Consider the following : 1. Braided system of Brahmaputra. 2. Frequent changes in the course of Brahmaputra. 3. Bank erosion. 4. Region prone to earthquakes and landslides. Which of the above is/are the reason/reasons for the floods in Assam?

The correct answer is 1, 2, 3 and 4. In News Torrential rainfall and landslides in the past few days have eroded sections of roads and railway tracks in Assam. Key Points Reasons for the floods in Assam are : Brahmaputra is braided and unstable in its entire reach in Assam except for a few places. The main reasons behind the instability of the river are high sedimentation and steep slopes. High percentage of flood prone region: 31.05 lakh hectares of the total 78.523 lakh hectares area of the state is prone to frequent floods. And the reasons behind this high flood prone area percentage are both man-made and natural. Assam and some other parts of the northeastern region are prone to frequent earthquakes, which causes landslides. The landslides and earthquakes send in a lot of debris in the rivers, causing the river bed to rise. Assam has also faced bank erosion around the Brahmaputra and Barak rivers as well as their tributaries. It is estimated that annually nearly 8000 hectares land is lost to erosion. Bank erosion has also affected the width of the Brahmaputra river, which has increased up to 15 km. Among the man-made reasons, the key cause of floods in Assam region is releasing of water from dams situated uphill. Unregulated release of water floods the Assam plains, leaving thousands of people homeless every year. Guwahati’s topography, it’s shaped like a bowl, thus make it susceptible to water logging. Unplanned expansion of the urban areas has led to severe encroachments in the wetlands, low lying areas, hills and shrinkage of forest cover. The river also changes course frequently and it’s virtually impossible to contain it within embankments. The pressure of the surging water takes a toll on these walls.