Statistical mapping of zones of focused groundwater/surface-water exchange using fiber-optic distributed temperature sensing

Authors

  • Kisa Mwakanyamale,

    Corresponding author
    1. Department of Earth and Environmental Sciences, Rutgers University, Newark, New Jersey, USA
    2. Now at Department of Geography, University of Calgary, Calgary, Alberta, Canada
    • Corresponding author: K. E. Mwakanyamale, University of Calgary, Department of Geography, 2500 University Dr. NW, Calgary, Alberta, Canada, T2N 1N4. (kisa010@gmail.com)

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  • Frederick D. Day-Lewis,

    1. U.S. Geological Survey, Office of Groundwater, Branch of Geophysics, Storrs, Connecticut, USA
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  • Lee D. Slater

    1. Department of Earth and Environmental Sciences, Rutgers University, Newark, New Jersey, USA
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Abstract

[1] Fiber-optic distributed temperature sensing (FO-DTS) increasingly is used to map zones of focused groundwater/surface-water exchange (GWSWE). Previous studies of GWSWE using FO-DTS involved identification of zones of focused GWSWE based on arbitrary cutoffs of FO-DTS time-series statistics (e.g., variance, cross-correlation between temperature and stage, or spectral power). New approaches are needed to extract more quantitative information from large, complex FO-DTS data sets while concurrently providing an assessment of uncertainty associated with mapping zones of focused GSWSE. Toward this end, we present a strategy combining discriminant analysis (DA) and spectral analysis (SA). We demonstrate the approach using field experimental data from a reach of the Columbia River adjacent to the Hanford 300 Area site. Results of the combined SA/DA approach are shown to be superior to previous results from qualitative interpretation of FO-DTS spectra alone.