Seasonality, barrage (Farakka) regulated hydrology and flood scenarios of the Ganga River: a study based on MNDWI and simple Gumbel model
The hydrology of the Ganga River is mainly characterized by high monsoon rainfall and seasonal variability in discharge flow. The study is focuses on both the up and down-streams of Farakka barrage. It has been executed with the help of Modified Normalized Difference Water Index using Landsat satellite images (2014), satellite based discharge data and Gumbel’s flood frequency analysis. The study aims to analyse the impacts of seasonality, floods and the construction of Farakka barrage on hydrology of the Ganga River. The study reflects higher values in annual maximum discharge near Jangipur which is probably a resultant of the extra water release from the barrage during the strong monsoon flow. The reduction of R2 value during the non-monsoon season in comparison to the monsoon season is because of the control of Farakka barrage on the discharge release. The monsoon season discharge is influenced more by the barrage than the monsoon season runoff. The magnitude of the floods in terms of their maximum daily discharge and flood volume is higher in the up-stream (Rajmahal station) than in the downstream of Farakka barrage. Furthermore, annual minor floods and floods with 10 years recurrence interval play a significant role in the river hydrology and morphology.