Flood dynamics of wetlands in Bangladesh

Flood dynamics of the wetlands of Bangladesh

Bangladesh is covered with large areas of wetland. These wetlands are an important part of Bangladesh livelihood, as they provide goods, services and food sources that otherwise would not be available.

The physical settings of Bangladesh provides a few clues for the abundance of wetlands:

• The climate in Bangladesh has a very distinct monsoon (wet) period. The months of April-September is the rainy season, and gives more than 1700 mm of rain (of a yearly total of over 2100 mm). This enormous amount of water easily saturates the soil.

• Bangladesh is the delta (lowest part) of three major rivers: Ganges, Brahmaputra and Meghna, which together drain the Southern slopes of the Himalayas. These rivers have high water levels during the same period that the monsoon saturates the soils.

• Slopes in Bangladesh are low. Land elevations in Bangladesh are low. Combined these three characteristics mean that an enormous amount of water is falling on a very flat area, of which the major drainage system is already chock-full of water. Drainage is severely congested, and thus the land is inundated.

During the monsoon season large parts of the lower land gets covered with over 30 cm of water, at some places reaching up to more than 2 meter.

Seasonal flood dynamics Haor region

Extreme situation June 2022

Normal inundation situation

Natural inundations versus human induced inundations

The water management community should start asking the hard questions again: Were we prepared for this situation? Could we have prevented the current disaster? Is there an adequate disaster response plan in place? Did human interventions aggravated the situation? As always, water management is only worth its salt if it improves the livelihood of people. Did we do that?

‘The present floods across the north-east haor region are mostly triggered by human causes’

Seasonal flood dynamics Atrai basin

About

The images in this document have been produced using Google Earth Engine and its archive of Landsat images. Many kudos go to Qiusheng Wu for providing the excellent tools for creating timelapses of Google Earth Engine data.