Infrastructure protectionProtecting cities from floods cheaper than post-flood damage repairs

Planning carries a lower cost than reacting // Source: princeton.edu

Researches have concluded that it would be more cost effective for the economies of most coastal areas to employ flood prevention strategies rather than pay to clean up after flooding that occurs as a result of global warming. In a paper published in the Proceedings of the National Academy of Sciences, the researchers discuss likely flooding scenarios in the future as global warming cause ocean levels to rise, and the costs of building structures to prevent flood damage.

A PNAS release quotes the researchers to say that global warming is here to stay, and thus it is time to start making plans for dealing with the inevitable flooding which will occur as ocean levels rise as a result of warmer water and melting snow and ice. They note that approximately a billion people currently live in areas that are likely to be at risk — low-lying coastal areas. Since it is not likely that towns and cities will be moved farther inland, other measures need to be taken. The researchers say that flood prevention strategies are well established, for example, building levees, barrier islands, etc., so it is not difficult to draw up estimates for such schemes for individual areas. What is difficult is convincing cities and towns to spend billions of dollars on preventing floods which will not occur for many years.

The paper highlights the high financial toll which floods take, compared to the relatively small investment which would be required for flood prevention. They note, for example, that one developed coastal urban area could see damages from increased flooding reaching to nearly $20 trillion annually – which is more than the U.S. annual GDP of about $17 trillion. It would thus be cheaper to prevent the flooding in the first place.

The paper acknowledges that there would be significant differences in the costs of building flood control measures in different parts of the world, but say that even in areas where flood prevention measures would be the costliest, they will still be less expensive than remedial measures taken time and again in the wake of repeated flooding.

The paper notes, though, that having flood prevention system in place should not lead to a sense of security and complacency. Flood-control levees along the Mississippi River led people to believe that it would be safe to build in flood plains, but when the levees failed, the results were catastrophic.

— Read more in Jochen Hinkel et al., “Coastal flood damage and adaptation costs under 21st century sea-level rise,” Proceedings of the National Academy of Sciences (20 December 2013) (doi: 10.1073/pnas.1222469111)