Sustainable Urban Drainage System Modeling for Managing Urban Surface Water Flood Risk

The identification of “critical drainage areas” to quantify “hotspot” flood and pollution risks associated with extreme event urban surface runoff is central to Stormwater Management Plans and Water Framework Directive catchment planning. An innovative geographic information system‐based 1D–2D modeling analysis coupled with a drainage assessment tool is described which addresses this methodological requirement. The modeling approach further integrates a sustainable urban drainage system (SUDS) tool called SUDSLOC to provide a stakeholder‐friendly surface water management framework. The modeling approach is illustrated by reference to two small urban catchments within the cities of Birmingham and Coventry in the Midlands region of England and the benefits of utilizing ground‐based “light detection and ranging” survey to build the surface micro‐topography are demonstrated. The performance effectiveness of the selected SUDS controls was explored and the utility of the graphical animated outputs are discussed. Whilst the implemented SUDS controls exhibit substantial reductions (>57%) in total discharge volumes for storms up to 1:30 year return periods, there are very limited volumetric reductions for storm events exceeding this return period. Accurate identification of critical drainage areas subject to pluvial flooding requires geographic information system (GIS)‐based 1D (sewer)–2D (surface) modeling with terrestrial LiDAR survey to define surface micro‐topography. The development of flood mitigating approaches demands the selection and location of appropriate sustainable drainage systems as evidenced by the SUDSLOC model and its GIS‐based decision‐support framework.