There are many types of open channel flow measurement, as well as weir and groove methods. Let's compare and introduce several common measurement methods.

① Measurement of channel flow in basher trough

The tank body is generally made of stainless steel or FRP, and the flow is generally small. The open channel flowmeter shall be installed to collect water level conversion flow data, and the open channel flowmeter shall be installed at one-third of the water inlet. Generally, more sewage outlets or small channels in irrigation areas are used; The instrument has low cost and high precision. Some civil engineering construction is not suitable for large channels.

② Measurement of channel flow by velocity area method

The main canal or main branch canal of large irrigation area has medium cost, general accuracy, simple installation process and basically no civil construction. The channel must be an artificial cement channel.

③ Doppler open channel flowmeter

The temperature probe is used for water temperature measurement, and the high-precision pressure sensor is used for water depth measurement. The measurement of flow rate is obtained by transmitting and receiving supergenerated wave signal by ultrasonic probe and doing corresponding calculation and processing. It is suitable for regular rivers or channels, has certain requirements for water quality, simple installation process and basically no civil construction.

④ Measurement of open channel discharge by water level velocity curve method

It is suitable for various channels or non-standard rivers, with general accuracy, no requirements for water quality, complex installation, civil construction and medium cost, but it needs additional cost to calculate the conversion relationship between water level and flow velocity.