The Dhaka City has been experiencing worsening waterlogging for the last couple of years. Moderate to heavy rain causes serious problems for certain areas of the City, namely, Malibagh, Mauchak, Shantinagar, Purana Paltan, Matijheel and Green Road putting ankle to knee-deep water on the streets. The situation was highlighted in September and October 1996, when the City dwellers experienced the worst ever waterlogging.

With a view to develop a Decision Support System (DSS) for Dhaka City, the objectives of the study were aimed at understanding the underlying processes involved in the Dhaka City drainage system, application of MOUSE modelling software by developing a pilot demonstrative mathematical model for a small part of the Dhaka City, and assessment of the data availability for a detailed modelling.

As part of the modelling study, a survey was carried out to measure top elevations of sewer manholes at important locations. Combining these with the contours developed by JICA (1987), an indicative Digital Elevation Model (DEM) for the model area was developed using Arc/Info GIS. Outputs of MOUSE were analysed spatially using GIS and produced waterlogging maps (depth and duration) for the model area under different hydrological conditions. The maps represent reasonably well the physical conditions of waterlogging existed during September and October 1996.

Hence, the model results are mostly indicative. The study results indicated that a meaningful solution to the recurrent waterlogging problem of Dhaka City could be obtained from incorporating alternative drainage options which have come-out from developed mathematical models.