Four pumps with a total power of 88 MW are used at Z’Mutt to pump around 140 million m3 of water every season. This water is pumped to a penstock which carries it to the Trift tunnel (altitude of 2400 metres) in the main collector.
The impact of the concrete on the environment has been kept to a minimum. The only major visible element is the arch dam which crosses the gorge. Apart from the service building, all of the facilities (gravel traps, sand traps and pumping station) are underground.
Afterbay reservoir
| Construction | 1961 – 1964 |
| Height | 74 m |
| Crest | 144 m |
| Thickness at the crest | 3 m |
| Volume of concrete | 32 000 m3 |
| Capacity | 800 000 m3 |
| Type | Arch dam |
Pumping station
| Power | 2 x 30 MW ; 2 x 14 MW |
| Flow rate | 17,4 m3/s |
| Discharge head | 365 m / 470 m |
