Journal of Remote Sensing & GIS

Estimation of river discharge exclusively from remote sensing-derived data: Method development and validation

3^rd World Congress on GIS and Remote Sensing

September 20-21, 2017 Charlotte, USA

Arthur W Sichangi

Dedan Kimathi University of Technology, Kenya

Posters & Accepted Abstracts: J Remote Sensing & GIS

Abstract:

Measurement of river discharge is necessary in hydrology and water resource management. However, the available recordings are intermittent or nonexistent, especially in underdeveloped countries and under proprietary control in developed nations. These practical realities limit the knowledge of river discharge data therefore limiting studies carried thereon. In this study, we develop a novel approach that estimates river discharge exclusively using satellite-derived parameters, without calibration of a rating curve by ground discharge observations. The temporal river width observations from MODIS, made at two stream segments a distance apart, are plotted to identify the time lag. The river velocity estimate is then computed using the time lag and distance between the width measurement locations. An empirical relationship is then utilized to estimate river depth. In addition, we employed the channel condition values published in tables to estimate the roughness coefficient. The channel slope is derived from the digital elevation model averaged over a river approximately 516 km long. Finally, we capture the temporal depth changes by adjusting the estimated depth to the ENVISAT-derived water level changes, and river width changes from Landsat ETM+. The newly-developed procedure has been applied to two river sites for validation. In both cases, the river discharges were estimated with Nash-Sutcliffe (NS) values greater than 0.50. Since the methodology for estimating discharge is solely dependent on global satellite datasets, it will be very promising for a wide use in the world.