Digital Modeling of Bar (Char) Incidence and Assessment of Braiding Intensity of the Padma River in Bangladesh

Abstract

This study has prepared bar (char) incidence map and assessed braided intensity of the Padma River in Bangladesh. GIS techniques have integrated the spatial data (satellite images) and attribute data to identify the char’s location and assess the braiding intensity on the Padma riverbed. According to the bar prepared maps chars have been developed in the reaches in the south of Harirampur, northeast of Faridpur district and upstream of the Padma Bridge crossing. But chars had never existed at the downstream of Paturia and close to the left bank at Mawa. The young chars with ages below eight years are 48%. The longstanding chars between 8-20 years are almost the same (43%) in the char incidence map. But the very long duration chars appeared only 9% on the river bed. In the late 1960s and early 1970s, the braiding intensity of the Padma River was 1.63 and 1.75 which is very close to each other. During 1976 to 1984, the braiding intensity dropped to a minimum, the range of which varied from 1.38 to 1.50. The braiding intensity started to rise very rapidly from the early 1990s and reached its peak value of 2.13 in 1997. The sediment input also cause changes in bed level, width and braiding intensity of the river.