Urban Flooding of Greater Dhaka in a Changing Climate

Dhaka, the capital of Bangladesh and one of the world’s rapidly growing megacities, is an urban hotspot for climate risks. Located in central Bangladesh on the lower reaches of the Ganges-Brahmaputra Delta, the city faces the recurring phenomena of urban flooding and waterlogging following intense rainfall nearly every year. As a low-elevation city with a tropical monsoon climate, Dhaka has a long history of river flooding as a natural hazard. Recent major floods have been worse in terms of depth and extent of inundation and duration, especially in fringe areas, where many of the city’s poor reside. Rapid, unplanned urbanization and the gradual filling up of low-lying flood plains, rivers, canals, and other water bodies traditionally used to drain or retain water during rainfall have exacerbated the problem. A growing concern is that, in a changing climate, characterized by heavier and more erratic rainfall in the Ganges-Brahmaputra-Meghna (GBM) Basin during the monsoon season, the situation may worsen.