ANALYZING THE ENVIRONMENTAL CONSEQUENCES OF FLOODING ON WATER QUALITY AND SANITATION IN LAGOS STATE

CHAPTER ONE

INTRODUCTION

Background of the Study

The prevalence of flooding in Nigeria is unparalleled among other types of disasters. Nigeria's states are experiencing escalating annual flooding throughout the rainy seasons due to heightened precipitation associated with climate change (Aja and Olaore 2024). The flooding in Nigeria is primarily caused by human activities, particularly due to the prevailing practices of bad urban planning and the lack of sufficient environmental infrastructure, which further worsen the problem. Lagos State is one of the fastest-growing urban centers in Africa, characterized by rapid population growth and unplanned urban development. The expansion of informal settlements and inadequate drainage systems exacerbates the city's vulnerability to flooding during the annual rainy seasons. Floodwaters overwhelms the existing infrastructure, including roads, bridges, and drainage networks, leading to widespread inundation of residential areas and public facilities, including healthcare facilities (Adesina et al., 2023).

Moreover, fflooding in Lagos is exacerbated by insufficient drainage infrastructure. For instance, communities in Lagos state, known as a 'ghetto' with longstanding issues of overcrowding, poor sanitation, and inadequate healthcare facilities common in many sub-Saharan countries, flooding poses significant challenges. These floods are associated with waterborne diseases (CIA World Factbook, 2023). Situated on low-lying land surrounded by rivers, creeks, and a lagoon, Lagos state coastal location makes it highly susceptible to flooding during heavy rainfall, exacerbated by water releases from the Oyan Dam and overflow from the Ogun River. These floods, lasting for days at times, severely impact water quality and sanitation .

It is worthy to note that the issue of flooding in the Lagos state is mostly caused by inadequate drainage systems, the relatively high water table, and the flat geography of the area (except the northernmost half). These factors impede the flow of surface water run-off and hinder its quick discharge into the sea. The flooding of Lagos state typically arises from a confluence of human and natural elements. The human causes contributing to the issue include inadequate wastewater disposal and other unsanitary habits, such as blocked drains caused by garbage, silt, sludge, and similar substances. The natural variables that contribute to drainage issues are rainfall, flat topography, and inadequate infiltration. However, these negative effects can be significantly mitigated via proper planning, design, operation, and maintenance of drainage systems. 

Although, multiple sanitation systems are presently employed in Lagos. These encompass both private and government arrangements. The sanitation procedures in use in Lagos state vary, including "bush" (or no system), pit latrines, VIP latrines, pour-flush toilets (due to water scarcity), standard water closets, and water borne sanitation and sewerage systems in certain areas. However, there are still many regions in the State that do not have sufficient sanitation coverage to suit the demands of the population. This dilemma is increasingly evident as many individuals now defecate into plastic bags and dispose of them haphazardly (Aderogba, 2024). The widespread and severe diffuse pollution connected with this technique is significant. 

Nevertheless, the dangers associated with ground and surface water in many regions of Lagos are often significant due to unsanitary and insufficient provisions for excreta and sewerage disposal, both for domestic and commercial purposes. Therefore, a survey will be conducted in order to analyze the environmental consequences of flooding on water quality and sanitation in Lagos state.

1.2 Statement of the Problem

In the major residential neighbourhoods of Lagos, the primary sanitation systems in place are the conventional pit latrines and water closet septic tanks. According to Babalobi (2018), the primary environmental issues in the Lagos state revolve around the management of sewage and other associated effluent, including their collection, treatment, and disposal.  Despite the restriction on the use of pail systems (bucket latrines) in Lagos by the government, specifically the Sewage and Water Department of the State Ministry of Environment, has not yet developed an effective method for disposing of the septage from septic tanks and soakaways. 

Consequently, all of these unprocessed bodily waste, along with the business and industrial effluent, are typically released into the Lagos lagoon system, other bodies of surface water, and occasionally infiltrate the groundwater. This leads to the hazards of water contamination and devastates marine fauna and aquatic food resources in the city. Moreover, the issue of domestic water pollution arises due to the high water table in certain regions of the city, where the water table is located close to the surface, often within a depth of 3 metres (Bolle et al., 2021). The permeable nature of the soil enhances the likelihood of sewage and other pollutants seeping into and contaminating groundwater and well water, which serve as primary water supplies in numerous regions. In the majority of households in the city, it is evident that the way they dispose of their wastewater is unsanitary and unsuitable. As an illustration, septic tanks are exclusively connected to toilet wastes, whilst other liquid wastes from households are immediately released into storm water drains located in front of the dwellings. In locations with high population density, the discharge is usually on the street in the absence of a drainage system (Aderogba,2024). 

Additionally, iinadequate disposal of industrial and home liquid waste, including both toxic and non-toxic substances, as well as human waste, results in significant soil contamination and the pollution of ground and surface water, particularly in coastal cities like Lagos (Echendu, 2020). However, due to the lack of wastewater collection systems, the wastewater produced from the decomposition of biodegradable materials in the garbage is able to infiltrate the ground or surface water.Succinctly, when there is widespread flooding, this leads to the contamination of water sources with sewage, causing the transport of sullage into wells. Additionally, there is a possibility of infiltration occurring from soakaways, as well as from industrial and commercial storage systems, into groundwater systems.  Hence, it is in the light of these problems that the study seeks to analyze the environmental consequences of flooding on water quality and sanitation in Lagos state.

 1.3  Objectives of the Study

The main purpose of this study is to analyze the environmental consequences of flooding on water quality and sanitation in Lagos state. Specifically, the study will;

Evaluate the impact of flooding on the quality of surface and groundwater in Lagos State.

Investigate the effect of flooding on the functionality of sanitation infrastructure in Lagos State.

Examine the correlation between flooding events and the incidence of waterborne diseases in Lagos State.

Assess the effectiveness of existing water management and sanitation policies in mitigating the environmental impact of flooding in Lagos state.

1.4  Research Questions

The following questions have been prepared for the study:

What is the impact of flooding on the quality of surface and groundwater in Lagos State?

What is the effect of flooding on the functionality of sanitation infrastructure in Lagos State?

Is there a correlation between flooding events and the incidence of waterborne diseases in Lagos State?

How effective are existing water management and sanitation policies in mitigating the environmental impact of flooding in Lagos State?

1.5 Research Hypotheses

H0: Flooding has no significant environmental consequences on water quality and sanitation in Lagos State.

Ha: Flooding has significant environmental consequences on water quality and sanitation in Lagos State.

1.6 Significance of the Study

This study will examine the ways in which flooding worsens water contamination and undermines sanitary infrastructure, leading to significant health hazards for the local community. Additionally, community leaders and NGOs will use the findings to advocate for better flood management practices and to educate local residents on maintaining hygiene and safe water practices during floods. Moreover, the findings from this research will assist in the formulation of flood management policies that are centred around the community. This will facilitate cooperation between governmental organisations and citizens in order to execute efficient measures for preventing and mitigating floods. Furthermore, subsequent researchers will use it as a literature review. 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 the environmental consequences of flooding on water quality and sanitation in Lagos state. Empirically, this study will evaluate the impact of flooding on the quality of surface and groundwater,investigate the effect of flooding on the functionality of sanitation infrastructure,examine the correlation between flooding events and the incidence of waterborne diseases and assess the effectiveness of existing water management and sanitation policies in mitigating the environmental impact of flooding.

Geographically, the study will be delimited to residents of some selected local government area 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

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

Water Quality:the chemical, physical, and biological characteristics of water, particularly influenced by flooding. This include levels of contaminants, pathogens, turbidity, and chemical pollutants.

Sanitation: the systems and practices in place to manage human waste, sewage, and wastewater. This includes the infrastructure for sewage treatment, disposal, and the provision of clean and safe toilet facilities.

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