THE EFFECT OF FLOOD ON ROAD USERS

THE EFFECT OF FLOOD ON ROAD USERS

ABSTRACT

Because of increased precipitation and its consequences, urban flooding has become a growing public concern. Accurate risk assessment is essential for effective urban flood management, especially in the transportation sector. The effects of flooding on road users in Lagos state, where some areas are prone to flooding, are described in this paper.

A descriptive study was conducted to assess the potential impact and risk of flooding on road users and road networks in Lagos.

The study’s population includes all road users, both motorists and pedestrians.

The results indicate that flood response is a function of precipitation spatiotemporal distribution and local characteristics (i.e. drainage and topography), and flood has a proportionate but nonlinear impact on intra-urban road traffic users. Based on our findings, we propose that there is constant flood information for smart management of the urban street network, which could be applied to other large cities where road flood risk is changing due to climate change and urbanization.

CHAPTER ONE

INTRODUCTION

1.1 Background of the study

Flooding is one of the most common and destructive natural hazards, causing significant direct losses (e.g., personal injury and property damage) and increasing indirect impacts (e.g., disruption of public services and economic activity), particularly in urbanized areas around the world (e.g. Ramos et al. 2005; Mejia and Moglen 2010; Smith et al. 2012; Wright et al. 2012). A regular pluvial flood can be caused by heavy rain on a short timescale, usually less than six hours. It is usually caused by their rapid evolution and occurs within minutes or a few hours of heavy rain (Naulin et al. 2013). There is widespread agreement that the combined effect of climate change and rapid urbanization is the primary cause.

for more frequent and intense 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 lack of short-term forecasting and warning, combined with insufficient, postponed adaptation measures (e.g. inadequate drainage capacity), severely limits the efficiency of urban flood risk management, resulting in the worsening of the consequences of these events in most cities, including Lagos.

Significant disasters associated with street networks and flooding events have occurred frequently in various urban environments such as New York and London in developed countries and Beijing and Bangkok in developing countries over the past several decades (Pitt 2008; Hung et al. 2009; NYC Emergency Management 2014). Lagos’s road networks are particularly poor. Flooding events are becoming more common as the conflict between rapid urbanization and lagging urban (infrastructure) planning emerges.

1.2 Statement of the Problem

Due to its low-lying nature in comparison to the neighborhood and high-density throughout urban territory, the urban road network may be the major asset affected first by inundations, causing not only infrastructure damage but also transportation disruption. More seriously, nearly half of all flash flood fatalities involve people trapped in their cars or fleeing in the rapid rise of open water on flooded roads (Drobot et al. 2007; Versini et al. 2010a).

Despite a high demand for understanding urban road network flood risk, very few studies have attempted to systematically examine the potential effects of flooding events on urban road systems, owing to a lack of adequate data and observations concerning road flooding. The difficulty in numerically modeling the PFF dynamics, as well as the complexity of cascading effects caused by temporary flooding on transportation systems (Suarez et al. 2005).

1.3 Aim and Objectives of the Study

The primary goal of this research is to determine the effects of flooding on road users. The specific objectives of this paper are as follows:

To gain an understanding of the current flooding situation in Lagos state.

examine the effect of flooding on intra-urban road networks

To ascertain whether flooding has increased the cost of transportation in Lagos State.

To determine whether flooding affects travel time on Lagos roads.

1.4 Research Hypothesis

The First Hypothesis

Ho: The cost of transportation in Lagos State has not increased as a result of the flooding.

Hi: In Lagos State, flooding has increased the cost of transportation.

Hypothesis No. 2

Flooding has a negative impact on Lagos road travel time.

Hi: Flooding has a beneficial effect on travel time on Lagos roads.

1.5 Significance of the Study

This study on the effects of flooding on road users is critical and will be useful to the government of Lagos state and other flood-prone states in the federation.

This study will add robustness to the existing but limited literature on the research topic.

1.6 Scope and Limitations of the Study

The city of Lagos was chosen as a case study area because its roads are particularly prone to flooding.

The Study focuses on transportation disruption rather than flooding-related infrastructure damage.

1.7 Definition of Terms

Flood: A large amount of water flowing beyond its normal limits, particularly over normally dry land.

A flood is an overflow of water that submerges normally dry land. Floods can also occur in rivers when the flow rate exceeds the capacity of the river channel, especially at bends or meanders. Floods frequently cause damage to homes and businesses that are located in natural flood plains of rivers.

Anyone who uses a road, such as a pedestrian, cyclist, or motorist, is referred to as a road user. Transportation refers to the movement of people, animals, and goods from one location to another. Modes of transport include air, land (rail and road), water, cable, pipeline and space.