lock

another lock, not far from the first, showing more of how they work the water from one level to the next..

For those of you unfamiliar with the 'lock phenomenon' (those living with too little or just enough water around!): a lock is an instrument to regulate water levels. In a system with canals and ditches, designed to keep low lands dry, the levels of one canal will get (too) high. In order to get rid of the surplus a lock is installed. In large canals used for transport a ship can use a lock to get from a lower to hiogher level canal or the other way around. I found you a good descrition of its workings here

Done