Mapping the danger to life in flash flood events adopting a mechanics based methodology and planning evacuation routes

Abstract

Extreme flood events are becoming more frequent and challenging due to climate change. Key objectives of this study are to evaluate different criteria used in assessing the hazard to people during flood events and, once determined, the most suitable method is then used to assess the hazard and the safest route(s) for evacuation during a flood event and for a particular case study. The results of the application of two criteria are analysed in terms of the flood hazard assessment with the two criteria being based on a widely used empirical approach and a mechanics based approach. Both criteria are used to assess the flood hazard to people during an extreme flash flood, which occurred on 16th August 2004 in Boscastle (UK). Results obtained for this study have highlighted that the mechanics based criteria are preferable in identifying the ideal escape routes, when considering the flood characteristics and the corresponding response of a human body. The main novelty of this study lies in linking the flood hazard rating with the human body characteristics, when determining the safest route and with a revised formula being developed, which includes the effects of ground slope in the application to a real case study.

Enhancing pedestrian evacuation routes during flood events

“…Topographic data for modelling have been extrapolated from LIDAR (Laser Imaging Detection and Ranging) data collected during a survey undertaken by the Environment Agency after the flood event. Constant roughness (Manning's coefficient) equal to 0.040 has been used for the whole catchment (Kvočka et al 2015;Musolino et al 2020b). The frequency of the flood event was estimated to be 1:400 years, with the peak discharge of the event estimated to be about 180 m 3 /s (HR Wallingford 2005;Roca and Davison 2010).…”

Experimental and Numerical Study of the Effect of Model Geometric Distortion on Laboratory Modeling of Urban Flooding

“…Elevation data from remote sensing (Neal et al., 2009; Yu & Lane, 2006) can be very detailed but they show limitations as they can be obscured by surrounding buildings and other obstacles. Moreover, flood hazard mapping requires not only the inundation extent and the flow depth but also the flow velocities (Costabile et al., 2020; Musolino et al., 2020; Xia et al., 2014), which are very hard and potentially dangerous to obtain in flood conditions. As a result, only a few studies have reported flow velocity data from measurements in urban floods.…”

Hydroinformatics education – the Water Informatics in Science and Engineering (WISE) Centre for Doctoral Training

“…if catchments have undergone significant land use change, experience more extreme rainfalls than previously recorded or see significantly changed streamflow characteristics due to the building of human infrastructure (Jain and Lall, 2001). Long-term planning in non-stationary systems requires a move away from traditional empirical approaches (widely used in operational engineering hydrology) towards process-based models which are necessarily more complex and require deeper process understanding (Milly et al, 2008;Wagener et al, 2010;Clark et al, 2015;Musolini et al, 2020). Process-based models -increasingly with unprecedented resolutions -will also demand better computational skills of their users to utilise them effectively and thus influence training and education (Hut et al, 2017).…”