This is how we repair the damaged water supply infrastructure

In many ways, without this kind of water engineering, it is difficult to imagine our world with a population of nearly 8 billion and US$85 trillion in goods and services each year. Cairo, Phoenix and other large desert cities will never develop to their current scale. California’s sunny Central Valley will not become such a rich production area of ​​vegetables, fruits and nuts.

However, when it comes to water, the past is no longer a good guide for the future. Global warming is fundamentally changing the water cycle, and most parts of the world are not prepared for the consequences.

One of the most shocking alarm bells came in 2018, when the city of Cape Town in South Africa was almost forced to shut down drinking water taps for 4 million residents. Three consecutive years of drought have dried up the reservoir. City officials began to publicly announce “zero day”-jujube water will no longer flow to household taps.

Although it may be tempting, the solution is not to further succumb to our wishes by building larger, taller and longer versions of water engineering infrastructure.

Protective measures helped Cape Town push the zeroth day farther-then, fortunately, the rain returned. But no city is willing to rely on luck to escape disaster. Scientists later determined that climate change increased the likelihood of extreme drought in Cape Town by five to six times.

Droughts, floods and other climate-related disasters are costly. In 2017, the three major hurricanes in the United States were the main cause of a record loss of US$306 billion, which was more than six times the annual average since 1980. Although 2017 seems to be an outlier, climate scientists predict that annual disaster losses of this scale will reach the end of the century.

Although it may be tempting, the solution is not to further succumb to our wishes by building larger, taller and longer versions of water engineering infrastructure. It makes more use of natural processes, rather than fighting against them, and repairing the water cycle, rather than continuing to destroy it. Together with water saving measures, these methods can create a more flexible water system. They can also help solve our interconnected water, climate, and biodiversity crises in a cost-effective manner at the same time.

For example, as floods worsen, we can consider how to strategically reconnect rivers with their natural floodplains, rather than raising the height of dams-which usually aggravates downstream flooding. In this way, we can reduce flooding, capture more carbon, replenish groundwater, and create important habitats for fish, birds and wildlife.

The Netherlands is a country known for its advanced water conservancy projects. Due to the adoption of new flood prevention methods, it provides room for expansion of the river during flood events, thus avoiding major losses caused by the historic flood in July 2021. The Maas River (called the Meuse River there) flowing from Belgium broke the 1993 record of high flow in July last year, but caused less damage than the earlier floods. One reason is a recently completed project that transfers floodwaters to 1,300 acres of wetland that stores water and lowers parts of the raging Maas River by more than a foot. Wetlands also sequester carbon and double as nature reserves, providing valuable climate and wildlife welfare and recreational opportunities. Through its “River House” program, the Netherlands is implementing these nature-based flood control projects in 30 locations across the country.