Improvement of Urban Drainage System Performance under Climate Change Impact: Case Study

Urban floods have adverse impacts on the performance of urban infrastructures and the life of residents. The floods cause heavy damages and perturbation in the serviceability of urban infrastructures as well as transportation. Therefore, different factors affecting the urban water flood characteristics should be considered in urban development planning, especially in metropolitan areas. In recent years, climate change and its consequences have affected the total components of the water cycle as well as floods. These effects are intensified in urban areas because of the anthropogenic effects they have on the water cycle, such as reducing the infiltration capacity of basins, construction regardless of the channel's right of way, and disposal of sediment and solid wastes into channels that will decrease the channels' safe carrying capacity. In this way, incorporating climate change impact on urban water studies could help to achieve more reliable results to be applied in real-time planning of urban areas through selection of best management practices (BMPs). In this study, an algorithm for selecting the BMPs to improve the system performance and reliability in dealing with urban flash floods is proposed that considers the anthropogenic and climate change effects. The suggested algorithm is applied to the Tehran metropolitan area drainage system as a case study. First, the future rainfall pattern of the study area under climate change impact is simulated. Then, the effectiveness of present and future development projects for improvement of drainage system performance is evaluated under different scenarios. Also, the effect of solid wastes and sediments carried with surface runoff in system performance is considered. Finally, feasibility of suggested BMPs and their effectiveness in urban flood management as well as their related costs and benefits are considered. The results of the study show the significance of using analytical and management tools in assessing and improving the urban drainage system. DOI: 10.1061/(ASCE)HE.1943-5584.0000317. (C) 2011 American Society of Civil Engineers.