With the rapid urbanization and development of city infrastructure, combined with the reduction of water storage and percolation areas, recent flooding and water logging from local rainfall combined with river spills has reached a dangerous magnitude. The drainage in Dhaka is dependent on two aspects:
- Operation of a storm-water drainage system including pumps and regulators
- Water levels on peripheral rivers
Thus, flooding in Dhaka may occur due to: congestion of storm-water/wastewater drainage systems inside the City area; the high water level in the peripheral rivers under which circumstance drainage is only possible through pumping; and the intrusion of floodwater from the peripheral rivers to city area through the drainage routes. In the future, the rise of rainfall intensity and sea level due to climate change will increase flood risk in Dhaka. This will be compounded by population growth and the resulting boost of unplanned development.