| Author | Mohiuddin, Faruq Ahmed |
| Call Number | AIT Thesis no.WM-96-01 |
| Subject(s) | Sediment transport--Bangladesh--Gorai River
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering. School of Civil Engineering |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. WM-96-01 |
| Abstract | The three major rivers, the Jamuna, the Ganges-Padma and the Meghna with their
inflows and outflows from tributaries and distributaries make up the largest delta of
Bangladesh in the whole world. The Gorai is the major distributary of the Ganges River as
well as supplier of freshwater to the South-West Area (SWA). Especially the dry season
supply of freshwater, which has been decreasing over the latest years is important for the
natural ecosystem, water resources and navigation of SW A. Morphological changes due to
upstream abstraction and control of the Ganges flow at Farakka barrage in India, may be partly
responsible for the decrease. Several mechanisms are available to improve the Gorai flow,
some with control structures and some without.
The most favourable options with dredging the Gorai mouth and about 30 km
downstream of the river are considered to see the impact on planform changes including
morpho-dynamic consequences. Planform characteristics could be determined from satellite
images taken during the low flow conditions. Furthermore, data on discharges, water levels,
cross-sections and bathymetry, bed material size, etc. were analysed to verify the behaviour of
changed planform in terms of morphological consequences. To get a clear understanding of the
planform development, investigated the reason for bar formation, siltation problem, erosion
potential, effect of morpho-dynamic consequence scenarios, etc. The results of twodimensional model were considered as a demonstration of the offtake mechanisms in terms of
one-dimension based on short term development. Finally, one dedicated version of
mathematical model was developed with application scenarios that can be used for planning
and management of Gorai River offtake features at medium-term intervals.
The following favourable measures are derived from the analyses of results of the
historical data analysis, interpretations of two-dimensional model and one-dimensional model
results. Dredging itself is not only the solutions to mitigate the siltation problem at offtake due
to variable hydraulic characteristics, disorganised planform patterns. The dredging operations
would be successful to get a long term benefit, if the river training works, such as bank
protection from erosion, artificially shift the main channel flow alignment took into account
simultaneously. It is recommended required minimum flow in the Ganges must be ensured in
the dry season to maintain the sufficient flow into the Gorai. |
| Year | 1996 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. WM-96-01 |
| Type | Thesis |
| School | School of Civil Engineering |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Water Engineering and Management (WM) |
| Chairperson(s) | Suphat Vongvisessomjai ; |
| Examination Committee(s) | Kyotoh, Harumichi;Sutat Weesakul;Paudyal, Guna Nidhi; |
| Scholarship Donor(s) | Danish International Development Agency (DANIDA) ; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1998 |