The water supply in Mont-Dauphin

Mont-Dauphin’s water supply relies mainly on water being drawn from springs located outside the fortress.

The spring in the Loubatière valley, situated more than two kilometres from Mont-Dauphin, is one of the main water collection points. The water is channelled to the fortress via a network specifically designed to overcome the distance and the terrain. The water supply network must then pass through the defensive structures. In particular, the incoming aqueduct crosses the moat surrounding the fortress before reaching one of the bastions. From there, various branches supply the reservoirs and several fountains scattered throughout the fortress.

Another spring, that of Champ-Chignon, situated closer to Mont-Dauphin, was also tapped. However, its flow rate was too low, leading to this source being abandoned over time.

To convey the water to the heart of the stronghold, engineers installed pipes known as ‘bourneaux’. The system evolved over the centuries and the materials used were gradually adapted. The pipes had to be sufficiently protected to withstand the site’s particularly harsh climatic conditions. Frost posed a recurring threat to the network: pipes that were not properly buried could freeze in winter and cut off the supply.

The water supplied fed several fountains intended for everyday use.

However, water supplied by springs and fountains is not sufficient to guarantee the safety of the stronghold in times of war. In the event of a siege, the external water mains could be cut off. It is therefore essential to have water reserves within the fortifications themselves.

Two large cisterns were therefore constructed. The first has a capacity of approximately 365 m³. The second is much larger, with a capacity of around 1,840 m³. Together, these cisterns constitute a considerable reserve. Their total capacity was theoretically intended to meet the needs of several thousand people for several weeks. However, it takes nearly two months to fill them, which highlights the importance of anticipating periods of crisis and maintaining reserves at maximum capacity.

Moreover, the stored water is not used solely for human consumption: the needs of the horses and livestock within the stronghold must also be taken into account. The management of this resource is therefore inextricably linked to the military organisation of Mont-Dauphin.

At Mont-Dauphin, water is thus an integral part of the defensive system. It is given the same consideration as the ramparts, storehouses, barracks or powder magazines: without water, a stronghold cannot hold out for long.

The water supply system is not static. The pipes are regularly repaired, replaced or modernised to meet the needs of the fortress and keep pace with technical progress.

The Champ-Chignon pipeline, in particular, was rebuilt in 1746, and the networks were modernised once again in the 19th century. These changes reflect the need to constantly maintain a particularly sensitive infrastructure in a mountainous environment.

In the 20th century, Mont-Dauphin’s water supply underwent further developments. A new catchment was constructed at the Gros spring between 1955 and 1957, followed by the construction of a new reservoir in 1980.

Even today, water remains a key issue for the town, which has inherited a supply system whose earliest infrastructure dates back to the construction of the fortified town.