After a 1953 North Sea storm surge killed nearly 2,000 people in the Netherlands, the country’s government built massive new protective seawalls along the coast. Today, faced with sinking land, rising sea levels, and the prospect of far worse floods, the nation is developing sophisticated computer models of climate, precipitation, hydrology, sea level, and economics to figure out how best to defend itself.
An initiative dubbed “Sustainable Deltas 2015” was launched last month at a conference in Rotterdam, the Dutch port city that includes neighborhoods 20 feet below sea level. It aims to share the tools developed in the Netherlands and elsewhere with the rest of the world. Initially it will offer technologies for assessing an area’s vulnerability over time.
The land area of the Netherlands includes a vast river delta formed by the Rhine and two other rivers. Its strategies, guided by sophisticated computer models, include building some inland water barriers as a second line of defense; making plans to allow some areas such as low-lying farms to flood in an emergency; constructing buildings that can float or at least withstand inundation; and creating new escape routes in case the worst happens (see “Saving Holland”).
Dutch researchers aren’t the only ones working to share the knowledge they’ve gained about flood control. For example, researchers at the University of Colorado at Boulder are using satellite data and local measurements to build a tool that can tell governments about expected patterns of land sinking in delta areas. The DELTAs project initially aims to deliver tools for assessing vulnerability over time for people in the Ganges-Brahmaputra-Meghna delta (which drains rivers that flow through China, India, Bangladesh, Bhutan, and Nepal), the Mekong River delta in Vietnam, and the Amazon River delta.
“It is about time that we take a more comprehensive global approach to delta sustainability, and this requires action,” said Efi Foufoula-Georgiou, a professor in the Department of Civil Engineering and former director of the National Center for Earth-Surface Dynamics at the University of Minnesota, in an interview after the conference.
Deltas cover about 1 percent of the surface of the earth, but they are home to more than half a billion people and generally include major cities, harbors, farms, and forests. Irina Overeem, research scientist for the Community Surface Dynamics Modeling System at the University of Colorado, says the proportion of world deltas vulnerable to flooding is expected to increase by 50 percent this century. The fastest change is that land is sinking. But seas are also rising, and rivers are disgorging more water during intense rainstorms.