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The number of people in cities is growing: By 2050, 80 per cent of the population in 89 countries will live in cities.
As this urban migration is increasing, so is the frequency of extreme weather such as the massive floods in Paris and Louisiana. Although their situation and topography differed, the main reason Paris fared relatively well is that they prepared and acted in accordance to certain principles that have been designed to improve resilience against extreme weather and natural disasters.
These principles enable smart cities of the future to save lives, prevent damage and reduce costs. The principles in question are the Principles of Water-Wise Cities set down by The International Water Association (IWA), a sixty-year old global knowledge hub for water professionals.
The 17 principles of water-wise cities encourage collaboration, underpinned by a shared vision, so that local governments, urban professionals, and individuals can actively prepare and find solutions to urban water management challenges.
Three of the principles directly help cities of the future improve their resilience: Design urban space to reduce flood risk, secure water resources while planning for drought mitigation, and plan for extreme events. The following paragraphs give examples of cities following the principles and describe how they are implemented.
Urban space designed to reduce flood risk can save lives and prevent damage, such as the destruction Copenhagen experienced in 2011 from their infamous cloudburst storm. In just three hours, 15cm of rain fell and the resultant flooding caused USD 863 million in damages. To avoid a repeat occurrence, the Copenhagen City Council signed off on a USD 1.4 billion plan.
The plan is to develop urban drainage solutions that are integrated with urban infrastructure design. This creates safe flooding spaces and enables the city to act like a ‘sponge’, limiting surges and releasing rainwater as a resource. It is estimated that integrating the drainage solution with urban design will provide a socio-economic surplus of USD 722 million over the next 100 years.
Urban design for flood safety can also bring increased water security in the face of drought, as shown by the Green Square Flood-Control and Water-Reuse Infrastructure being built in Sydney. This project provides both flood safety and a precious reserve of rain and storm water capture for use in parks and new buildings.
The Green Square project is a response to water scarcity becoming increasingly common. Cities need to be water-wise and understand exactly where in their basin’s water is coming from and how these will fare in the face of water scarcity and drought.
Due to its water scarcity, Sydney cannot allow individual users to use their water resources as they desire, but instead must match their demand to the resources they actually have. This invariably leads to reuse initiatives and a reduction in overall consumption. Modular solutions and multiple sources of water further increase resilience if one source fails. Securing water resources in the face of drought is helpful for all cities, yet other extreme events need extraordinary preparation.
Paris made extraordinary preparations when faced with the biggest flood in 100 years. By planning for the extreme flood in 2016, Paris reduced the damages by an estimated 96 per cent: that’s USD 1.1 billion as opposed to USD 33.5 billion.
In March 2016, Paris urban services underwent the Sequana Exercise, which simulated the impacts of the very high, 1910 Seine levels. All vulnerable departments had to review measures to be taken if such a flood was to re-occur.
From this exercise, Paris understood how they were vulnerable and took preventative measures, including building dikes and emergency walls in key areas as soon as the water began to rise. The public transport system RER C was also suspended, as Paris predicts that this is at risk of collapsing under flood conditions.
Many cities are realising that their current approach to extreme weather mitigation is not working. Some of the 17 principles of water-wise cities can be used by cities to prepare for extreme weather and natural disasters in order to save lives and reduce damages. This includes designing urban space to reduce flood risk, securing water resources, and planning for extreme events.
Paris, Sydney and Copenhagen have already mitigated damage by embracing these principles. To ensure that these principles are readily accessible for all smart cities, The International Water Association will be officially launching them at the World Water Congress and Exhibition (WWCE) currently in progress in Brisbane, Australia. The cities of Amsterdam, Gothenburg, Kaohsiung, Kunshan, Lyon, Sydney, Xi’an and Brisbane will be endorsing them for their efficacy at the WWCE.
Corinne Trommsdorff has a Master’s in agriculture science and environmental engineering from the Institut National Agronomique Paris-Grignon, AgroParisTech, and has over 15 years of experience working as a consultant, with a focus in later years on energy efficiency and optimisation in the water sector. As manager of the Cities of the Future Programme at IWA, Corinne is leading the development of a water-energy-carbon framework which will guide utilities to improve energy optimisation, and balance their water, energy and GHG footprints; she is also developing a framework for cities to transition to an integrated urban water cycle with cross-sectoral synergies to improve resilience, resource recovery and liveability.