One balmy summer evening in mid-July last year, the tiny river Kyll flowing out of the Eifel Mountains in Germany turned from its normal placid flow into a raging torrent that engulfed several riverside towns in its path. By the morning, more than 220 people had died here and along several other German and Belgian mountain rivers. It was the worst flood disaster in Western Europe in several decades.
Politicians rushed to blame climate change for the intense rains that flooded the rivers that night. The world had to be “faster in the battle against climate change,” said German Chancellor Angela Merkel, as she toured devastated communities. Climate scientists later concluded that a warmer atmosphere had made such downpours up to nine times more likely.
But there was another factor behind the floods that few politicians or media have mentioned, then or since. Hydrologists monitoring the river flows say that the spread of farms in the once-boggy hills where the rainfall was most intense had destroyed the sponge-like ability of the land to absorb heavy rains. Field drains, roadways, and the removal of natural vegetation channeled the water into the rivers within seconds, rather than days.
That suggested a way to prevent future floods here and elsewhere that would be much faster than fixing climate change. Unpublished analysis of the Kyll by Els Otterman and colleagues at Dutch consultantcy Stroming, reviewed by Yale Environment 360, had found that blocking drains and removing dykes to restore half of the former sponges could reduce peak river flows during floods by more than a third.
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The flooded Kyll river rages through Erdorf, Germany in July, 2021. Photo Credit: HARALD TITTEL / DPA / ALAMY LIVE NEWS)