The gravity dam of this intake is equipped with a surface spillway (weir), a trap screen and a bottom drain valve. The maximum flow of the Drance de Ferret at the level of the water intake is over 20m3/s. The intake is also equipped with a mechanical trap screen allowing the intake grate to be cleaned automatically in the event of storms or strong flows. A return flow rate of 500 litres/second (during the day) and 200 litres/second (during the night) applies from June 01 to September 30.

Once the water is captured by the grate, it passes through two sliding-slide type inlet valves. Then the water is directed through two grit traps that work identically in parallel. Each grit trap is equipped with two Bieri detection system units.

The length of each grit trap is 40 metres for a width of 4.60 metres. The water is then funnelled into a buried channel via a weir set at an elevation of 1573 metres. The water heads towards Amône.

This intake is drained around once a year. as a great deal of sediment accumulates upstream of the trap. Without an annual drain, the Fouly intake would quickly become unusable.

Risk of overflowing