The Rivers of Touraine
Although I usually open my guides my diving head first into the region’s geology, the river system which crosses the Touraine region is sufficiently important and complex for me to first take a quick detour with this introduction to the many rivers of Touraine.
Once the waters of the Loire have passed Gien, the town for which the Coteaux du Giennois appellation is named, France’s greatest river leaves the Central Vineyards behind, and begins its journey towards the vineyards of Touraine.
Up until this moment its course, all the way from its origin on the slopes of Mont Gerbier de Jonc in the Massif Central down to the vineyards of Sancerre and Pouilly-Fumé, has been in a largely northerly direction. It is not widely appreciated but in prehistory this upper part of the river, known as the Loire Séquanaise, stayed on this course, continuing north and eventually joining what is today the Seine. The lower part of the Loire also existed, but as a quite separate river which originated from headwaters somewhere between Orléans and Gien.
The uplifting of the extensive limestone beds of the Bassin Parisien during the Pleistocene (between 2.5 million and 11,700 years ago) diverted the flow of the Loire Séquanaise, shifting its course away from the north. As it did so it joined up with the lower section, creating the Loire as we know it today. The old riverbed of the Loire Séquanaise as it made for the Seine is now occupied by the Loing, a tributary of the Seine which arises 40 kilometres north-east of Sancerre. It was only the opening of the Canal de Briare (pictured above), running from the Loire to the Loing and completed in 1642, which ‘recreated’ the prehistoric union between the Loire and Seine.
So today the Loire turns west, taking the course with which we are all familiar, through Tours, Saumur and Nantes, before it finally flows out into the Atlantic Ocean. By the time it reaches Gien it is heading more west than north, and soon afterwards it reaches Orléans.