A violent torrent formed from the tiny River Kyll in mid-July 2021 close to the German/Belgian border.
Its quiet summer trickle, which was routinely measured at a fractional of one cubic meter per sec, suddenly jumped to more than 50 cubic metres per second.
Riverside towns like Kordel or Gerolstein were flooded by the rising waters. Other small rivers also burst into their banks in the region. It was one of the worst flooding disasters in the country’s history. It caused more than 220 deaths and cost Germany an estimated $40 billion. This made it the most expensive natural catastrophe in Germany.
Many blamed the climate crisis, blaming the record-breaking rainfalls that flooded the Ardennes and Eifel mountains in midsummer. Angela Merkel stated, as she toured devastation, “We need to accelerate the fight against climate change.”
Merkel was correct. The downpour was unimaginable. There was another cause for the floods. Changes in Europe’s land usage are destroying natural sponges, such as wetlands and rough grasslands, across Europe. Their ability to absorb heavy rains is decreasing, which results in rain running downstream through drainage channels and across hard surfaces into rivers.
The tiny Kyll became a raging river within a matter of hours in July.
We can expect more floods if we don’t restore natural sponges
Germany has set aside 30 million to repair the damage from that night of floods. However, if the continent’s upland sponges are not repaired, there will be many more nights like this.
Upland ecosystems once held large quantities of water from heavy rain and released it gradually into rivers over days or weeks. The absorption capacity has been drastically reduced by drainage for agriculture, commercial forestry, reclamation and construction of buildings, impermeable surfaces and asphalt.
Concrete and asphalt can increase the flooding impact.
It is typical for the land at the Eifel Mountains’ upper reaches of river Kyll. It has been extensively drained. Dutch hydrologists Bureau StromingThe floodwater volume sent downstream by last July was disproportionately influenced by the areas further upstream.
Even roads were involved. Country lanes can quickly transport water into rivers when they flood. According to hydrologists, roads are the best drainage system for heavy summer rain events.
Restoring nature to prevent disasters
It has been two decades since the Elbe floods triggered the resignation of Germany’s environment minister. Juergen Trittin promises“Give our rivers more room; otherwise, they’ll take it.”
However, efforts have centered on restoring natural floodplains along the lower reaches large rivers. Crucial upland sponges have been largely forgotten in river basin plans, such as the Rhine 2040 program that aims to create a sustainably managed catchment area that is resilient to the effects of climate change. This must change.
The solution to flooding is not to pour concrete in vain to keep rivers in their banks, but to block drains, reduce intensive cropping, restore soils and wetlands and reconnect rivers with their floodplains.
The Stroming study estimates that restoring half of the sponges along the upper Kyll could reduce peak discharges into the river by up to 35% enough to prevent the devastation seen in towns like Gerolstein and Kordel. This would reduce river levels all of the way to the ocean. Wetlands International estimates that restoring the sponges from the uplands that drain into rivers would reduce river flows over 125,000 kilometers in Germany, France and Belgium.
Protecting biodiversity and communities
There are other benefits. There are other benefits, too. Restored sponges, wetlands, and carbon capture systems protect biodiversity and keep rivers flowing during droughts.
Wetlands worldwide are disappearing at alarming levels. With 35% lost globally in the last 50 years, wetlands are our most threatened ecosystem, disappearing three times faster than forests. The protection of wetlands is vital for communities, and their destruction puts lives at risk.
Yes, we must fight climate change. Extreme meteorological events do not have to become extreme flooding events. We must also fix the landscape as we work to change the climate.
Jane Madwick, an ecologist and conservationist, is the head of Wetlands International. The organisation works in over 100 countries to restore and protect wetlands and associated ecosystems, and supports sustainable development and community approaches.
Edited by Anke Rasper