Using the supplied weir plates, the measurement of flow rate in open channels can be investigated. They are used together with the hydraulic bench. Water is fed from the hydraulic bench into a section of channel, the water then flows over the weir into the volumetric tank and back to the sump tank. A weir with a V notch (Thomson weir) and a weir with a rectangular notch are provided for the investigations. A depth gauge for the determination of the weir head is included.