They regulate the flow of water by the sluicegate.
他们用水闸门控制水的流量。
2
As soon as the sluicegate was opened, the water surged in.
水闸门一开，水便一下子涌了出来。
3
Automatic watersluicegate is under the waterpower and action of gravity, in the given water height condition; and it start and stop automatically as the flux change.