Saône

• 1. The Goddess And The Name

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  A sacred spring at Chalon once bore the name Sauc-Onna. Roman legionaries used this name to refer to the entire river that flows through eastern France. Monastic copyists later transformed Souconna into Saoconna over many centuries. This linguistic shift created the modern name Saône from an ancient Gallic goddess. Julius Caesar described the water as Arar in his Commentaries on the Gallic War. He noted a doubling of the Indo-European root ar for water. This repetition reflected the difficulty of identifying the direction of flow due to its slow rate. Ancient historians also recorded names like Arar and others before the current designation emerged. Northern Burgundian lands were sometimes designated as on this side or on the other side of the river depending on the author's perspective.

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• 2. From Vosges To Lyon

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  The river rises at Vioménil at the foot of a cliff in the Vosges department. It begins at an elevation of 350 meters above sea level. Its total length spans 481 kilometers across the region. The largest tributary is the Doubs which joins near Verdun-sur-le-Doubs. Upstream of this junction the river carries the name Petite Saône. The Doubs mean annual flow rate slightly exceeds that of the Petite Saône itself. Some observers assert the Saône actually flows into the Doubs rather than vice versa. Nonetheless the Saône possesses a substantially larger watershed covering approximately 32,000 square kilometers. At 32,000 square kilometers it holds the largest watershed of any French river not flowing directly into the sea. This area covers roughly one eighteenth of metropolitan France. Cities traversed include Darney Monthureux-sur-Saône Châtillon-sur-Saône and Gray. Further downstream lie Auxonne Saint-Jean-de-Losne Seurre and Mâcon before reaching Lyon.

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• 3. Seasonal Flow And Floods

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  Winter floods occur from December to March inclusive with strong oceanic effects on the upper basin. Soils saturate quickly contributing to rapid surface runoff after heavy rainfall. The mean annual flow rate measured over fifty years reaches 360 cubic meters per second at Ray-sur-Saône. An annual maximum of 4,500 cubic meters per second was recorded in February while July averages drop to 180 cubic meters per second. The specific flow rate rises to 16.0 litres per second per square kilometer of watershed in the upper region. A maximum instantaneous recorded flow reached 7,900 cubic meters per second on the 19th of December 1982. The greater Saône flows through a vast plain approximately 10 kilometers wide as far as Lyon. It moves within the basin of the former Bressan lake where slopes remain very gradual. Without hydraulic projects up to the north of Chalon overflows would be more frequent than they are today.

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• 4. Locks And Canals

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  The river is navigable from its confluence with the Coney at Corre all the way to La Mulatière in Lyon. This navigable stretch spans 530 kilometers and includes five locks for the lower section. Another 161 kilometers upstream from Saint-Symphorien-sur-Saône to Corre remains navigable for Freycinet gauge ships. That segment contains nineteen additional locks along its course. The Saône links with the Loire via the Canal du Centre and connects to the Yonne by the Canal de Bourgogne. It joins the Marne through the Canal entre Champagne et Bourgogne previously known as the Canal de la Marne à la Saône. The Meuse connects via the Canal de l'Est whose southern branch now bears the name Canal des Vosges. A final link reaches the Rhine through the Canal du Rhône au Rhin. All these canals maintain the Freycinet gauge standard for inland waterways. Small sections like the Canal de Pont-de-Vaux span only three kilometers while the Seille extends seven kilometers up to Louhans.

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• 5. Disasters And Planning

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  A flood of November 1840 carried an estimated flow rate of nearly 7,900 cubic meters per second. This event destroyed numerous habitations along the river valley leaving visible plaques in affected villages. High water measured at flood scales reached 2.5 meters at Mâcon and 3.1 meters at Chalon above normal levels. Other significant floods occurred in May 1856 January 1955 March 1970 December 1981 and 1982. The largest floods in the last fifty years included events in May 1983 March 2001 and 2006. Town planning references rely on a 100-year flood model updated as maps linked to modeling the 1840 flood were distributed to local mayors in December 2008. New prevention plans were ordered for 2012 following these updates. A large flood with strong upstream flow can be largely attenuated in the Bressan plain to moderate impact at Mâcon. By contrast a medium-sized flood of the lesser Saône turns into a significant downstream disaster if the Doubs contributes similar volume simultaneously.

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