Urban Approaches

	Domain 4- Performance Based Built Environment

Compact City
Creative City
High Density City

Sustainable Urban Approaches

The concern with sustainable development, or sustainability, has grown enormously in the last 15 years. Following the publication of the World Commission on Environment and Development’s (WCED) Our Common Future in 1987, which introduced the idea of sustainable development, there has been a focus around the world to pursue policies seen as sustainable. Defined by the WCED, sustainable development is: development designed “to ensure that it meets the needs of the present without compromising the ability of future generations to meet their own needs.” (WCED, 1987: 8).

Urban growth has brought several major concerns about the future of cities, notably what may be defined as their sustainability. A sustainable city must offer to its population a suitable urban environment, employment, food, housing and transportation without compromising the welfare of the future population of that city. Overall, the concept of sustainability can be defined according to three points:

	Intergenerational equity. The success of cities of the future will largely depend upon the legacy on current cities on resources and the environment. National capital assets passed on to the next generation must be at least equal value.
	Social equity. Implies a fair and equitable distribution of resources among the current generation. In terms of the urban environment, the city should provide a place of equal opportunity and not be an agent of segregation.
	Spatial responsibility. Involves that the city has a "footprint" is which considerably larger than the area it occupies. This includes supply of resource, but also wastes and their impacts must be considered in the total space a city occupies.

Cities do not contribute to environmental problems at the same level. A comparison between cities of developed countries and cities of developing countries reveals that the developed world consumes 70% of the world’s energy, 75% of minerals and 85% of wood. For example, the Sears Tower in Chicago consumes more energy than an American city of 150,000 or an Indian city of 1 million. Urban sustainability can be expressed at two spatial levels:

	Global. Long term stability of the earth’s environment.
	Local. Degradation of urban life due to congestion and pollution with socio-economic consequences.

Major cities are requiring a vast array of supporting infrastructures including energy, water, sewers and transport. A key in urban sustainability issues is linked with the provision and maintenance of a wide range of urban infrastructure. Every city has specific infrastructure and environmental problems. For instance, Third World cities have chronic deficiencies in the provision of the most basic infrastructure while their environmental conditions are deteriorating. There are huge costs linked to this. Among the most important urban infrastructures we can note:

	Public utilities. Including power, telecommunications, piped water supply, sewage, waste collection and disposal and piped gas.
	Public work. Including public transit, roads and transport terminals (ports, rail stations, airports).

Infrastructures can be publicly or privately owned. Public infrastructures have the advantage to be available to a larger share of the population at a low cost, but are expensive for the government to maintain. Private infrastructures are only servicing a limited share of the population, at the choice of the infrastructure company, but are financially profitable. As the income increase, some infrastructure problems are solved while some environmental problems are created. For instance, in increase in income is linked to better sanitation and water provision, but at the expense of waste and carbon dioxide emissions.

Another important part of urban sustainability is land use, which is how a city uses the territory. Once again huge differences are observed the urban land use over the world, and this has impact on energy consumption. However, transportation is one of the key factors linked with the issue of sustainability.

In their seminal work, Newman and Kenworthy (1999) identify a set of global indicator reflecting the sustainability of cities. Although a plethora of indicators can be used – 150 indicators were suggested by the World Bank – the authors suggest five major categories. They include energy and air quality, water, materials and waste, land grand spaces and biodiversity, transportation and livability, human amenities and health. The Environmental Protection Agency (1996) has also published an extensive report on the indicators of the environmental impacts of transportation. Strategic indicators that are recurrent in the literature involve VMT (vehicle-mile traveled), transit ridership and average commuting distance to the workplace (OECD, 1996), which are all spatial interactions variables. All studies agree that the automobile dependence is the key to an unsustainable urban environment.

Sustainable urban approaches are many however we have considered the following approaches for urban developments:

Creative City

Compact City

High Density Urban Development

Urban Approaches Issues

The contemporary debate is: Urban compaction or decentralisation? What kind of cities we should have? Should our cities spread out across the landscape or be limited to compact urban areas?

The following are list of issues for the above debate:

Cities

Decentralisation

High-density development

Mixed-use development

Development in rural areas

	Incremental expansion of housing in villages and small towns
	Sporadic housing development in the open countryside
	Small new settlements

Environmental capacity of a city

Modelling urban spaces

Expected and desired development at the urban scale

Land

Land requirements in order to sustain city population – the food and timber requirements as well as the vegetation necessary to absorb carbon dioxide emissions.

Reducing, reusing and recycling of land

Disused industrial areas, brown fields, contaminated land, problems of land acquisition

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Urban densities

The effect of urban densities on travel fuel consumption

The effect of urban densities on car parking

The effect of urban densities on urban size wild / rural size

The effect of urban densities on urban size infrastructure

The effect of urban densities on consumption rates

The effect of urban densities on quality of life

Other effects of urban intensification

The quality of urban environment, public spaces and green areas

The image and vitality of the city, cultural and community activities on streets etc.

Urban intensification social impact and effect on service provision

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Urban Size and Form

The effect of urban size on travel fuel consumption

The effect of urban size infrastructure

The effect of urban size on consumption rates

The location of different types of development relative to transport provision and vice versa

Forms of development that encourage walking, cycling and public transport

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Transport

Public transport versus private cars issues (environmental, health, social, accidents, market, political, media, educational, psychological etc.)

Residential densities, city size and travel behaviour

Travel behaviour and local accessibility to services and facilities, mode of travel, distance of travel etc.

Transport and urban forms: locations of residences, industries, public services, recreational areas, etc. and transport needs land use and planning

Transport and economic and institutional factors

Transport and socio-psychological factors

Expected and desired transport policy measures

Expected and desired use of conventional modes of transport

Expected and desired use of new modes and technologies of transport

Growth in car ownership as well as increasingly diffuse life patterns are considerable factors that have led to the inability to reduce travel demands of energy-rich modes of transport, and it seems that changes outside the realm of planning through education or culture change will be required to influence travel patterns at a sustained level. (Williams, 2000)

Market

Planning policies and property market

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Lifestyle and Society

Urban approach implications for individual lifestyles

Equity and community issues: The urban periphery, doughnuts of deprivation, social inclusion / exclusion, crime and security issues

Urban management and safety

Industry structure and the redistribution of population

Family size, lifestyle, culture etc. effect on dwelling / building size, type and design, housing needs, relocation and transaction costs, health, education infrastructure, facilities and services etc.