Evaluating urban stormwater drainage using GIS and RS techniques—a case study in Dhaka, Bangladesh

A method is described, integrating Geographical Information System (GIS) functions, remotely sensed images and hydrologic data, to assess the impact of urbanisation on stormwater runoff and drainage. A sample area is selected in the western part of Dhaka City. First, the urbanization trend of Dhaka was assessed, using multitemporal aerial photographs and satellite images. By combining a spaceborne panchromatic image, the digital terrain model (DTM) and reported hydrological data, an assessment was made of the areal extent of the inundations by stormwater runoff within a specific urban drainage area. The DTM was then modified to accommodate expected urbanization trends and conditions. An assessment was then made of the areal spreading and inundation by the floodwaters, illustrating the impacts of future urbanization on urban storm water drainage