Riverbank Erosion in Bangladesh

Every year millions of people of the country are affected by riverbank erosion that destroys standing crops, farmland and homestead land. It is estimated that about 5% of the total flood plain of Bangladesh is directly affected by riverbank erosion. Riverbank erosion is taking place in about 94 upazilas out of 496 upazilas/thanas of the country. Over 25,000 families were rendered homeless in June 1993 by riverbank erosion in 16 districts. During monsoon, extensive overbank spills, bank erosion and bankline shifts have become typical. 

 The unpredictable shifting behavior of the rivers and their encroachments not only affect the rural floodplain population but also the urban growth centres and infrastructures. The rivers that are highly susceptible to riverbank erosion are Ganges, Jamuna, Padma and Lower Meghna. Along the right and left banks of the Ganges, erosion rates are 56m and 20m per year respectively. The rate of widening of the Jamuna within the period 1973 to 2000 is 128m/year. In this period, the average width of Jamuna increased from 9.7 to 11.2 km. The maximum bank erosion during 1984-92 occurred at the left-bank, just upstream of Aricha. The widening of Jamuna in a 28-year period resulted in a loss of floodplain of 70,000 ha over the total 220-km length of the river in Bangladesh. Banklines of Padma are very unstable and the widening rate is 159m/year. The Lower Meghna river eroded  both its banks, causing formation of medial bars. Downstream of Chandpur, the westward bank erosion during 1984-1993 was severe with the rate of erosion at times getting as high as 824m/year, higher than the widening rate of the Jamuna during the same period (184 m/year). This erosion-accretion phenomenon is a characteristic feature of the courses of the rivers in Bangladesh and gives rise to a lot of local politics.