Integrated approach of remote sensing and field survey data in assessment of bank erosion intensity of the Padma river in Bangladesh

摘要

This study has explored the erosion intensity of the Padma river at Harirampur upazila in Bangladesh integrating the remote sensing and field survey data. The superimposing maps for the period of 1860-2009 illustrate extreme bank line migration has occurred along the Harirampur section (A-A). The northeast migration of the left bank at Harirampur was limited 2-2.6 km during the period of 1860-1963. But in the following 46 (1963-2009) years the left bank migration towards the upazila was more than 12 km and maximum left bankline migration occurred at this location where the river developed a meandering bend that sustained for long (1992-2005) 13 years. The recent remote sensing images provided that the three unions namely Azimnagar, Lesraganj and Sutalary out of thirteen unions of the upazila have been disappeared completely in the Padma while the river eroded about 90, 85, and 80 percent landmass of Harukandi, Khanchanpur and Dhulsura unions respectively. As a whole, the Padma devoured about 35625.20 acres landmass which is accounted 59.70 percent area of the upazila. The stratified questionnaire survey revealed that all the households of Lesraganj, Sutalary and Harukandi unions have experienced 2-7 times erosion frequency in their lifetime. A total 3483 families compromising of about 25,000 people were the victims of erosion during the period of 1993-1999 while 2320 families compromising of about 18560 people became landless and homeless by the ferocious erosion of the river during the period of 2000-2005. Monitoring and quantifying of bank erosion intensity is significant to have better understanding of the fluvial process and in disaster management.