One of the report's lead authors, World Bank expert, Abhas K. Jha, said: "we need to worry about people and assets in harm's way for the foreseeable future."
The report highlights the staggering growth in economic losses over the last two decades even though flood deaths have declined in many parts of the world. By 2030 the majority of urban dwellers will live in cities of less than one million people "where urban infrastructure and institutions are least able to cope."
"Cities and Flooding: A Guide to Integrated Urban Flood Risk Management for the 21st Century, " published by the World Bank and the Global Facility for Disaster Risk and Recovery, was launched by Jha, Lead Urban Specialist for the East Asia and Pacific Region with the World Bank.
Jha said urbanization is a tremendous force for good but if not managed well it puts people in harm's way.
"Policymakers overestimate the value of concrete. Continuous communication is critical as we suffer from 'half-life memory' when it comes to disasters," said Jha as underscored that although disasters normally stay in living memory for 25 years, they can also be easily forgotten. He cited the case of Brisbane which was badly flooded in 1974 and again in 2011 when major Government buildings were found to have installed expensive generators in their basements.
Jha also called for communication with threatened populations to emulate the example of "last mile connectivity" in Bangladesh where community alerts can depend on a volunteer with a megaphone on a bicycle.
In contrast, even though the first warnings for Cyclone Nargis were issued 10 days before it made landfall in Myanmar, 100,000 lives were lost because "something was missing in the chain of communication" to vulnerable remote coastal communities.
Jha also warned that while climate change may contribute to weather extremes, many coastal cities were more exposed to flooding because of subsidence due to poor ground water management rather than from rising sea-level.
It is impossible to completely eliminate flood risk even in countries where disaster risk management is well-funded and understood, noted Jha. And although flooding cannot be avoided totally, "we need to design systems that fail gracefully" and to focus on early warning systems, reducing social vulnerability and resettlement of endangered populations, he said.
Helena Molin-Valdés who leads UNISDR's World Disaster Risk Reduction Campaign Making Cities Resilient -- My city is getting ready, speaking at the launch event, said: "This guide's 12 key principles for integrated urban flood risk management are a very good complement to the Ten Essentials of the Making Cities Resilient Campaign when it comes to managing risk at local authority level.
"There is no doubt that floods are the single most widespread and increasing disaster risk to cities worldwide. As populations grow, drains are clogged and exposure widens," she said.
According to the publishers, "This Guide provides forward-looking operational guidance on how to manage the risk of floods in a quickly transforming urban environment and changeable climate. The Guide serves as a primer for decision and policy makers, technical specialists, central, regional and local government officials, as well as concerned stakeholders in the community sector, civil society, non-governmental organizations, and the private sector."
- Download the report from PreventionWeb
- Website: Cities and Flooding: A Guide to Integrated Urban Flood Risk Management for the 21st Century