THE EFFECT OF FLOOD ON ROAD USERS
Urban flooding has attracted growing public concern due to rising intense precipitation and increasing consequences. Accurate risk assessment is critical to an efficient urban flood management, particularly in transportation sector. This paper describes the effects of flood on road users in Lagos state, where some areas are prone to flooding.
A descriptive study to evaluate the potential impact and risk of flood on road Users and road networks in the city of Lagos.
The population of the study includes all the road users from both Motorist and pedestrian.
Results suggest that the flood response is a function of spatio-temporal distribution of precipitation and local characteristics (i.e. drainage and topography), and flood is found to lead to proportionate but nonlinear impact on intra-urban road traffic Users.
Based on the findings we suggest that there is constant flood information for smart management of urban street network which may be applied to other big cities where road flood risk is evolving in the context of climate change and urbanization.
1.1 Background of the study
flooding is among the most common and destructive natural hazards, resulting in considerable direct losses (e.g. personal injury and property damage) and increasing indirect impacts (e.g. interruption of public services and economic activities), especially in the urbanized areas around the world (e.g. Ramos et al. 2005; Mejia and Moglen 2010; Smith et al. 2012; Wright et al. 2012). Flood can be caused by heavy rain can be a regular pluvial flood by a short timescale, generally less than six hours. It is usually by their very fast evolution and occurs within minutes or a few hours of excessive rainfall (Naulin et al. 2013). There exists a broad consensus that the combined effect of climate change and rapid urbanization is generally recognized as the primary cause for more frequent, heavier rainfall-runoff (IPCC, 2013; Du et al. 2012; Suriya and Mudgal 2012; Zhou et al. 2012). Furthermore, the lack of anticipation of flooding events such as the unavailability of short-term forecasting and warning, combined with insufficient, postponed adaption measures (e.g. inadequate drainage capacity) largely limit the efficiency of urban flood risk management, leading to the enhanced consequences of these events in most cities like lagos.
Over the past several decades, the significant disasters associated with street networks and flooding events have been frequently occurring in different urban environments such as New York and London in developed countries as well as Beijing and Bangkok in developing countries (Pitt 2008; Hung et al. 2009; NYC Emergency Management 2014). Road networks in Lagos are particularly vulnerable to flooding events as the conflict between rapid urbanization and the lagging urban (infrastructure) planning is emerging onto the surface.
1.2 Statement of the Problem
In all the flood prone areas, urban road network may be the major assets affected first by inundations, which cause not only infrastructure damage but also transportation disruption, due to its low-lying nature compared to the neighborhood and high-density throughout urban territory. More seriously, almost half of the flash flood casualties involve people on flooded roads by trapping in their cars or by escaping in the rapid rise of open water (Drobot et al. 2007; Versini et al. 2010a).