Developing surface water flood forecasting capabilities in Scotland: an operational pilot for the 2014 Commonwealth Games in Glasgow

Existing surface water flood forecasting methods in Scotland are based on indicative depth-duration rainfall thresholds with limited understanding of the likelihood of inundation or associated impacts. Innovative risk-based solutions are urgently needed to advance surface water forecasting capabilities for improved flood resilience in urban centres. A new model-based solution was developed for Glasgow, linking 24-h ensemble rainfall predictions from the Met Office Global and Regional Ensemble Prediction System for the UK (MOGREPS-UK) with static flood risk maps through the Grid-to-Grid hydrological model. This new forecasting capability was used operationally by the Scottish Flood Forecasting Service during the 2014 Commonwealth Games to provide bespoke surface water flooding guidance to responders. The operational trial demonstrated the benefits of being able to provide targeted information on real-time surface water flood risk. It also identified the high staff resource requirement to support the service due to the greater uncertainty in surface water flood forecasting compared to established fluvial and coastal methods.