AN EXAMINATION OF HEAVY DOWNPOUR AS A CAUSE OF BUILDING COLLAPSE IN LAGOS STATE (MUSHIN INCIDENCE, 2024)

CHAPTER ONE

INTRODUCTION

Background of the Study

Over the past few years, Nigeria has experienced a significant increase in construction failures, leading to the loss of both lives and properties. However, media recently reported on the occurrence of building collapses in major Nigerian cities such as Lagos, Abuja, and Jos, as well as in other parts of the world. As the consequences of climate change become increasingly evident worldwide, it is now understood that no country, including Nigeria, is immune from its impacts. Nevertheless, the phenomenon of climate change is causing a rise in both the frequency and severity of extreme weather events, and these impacts are already observable throughout Nigeria.

More so, the swift growth of informal settlements and insufficient building rules lead to the spread of poor structures that are susceptible to environmental pressures, such as heavy rainfall. Heavy rainfall is a significant factor that exacerbates the city's susceptibility to floods, in addition to other contributing factors. According to  Mukhopadhyay (2020), flood occurs when an abundant quantity of water accumulates and rises to a level that leads to it spilling over into areas that are not usually flooded. Likewise, flooding can result from various factors such as prolonged seasonal rainfall, intense rainstorms, dam malfunctions, accumulation of precipitation in low-lying areas with a high water table, or inadequate storm drainage. Floods can also occur when seawater enters coastal regions due to cyclonic or tidal surges (Handmer, Penning-Rowsell, and Tapsell, 2019; Stoltman, Lidstone, and DeChano, 2017).  Lagos State, being a swiftly expanding metropolis, has significant obstacles associated with urbanisation and infrastructure advancement. The heavy rainfall during the rainy season in Lagos State poses substantial dangers to the structural integrity of buildings. Extended or severe precipitation elevates the hydrostatic pressure exerted on the foundations and walls of buildings, resulting in soil erosion, instability of the foundation, and gradual degradation of the structure. Beyond that, inadequately designed structures, frequently missing sufficient reinforcement and waterproofing measures, are especially vulnerable to water penetration and structural deterioration during intense rainfall. These elements cumulatively enhance the probability of building collapses, posing a threat to residents and nearby structures (Oyedepo et al., 2023). 

Furthermore, Mushin, a highly populated region in Lagos State, serves as a prime example of these difficulties, since several structures have been erected without compliance to safety regulations, and inadequate drainage systems further intensify the threat of flooding (Ojo et al., 2023). Nevertheless, the occurrence of building collapse is rapidly becoming a widespread issue that has received minimal attention in terms of prevention, particularly in developing nations.  Therefore, a survey will be conducted in order to examine heavy downpour as a cause of building collapse in Lagos state

Statement of the Problem

It is no doubt that one of the essential criteria for a building is that its construction is solid and that it can serve its intended purpose effectively during its entire duration. Buildings are architectural constructions specifically engineered to withstand various live loads, including the weight of people, objects, wind pressure, and heavy rain, in addition to their own dead loads. However, any failure in this regard may result to a complete collapse of the structure.  Contextually, the inhabitants residing in the low-lying coastal regions of Southern Nigeria, namely in Lagos, are facing a significant risk. Approximately 50% of the residents of Lagos, primarily residing in slums, are vulnerable to this peril. All of these factors will result in harm to the limited existing infrastructure and pose risks to the safety and well-being of the population.

Additionally, Zack and Jane (2022) maintained that an obvious issue lies in the structural weaknesses of buildings in Lagos State, specifically in heavily populated regions such as Mushin. A significant number of structures are inadequately built, frequently failing to comply with building laws and requirements. This includes insufficiently designed foundations, substandard construction materials, and inadequate reinforcement against environmental pressures like intense rainfall. For instance, a recent incidence of a two storey building that collapsed on July, 3rd, 2024 in Mushin amid the heavy rainfall (TheCable, 2024) . The latest incident adds to the growing list of building collapse in Lagos.  Furthermore, according to Ogunsemi et al. (2023), buildings are increasingly vulnerable to structural collapses during severe weather conditions, such as intense rainfall, which endangers the safety and lives of occupants.

Whereas existing g studies has looked at impact of flood in coastal areas in Nigeria, little or no attention has been paid to impact of heavy downpours on structure collapse Hence, it is in the light of these that the study seeks to examine heavy downpour as a cause of building collapse in Lagos state.

 1.3  Objectives of the Study

The main purpose of this study is to examine heavy downpour as a cause of building collapse in Lagos state. Specifically, the study will;

Determine the extent to which heavy downpour contributes to building collapse in Mushin, Lagos state

Find out whether inadequate drainage infrastructure contributes to building collapses during heavy downpour in Mushin, Lagos state.

Evaluate consequences associated with building collapse as a result of heavy rainfall in Mushin, Lagos state.

Proffer recommendation on how to effectively prevent possible flood occurrences as a result of heavy rainfall in Mushin, Lagos state

1.4  Research Questions

The following questions have been prepared for the study:

To what extent does heavy downpour contribute to building collapse in Mushin, Lagos State?

Does inadequate drainage infrastructure contribute to building collapses during heavy downpours in Mushin, Lagos State?

What are the consequences associated with building collapse as a result of heavy rainfall in Mushin, Lagos State?

1.5 Research Hypotheses

H0: Heavy downpour is not a significant cause of building collapse in Lagos State.

Ha: Heavy downpour is a significant cause of building collapse in Lagos State.

1.6 Significance of the Study

The findings will enable urban planners to design urban development plans and infrastructure projects that are more resistant to floods. Possible solutions may include the implementation of improved drainage infrastructure, flood control methods, and land-use policies aimed at reducing the vulnerability of Lagos Island to future floods.This includes enhanced drainage infrastructure, flood prevention measures, and land-use rules designed to decrease the susceptibility of Lagos Island to future flood occurrences.The study will also contribute to the academic fields of environmental science, agricultural economics, and disaster management by providing empirical data on the relationship between flooding and agricultural productivity. This means that other students who may decide to conduct studies in this area will have the opportunity to use this study as available literature that can be subjected to critical review. 

1.6 Scope of the study   

The scope of this study is boarded on heavy downpour as a cause of building collapse in Lagos state. Empirically, this study will determine the extent to which heavy downpour contributes to building collapse, find out whether inadequate drainage infrastructure contributes to building collapses during heavy downpour, evaluate consequences associated with building collapse as a result of heavy rainfall and proffer recommendation on how to effectively prevent possible flood occurrences as a result of heavy rainfall.

Geographically, the study will be delimited to residents of Lagos state

1.7 Limitation of the study

In the course of carrying out this study, the researcher experienced some constraints, which included time constraints, financial constraints, language barriers, and the attitude of the respondents. In addition, there was the element of researcher bias. Here, the researcher possessed some biases that may have been reflected in the way the data was collected, the type of people interviewed or sampled, and how the data gathered was interpreted thereafter. The potential for all this to influence the findings and conclusions could not be downplayed. More so, the findings of this study are limited to the sample population in the study area, hence they may not be suitable for use in comparison to other schools, local governments, states, and other countries in the world.

 1.9 Definition of Terms

Heavy rain: intense precipitation characterized by a significant amount of rainfall within a short period.It often leads to various impacts such as flooding, disruption of transportation, damage to infrastructure, and occasionally, loss of lives and property.

Flood: the overflow of water onto normally dry land due to heavy rainfall, poor drainage systems, or other contributing factors.

Disaster: is a sudden, catastrophic event that causes significant disruption, damage, or destruction, often resulting in loss of life, property, and resources.

Climate: refers to the long-term patterns and average conditions of temperature, humidity, wind, precipitation, and other atmospheric variables in a particular region over extended periods.