WORLD BIGEST SHORT CUT 02

Filling and draining

Each lock chamber requires 101,000 m3 (26,680,000 US gal; 22,220,000 imp gal) to fill it from the lowered position to raised; the same amount of water must be drained from the chamber to lower it again.[1] Embedded in the side and centre walls are three large water culverts, which are used to carry water from the lake into the chambers to raise them, and from each chamber down to the next, or to the sea, to lower them. These culverts start at a diameter of 22 ft (6.71 m), and reduce 18 ft (5.49 m) in diameter — large enough to accommodate a train. Cross culverts branch off from these main culverts, and run underneath the lock chambers to openings in the floors. There are fourteen cross culverts in each chamber, each with five openings; seven cross culverts from the sidewall main culverts alternate with seven from the centre wall culvert.
The water is moved by gravity, and is controlled by huge valves in the culverts; each cross culvert is independently controlled. A lock chamber can be filled in as little as eight minutes; there is significant turbulence in the lock chamber during this process