Weirs are used for the measurement of flow rate in open channels. The measurement system is constituted by the weir linked with a level meter. As a result of regulation of the flow ensured by the weir, which has an overflow section note, instantaneous flow rates can be calculated using the value of the water surface level measured upstream of the weir.

Made of a stainless steel plate suitably chamfered at the overflow mouth and a metal support frame, allows a quick and easy installation.

Level measurement can be performed by means of the graduated staff gauge (local manual reading) or using a suitable automatic sensor with remote transmission of data for remote monitoring.

Float, ultrasonic, radar and pressure transducer type sensors are also available. It is possible to choose from a wide range of measuring ranges, depending on specific use



Flow rate measurement in open channels is widely used and applied in environmental and geotechnical fields. In particular, the measurement of water leakage in earth fill or concrete dams, is one of the most important indicators of health status and work performance of a structure.

Typical applications for this instrument are level measurements in:

  • Traditional concrete, RCC and earth fill dams
  • Channels


Features and Benefits:

  • Robust and easy to install
  • Precision construction
  • Easy to use
  • Low cost


Measuring Principle:

The weir, inserted in an open channel, allows the regularization of the cross section and the possibility of correlating the instantaneous flow rate with simple level measurements taken upstream of the same weir. Measurement is carried out using simple hydrometric rods or electric transducers. Our weirs can have a triangular (90 ° as standard, other on request) or rectangular spillway shape, depending on the entity of the flow rate to be measured. Level transducers of different types and different full scales are available.


FLM2001001: triangular type 90°

FLM3001001: triangular type  30°

FLM9001001: rectangular type

Material: stainless steel

Dimension: standard (400x300mm); other dimensions on request

Related products:

Radar Level Meter For the automatic measurement of level
Piezometric Level Meter For the automatic measurement of level
Enamelled Staff Gauge For the manual and measurement with direct reading
Stainless Steel Staff Gauge (special version) For the manual and measurement with direct reading


Technical Assistance:

If you have any requests or questions about our instruments or if you have special needs that require different solutions from the standard, please contact us. Our team will provide all the necessary information and will be very happy to work with you to study, develop and customize instruments and solutions suitable for your specific needs


All information in our datasheet is subject to change without prior notice.

Please check the datasheet/details carefully and contact Pizzi Instruments for further information