An applied geomorphological study on the selected bridge site along the Brahmaputra- Jamuna River in Bangladesh.

Abstract

The Bangladesh government requested that Japan build a bridge across the Brahmaputra-Jamuna River. Shifts in the river course are extreme, a major change from the Old-Brahmaputra River course having occurred between l720 and l830, and it seems impossible to stabilize the river bed. Oya investigated four sites and made a l:50,000 geomorphological classificatory map of the river's banks from aerial photographs and a similar l:l00,000 map of the Brahmaputra-Jamuna and Ganges Rivers' Plain from Landsat I imagery. The maps revealed that the natural levees from Sirajganj south are on an old alluvial plain with narrows that should last for about one hundred years, while the Gabargaon site is on an alluvial fan which was formed only l80 years ago and is likely to experience a shift in the near future. -Richard Louis Edmonds