Testing protocols for smoothing datasets of hydraulic variables acquired during unsteady flows

Flood wave propagation involves complex flow variable dependencies. Continuous in-situ hydrograph peak magnitude and timing data provide the most relevant information for understanding these dependencies. New acoustic instruments can produce experimental evidence by extracting usable signals from noisy datasets. This study presents a new screening protocol to smoothen streamflow data from unwanted influences and noise generated by flow perturbations and observational fluctuations. The protocol combines quantitative (statistical fitness parameters) and qualitative (domain expert judgments) evaluations. It is tested with 18 smoothing methods to identify optimal data conditioning candidates. Sensitivity analyses assess the validity, generality, and scalability of the procedures. The goal of this analysis is to set a mathematical foundation for empirical results that can lead to unified, general conclusions on principles or protocols for unsteady flows propagating in open channels, formulating practical guidance for future data acquisition and processing, and using in-situ data to better support data-driven modeling efforts.