Abstract:
The present study has been conducted to investigate the influence of natural and
manmade hard points on the morphological development of the Ganges river ly~ng
within Bangladesh. This study is also aimed to identify the location of natural and
manmade hard points along the Ganges River. To carry out the study satellite images
covering the period from 1973 to 2003, aerial photographs, historical maps, borehole
data, water level and discharge data have been used. All of the data have been
collected from CEGIS office.
From this study it has been found that over the years Ganges is flowing within a
morphologically active corridor within which the channel is highly mobile. Along the
both sides of this con"idor, several locations such as Godagari, Rougtha, Talbaria,
Shilaidaha, Nazirganj Bazar, Joukura etc are identified where the boundary materials
are comprised of cohesive materials (natural hard point) of different degree with
respect to erodibility.
In addition, there are several locations where bank protection structures (manmade
structure) were implemented during the last about 100 years both in Bangladesh and
Indian portion along this river. The major identified manmade hard points in
Bangladesh portion are spur at Pakkanarayanpur in Chapai Nawabganj, revetment to
protect Godagari town, revetment and groyne to protect Rajshahi town, revetment to
protect Rajshahi Cadet College at Sarda and guide bund to protect Hardinge Bridge
at Pakshi. In Indian side, in addition to the Farakka Barrage, several locations were
identified along the right bank where bank protection structures have been set up in
the recent years.
The study findings show that the presence of any hard points (either natural or
manmade) at an aggressive bend along the Ganges river strongly influences the
morphology of that particular bend. The presence of hard point not only affects on
the erosion-accretion rate but also it influences on the erosion pattern and plan fornl
development upstream and downstream of the hard point for a certain period.
