Richmond Half Tide Lock
Grid Ref: TQ 1700 7504 [TR-208-470]. Each of the spans contains a guillotine gate that is held horizontal when fully up to allow sufficient head room. These are lowered two hours after high tide at Teddington to retain a navigable depth above the lock and raised again two hours before the next one. The top gate of the pound lock that operates when the gates are down can be seen in the foreground.
ROMA ID: 058065E