Flood impacts on emergency responders operating at a city-scale

Emergency responders often have to operate and respond to emergency situations during dynamic weather conditions, including floods. This paper demonstrates a novel method using existing tools and datasets to evaluate emergency responder accessibility during flood events within the City of Leicester, UK. Accessibility was quantified using the 8- and 10-minute legislative targets for emergency provision for the Ambulance and Fire & Rescue services respectively under ‘normal’, no flood conditions, as well as flood scenarios of various magnitudes (namely the 1 in 20 year-, 1 in 100-year and 1 in 1,000-year recurrence intervals), with both surface water and fluvial flood conditions considered. Flood restrictions were processed based on previous hydrodynamic inundation modelling undertaken and inputted into a Network Analysis framework as restrictions for surface water and fluvial flood events. Surface water flooding was shown to cause more disruption to emergency responders operating within the city due to its widespread and spatially distributed footprint when compared to fluvial flood events of comparable magnitude. Fire & Rescue 10-minute accessibility was shown to decrease from 100 %, 66.5 %, 39.8 % and 26.2 % under the no flood, 1 in 20-year, 1 in 100-year and 1 in 1,000- year surface water flood scenarios respectively. Furthermore, total inaccessibility was shown to increase with flood magnitude, increasing from 6.0 % to 31.0 % under the 1 in 20-year and 1 in 100-year surface water flooding scenarios respectively. Further, the evolution of emergency service accessibility through a surface water flood event is outlined, demonstrating the rapid onset of impacts on emergency service accessibility within the first 15-minutes of the surface water flood event, with a reduction in service coverage and overlap being witnessed for the Ambulance service under a 1 in 100-year flood event. The study provides evidence to guide strategic planning for decision makers prior to and during emergency response to flood events at the cityscale and provides a readily transferable method to explore the impacts of natural hazards or disruptions on additional cities or regions based on historic, scenario-based events or real-time forecasting if such data is available.