Map of Loire levees according to Roger Dion

“Turcies” (levees), gabion walls and stone embankments once connected residential areas with the aim of preventing minor river floods and of allowing alluvium deposits to collect from larger flooding events. These small rural structures were inadequate for a large-scale agricultural expansion and development of housing that the 11^th-century population surge would require. The Plantagenet King, Henry II, thus permitted Saint-Florent Abbey in Saumur to build the first of the major dykes, mentioned above, from Saint-Martin-de-la-Place to Saint Patrice. Henceforth, the Loire had a more secure riverbed - ordinary floods were contained and the growing population could settle on the fertile land ready for clearing, while the lower areas, former high water channels or even former Loire branches from a time when it was more abundant, would gradually be turned into grasslands for reaping the precious fodder for draught animals.

But this “confinement” only met navigational needs along a short stretch. So, over the centuries, the system of levees was expanded, with the high water channel narrowed to around 300m between Vouvray and Chouzy to help with sand evacuation. Such developments, during the reign of King Louis XI, would fall short of expectations, as would a similar adjustment of the width of the dyked-up bed upstream of Blois.

Be that as it may, to this day the levees remain the main structure for protecting the Valley from floods, even if these still occurred through the 19^th century, with particularly devastating effects. That they have become less common today is not so much down to structural reinforcements as it is the reforestation of the upper Loire basin, where the clearing of the Vivarais, Velay and Auvergne forests, not least to make way for the Nivernais ironworks, had a disastrous effect on flow regulation.