Urban growth of the past 30 years has largely resulted in crowded slums and sprawling settlements in the urban fringe. Cities are consuming land, increasingly, to accommodate new developments. In some regions, urban land has grown much faster than the urban population, resulting in less dense and, in general, more inefficient land use patterns. In addition, this is often happening in the absence of a viable spatial structure.
Pressure on land also results in increased land prices and consequent occupation of marginal land by slums or leapfrogging development with urban sprawl. As a result, living conditions deteriorate and low density makes it costly and inefficient to provide services and infrastructure. The overall efficiency of settlements is reduced and city development hindered.
Mechanisms for ensuring an orderly expansion and densification of existing and planned neighbourhoods are needed in order to provide the city with a spatial structure that can support socioeconomic and environmental sustainability. In order to create this structure, expansions and densification plans are needed to enable cities to accommodate the expected growth in the next decades in a sustainable way.
City expansions and densification plans shall provide for a rational urban structure to minimize transport and service delivery costs, optimize the use of land, and support the protection and organization of urban open spaces. The densification initiatives include suburban densification, area redevelopment, layout of new areas with higher densities, brownfield development, building conversions and transit-oriented developments.
UN-Habitat's support on planned city extensions
City expansion and densification plans have been worked out in a limited way in developing countries. Experiences from Brazil, Ecuador and Egypt offer important lessons in this area. UN-Habitat has supported Egypt in defining new city limits and to structure expansion for 50 small towns. The agency has experience in assisting in the integration of internally displaced persons in Somalia and South Sudan, using these techniques.
The aim of UN-Habitat's support on planned city extensions is to increase residential and economic densities with compact communities while guiding new redevelopment to areas better suited for urbanization. This would contribute to more efficient and sustainable development. This type of intervention would also free more land for development, thus reducing speculation and increasing accessibility for the poor, as well as local revenue. The transformation of land use from rural to urban uses creates wealth and value, it produces assets and income. Tapping into such wealth is a key challenge for local governments in any developing city. By avoiding leapfrogging practices, urban expansions fight against speculative behaviour, minimize the city’s ecological footprint and reduce pressure of development on environmentally sensitive areas.
Services related to UN-Habitat's work include adaptation of tools for extension and densification planning at national and local levels; documentation of planning experiences, capacity-building for planners, planning tools of city managers and leaders; development of extension and densification plans; support of implementation through partnership building; and development of financial solutions to implement these plans.
City expansions and densification plans can be realized in large areas of vacant or underutilized land in central areas or on the fringes of the city. These plans need to provide sufficient land supply to minimize the fragmentation of the built-up area, particularly farther out of the urban periphery. In addition, city expansions and densification plans are to be developed in a progressive manner, selecting some areas which could be further developed in the coming years as demand grows and financial conditions are available. It is important to go “back to basics” and prioritize the resolution of core issues, providing a foundation for more complex interventions in the future.
Benefits for all - results of planned city expansions
The results that should be achieved through the development of city expansions and densification plans are:
- the creation of spatial structures in order to support urban development and attract investments;
- availability of large areas of land for development, thus reducing land prices and speculation;
- increase in urban densities, accommodating population growth more efficiently; and
- minimization of the city’s ecological footprint with more compact cities.
Additional benefits include:
- increased density that promotes economic agglomeration advantages, including lower costs of providing infrastructure and services;
- strengthened social interactions and reduced mobility demand; and
- mixed use of land that increases social heterogeneity and generates economic densities.