Design of urban storm water drainage network using EPA SWMM and WMS

• Main Authors: Alam, Siam, Yunus, Anika
• Format: Conference Proceeding
• Language: English
• Subjects: Catchments; Conduits; Drainage; Drainage systems; Flood mapping; Land use; Mathematical models; Rainfall; Runoff; Satellite imagery; Simulation; Stormwater
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0129838

In the southern portion of Dhaka, adjacent areas like Shantinagar, Rajarbag, Motijheel, Naya Paltan, Puran Paltan, T&T Colony can be called the busiest economic hub of South Dhaka. Almost all of these areas are included in DWASA Zone 6 and the whole region is one the most highly urban flood susceptible regions of Dhaka. These areas get inundated even in the slightest amount of rainfall. This study focuses on designing an adequate drainage system for this economic hub of Dhaka. It is hoped that this research may be helpful to related organizations and experts in solving the drainage congestion problem of Dhaka city. In this study, different parameters of each sub-catchments, conduits, junction node, and outlets are calculated through EPA SWMM 5.1. Initially, the whole drainage network (including sub-catchments and junctions) was drawn on ArcGIS 10.4.1. There are in total 141 sub-catchments, 665 junction nodes, 678 conduits, and 4 outfalls. The whole network was then transferred to WMS 11.0 where the outlets were denoted and the sub-catchments were delineated and a 1D schematic map was created. Afterward, the map was transferred to EPA SWMM 5.1, and data like invert elevation, % slope, % impervious, and many more were inserted into the model. After the model simulation, runoff coefficients of every sub-catchments were obtained. In around 42 sub-catchments, the peak runoff was greater than or equal to 0.1 m3/s. Runoff coefficients for every sub-catchments were simulated from the model. These values are calibrated to match the estimated values from the land use map of the study area (generated from satellite images). The RMSE value for this comparison was 0.0048. The total runoff volume from the model simulation is used to design the minimum cross-section of every conduit which is the prime objective of this study. These conduit areas ranged between 0.00125m2 to 6.8725m2. Apart from these, flood hazard maps, flood risk maps, and % slope maps were also created using ArcGIS for supporting different causes.