Our series on Artificial Features takes us to Southern France, where an ancient engineering feat changed and stabilized the course of the River Adour in 1578.
The Adour reaches the Bay of Biscaye at the southern end of a long coastal strip where the sea is separated by sand bars from one of Europe's largest marsh regions: the Landes. Because of its erratic flow, the river changed course many times. By the end of the middle ages, it reached the coastal region near the city of Bayonne, but then took a course North and followed the dune strip for over 50km to finally reach the Ocean at Vieux-Boucau.
The port of Bayonne, which had received the waters from the river for a long time but was then cut off, was quickly sanding up. After a 16 year effort, a new channel was dug, which send the quasi-totality of the Adour's flow through Bayonne, resulting in the rapid filling of the other branches of the river.
As of 2022, Bayonne is the largest city and port in the region.
The Adour
