Exploring the Spatio-temporal Patterns and Driving Forces of Urban Growth in Dhaka Megacity from 1990 to 2020

Dhaka is one of the most populous megacities, facing rapid urbanisationRapid urbanization and population growthGrowth. It has been undergoing vast territorial expansion and infrastructural developmentDevelopment in recent decades. These uncontrolled changes in the cityCities degrade the environmental quality and reduce the health status of cityCities dwellers. Understanding patterns and drivers is critical to regulating these changes and practising sustainable managementSustainable Management. Therefore, this chapter aims to identify urban growthUrban growth patterns and their pivotal driving forcesDriving forces in the megacity. LandsatLandsat (TM, OLI sensors) satellite imageries from 1990 to 2020 were used at decadal intervals to identify change patterns. Urban LULCLand use land cover was prepared using a hybrid classification method (combining supervised and unsupervised techniques). Afterward, the driving forces of urbanUrban growthGrowth in the cityCities were investigated using spatial data layers in geodetectorGeodetector and data obtained through questionnaires survey, and previous literature. According to the analysis, the urban area increased by 40%, whereas green space declined by 41%. Major driving forcesDriving forces are anthropogenic, such as economic opportunities, education, and medical facilities, which worked as pull factors for rural–urban migrationUrban migration resulting in urban population growth. Natural determinants, such as drainage systems, inundated lands, suitable soil types and textures for building infrastructures; artificial determinants, such as distance from the city core, roads and railways worked together in shaping the spatial locations of the city expansion. To transform Dhaka into a sustainable cityCities, policymakers should regulate or control these determinants.