Résurgence de la Mouyssaguèze

The entrance is very modest and would go completely unnoticed if sudden, large floods did not signal its presence. A narrow forced conduit, about ten metres long, leads into a joint fissure averaging 2 m high and about fifteen metres long. Its upstream end finishes in a clayey, stony slope. Downstream it ends at a deep pool in which the beginning of a submerged conduit can be seen. On the right-hand wall, almost opposite the access crawlway, a window passage enlarged on 18 May 1980 leads into a second joint fissure oriented at 500 relative to the first. It is about twenty metres long. The floor is clayey and stony like the first joint fissure. It is 2 m to 3 m wide and about 1 to 3 m high. It too leads to a sump pool. Both pools are at -3.8 m relative to the entrance. There is unquestionably a communication between them. An upper passage located directly above the pool is too narrow to allow progression.

During flood periods, we can consider that the total discharge of all the emergences is on the order of a few cubic metres per second. Those of R4a1-Bas is one of the most important.

Most of these cavities are under study and exploration. A systematic survey of the catchment area must be carried out.