GUWAHATI, Feb 8 � The Brahmaputra is found to have been maintaining a braided course for the past 186 years, since 1829. Its northern tributaries are transporting huge sediment loads to its bed from their sources in the hills. These tributaries of the Brahmaputra traverse more through the hilly areas, whereas the southern tributaries of the river have defined meandering courses.
This was claimed by Prasanta Dutta, a superintending engineer of the State�s Water Resources Department (WRD) with the help of maps and satellite imagery. He was making a presentation at an interactive session on futuristic planning for the Brahmaputra river drawing lessons from the past at the concluding day of the two-day Assam Water Conference organised by the WRD at its Basistha Chariali Assam Water Research and Management Institute (AWRMI) here on Saturday.
Dutta, who has been working on the Brahmaputra for the past about two decades, said that under the impact of the loads of sediment carried by the northern tributaries of the Brahmaputra, the narrow valley of the river is facing recurring floods and its area is also reducing. On the other hand, he said the population of the valley is rising, making things more complex.
The sediment deposited in the upper reaches of the Brahmaputra bed have thin silt layers compared to the thick silt layer they have in the lower reaches of the river�s bed, he said, referring to the fertility of the sand bars in the lower reaches of the river�s bed.
Similarly, the failure pattern of the bank materials of the mighty river also varies in reaches and researchers should consider the pattern of the failure of these materials while studying the erosion caused by the river.
Earlier, taking part in an interaction with Prof Albert Wolfgang Flugel, Dutta said that the RCC porcupines laid in a reach downstream of the Saraighat Bridge over the Brahmaputra and land spurs in a reach in Futuri area have been found to be effective in land reclamation in those areas and diverting the river channel to the middle of its course.
Prof Flugel, a Professor Emeritus of the Freidrich-Schiller University, Jena, Germany, was making a presentation on a study of Guwahati Field Trial by Freidrich-Schiller University.
He said that about 60 sq km area, in a 120-km-long stretch of the Brahmaputra bank, between Guwahati and Goalpara, may be reclaimed with the help of anti-erosion measures. Referring to the satellite imagery, he claimed that there has been a distinct change in the braided channels of the Brahmaputra.