Sluice
It can also be an open channel which processes material, such as a river sluice used in gold prospecting or fossicking.
When a sluice is lowered, water may spill over the top, in which case the gate operates as a weir.
[citation needed] Sluice gates are one of the most common hydraulic structures [2] used to control or measure the flow in open channels.
Nineteenth-century logging was traditionally a winter activity for men who spent summers working on farms.
[citation needed] The Sinhala people in Sri Lanka, who had an ancient civilization based on harvested rain water, refer to sluices as Horovuwa.
1: Tube connecting the chamber to the high water side of the sluice
2: Gates to regulate the water level in the chamber. Only one gate may be opened at a time
3: Tube connecting the chamber to the low water side of the sluice
4: The chamber in which the water level can be controlled
5: Door with larger surface
6: Door with smaller surface.
When the tube to the high water level side (1) is opened, the water level in the chamber (4) will rise to this same level. As there is no height difference across the larger gate (5), it exerts no force. However, the smaller gate (6) has a higher level on the upstream side, which exerts a force to close the gate (counter-clockwise). When the tube to the low water side (3) is opened, the water level in the chamber (4) will fall, and a force will be exerted on the large door (5) in the opening direction (clockwise). The pressure difference on both doors is the same, but the surface area is not. This ensures that the opening force (on 5) overcomes the closing one (on 6), which causes the gate to turn clockwise and open.
