With the number of people around the world affected by flooding rivers, storm surges, and sea level rise set to double by 2030, aggressive investment in flood protection infrastructure could prove to be very cost-effective in the long term, the World Resources Institute (WRI) concludes in a recent blog post.
Flooding has already produced more than US$1 trillion in global losses since 1980, and “the situation is poised to worsen,” writes WRI. The organization’s new Aqueduct digital flood mapping tool predicts that “the number of people affected by riverine floods will rise from 65 million in 2010 to 132 million in 2030, and the number impacted by coastal flooding will increase from seven million to 15 million.”
The economic inundation from urban property damage by river flooding alone “will increase threefold—from $157 billion to U535 billion annually,” while property damage from coastal storm surges and sea level rise “will increase tenfold, from $17 to $177 billion per year.
India, Bangladesh, and Indonesia face the most severe treat, with flood risk accelerated by “heavier rains and storms fuelled by climate change, socioeconomic factors such as population growth and increased development near coasts and rivers, and land subsidence driven by overdrawing groundwater.” WRI reports that, by 2030, “these three countries will account for 44% of the world’s population annually affected by riverine floods, and 58% of population affected by coastal floods.”
Also in the path of rising waters is beleaguered Puerto Rico. Still reeling from a series of hurricanes, the island faces the prospect of being “unable to cope with an expected doubling of the numbers of people annually afflicted by riverine flooding,” and has been left with coastal protection systems projected to be “effectively obsolete” by 2030.
“Even extremely water-stressed nations like Saudi Arabia will suffer,” writes WRI. That country’s boom in urban development, both on flood plains and along its coasts, has left some 630,000 people—and $2.7 billion in urban assets—at risk from rising waters.
Also increasing the threat for an additional two million people is the subsidence of the land upon which coastal cities rest, “largely caused by the overexploitation of groundwater.” The United States will be at greatest risk, with WRI projecting “an additional $16 billion in flood damages to urban property annually by 2030, with $4 billion caused by subsidence.” The effects will be greatest along the country’s west coast, “where groundwater pumping is common to supplement scarce surface water supplies.”
With its Aqueduct platform making it possible to “assess the costs and benefits of adapting to riverine flood risk with flood protection infrastructure,” WRI is urging policy-makers to recognize that, “in many cases, flood protection measures offer a strong return on investment.”
In Bangladesh, for example, “every $1 spent on dike infrastructure…may result in $123 in avoided damages to urban property, when moving from the existing three-year flood protection system to a 10-year flood protection system by 2050,” the institute says. Such investment “would reduce the likelihood of floods from 33% to 10%.”
The development of such flood protection systems would also create jobs, during their construction and through their long-term maintenance. “As governments look to rebuild their economies in the wake of COVID-19, investments in flood protection could be an important component of stimulus packages,” notes WRI.
And going beyond traditional “grey” flood protection infrastructure like levees and dikes to also develop green infrastructure like mangrove forests and reefs systems would have myriad additional benefits, the institute adds. Deployed together, the two systems could create a “resilient, high-performing solution” to rising waters and job creation.