RIVER BANK EROSION HAZARD STUDY OF RIVER GANGA, UPSTREAM OF FARAKKA BARRAGE USING REMOTE SENSING AND GIS

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Praveen K Thakur

Water Resources Department (WRD), Indian Institute of Remote Sensing (IIRS),

Indian Space Research Organisation (ISRO), 4-Kalidas Road Dehradun

 Abstract 

This work has been carried out to analyze and report the river bank erosion hazard due to morphometric change of the Ganga River in the upstream of Farakka Barrage upto Rajmahal. Morphometric parameters, such as, Sinuosity, Braidedness Index and percentage of the island area to the total river reach area were measured for the year of 1955, 1977, 1990, 2001, 2003 and 2005 from LANDSAT and Indian Remote Sensing Satellite (IRS) images. The analysis shows that there is a drastic increase in all of those parameters over the period of time. This study has found that bank failure is because of certain factors like, soil stratification of the river bank, presence of hard rocky area (Rajmahal), high load of sediment and difficulty of dredging and construction of Farakka Barrage as an obstruction to the natural river flow. For the increasing sinuosity, the river has been engulfing the large areas of left bank every year. The victims are mostly Manikchak and Kaliachak-II blocks of Malda district, with a loss of around 1670 ha agricultural land since 1977. Temporal shift measurements for the river reach between Farakka and Rajmahal has been done with help of 22 cross-sections in this reach. Erosion impact area has also been estimated to emphasize the devastating nature of the hazard.