The scour gate opens automatically when a flood passes through the dam or weir to pass the sediment laden water, either in suspension or rolling along the river bed, through the weir before the sediment settles out and consolidates. It automatically closes as the flood recedes to retain the full supply level in the dam or weir.
The scour gate can also be fitted retrospectively into an existing weir or dam structure to then remove sediment in a series of flushes. The scour gate can also be opened manually, as and when required, to flush out sediment.
The scour gate is in particular effective in river off-takes to pump stations, canals, or penstocks.
The scour gate, in addition to removing sediment, also serves as a valuable flood routing gate to pass floods.