kOmega - a Matlab script to estimate river discharge remotely based on water surface dynamics

kOmega is a Matlab script to calculate the average flow velocity and water depth of rivers and open-channel flows from sequences of images of the water surface recorded with a camera. The analysis is based on the method described in Dolcetti et al., 2022, Using noncontact measurement of water surface dynamics to estimate river discharge, Water Resources Research, 58 (9), e2022WR032829. https://doi.org/10.1029/2022WR032829. The script computes the frequency-wavenumber spectra of the input set of images, and runs an optimisation routine to compare the measurements with the theoretical dispersion relation of water waves and to identify the set of flow parameters that provide the best fit with the measured data.

The method allows the estimation of the average flow velocity without requiring the presence of artificial tracers. It implements a robust analytical model of the water surface dynamics, therefore the accuracy is not undermined by the presence of gravity waves (including standing/stationary waves). The method is best suited for the analysis of videos or sets of images where surface deformations such as gravity waves are clearly visible, although it can also be applied in the absence of visible waves in the presence of artificial or natural floating tracers with suitable density.