Temporal Mapping and Spatial Analysis of Land Transformation Due to Urbanization and Its Impact on Surface Water System: a Case from Dhaka Metropolitan Area, Bangladesh

Temporal urban mapping develops a historical perspective of urban development by combining a variety of data sources into an integrated, multi-scale, and multi-resolution database. Temporal map and databases can be used to document human-induced land transformations in Dhaka Metropolitan Area (DMA), where the human induced land transformation rate is very high. Two main features – Arial expansion, and population increase characterize this land transformation processes as well as growth. An unplanned urbanization and landuse change has resulted into impediment of the natural drainage system, which has substantially reduced its water carrying capacity. This in turn alters the physical characteristics of the basin resulting in a change of response. Temporal urban map and database provides the baseline information for the planner and decision-makers to monitor and predict the patterns and future trends of urbanization. Temporal urban mapping relies on modern mapping techniques, such as remote sensing and geographic information systems (GIS), to capture information from both historical and modern records. The map and database highlights the profound changes to the landscape that have incrementally developed over time. In this research attempt has been made to develop several temporal databases based on historical maps/information and aerospace data to map and analyze the human induced land transformations for the Dhaka Metropolitan Area (DMA). GIS and remote sensing (RS) were used to compile and create database that provided a visual and historical perspective of the urban expansion experienced in DMA since before 1608 to 1996. This historical overview of the urban expansion was used to project the future urban expansion trend for the year 2010. This paper reviews that temporal urban map and databases have immediate applications in monitoring urban sprawl, watershed analysis, environmental assessment, hydrologic modeling, sustainable development studies and developing predictive modeling techniques to better forecast future areas of urban growth of DMA. This can also play a vital role to bridge the technological gap between different professional.