Water features on the Canal du Midi

The balancing of incoming and outgoing water allows the Canal du Midi to operate as it does. Each time a lock operates, large quantities of water are either required to fill it or dump from it into the lower level pound. There must be a constant source of water in order to fill and the excess water dumped must have a place to exit the canal without it overflowing. Being able to provide this water source was one of the most important problems to be solved by Pierre Paul Riquet, its creator. ()