City-scale accessibility of emergency responders operating during flood events

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

doi:10.5194/nhess-17-1-2017

Abstract

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.

Highlights

Floods are one of the most significant natural hazards, affecting 116 million people globally, causing approximately 7000 deaths and damages in the region of USD 7.5 billion annually (UNESCO, 2010)
Green et al.: City-scale accessibility of emergency responders operating during flood events considerable work has focused on understanding the UK’s direct flood risk, flooding often has associated indirect or cascading impacts that extend beyond the area experiencing inundation
Flooded transport infrastructure may affect the transit of vehicles across the network (Gil and Steinbach, 2008; Lhomme et al, 2013; Yin et al, 2016), which is of particular importance to the emergency services that may be required to respond to emergency calls during flood events

Summary

Introduction

Floods are one of the most significant natural hazards, affecting 116 million people globally, causing approximately 7000 deaths and damages in the region of USD 7.5 billion annually (UNESCO, 2010). Indirect impacts relate to a series of interconnected or related infrastructural failures that are initiated by a natural hazard or disturbance such as a flood event (Pescaroli and Alexander, 2015). Critical infrastructure, such as utility services, hospitals, emergency service locations (police, ambulance, and fire and rescue stations), and the transportation networks that connect these services are susceptible to flooding (Douglas et al, 2010; Stålhult and Andersson, 2014). Flooded transport infrastructure may affect the transit of vehicles across the network (Gil and Steinbach, 2008; Lhomme et al, 2013; Yin et al, 2016), which is of particular importance to the emergency services (e.g. fire and rescue, ambulance, police) that may be required to respond to emergency calls during flood events

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Conclusion