State of the Environment Report 2007
Settlement patterns refer to the form, density and distribution of human settlements, and how these change over time. Settlement patterns influence the environmental impacts of settlements, how populations use resources and produce wastes, and affect social and economic prosperity. Ideally, higher density human settlements and a more compact urban pattern are better for reducing resource inputs (such as land, infrastructure materials, transport, water and energy needs) and for reducing waste outputs (such as air pollutants and greenhouse gases). However, these aspects are often balanced against social, economic and other environmental costs.
Over the past decade, WA has exhibited patterns of increasing urbanisation, particularly a shift towards coastal population growth and rural population decline in some areas. Perth, the capital city, has exhibited unprecedented strong urban growth over the past decade, particularly along the coast. Historically, State Government policy has encouraged peripheral suburban growth, most notably along the coastal corridors, creating a high dependence on private motor vehicle use, particularly for journeys to work. In other parts of the State, settlement patterns reflect the economic and social development of different regions, including holiday centres along the coast, remote mining towns in the north and east, and small towns scattered throughout the agricultural regions (Western Australian Planning Commission, 2005a). Many rural settlements in WA are currently experiencing population decline, largely as a result of increasing economies of scale in primary production, but also because of social and environmental issues (such as persistent drought and land salinisation).
The historical and current patterns of settlement in WA have had a major influence on both the distribution and nature of environmental impacts. Perth's pattern of growth has placed enormous pressure on the land resource, with increasing land use conflicts and contributed to substantial loss of biodiversity on the Swan Coastal Plain. Continued growth will further increase pressure on already stressed native vegetation, wetlands, estuaries, beaches and neighbouring marine ecosystems. The impacts of unchecked urban growth are increasingly of concern in view of the continued approval and development of new urban areas with low residential densities. Low density urban development carries a high environmental cost associated with requirements for land and expanded infrastructure (e.g. roads, sewerage) and services (e.g. water supply, electricity) in order to function. Similar pressures are now of concern in other parts of the South West that have also experienced rapid population growth.
Manage urban growth to limit urban spread by:
The urban area of Perth, and more recently the Peel region, has expanded progressively over the past 80 years (Figure HS1.1). Perth has doubled in area since the 1970s to around 63 000 ha in 2002. The rate of urban growth in the Peel region over this period has been similarly high. The developed part of the metropolitan area is spread throughout the designated Metropolitan Region Scheme in four linear corridors: North West, Eastern, South East and South West as outlined in the 1970s Corridor Plan for Perth (Metropolitan Region Planning Authority, 1970). A fifth corridor (North East) was added in 1990 with adoption of Metroplan (Department of Planning and Urban Development, 1990). This pattern of settlement is the result of a complex interplay between various policies, strategies, programs and scheme provisions established and implemented over several decades. The undeveloped areas of land within the urban periphery are progressively developed or used over time for urban or urban-related purposes.
Rapid urban expansion has also been occurring in the South West coastal centres of Bunbury, Busselton and Margaret River. Information on the extent of urban areas in the South West is not available.
![Figure HS1.1: Urban land growth in the Perth and Peel regions, 1925–2004. [Data source: Department for Planning and Infrastructure; Analysis: Department for Planning and Infrastructure; Presentation: EPA.]](/site/files/images/Figure-HS1.1_Large.jpg)
Approximately 22.5% of the Metropolitan Region Scheme is designated for urban purposes such as residential and associated land uses including education, industry, administration, and transport corridors. Approximately half of this urban zoned land had already been developed in 2004 (Figure HS1.2). Nearly 42% of the Metropolitan Region Scheme is designated and used for non-urban purposes such as State forest, regional recreation, public open space and water-related (land-based) purposes. Most of the balance (35%) is zoned for rural purposes.
![Figure HS1.2: Actual used versus designated urban development areas of the Perth and Peel regions, 2004. [Data source: Department for Planning and Infrastructure; Presentation: EPA.]](/site/files/images/Figure-HS1.2_Large.jpg)
There has been a general trend of increasing annual approvals of new residential dwellings in WA since 1995-96 (Figure HS1.3). Residential dwellings are buildings intended for long-term residential use. Approximately 18 200 new residential dwellings were approved in Perth during 2005-06, representing 71% of total new dwelling approvals in WA in that period. The significant increase in construction activity in 1999-00, and decline in approvals in 2000-01, can be attributed to introduction of the new taxation system in 2000. Work was brought forward prior to introduction of the goods and services tax, and this was followed by a downturn after its implementation (Australian Bureau of Statistics, 2003d).
The number of 'other new residential' dwellings (i.e. flats, units, townhouses and apartments) approved in Perth has increased but remained roughly proportional to the number of new houses approved. Single houses remain the dominant dwelling type in Perth, representing around 83% of dwelling approvals in 2005-06. Analysis of approved houses between 1998-99 and 2000-01 showed 14% of approved houses were grouped dwellings (where two or more houses are constructed on a single parcel of land), reflecting the urban infill occurring in many established Perth suburbs (Australian Bureau of Statistics, 2001d).
The number of dwellings in the Peel and Bunbury regions has been growing steadily since the early 1990s. Between 1990 and 2004, the number of dwellings in Mandurah doubled to over 25 000 and increased by approximately 40% in Bunbury (Montgomery & Saunders, 2005).
![Figure HS1.3: New residential dwelling approvals in Perth and Western Australia, 1995–96 to 2005–06. [Data source: Australian Bureau of Statistics (2006c). Note: Other residential buildings contain more than one dwelling unit and include flats, units, apartments and townhouses.]](/site/files/images/Figure-HS1.3_Large.jpg)
'Residential density' refers to the number of dwelling units within a defined site, suburb or region. The residential density of settlements can significantly influence environmental impacts. Low residential density results in high per capita land consumption and requires additional infrastructure such as roads, water supply, recreational space and retail facilities. Perth has low residential density by international standards.
Measuring residential density is complex. There is little agreement on the definition of terms used and several different measures exist. Two measures of residential density in the Perth metropolitan region are considered here: net residential density and gross residential density.
'Net residential density' is the number of dwellings on the residential-zoned portion of a defined area, and is expressed as the number of dwellings of 'per net hectare'. The average net residential density in the Perth metropolitan region is approximately 14.9 dwellings per hectare for fully developed lots, and approximately 8.4 dwellings per hectare if vacant residential lots are included (Montgomery & Saunders, 2005).
'Gross residential density' is the number of dwellings within a defined area, including residential and non-residential zones, the latter including roads, open space, schools and other local and regional uses. It is expressed as the number of dwellings 'per gross hectare'. It is used in addition to net residential density because it takes into account all land required for urban development, instead of just residential areas. A preoccupation with net residential density often obscures the fact that other land used for urban and urban-related purposes tends not to be subject to the same scrutiny of resource-use efficiencies. The gross average residential density in the Perth metropolitan region is less than one dwelling per hectare. The highest gross regional average residential density, six dwellings per gross hectare, is achieved in more established inner parts of Perth (Montgomery & Saunders, 2005).
Dwelling density in WA is largely determined and restricted by the Residential Design Codes of Western Australia, which sets maximum density limits at the site level (Western Australian Planning Commission, 2003). There has been a trend towards increased densities in the metropolitan region since the 1990s. This is reflected in changes observed in the number of new dwellings developed in each density code over this period, with a significant reduction in low density lots (R0.5 to R12.5) and an increase in medium density lots (R17.5 to R30), (Figure HS1.4). The proportion of high density (R40 to R160) lots has decreased over this period, representing a decline in construction of large apartment style buildings.
![Figure HS1.4: New dwelling development by density code, Perth metropolitan region, 1970s–2002. [Data source: Department for Planning and Infrastructure. Note: There are 10 dwelling units per hectare on an R10 lot and 160 dwelling units on an R160 lot.]](/site/files/images/Figure-HS1.4_Large.jpg)
The predominant social preference for large blocks has historically driven the low density character of housing in Perth. The average area per dwelling is approximately 13-60% larger than the statutory minimum lot size of the residential codes in all density categories (Montgomery & Saunders, 2005). Anecdotal evidence indicates that developers in Perth are responding to perceived buyer demand for lower densities. Analysis of all lots within the Perth metropolitan region (Western Australian Planning Commission, 2003) has shown that more than one-third of all developed lots are zoned at the density standard of 20 units per net hectare (R20), but a high proportion of these lots are actually subdivided at a much lower net site density, equivalent to 12.5 units per net hectare (R12.5), (Figure HS1.5). This represents loss of a considerable proportion of the dwelling development potential. Had this land been subdivided in close conformity with the coding, an additional 184 300 residential lots could have been accommodated on the same area of land.
![Figure HS1.5: Coded versus actual lot development density in the Perth metropolitan region, 2002. [Data source: Department for Planning and Infrastructure. Note: There are two dwelling units per hectare on an R2 lot and 80 dwelling units on an R80 lot.]](/site/files/images/Figure-HS1.5_Large.jpg)
The State's population is concentrated in the Perth metropolitan area, which in 2005 accounted for 74% of the total WA population (Australian Bureau of Statistics, 2006f). Over the past 30 years, Perth's population has doubled to an estimated 1.5 million, and is currently growing at a rate of over 1.6% per annum (Australian Bureau of Statistics, 2006e).
Western Australia's population is dynamic with significant changes in distribution over the past decade or so (Figure HS1.6). The South West has experienced sustained growth, particularly in coastal population centres, reflecting movement of people from Perth and regional inland areas to coastal South West settlements. Other regional centres, such as Karratha, Broome, Albany and Esperance, have also experienced significant growth. Some of the reasons that may be driving this shift include leaving the congestion of Perth, wanting a more pleasant environment or climate, finding more affordable housing, looking for work and retiring from work (Australian Bureau of Statistics, 2004b).
Most of the Wheatbelt experienced a slight decline in population over the past decade, while significant loss was recorded in the Mid West and more remote inland communities. Of the top ten local government areas in Australia that experienced the fastest population decreases over the past five years, nine were in WA (Australian Bureau of Statistics, 2006b).
![Figure HS1.6: Population change in Western Australia, 1996–2006. [Data source: Australian Bureau of Statistics (2003a & 2005d); Presentation: EPA.]](/site/files/images/Figure-HS1.6_Large.jpg)
Western Australia's population is projected to grow by another 41% (approximately 800 000) by 2031. Most of this growth will occur in the Perth, Peel and South West regions. Population in the Peel region alone is projected to double and in Perth the population is expected to reach over 2 million by 2031 (Western Australian Planning Commission, 2005b). Population in the Kimberley region is also projected to nearly double over this period. Migration away from the agricultural zone and to coastal towns of the South West, are projected to continue (Western Australian Planning Commission, 2005b).
The rate of household formation is another factor contributing to urban growth, having a considerable influence on the rapid growth in Perth housing stock. Household formation has been occurring at a faster rate than population growth. Between 1991 and 2001, average rate of population growth in Perth was 1.6%, while over the same period average rate of growth in the number of households in Perth was 2.5%. Housing stock increased by 130% in Perth between 1971 and 1996 (Newton et al., 2001).
A significant factor influencing household formation is the trend in household size, which has been declining since the 1960s (Figure HS1.7). In 1961, around 30% of WA households consisted of one or two people. By 1991 this figure had increased to just over 50%, and by 1996 was over 55% (Western Australian Planning Commission, 2002). Household size is declining for a number of reasons including ageing of the population, increased divorce rates (resulting in families splitting into smaller units), increased life expectancy and economic prosperity of older persons, declining fertility rate, and the increased tendency of widows and widowers to remain as individual householders.
![Figure HS1.7: Estimated resident households and household size in Perth, 1996–2001. [Data source: Australian Bureau of Statistics (2004a & 2005b).]](/site/files/images/Figure-HS1.7_Large.jpg)
Network City: The State Government, in consultation with the community, has prepared Network City: Community Planning Strategy for Perth and Peel (Western Australian Planning Commission, 2004). This outlines actions to improve the efficiency of urban land use and encourage a more compact and integrated urban form, including a policy objective of limiting development on the urban fringe to a total of 40% of new residential building lots.
Review of strategic planning and processes: The Department for Planning and Infrastructure is undertaking a review of strategic planning and processes to guide future growth and urban development in the metropolitan area toward more sustainable outcomes. This process includes an investigation of the characteristics of current zoning, use and development of urban land, and proposed revision of the Statement of Planning Policy No. 4.2: Metropolitan Centres Policy Statement of the Perth Metropolitan Region (Western Australian Planning Commission, 2000), aimed at encouraging concentrated development at designated strategic, regional and district centres which can be served more efficiently by public transport. The Western Australian Planning Commission has released the Statement of Planning Policy No. 3: Urban Growth and Settlement (2006) which aims to facilitate sustainable and efficient patterns of urban growth and settlement by guiding regional and local planning strategies and planning schemes.
Liveable Neighbourhoods: This policy provides an alternative approach for town and neighbourhood design to conventional development control policies. The policy aims to achieve more compact, well connected and resource efficient communities. The Western Australian Planning Commission has formally adopted Liveable Neighbourhoods as its preferred policy for controlling all subdivision and structure plan approvals from mid 2007.
If current patterns and rates of urban growth in Perth and parts of the South West continue, there will be serious consequences for the State's biodiversity. Pressures will increase on already stressed ecosystems, resulting in the ongoing loss or degradation of remaining native vegetation, threatened ecological communities and coastal environments on the Swan Coastal Plain. Under current development trends, households are becoming increasingly isolated, more car-dependent, and have fewer people living in each dwelling. This may lead to increased resource consumption (e.g. electricity, water, land, infrastructure materials), exacerbate motor vehicle dependence and increase the challenges of managing wastes.
7.6 Implement Statement of Planning Policy 3: Urban Growth and Settlement.
7.7 Promote sustainable regional growth in areas suitable for population growth.
7.8 Implement the State Buffer Policy to avoid land use conflicts in WA's settlements.
7.9 Develop mechanisms to assess and record the cumulative impacts of clearing in urban areas.
