Applicability of urban streets as temporary open floodways

Abstract

Climate change coupled with urbanization and its increasing impervious surfaces have caused major challenges for the water sector worldwide. In Norway, an ageing infrastructure with already insufficient drainage capacities results in large amounts of runoff during high-intensity rainfall events causing frequent floods in urban areas. Due to limited available space to handle the future projected increase in stormwater, there is a need to utilize already occupied space for stormwater management, such as roads and streets, during extreme events. Limited research has been done on the design and applicability of urban streets as temporarily flood ways diverting stormwater to the nearest recipient. This paper will study the benefits and limitations of adapting urban streets as safe flood ways to route stormwater by modelling an urban street as a floodway. Streets as floodways will require additional hydraulic performance criteria and safety criteria. Performance criteria are identified and evaluated, and a method is proposed for the evaluation of urban streets applicability as floodways. The method can be used to evaluate the applicability of multifunctional streets used as urban floodways and can be adapted by municipalities as a decision support tool for stormwater management.