Abstract
Abstract. We propose an innovative methodology to estimate the formative discharge of alluvial rivers from remote sensing images. This procedure involves automatic extraction of the width of a channel from Landsat Thematic Mapper, Landsat 8, and Sentinel-1 satellite images. We translate the channel width extracted from satellite images to discharge using a width–discharge regime curve established previously by us for the Himalayan rivers. This regime curve is based on the threshold theory, a simple physical force balance that explains the first-order geometry of alluvial channels. Using this procedure, we estimate the formative discharge of six major rivers of the Himalayan foreland: the Brahmaputra, Chenab, Ganga, Indus, Kosi, and Teesta rivers. Except highly regulated rivers (Indus and Chenab), our estimates of the discharge from satellite images can be compared with the mean annual discharge obtained from historical records of gauging stations. We have shown that this procedure applies both to braided and single-thread rivers over a large territory. Furthermore, our methodology to estimate discharge from remote sensing images does not rely on continuous ground calibration.
Highlights
The measurement of river discharge is necessary to investigate channel morphology, sediment transport, flood risks, and to assess water resources
This regime equation only provides an estimate of the formative discharge, and it can not capture the instantaneous variations in discharge
As our regime equation is established from measurements of a wide range of channels spanning over the Ganga and Brahmaputra plains, we believe that it can be used to obtain a first-order estimate of the formative discharge of rivers in the Himalayan foreland by just measuring their channel width on satellite or aerial images
Summary
The measurement of river discharge is necessary to investigate channel morphology, sediment transport, flood risks, and to assess water resources. The discharge is interpolated using routine techniques (Smith and Pavelsky, 2008) These local measurement stations are installed where the river flows as a single-thread channel and has a stable boundary. This is often not the case for braided rivers, where the flow is distributed through multiple and mobile threads (Smith et al, 1996; Ashmore and Sauks, 2006). Braided rivers are often not gauged; when this does occur, the gauging stations are located in places like dams with artificially regulated flow. This hinders our ability to assess discharge in the individual threads of a braided river
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
