Author(s): Carl J. Legleiter; Ryan L. Perroy; Richard R. Mcdonald; Jonathan M. Nelson; Paul J. Kinzel
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Abstract: The dispersion processes that control the spread of contaminants and other materials in river channels can be characterized via tracer experiments with visible dye. We evaluated the potential of remote sensing techniques to facilitate these studies by estimating dye concentrations from hyperspectral images that, unlike in-situ instruments, provide spatially distributed information on dispersion patterns. During tracer tests performed in both an outdoor flume facility and a large natural channel, we made field measurements of concentration and reflectance and acquired images from an unmanned aircraft system (UAS) and a conventional aircraft. We modified an Optimal Band Ratio Analysis (OBRA) algorithm to identify wavelength combinations that yielded strong correlations between a spectrally based quantity X and dye concentration C. For both the flume and field tests, we obtained very strong (R up to 0.95) relationships between X and C across a broad range of visible wavelengths. These results imply that remote sensing could become a powerful tool for mapping dye patterns and thus help to advance our understanding of dispersion processes by enabling more rigorous testing and refinement of hydraulic models.
Year: 2018