Durolle

The Durolle (formerly ''Dorole'') is a 32-kilometer-long French river in the departments of Loire and Puy-de-Dôme region. A right-bank tributary of the Dore, which it joins downstream of Thiers, it is a sub-tributary of the Loire via the Allier.

The river rises in the Forez mountains, where rainfall is high throughout the year. After flowing past the town of Noirétable, the Durolle plunges into deep canyons (until it exits the Vallée des Rouets and the Vallée des Usines) renowned for their rich natural and industrial heritage. Known since the Middle Ages for its paper mills, the river owes its fame to its motive power, which enabled cutlery factories to sharpen knives. Today the river's industrial past is used as a tourist attraction.

Toponymy

The river's name is thought to derive in part from the (presumed) Celtic root ''dour'' or ''dor'', meaning "river" in French. The Dore (the river into which the Durolle flows) also takes its name from these "Celtic" roots. However, the authoritative ''Dictionnaire étymologique des noms de rivières et de montagnes de France'' by Albert Dauzat, Gaston Deslandes and Charles Rostaing (Paris, Klincksieck, 1978) explains Dore (and Durolle) by a pre-Celtic radical "found in the ''Douro'' of Spain, the two ''Dora'' of Piedmont, etc." (article DORE). Moreover, Xavier Delamarre's ''Dictionnaire de la langue gauloise'' (2nd edition, Paris, Errance, 2003) does not indicate any Celtic term ''dor'' or ''dour'' meaning river.

The Durolle, formerly "Dorole", means "little Dore". Its nickname, the ''Goutte noire'' (black drop), refers to its color in the 19th century when spinning wheels used the river's water, and is borne by a village crossed by the river in the commune of Chabreloche. The river's name is also used by two communes in the region: Celles-sur-Durolle and Saint-Rémy-sur-Durolle, and a place called Durolle in the commune of Noirétable.

It is called ''Duròla'' in Occitan, the regional language of Auvergne.

Geography

River course

Just over 32 km long, the Durolle begins its course at an altitude of around 815 m southeast of the Puy de la Chèvre in the commune of Noirétable in the Loire department. It skirts the town of Noirétable without crossing it, then passes through a number of villages overlooking it, before passing through towns such as Chabreloche and La Monnerie-le-Montel, and finally arriving at the largest town it flows through, Thiers, a town with a strong historical link to it, where it also flows into the Dore.

Upstream, the river follows part of the Forez mountains where it rises, until it enters the commune of La Monnerie-le-Montel, where it divides the Forez foothills. From here, until it leaves the Vallée des Usines in the Moutier district of Thiers, the river flows through a deep valley with small banks, where the cliffs and rocks of the Margerides plunge. The rugged, largely wooded terrain gives the river a sinuous course that follows the steep curves of the mountain. From the point where it passes near Moutier Abbey, the Durolle becomes calmer and the very flat terrain divides its bed into two branches, before these join the Dore at different geographical positions.

Hydrology

The drainage basin of the river Durolle measures 172 km2. Its modulus, measured near the Saint-Roch bridge in Thiers, halfway between the source and the mouth, is 3 m3/s. Flow varies significantly throughout the year, and from one year to the next. In dry summer months, the river's flow may drop to 0.05 m3/s; but in winter or autumn, it can rise rapidly to 82 m3/s, as was the case during the flood of March 1988. The river's tributaries are generally small streams with low flows. The main ones are, from upstream to downstream, the Membrun stream, the Pigerolles stream, the Prade stream, the Aubusson stream, the Jalonne, the Semaine, the Dauge, the Martignat, the Bouchet, the Ris and the Boucheries stream.

The Membrun dam, in the commune of Thiers, lies on the course of the Durolle. It was impounded on 22 May 1985 to regulate the river's flow, particularly during periods of drought. Since the late 1980s, the dam has become a popular destination for hikers and walkers.

Communes and cantons crossed

In both the Loire and Puy-de-Dôme