Modeling flow of the major canals of Sylhet city using the EPA SWMM runoff model

Abstract

Geographically, local canals in Sylhet city, Bangladesh, mostly transport the rainwater to the Surma River as the city lacks typical drainage infrastructure for runoff control. Hence, proper hydraulic and hydrologic models are required to assess the current potential of these canals to withstand significant runoff and enhance the protection of flood problems during a severe storm. In this study, Malni Chara and Goali Chara sub-systems of Sylhet city's major drainage networks were calibrated and verified using the EPA Storm Water Management Model (SWMM), respectively, using the hydrological data from 2016 to 2019 and the meteorological data from 1975 to 2019. The models were suitable for measuring the runoff quantity since the simulated results matched the observed data well. For the Malni Chara sub-system, R2 of 0.94, Nash–Sutcliffe efficiency (NSE) of 0.92, d of 0.97, percent bias (PBIAS) (%) of 2.96%, and RMSE standard deviation ratio (RSR) of 0.05 have been found and for the Goali Chara sub-system, R2 of 0.96, NSE of 0.90, d of 0.93, PBIAS (%) of 1.54%, and RSR of 0.08 have been found. HIGHLIGHTS The innovative SWMM-based flood model for Sylhet, Bangladesh, addresses data scarcity and serves globally.; Unique sub-system analysis improves drainage capacity accuracy.; The robust SWMM model calibration and verification ensure reliability.; Canal response to the 25-year design rainfall informs urban planning.; Transferable findings benefit data-scarce flood-prone areas worldwide.;

Keywords

• drainage
• goali chara
• malni chara
• runoff
• swmm
• sylhet