In many ways, it’s hard to imagine our world of nearly 8 billion people and $85 trillion in annual goods and services without this water engineering. Cairo, Phoenix, and other large desert cities could never have grown to their present sizes. California’s sunny Central Valley would not have become such an abundant producer of vegetables, fruits, and nuts.
Yet when it comes to water, the past is no longer a good guide for the future. The heating of the planet is fundamentally altering the water cycle, and most of the world is unprepared for the consequences.
One of the most alarming wake-up calls came in 2018, when the city of Cape Town, South Africa, was nearly forced to shut off the drinking water taps of 4 million residents. Three consecutive years of drought had dried up its reservoirs. City officials began publicly announcing “Day Zero”—the date water would no longer flow to household faucets.
Tempting as it might be, the solution is not to further bend nature to our will by building bigger, higher, and longer versions of water-engineering infrastructure.
Conservation measures helped Cape Town push Day Zero further out—and then, luckily, the rains returned. But no city wants to rely on luck to bail it out of disaster. Scientists later determined that climate change had made Cape Town’s extreme drought five to six times more likely.
Droughts, floods, and other climate-related disasters come with big price tags. In 2017, three large hurricanes in the US were the primary cause of a record $306 billion in damages, more than six times the yearly average since 1980. While 2017 appears to be an outlier, climate scientists expect annual disaster costs of that magnitude to be common by the end of the century.
Tempting as it might be, the solution is not to further bend nature to our will by building bigger, higher, and longer versions of water-engineering infrastructure. It is to work more with natural processes, rather than against them, and to repair the water cycle, rather than continue to break it. Along with water-saving measures, such approaches can create more resilient water systems. They can also help solve our interconnected water, climate, and biodiversity crises simultaneously and cost-effectively.
As floods worsen, for example, instead of raising the height of levees—which often intensifies flooding downstream—we can consider ways to strategically reconnect rivers to their natural floodplains. In this way, we can mitigate floods, capture more carbon, recharge groundwater, and build critical habitat for fish, birds, and wildlife.
The Netherlands, a country renowned for its advanced water engineering, avoided major damage from the historic floods in July 2021 thanks to its new approach to flood control, which gives rivers room to spread out during flood events. The Maas River, which flows in from Belgium (where it is called the Meuse), broke its 1993 high-flow record last July, but it caused less damage than that earlier flood. One reason was a recently completed project that diverted floodwaters into a 1,300-acre wetland, which held the water and lowered parts of the raging Maas by more than a foot. The wetland also sequesters carbon and doubles as a nature preserve, offering valuable climate and wildlife benefits as well as recreation opportunities. Through its “Room for the River” program, the Dutch are implementing these nature-based flood control projects at 30 locations around the country.