Significats de great sluice en anglès

This one is like a little key which opens a great sluice.

Vuyning walked along Forty-fourth Street to Broadway, and then drifted down the great sluice that washes out the dust of the gold-mines of Gotham.

He determined, that these should be pierced, while, at the same time, the great sluices at Rotterdam, Schiedam, and Delftshaven should be opened.