V-Notch Weir Monitor

The V-Notch Weir Monitor is typically installed in open channels such as streams to determine discharge (flow rate). The main component is a cylindrical weight suspended from a vibrating wire force transducer. As the water level changes, the changing buoyancy force on the cylinder acts directly on a vibrating transducer.

Product Features 

  • Vibrating Wire precision water level sensor
  • Simple in, low cost and robust instrument
  • Accurate and sensitive water level monitoring
  • High resolution monitoring
  • Low maintenance system
  • Range: 300mm
  • Resolution*: 0.025% full scale (minimum)
  • Material: Stainless Steel


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The Vibrating Wire V-Notch Weir system has three notch options to suit different water flows and a choice of using manual or remote monitoring.

Manual reading has two options:

  • Manual reading of the optical readout by eye
  • Manual reading of the VW transducer using a VW readout

When using remote reading, the Vibrating Wire transducer is connected to a data acquisition system. Once the user has chosen which notch option is most suitable for a specific project, the weir plate is mounted at the exit of an approach channel or stilling basin through which the flow to be measured is channeled.

The measuring point for the head of water is located upstream of the weir plate and comprises either an optical Stainless Steel scale fixed to the basin wall for manual readings by eye, or a Vibrating Wire transducer suspended in the head of water.


The Vibrating Wire V-Notch Weir system uses the principle of gravitational discharge of water over a triangular or rectangular notched weir plate.

Typical applications include:
  • Long-term monitoring of dams
  • Drainage systems in dams and tunnels
  • Springs and artesian wells

If you have any questions or would like more information, please contact us.