Stilling wells are chambers isolated from, but still connected to, a main flow of water. In clean water applications, the connection or pipe between the flume or weir pool and the stiling well is typically 1/10th the diameter of stilling well. This is usually large enought to allow the water level in the stiling well to quickly respond to changes in the water level in the main body of the flume or weir pool
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Where more dampening is requried, using a smaller connection / pipe will serve to dampen translocation of the water level between the main flow and the stililing well. Remember, though, that as the connection / pipe size decreases, the likliehood of clogging increases.
