IJEP 43(2): 184-192 : Vol. 43 Issue. 2 (February 2023)
Sunny Agarwal and Sanjeet Kumar*
Koneru Lakshmaiah Education Foundation, Department of Civil Engineering, Guntur, Andhra Pradesh – 522 502, India
Abstract
Urbanization aggravates floods by increasing impermeable surfaces and by modifying flow routes. The increase in the impervious area associated with urban development affects the hydrologic cycle and consequently, there is an enhanced risk due to urban flooding. Presently stormwater management model (SWMM) is setup for flow routing and to check the adequacy of the drainage networks to cater for the extreme rainfall events of Vijayawada city. Daily rainfall events of 23rd July 1989 having magnitude of 198.6 mm (historical); 22nd June 2026 having magnitude of 232.49 mm (RCP 4.5) and 24th June 2044 having magnitude of 173.35 mm (RCP 8.5) was used as rain gage data for the model. Modified green-Ampt method was used for the infiltration and dynamic wave method was chosen for flow routing while non-linear reservoir method was considered to simulate the rainfall-runoff process. The study indicated the capability of the model to visualize the outflows at nodes and channel sections. The runoff volume contributed by the imperious surface is 85.48-96.87% of total runoff for all sub-catchments which favours incorporation of various lower impact developments (LID) and best management practices (BMPs). For RCP 4.5 scenario model simulated 9-11% more runoff volume while for RCP 8.5 scenario it is generating 3-6% less runoff for each sub-catchments as compared to historical rainfall events. This study approach is helpful to assess future floods and guide policymakers in designing adequate urban drainage systems in developing cities across the globe.
Keywords
Stormwater management model, Modelling, RCP, Urban flood, LID, Best management practice
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