Uncertainty in open channel discharge measurements acquired with StreamPro ADCP

The StreamPro Acoustic Doppler Current Profiler (ADCP) is a favorite solution for making discharge measurements of medium and small streams in practical situations. This paper investigates the implementation of a rigorous uncertainty analysis protocol to measurements conducted with StreamPro ADCP operated with the stationary method (a.k.a. section-by-section). The assessment of individual uncertainty components is based on the best available information and the results of customized experiments. The main contributions of this paper are: (a) estimating StreamPro ADCP discharge measurement uncertainty by a rigorous, standardized approach; and (b) the assessment of some uncertainty sources in the functional relationship of the discharge measurement process. Uncertainties were estimated through a practical end-to-end approach, whereby the effect of the targeted uncertainty was isolated and subsequently estimated based on direct measurements, rather than analytically deriving them via uncertainty propagation equations. The implementation example illustrates that the standardized uncertainty analysis framework can be successfully applied for hydrometric measurements. Elements and framework of the uncertainty analysis presented in this paper can be applied to other instruments that estimate stream discharge using a section-by-section method.