Quantifying river form variations in the Mississippi Basin using remotely sensed imagery

摘要

Geographic variations in river form are often estimated using the frameworkof downstream hydraulic geometry (DHG), which links spatial changes indischarge to channel width, depth, and velocity through power-law models.These empirical relationships are developed from limited in situ data and do notcapture the full variability in channel form. Here, we present a data set of 1.2 ×106 river widths in the Mississippi Basin measured from theLandsat-derived National Land Cover Dataset that characterizes widthvariability observationally. We construct DHG for the Mississippi drainageby linking digital elevation model (DEM)-estimated discharge values to each width measurement.Well-developed DHG exists over the entire Mississippi Basin, thoughindividual sub-basins vary substantially from existing width–dischargescaling. Comparison of depth predictions from traditional depth–dischargerelationships with a new model incorporating width into the DHG frameworkshows that including width improves depth estimates by, on average, 24%.Results suggest that channel geometry derived from remotely sensed imagerybetter characterizes variability in river form than do estimates based onDHG.