Like all the rivers originating from the alpine regions, the Buëch is an abundant river fed by rainfall and the lasting snow cover of the mountainous upper part of its basin. However, it presents the typical seasonal fluctuations of a predominantly snowy hydrological regime with two periods of flooding. The high waters of autumn, especially in April (43.5 cubic meters per second) and May, are linked to the melting of snow associated with the spring rains. The summer low waters (photo), on the other hand, result in the lowest average flow in September at 3.12 cubic meters per second.