CHALLENGES OF POOR DRAINAGE SYSTEMS AND FLOODS CONTROL IN LAGOS METROPOLIS, NIGERIA

1.1 Introduction

Poor drainage systems in Lagos State have caused tremendous environmental challenges. These menaces are primarily attributed to poor maintenance of drainage system and flood which can cause environmental hazards as a result of pollution. Some places were flooded, making the roads practically impassable for motorists. In many instances, torrential rainfall literally submerged the cities, halting human and vehicular activities thereby forcing residents to stay indoors as a pre-emptive measure against human disaster. Drainage systems are constructed to ensure that waste water and sewage is transported neatly to disposal points, thereby keeping the environment well drained and free of waste. Examples of components that make up a good drainage system includes; closed ditches having pipe drains, drainage pipes, channels and conduits. Sustainable Drainage Systems are approaches put in place to manage the water quantity (flooding), water quality (pollution) and amenity issues in the environment. Sustainable drainage is a concept that includes long term environmental and social factors in decisions about drainage.

As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Research hypothesis and questions, Limitations of the Study and Definition of technical terms.

1.2 Background of Study

Floods are the most recurring, widespread, disastrous and frequent natural hazards of the world. It is worthy to note that all floods are not alike, while some floods develop slowly and last for a period of days; flash floods can develop quickly, sometimes in just a few minutes and without any visible signs of rain flooding some cities, towns, farmlands and major industrial installations over a distance of about 250km and ravaging Iowa before it heaped downstream. The occurrence of flood represents a major risk to riversides populations and floodplains, in addition to causing substantial impacts on the environment, including aquatic fauna and flora, and bank erosion. Flooding is becoming an increasingly severe and more frequent problem in Nigeria. Unfortunately, the impact is more felt by the urban poor in such a way that recovery is unlikely to be achieved without external aid (Blaikie, 2004).

Presently, about 2.6 billion people are living without proper sanitation, of which Africa is not exempted (Olukanni, 2013a; WHO/UNICEF, 2012). The need to provide proper drainage and sanitation facilities is essential to match up with the ever increasing population growth (Banerjee and Morella, 2011). The increase in the population of a settlement and the attendant growth of the needs of the residents in both quantity and variety, bring about intensive exploitation of the resources of the environment. Such exploitation might increase to a level that the resources would not be able to sustain the population, and in some cases the environment would collapse resulting in serious environmental problems (Asoegwu, 2009).

This is further buttressed by Belete (2011) who expressed that high urban population growth rate also results in drainage system challenges because an increase in population requires a proportionate increase in infrastructure (roads and drainage systems) of which when not properly catered for, the facilities will be imperfect. Also, inadequate integration between road and urban storm water drainage can be attributed to natural causes such as intense rainfall, flat topography and poor soil infiltration or man-made causes such as improperly laid and graded street, poor and inefficient drainage facilities that aggravate the flooding problem (Jimoh, 2008).

Urban environments in Nigeria are faced with myriad of issues regarding poor drainage systems (Offiong et al., 2009) and water tight structures which are the major causes of flooding (Belete, 2011). Urban flooding which is the inundation of land or property in a built environment, particularly in more crowded areas are caused by rainfall overwhelming the capacity of drainage systems. Although this is sometimes caused by events such as flash flooding (Tucci, 2001).

Urban flooding is a condition characterized by its repetitive and systemic impacts on communities whether or not the affected communities are located within floodplains or near any body of water (CNT, 2013). Sule (2001) described Lagos, Abuja, Calabar and Ibadan as cities where houses are constructed directly on drain channels and that this practice has resulted to blockage of storm drains and consequently leading to overflow and flooding of streets.

In the past year Loko Goma community faced extensive water logging during the rainy season (July to September) as result of a serious problem of poor drainage. Inadequate drainage problems become one of the most common sources of compliant from the residents in Loko Goma community and this problem is becoming worse every year. Poor existing drains and their improper operation and management mainly cause severe flooding which creates a lot of damages.

In addition, deceases are spread and give problems to the population such as malaria and diarrhea. This critical situation was severely aggravated because the natural drainage system, which conveys storm runoff from the areas to the river were not fully operated and the existing drains blocked with huge amount of garbage, solid waste, silt sand accumulation and vegetation.

Therefore, in Lagos Metropolis where the research was carried out, the activities that was conducted is to know the Challenges of Poor Drainage Systems and Floods Control.

1.3 Statement of Problems

Investigate the poor drainage systems in some part of the Lagos have caused tremendous environmental challenges. These challenges are basically associated with poor maintenance of drainage system and flood which eventually leads to environmental hazards. Some places were flooded, making the roads practically impassable for motorists. In many instances, torrential rainfall literally submerged the cities, halting human and vehicular activities thereby forcing residents to stay indoors as a pre-emptive measure against human disaster.

Successful drainage depends on early detection of problems before conditions require major action. Signs of drainage problems requiring attention include: puddles on the surface area, poor surface flow, slope erosion, clogged ditches, pavement edge raveling, preliminary cracking, pavement pumping, and surface settlement (L.M. Nyuyo, 2003). These signs indicate the start of failures which occur as soil particles are gradually washed away and as excess water seeps in to the roadway reducing the load carrying ability of the sub grade. Major failures caused by poor drainage conditions include washouts, slides, slip outs, road and pavement breakup and flood damage. This study is to examine the Challenges of Poor Drainage Systems and Floods Control in Lagos Metropolis, Nigeria.

1.4 Aim and Objectives of Study

The aim of the study is to examine the Challenges of Poor Drainage Systems and Floods Control in Lagos Metropolis, Nigeria. In achieving this aim, the following specific objectives were laid out as follows:

1. To examine the intensity and frequency of floods;
2. To examine the impact of poor drainage system and floods control;
3. To identify the causes of flood in Lagos Metropolis;
4. To determine the relationship between poor drainage system and floods control;
5. To proffer solution to the causes of flood in Lagos Metropolis.

1.5 Research Questions

The study came up with research questions so as to be able to ascertain the above stated objectives. The specific research questions for the study are stated below as follows:

• Is there any relationship between poor drainage system and floods control?
• What is the intensity and frequency of floods?
• What is the impact of poor drainage system and floods control?
• What are the causes of flood in Lagos Metropolis?

1.6 Research Hypothesis

In order to pursue the objective of this study, the following generalized statements have been designed to guide and aids in obtaining the result for the experiment to be conducted. For this work, the null hypothesis will be represented with H0 while the alternative hypothesis will be represented with hypothesis H1.

Hypothesis One

• H0: Poor drainage system has no significant impact on floods control in Lagos Metropolis
• H1: Poor drainage system has a significant impact on floods control in Lagos Metropolis

1.7 Significance of Study

This study is beneficial to Lagos Metropolis for future road drainage system construction to avoid problems by assessing the performances of the current drainage systems and proposing mitigation measures to avoid improper functioning. The study will propose appropriate solutions to the drainage systems whose implementation would contribute to floods control in Nigeria especially in Lagos Metropolis.

The findings of this study will also expose the effect and discomfort flood can have on an individual and the community as well. It will also educate them on the dangers of flood and its destructive nature to lives and properties.

The study will also be beneficial for academicians and researchers, who conduct similar researches on the impact of poor drainage system and floods control in Nigeria.

1.8 Scope of the Study

The scope of the study focused on the Challenges of Poor Drainage Systems and Floods Control in Lagos Metropolis, Nigeria.

1.9 Limitations of the Study

During the course of this study, many things militated against its completion, some of which are:

1. Time Constraint: The time frame given to accomplish this project was very short due to school academic calendar and it was carried out under pressure which made the researcher not to implement some necessary features.
2. Research material: availability of research material is a major setback to the scope of the study.
3. Frequent power failure: This made the researcher append more money on fuel to ensure sustainable power.
4. Financial Constraint: Insufficient fund tends to impede the efficiency of the researcher in sourcing for the relevant materials, literature or information and in the process of data collection (internet, questionnaire and interview).

1.10 Definition of Terms

Impact: the action of one object coming forcibly into contact with another

Poor: of a low or inferior standard or quality.

Drainage system: Drainage systems are constructed to ensure that waste water and sewage is transported neatly to disposal points, thereby keeping the environment well drained and free of waste.

Floods control: Flood control refers to all methods used to reduce or prevent the detrimental effects of flood waters.