Uncontrolled rapid urban expansion poses a number of resilience challenges, including increased levels of informality, environmental degradation, decreased social equity, and increased disaster risk exposure. Recognizing the complex relationship between the growth of cities and their resilience, 100 Resilient Cities partnered with New York University’s Marron Institute of Urban Management to study the trajectory and consequences of rapid urban expansion in 20 of our fastest-growing cities. The findings of this study informed the creation of the new 100RC Handbook: Planning for Resilient Urban Growth, which explains how cities experiencing high levels of urban growth and informality can build resilience through the implementation of cost-effective urban expansion plans.
Central to this handbook is the idea that cities should take a proactive approach to addressing urban growth, rather than attempting to limit or prevent growth. This starts with acknowledging that efforts to prevent growth are often unsuccessful, and that action must be taken to accommodate new residents within the city. Planning to accommodate urban expansion includes providing sufficient opportunities for densification, while allowing development to take place in order to maintain housing affordability without overburdening existing infrastructure. The appropriate strategies should be based on global evidence and also on the specific conditions in each city. The principle of proactively addressing urban growth closely aligns with 100RC’s forward-looking and risk-aware approach to resilience.
The four-step municipal action program outlined in the handbook is a simple, inexpensive methodology for use when planning for urban growth, particularly for cities with resilience challenges due to increasing levels of informality. Viewed through the City Resilience Framework (CRF) – a baseline for 100RC city work developed by the global design firm Arup – the approach holds great potential for delivering real benefits to all citizens, including inclusive and affordable growth, disaster risk management, and accessible public transit networks.
A starting point in planning for urban expansion is understanding the magnitude of urban growth. Accurate, realistic projections of expansion over 20-30 years allow cities to determine what their future land needs will be, and how to plan to accommodate them. These growth models also serve as reminders to local and regional authorities that cities are dynamic ecosystems with changing environments that should be considered in planning processes. Making growth projections available to government officials can thus elevate urban expansion as a priority requiring immediate action.
Once these estimates are in place and growth trends are understood, the next step is to work with a broad range of stakeholders to create and implement an expansion plan that will guide the development of the city. To achieve this, given that these plans may need to extend beyond a city’s administrative limits, cities must establish close working relationships with regional and national authorities and other key stakeholders in the public, private, and civic sectors.
Securing the land and rights-of-way for an arterial road grid throughout the expansion area before development occurs is critical when preparing for urban expansion. Strong networks of arterial roads – roads able to carry public transport and critical infrastructure – make cities more connected, productive, and prosperous. Proactively planning and securing land for connective infrastructure in advance of development allows cities to save on costs while staying in control of the urban development process.
Finally, cities must identify and protect a selection of public open spaces, particularly environmentally-sensitive and high-risk areas such as marshlands and land adjacent to water. This ensures that citizens have access to public open spaces, and also reduces exposure to disaster risk by preventing development of hazardous areas.
The handbook provides a series of goals and questions that should be taken into account before the implementation of an urban expansion plan or during the development of a city resilience strategy. Cities and urban resilience practitioners should consider the shocks and stresses that might be exacerbated by urban growth, as well as the ways proactive expansion planning could mitigate the effects of those shocks and stresses in the future. By using an urban growth lens in planning, rapidly growing cities can transform the stress of uncontrolled rapid urbanization from a liability into an advantage and leverage it to build resilience and transform into safer, more equitable, connected, and sustainable places.