Flow measurements using an upward-looking Argonaut-SW Doppler current meter

Doppler velocity sensors have become increasingly common for flow monitoring in open channels. The most common configuration is a side-looking sensor that measures velocity at a single depth within the water column. Side mounted systems offer a number of advantages, including easy installation and maintenance. Their limitations include sites with highly variable water level or stratified flow; it can also be difficult to produce, a robust theoretical flow calculation based on velocity and water level data. This paper describes the development and use of a bottom mounted Argonaut-SW Doppler current meter that is capable of flow measurements in channels with water level from 0.2 m to 5 m. The new meter provides a vertically integrated velocity measurement. This measurement configuration provides an improved index velocity in complicated flow regimes, including highly variable water levels and stratified flow. It also provides improved performance for theoretical flow calculations, which are important in smaller channels where an index calibration may not be practical. The sensor is also intended for use in pipes with diameter from 0.3 to 5 m. This paper describes the sensor configuration, preliminary specifications and theoretical flow models used to calculate open channel discharge and flow in partially and completely full pipes. Flume tests demonstrate good agreement with independent measurements.