ABSTRACT

This study examined the assessment of environmental and health risk of urban flooding. Nigeria is the most populous Black race country in Africa and in the world with a total land area of 983,213 km² occupied by over 160 Million people: The interaction of these millions of people with their environment has left indelible mark on the landscape. Urbanization, deforestation, flooding, desertification, over population and all kinds of pollution are some of the resultant effects of man’s interaction with his environment. These changes result from the populace attempt to achieve their seemingly endless desire for food, shelter, recreation and infrastructural facilities and urbanization in general. This has placed a lot of pressure on the environment. Flooding has become the annual experience of Nigerian cities especially in Aba, Abia State where it has causes economic stampede in the rainy seasons of the year. Effort made by the government and residents to forestall the menace has produced sub-optimal results. There is hence, the need to adopt more proactive, standard and reliable procedures that can give sustainable outcome and restore the socio-economics growth of the urban centre.

 

 

TABLE OF CONTENTS

ABSTRACT

CHAPTER ONE: INTRODUCTION

1.1     BACKGROUND OF STUDY

1.2     STATEMENT OF PROBLEM

1.3     AIM AND THE OBJECTIVES

1.4     RESEARCH QUESTION

1.5     SIGNIFICANCE OF STUDY

1.6     THE STUDY AREA

CHAPTER TWO: LITERATURE REVIEW

2.1     INTRODUCTION

2.2     FLOODING

2.3     IMPACT OF CLIMATE CHANGE ON FLOODS

2.4     URBANIZATION AND FLOODS

CHAPTER THREE: RESEARCH METHODOLOGY

3.1     INTRODUCTION

3.2     SOURCES OF DATA

3.3     METHOD OF DATA COLLECTION

3.4     METHOD OF SAMPLE SELECTION

3.5     STUDY POPULATION

3.6     METHOD OF STATISTICAL ANALYSIS

CHAPTER FOUR

DATA ANALYSIS, PRESENTATION AND DISCUSSIONS

4.1     INTRODUCTION

4.2     RAINFALL ANALYSIS OF THE STUDY AREA

4.3     PRESENTATION OF PRIMARY DATA

4.4     DATA PRESENTED IN RESPECT TO OCCUPATION

4.5     DISCUSSIONS

CHAPTER FIVE: RECOMMENDATION AND CONCLUSION

5.1     SUMMARY OF FINDINGS

5.2     CONCLUSION

5.3     RECOMMENDATIONS

REFERENCES

APPENDIX

 

 

 

CHAPTER ONE

INTRODUCTION

1.1  BACKGROUND OF STUDY

Flooding in urban areas can be caused by flash floods, or coastal floods, or river floods, but there is also a specific flood type that is called urban flooding.  Urban flooding is specific in the fact that the cause is a lack of drainage in urban area.  As there is little open soil that can be used for water storage nearly all the precipitation needs to be transport to surface water or the sewage system.  High intensity rainfall can cause flooding when the city-sewage system and draining canals do not have the necessary capacity to drain away the amounts of rain that are falling.  Water may even enter the sewage system in one place and then get deposited somewhere else in the city on the streets.

Climate change acts as a trend-breaker as well as creating a larger variability in the occurrence of extreme events.  This result in increasing degrees of uncertainty towards which traditional probability based flood management policies might not provide adequate responses.  Furthermore, ongoing processes of urbanization (both expansion and densification) increase susceptibilities of asset concentrations to floods, thus increasing overall vulnerability of urban areas to an increasing degree.

Although we can’t say whether climate change caused the heavy rainfall, scientist predict we will see more heavy raianfall days in the future than we curently get.  The Environment Agency Sustainable Development Unit said in June 2001:

‘Major floods that have only happened before say, every 100years on average, may now start to happen every 10 or 20years.  The flood season may become longer and there will be flooding in places where there has never been any before’.

Thus, the risk of flooding looks greater than ever and not just in one country or the other, but throughout the whole world.

In discussion on urban flood risk, the focus is mainly on the financial consequences of flood events (Ashley et al, 2005).  Consequences related to public health are easily overlooked.  Two important types of health consequences are: ingestition of contaminated water and physical injuries as a result of stumbling over objects under the water surface or even falling into manholes.

When combines sewer systems flood as a result of heavy rainfall, humans can come into contact with the mixture of water – and stormwater that flows onto the surface and may contain various types of pathogens.  Different contamination routes are possible; the most important route is ingestion of the flood water, as a result of playing in it or being splashed.  Possible healthrick include, mental health impacts, physical effects (such as falls, cuts, heart attacks), infection (due to exposure to pathogenic microorganisms) and exposure to chemical.

Persistent organic and inorganic chemical contaminants can enter urban riverine systems from a range of different sources and in a range of forms.  Atmospheric disposition, urban runoff, agricultural runoff, remobilization from floodplains and within – channel deposits, industrial discharges, and sewage outfalls all contribute to the chemical contaminant load of the fluvial system.

Aba urban Area remains the commercial and industrial nerve Area of Abia state, with a very high population of about 8.5 million people (U.N, 2010). Aba urban Area is known for intense commercial and manufacturing activities in the markets, most popular among them is Ariaria international market.

These intense human activities and high population family contribution to increase the flood risk potential of the study area. Moreover, the physical attribute of the study area in terms of its relief, geology and soil also favor flood occurrence. Hence proffering solution to the flood situation in the study area would involve an in depth understanding of this socio-economic and physical attributes.

Flood occurrences are always occurring in rainy or wet season from April to September. Most areas that are more prone to flood are high relief areas which are peneplain in nature. They include; Okigwe road, Omuma road area, faulks road area, Ariaria market area, ngwa road area, ohanku road area, over railareas, and most areas in osisioma.

1.2            STATEMENT OF PROBLEM

There is indeed urgent need to provide reliable solution to the occurrence of flooding in Aba urban Area, the study area. Therefore, attempts shall be made to provide answers to the following questions which will arise in the study.

• The physical nature of the study area Aba urban and how it encourages flood occurrences.
• The diverse causes of flooding in Aba urban and the most affected areas.

How these floods can be effectively controlled, eliminated or even avoided to avert its impact on human activities in the study area.

 

1.3             AIM AND THE OBJECTIVES

This research is aimed at assessing the environmental and health risk of urban flooding in Aba urban Area. To achieve this, the following objectives are set for the research:

1. To determine the factors that are responsible for flooding in Aba urban Area.
2. To find out the flood prone areas in Aba urban Area.
3. To present a flood risk map of Aba urban Area.

• To assess the major impacts of flooding in Aba urban Area.
• To study with a view to establishing reliable control and management measures of flood hazards in Aba urban Area.

1.4      RESEARCH QUESTION

1. What are the factors that are responsible for flooding in Aba urban Area?
2. Where are the flood prone areas located in Aba urban Area?
3. What are the major impacts of flooding in Aba urban Area?
4. What control and management measures of flooding are more reliable for managements of floods?

 

1.5     SIGNIFICANCE OF STUDY

 The following are the significance of this research; as the research is supposed to solve the following needs;

1. To be able to identify causes and sources of flooding in Aba urban especially in Aba south, Aba north and osisioma.
2. To assess the effects and discomfort there flood can have on individuals.
3. To enlighten the public on the dangers of floods and its destructive nature on life and property.
4. To serve as a base for more research work on the problems and prospects of flooding in urban Areas of the world.
5. To identify and map the various flood prone areas in Aba urban.

1.6            THE STUDY AREA

1.6.1               LOCATION

Aba Urban Area is located in southern part of Abia state in south eastern

Nigeria. Aba Urban is located within latitude 5⁰02’ N to 5⁰10’ N and longitude 7⁰17’ E to 7⁰25’ E. Aba Urban Area is bounded by the rural communities of osisioma on the west and north, it bounded by Obingwa rural communities on the east and Ugwunagbo rural communities on the south.

1.6.2                CLIMATE

Climate of Aba urban Area is made up of climate variables such as rainfall, temperature, humidity and wind system in the area.

Rainfall:

Aba urban Area and its environs experiences intense rainfall especially in the rainy or wet season. Rainfall is present all year and with and annual total of 2000mm-2300mm, with monthly average of about 180mm. This intense rainfall is induced by excessive evapotranspiration in the urban Area due to prevalent high temperature.

Temperature:

Temperature experienced in Aba Urban is very high with an average daily temperature of about 28’c in the dry season and about 24’c in the wet season. The study area has low temperature range. The temperature situation is caused by study areas perpendicular position to the sun, since it is located in the subequatorial climate region.

Relative Humidity:

Relative humidity in the study area is also high, reaching about 80% in the wet season and 70% in the dry season. Relative humidity is the amount of moisture in the air compared to what the air can hold at that particular temperature.

1.6.3      VEGETATIONAL ATTRIBUTES

The vegetation of Aba Urban Area falls within the rainforest vegetation belt. Trees found in this area are very tall, characteristics of the rainforest vegetation zone. These trees are about 30metres tall. These trees are evergreen with branches which interlace themselves to form canopies. The trees are close to each other in pure stands. This arrangement prevents intense rainfall and temperature from impacting directly on the soil. Trees found within the study area include; Iroko, Obeche, Oil palm mahogany etc.

1.6.4       SOIL AND AGRICULTURE

Soil of any geographical area to a far extent determines the nature and type of agricultural practice that the environment would adopt.

Aba urban Area and its environs have predominantly sandy and loamy soil which is a characteristic of coastal areas. This two soil types have relatively high porosity, infiltration capacity and low water retention capacity.

Unprecedented loss of agriculture land use space has intensified agriculture in this area. Continuous cropping is the predominant agricultural practice in Aba and its environs. Crops cultivated include; yam, cassava, maize, cocoa, Oil palm etc.

1.6.5           GEOLOGY RELIEF AND DRAINAGE

The geology of Aba Urban Area and the adjourning areas is made up of the coastal plain sand due to the areas proximity to the Atlantic Ocean. Aba Urban has a low and relatively even topography which could also be called Peneplain. Its lowest relief is along the Aba River with about 12metres (40 feet) and the highest relief is about 21metres along Portharcourt-Aba express way near Alaoji area in Aba. Aba Urban Area is mainly drained by the Aba River and other streams such as Okpuloumuobu stream etc.

$39.69 – DOWNLOAD FULL PROJECT DOWNLOAD FULL PROJECT Added to cart