A backboard with a graduated scale holds each manometer tube. For safety and convenience the manometer uses water as the manometer fluid. The top of each tube is open to the atmosphere. The bottom of each manometer tube has a connection piece for tubing to connect to pressure tappings on the equipment being monitored. The manometer is designed to be hung on the top rail of an FC300 Flume. It can be adjusted both horizontally and vertically for levelling. The tubing between the manometer and the equipment being tested must be completely filled with water. It can be connected, to the tappings in the bed of the flow channel to measure the changes in depth along the length.