How do the Brahmaputra River and hill streams contribute to flooding in Assam?

Flooding in Assam is a recurring and destructive phenomenon driven by the region's unique hydrology and geography.

The Brahmaputra River contributes significantly to flooding due to the enormous volume of water it carries, which is exacerbated by the monsoon climate. The valley receives over 100 inches of annual rainfall, with the heaviest precipitation occurring between June and September. The river’s northern tributaries, originating from rain-soaked Himalayan slopes, carry a heavy silt load that increases the river's speed and volume, often pushing the main channel toward the southern bank.12

Hill streams also play a critical role in regional flooding. Numerous streams and rivulets flow from the surrounding mountains into the Brahmaputra. These streams can become particularly dangerous when their courses are blocked by landslides—often triggered by the earthquakes common to the region—creating natural dams. When these dams burst, they release sudden, catastrophic floods that can cause more destruction than the initial seismic event.3