Articles | Volume 17, issue 1
https://doi.org/10.5194/nhess-17-1-2017
https://doi.org/10.5194/nhess-17-1-2017
Research article
 | 
03 Jan 2017
Research article |  | 03 Jan 2017

City-scale accessibility of emergency responders operating during flood events

Daniel Green, Dapeng Yu, Ian Pattison, Robert Wilby, Lee Bosher, Ramila Patel, Philip Thompson, Keith Trowell, Julia Draycon, Martin Halse, Lili Yang, and Tim Ryley

Abstract. 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 min legislative targets for emergency provision for the ambulance and fire and rescue services respectively under "normal" no-flood conditions, as well as flood scenarios of various magnitudes (1 in 20-year, 1 in 100-year and 1 in 1000-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 and rescue 10 min 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 1000-year surface water flood scenarios respectively. Furthermore, total inaccessibility was shown to increase with flood magnitude from 6.0 % under the 1 in 20-year scenario to 31.0 % under the 1 in 100-year flood scenario. Additionally, the evolution of emergency service accessibility throughout a surface water flood event is outlined, demonstrating the rapid impact on emergency service accessibility within the first 15 min of the surface water flood event, with a reduction in service coverage and overlap being observed for the ambulance service during 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 city scale. It also provides a readily transferable method for exploring the impacts of natural hazards or disruptions in other cities or regions based on historic, scenario-based events or real-time forecasting, if such data are available.

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Short summary
This paper demonstrates a novel method of evaluating emergency responder accessibility at the city scale during fluvial and surface water flood events of varying magnitudes. Results suggest that surface water flood events within the city of Leicester, UK, may cause more disruption to emergency responders when compared to fluvial flood events of the same magnitude. This study provides evidence to guide strategic planning for decision makers prior to and during flood events.
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