Ultrasonic Open-Channel Flow Meter An ultrasonic open-channel flow meter consists of an ultrasonic probe for liquid level measurement and a flow calculation transmitter. Structurally, it can be either integrated (one-piece) or split-type (remote). It is suitable for measuring flow in open channels—such as rectangular, trapezoidal, or U-shaped flumes—in applications including reservoirs, rivers, hydraulic engineering projects, municipal water supply, wastewater treatment, agricultural irrigation, and water resource management. This type of flow meter must be used in conjunction with a calibrated weir or flume structure. Commonly used structures include Parshall flumes, rectangular weirs, and V-notch (triangular) weirs, allowing selection based on specific site conditions.