The works of Franz Kafka often describe people trying to reach a goal but never arriving – all ways are blocked, any possible detours turn out to be impassable. Migratory fish and invertebrates in European rivers today are in a similarly Kafkaesque situation. New research in the journal
Nature, published December 17, reveal that on average, there are at least 0.74 barriers per kilometre of European waterway. This means that an organism can hardly travel more than 1,000 meters without being stopped by a dam, weir, culvert, sluice or ramp.
The movement of flowing water is the essential nature of all running water systems, from small rivulets to large rivers. But this natural movement, and especially its pulsing nature, with flood events and droughts, is too dynamic for human beings who have sought to become “master and possessor of nature” (Descartes,