A Study on Seasonal Variation of Hydrodynamic Parameters of Padma River

Iskandar Haiyat Mahmud, Probir Kumar Pal, Afeefa Rahman and Anika Yunus

Padma, a major river in Bangladesh is the main distributary of the Ganges flowing generally southeast for 120 kilometres to its confluence with the Meghna river. It has been traditionally considered a dominantly meandering river but recently switching over into a braided river due to its highly susceptible nature of erosion and deposition. To identify proper behavior and seasonal hydrodynamic variation of the Padma river, different hydrodynamic parameters have been included in this study. The reach is selected from Baruria transit at upstream to Mawa at downstream. Data of hydrodynamic parameters such as water level, velocity, discharge have been sorted, analyzed and plotted for the investigation of variation of various parameters during pre-monsoon, monsoon and post-monsoon seasons. The velocity, water level and discharge are found to be maximum during monsoon than pre-monsoon and post-monsoon. Discharge and water level approximately decrease in pre-monsoon and post-monsoon period by 76.3%, 75.7% and 59.3%, 57.4% respectively in comparison to monsoon period. From the data analysis, discharge and water level have been found to be maximum in monsoon 1998. It is also known that sediment transport rate is closely related to the velocity. The analysis also shows that velocity at monsoon period increase about 50% to 65% than pre-monsoon and post-monsoon period. Therefore during monsoon, high velocity results high sediment transport rate and ultimately contributes in erosion/deposition of river bed. It is hoped that the findings of this assessment will be helpful to understand the seasonal hydrodynamic nature of the Padma river and suggest possible future development works to be implemented on this river.