ABSTRACT
Digital signal processing and cross-correlation methods are implemented to extract transit velocities studying the time delay between signals provided by two stand-alone probes. By use of hightime resolution sensing in the river, non-periodical naturally present disturbances found in the fluvial water composition can serve as spontaneous tracers to determine the transit velocity in the considered river reach. In essence, the method has the potential to deliver tracer-grade velocity information, while not relying on actual tracer injection interventions. The method can also be operated, continuously, on a 24/7 basis. Different correlation methods (correlation coefficient, cross-correlation, least squared differences and phase transform) are implemented in Matlab and tested using as an input high time resolution records of parameters measured by YSI quality probes in a reach of the Zenne river (Central Belgium).
