Dhaka City Water logging Hazards: Area Identification and Vulnerability Assessment through GIS-Remote Sensing Techniques

Water logging is one of the most detrimental phenomena continuing to burden Dhaka dwellers. This study aims to spatio-temporarily identify the water logging hazard zones within Dhaka Metropolitan area and assess the extent of their water logging susceptibility based on informal settlements, built-up areas and demographical characteristics. The study utilizes integrated Geographic Information System (GIS)-Remote sensing (RS) methods, using Normalized Difference Vegetation Water and Moisture Index, distance buffer zone from drainage streams and built-up distributions to identify waterlogged zones with a temporal extent, incorporating social and infrastructural attributes to evaluate water logging effects. All the indicators were integrated into an overlay GIS method to measure the vulnerability level across Dhaka city areas. The findings reveal that south and south-western parts of Dhaka were more susceptible to water logging hazards. Almost 30–40% of Dhaka belongs to the high/very highly vulnerable zone. Greater number of slum households were observed within high to very high water logging vulnerable zones with approximately 70% of poorly structured households. The built-up areas increased around the northern part of Dhaka across time and exposed to severe water logging issues. A holistic and integrated approach is necessary in future development plans to mitigate the risk of water logging.