Every country is looking for ways to avoid climate change-related disasters such as floods and fires, and the presence of a once unloved little rodent can provide many solutions: the beaver. And when the beaver doesn’t like a particular region, it’s sometimes possible to imitate it.
The natural work of beavers in nature has been proven beyond doubt, so much so that this mammal is now considered one of the world’s most important animals in the fight against weather disasters.
The small dams of branches and wood they build create small water retention basins, thus limiting river overflows in the event of heavy rainfall. For some years now, scientists have been observing beaver dams, trying to learn lessons that can then be applied to agricultural and urban areas. The Universities of Cardiff and Worcester in England have just published a joint study on natural flood risk management in the Journal of Hydrology.
The researchers carried out an experimental test on the River Shrophire over a two-year period: as there are no beavers in England, they placed 105 barriers over a distance of almost 5 kilometers. These artificial barriers, imitating those of beavers, slowed the flow of the river, storing water in some areas and diverting it in others.
The gain is obvious, and it helped prevent flooding during Storm Dennis, which hit the British Isles in February 2020, as the barriers were able to store excess water equivalent to four Olympic-sized swimming pools. Thanks to these nature-inspired mini-dams, the water rose by 80 centimetres near each element, and then gradually lowered over 7 to 10 days. This very gradual return to normal prevented any violent overflow as the storms passed.
The research team points out that, as well as being effective, these small barriers are very inexpensive. It’s a solution that can easily be implemented in high-risk areas. And, just like the natural dams created by beavers, the process has other advantages too: the small retention basins that are created provide shelter for biodiversity and water for many animal species.
After years of being hunted as a dangerous species, the beaver is now the focus of attention. Especially in California, a state ravaged by fires every summer. The animal is not protected in the USA and can still be hunted, but only with special permission. Some American scientists, like Emily Fairfax, are fighting to make the public hear about the invaluable role of beavers in fighting drought and fires.
English