Water can be a dangerous force when it escapes the banks of a river. During a flood, water can carve new channels through solid earth, it can fill entire basements, it can float buildings right off their foundations, and it can displace millions of tons of sand and soil. Even a flash flood can cause serious property damage, make permanent changes to the landscape, and injure or kill humans and animals.
Even if a building is sturdy enough to survive intact, floodwaters can cause significant damage to its structure and interior. The water will soak through wood, leather, and other materials, causing them to weaken and inviting mold and bacteria to grow inside them. Floodwater isn’t clean, either: it contains dirt, debris, and pollutants that will stick around and need cleaning up after the waters recede.
Floods also hurt the economy by disrupting people’s lives. You can’t go to work if the current swept your car away, especially if the building you work at is currently underwater. If a flood were to hit, there would have to be a lot of cleanup and rebuilding before life went back to normal, and that’s assuming you have the flood insurance and government relief needed to pay for the repairs and tide you over until you can live in your home again.
When a flood hits a populated area, the waters pick up caustic chemicals, machine oils, and other substances that would have stayed safe and isolated if a flood hadn’t destroyed their containers. Floods can also damage important infrastructure like dams or power plants. In 2011, a tsunami, a kind of flood caused by an earthquake, caused the Fukushima nuclear disaster by damaging the nuclear plant’s emergency generators. Flooding can also destroy roads, displace fish and wildlife, and kill off animal populations. This can disrupt an ecosystem for decades.
Humans are much more than just economic units. When a flood hits, people can often be caught off-guard and end up trapped on the second story of their homes or on their rooftops. Rescue crews do what they can to find these people and bring them to safety, but people die in floods and flash floods every year. Even more people lose everything they own, including their jobs and their homes, forcing them to start from square one somewhere new. Floods can also spread diseases thanks to the dirty water and makeshift living conditions.
Still, floods aren’t all bad. A flood can deposit fertile soil on a river’s floodplains, encouraging plant growth. Ancient Egypt built its civilization around the Nile and the annual flood that would bring in good soil for planting year after year. However, to people today a flood is always bad news. Have a look at your home’s flood risk level, make sure you have an appropriate amount of insurance to cover your risk, and be sure to keep a flood emergency kit in your home in case the worst happens.