After flash flooding in the Valencia region of Spain claimed more than 200 lives at the end of October, social-media users blamed the removal of dams and circulated a map as evidence. But the map does not show dam removal; it shows the number of existing barriers, including weirs, dams and culverts, and was derived from the data obtained in a pan-European mapping project (B. Beletti et al. Nature 588, 436–441; 2020).
Competing Interests
The authors declare no competing interests.