Developing a Baseline Characterization of River Bathymetry and Time-Varying Height for Chindwin River in Myanmar Using SRTM and Landsat Data

In this study, a method was developed for the baseline characterization of river bathymetry and time-varying heights using globally available datasets from the Shuttle Radar Topography Mission (SRTM) elevation data and Landsat visible imagery. Using independent data on river water elevations from satellite altimetry, the SRTM-Landsat approach was verified as to how well it can work for baseline characterization. The technique was demonstrated for Chindwin River locations in Myanmar that were also independently sampled by Sentinel 3A and Jason 3 altimeters. The Modified Normalized Difference Water Index (MNDWI) was used for estimating the water areas and widths using Landsat 8 from 2016 to 2019. A comparison of SRTM-Landsat with Sentinel 3A/Jason 3-based elevation changes resulted in a correlation coefficient up to 0.89 and 0.82 using area-elevation and width-elevation curves, respectively. The presence of river islands during the dry season resulted in a weaker correlation between our proposed SRTM-Landsat technique and altimeter water elevations. This case study over the Chindwin River in Myanmar demonstrated that the use of the SRTM-Landsat combined technique could yield an acceptable baseline for characterization of river bathymetry and time-varying heights at ungauged locations around the world.