RajeswariKnowledge Contributor									
															
						If S is the length of the crest, H is the height of water source of a weir whose length is L and discharge is Q m3/sec, the velocity of approach Vd is
													If S is the length of the crest, H is the height of water source of a weir whose length is L and discharge is Q m3/sec, the velocity of approach Vd is												
												
												
		 
                    
Weir or notch. It is a physical structure of masonry constructed across the channel width to calculate the discharge of the channel section.