Urban drainage challenges and mitigation approaches in Sylhet city

This study focuses on the urban drainage problems in Sylhet City, which is susceptible to flooding because of its particular location and hasty urbanization. The study examines the existing situation of the drainage system in Sylhet which achieves the main shortcoming of Sylhet’s drainage in terms of blockage, pollution and lack of maintenance, causing poor water dissemination and continual occurrence of urban flood. This is further compounded by uncontrolled and illegal expansion and development that encroach on natural water bodies which subsequently interfere with the natural flow of water and minimize the capacity for drainage. Based on hydrological and hydraulic modelling calculation of the main canals, critical flood ⁃ prone zones and constrained areas for the drainage are emphasized in this study. It also evaluates the effect of other infrastructure development practices such as road-raising on drainage functionality. Its research suggests an integrated suite of mitigation options that could combine structural measures such as canal dredging and stormwater management improvements with non-structural actions such as urban planning changes, engagement with communities and installation of sustainable drainage systems. Emphasis is given to the combination of nature-based solutions with advanced monitoring and controlling devices of the urban drainage network. The results suggest the needs of coordination of local governments and planners, as well as society, to improve the drainage capacity and prevent water logging. This research offers policy advice for future urban planning and development intended to enhance flood resilience and quality of life in Sylhet City.