwood, Blacktown, Penrith, Sutherland, Dee Why, Kogarah and Hurstville. In the case of Dee Why, it is within 800 m of Pittwater Road and Dee Why Parade intersection which have access to the Pittwater Road transit corridor. Sub-regional centres have similar characteristics to the multi-node city, but on a smaller scale, with less employment opportunities and a mix of apartment types.

Corridor: Any areas outside the previous categories that are located within 800 m walking distance of a railway station or 400 m of a high-order bus corridor (such as Anzac Parade and Pittwater Road). Characterised by good accessibility to local shopping precincts with a mixture of housing choice (other than four-storey and above apartments).

Dispersed: Areas constituting Sydney's traditional suburban environment. Generally comprises a mixture of old and contemporary detached dwellings dominated by car access and local bus services.

Fringe: Designated areas beyond the traditional dispersed suburban environment. Primarily consists of contemporary build (including McMansions), with poor public transport and local service accessibility.


30 March 2015

Mark Smith, Senior Media Officer

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