What is a V-Notch Weir?  

• A plate across a channel that is thin, in relation to the channel width, and into which a V-shaped notch has been cut.  
• Flow goes over the notch (versus through a flume).  
• The notched plate is set perpendicular to the direct of the flow of water and results in a pool of water upstream.  
• This pool of water helps to dissipate turbulence and normalize the approaching velocity.  
• The water level upstream of the V-notch is a direct function of the flow rate over the weir plate and is measured from the upstream surface of the water to the elevation of the lowest portion of the V-notch (also known as the crest).