Cities are becoming increasingly vulnerable to flooding because of rapid urbanization, installation of complex infrastructure, and changes in the precipitation patterns caused by anthropogenic climate change. This is partly because of decreasing volumetric rainfall trends in many parts of the world, which might have severe effects on reservoir yields and operational practices. In addition, more frequent and more severe intensity rainfall events can cause substantial urban inundation problems.
For many cities in the world, future projections of climate change impacts on extreme short-duration rain showers and urban drainage show significant increases in the frequency of sewer surcharge, flooding and overflow spills. At the same time, due to the difficulties and uncertainties in climate change impact modelling and analysis on the urban scales, caution must be exercised when interpreting climate change scenarios. These uncertainties can however not be used as an argument for not taking determined actions. Instead, uncertainties should be accounted for and flexible and sustainable solutions aimed at.