Suspended sediment in the Ganges and Brahmaputra Rivers in Bangladesh: observation from TM and AVHRR data

Remote sensing was used to understand the seasonal and spatial variation of suspended sediment in the Ganges and Brahmaputra Rivers in Bangladesh for two different discharge periods. Suspended sediment concentration (SSC) in these rivers was estimated from the reflectance of Landsat TM band 3. Durin g the high discharge period, SSC in the Ganges is higher than that in the B rahmaputra. But in the low discharge period, this is reversed. Both erosion al and depositional processes are active on their:flood plains. Significant fluctuations in SSC and in suspended sediment load were observed along the ir courses because of river bank erosion and deposition and/or scouring and aggradation of river beds. Owing to scouring and turbulence, SSC increases markedly at the confluence of these rivers. Reflectance of AVHRR band 1 da ta was also analysed to study the distribution of suspended sediment along other reaches of these rivers. Like SSC, reflectance at the confluence zone increases compared with that in the Brahmaputra. However, this increase is not marked compared with the Ganges. The influence of their tributaries on the suspended sediment load could be inferred from the pattern of reflecta nce. Remote sensing data used in this study was corrected for atmospheric e ffects. Copyright (C) 2001 John Wiley & Sons, Ltd.