may. 2020. vol. 16, no.1 issn 2311-2484 international

May. 2020. Vol. 16, No.1 ISSN 2311-2484

International Journal of Research In Earth & Environmental Sciences © 2013-2020 IJREES & K.A.J. All rights reserved www.ijsk.org/ijrees

1

Flood Vulnerability, Land Use Relationship and Topographic Information

Assessment in Ibadan Metropolis, Oyo State, Southwest Nigeria 1Adewuyi Gbola Kehinde*, 2Adejumo Saheed Adesanjo, 3Ajibade Oludare S

1 & 3 Department of Surveying and Geoinformatics, Faculty of Environmental Studies 2 Department of Geology, Faculty of Science

The Polytechnic Ibadan, Oyo State, Nigeria

*E-mail: [email protected]

ABSTRACT

This study assesses the flood vulnerability, land use relationship and topographic information of the Ibadan

metropolis consisting of eleven local Government areas namely; Ibadan North, Ibadan North East, Ibadan North

West, Ibadan South East, Ibadan South West, Akinyele, Egbeda, Ido, Lagelu, Ona-Ara, Oluyole of Oyo State,

Nigeria using geospatial analysis with the objectives of analysing the areas vulnerable to flood, land use/land cover,

determine the topography of water flow and identifying the watershed of Ibadan. Topographic map sheet at a scale

of 1:50,000 used to extract the attribute such as place names; drainage network and other cultural features, Quick

bird satellite image used to extract the building footprints and the road network. Shuttle Radar Topographic mission

(SRTM) with one image scene consisting of 4,100 x 4,200 lines with a spatial resolution of 30m over a swath width

of 60 x 60 kilometres acquired in 2017 and referenced to the WGS84/EGM96 Geoids was used for the delineation of

floodplains. Geology Map was used in determining areas whose surfaces will be likely to retain surface runoff and

hence cause secondary flooding. Land Use Map of Ibadan was derived from the reclassification of a 2018 medium

resolution landsat satellite image of Nigeria. The results showed that 82.75% are vulnerable to flood. Only the

highly developed and commercialized area shows presence of pavements and impervious surfaces. It also showed

that land use has a direct relationship with flood vulnerability. Oluseyi, Oremeji Agugu, Olorunsogo, Cocacola,

International Institute of Tropical Agriculture (IITA), Ojoo, Shasa, Sagbe, Agbowo, Yemetu, Obasa, Elewure, part

of Old Ife road and Iwo Road among others are highly vulnerable to flooding. On the other hand, Akinyemi, Ring

road, Ojaba-Mapo Hall, New Garage, Lekan Salami stadium, Eleyele, Bere, Challenge and Ring Road among

others are moderately vulnerable to flooding.

Keywords: Flood Vulnerability (FV), Geospatial Analysis (GA), Satellite Imagery (SI), Shuttle Radar Topographic

Mission (SRTM), Delineation of Floodplains (DF)

1. INTRODUCTION

Over forty years ago, financial loss and damage

surfer due to natural hazards such as, floods

disasters have increased in many times which also

resulted majorly on loss of human lives and

livelihoods, causing so much damages to economic

and social infrastructure, and as well causes

environmental damages (Munich, 2002). The most

common natural disasters in the world today is

flood. One of natural hazards that may result from

the potential for extreme geographical events which

create sudden threat to human life and property is

Floods (Smith, 1996). With several occurrence of

flood in areas occupied by humans, it can lead to

natural disasters involving loss of human life and

property coupled with serious disturbance to the

continuous activities of wide urban and rural

communities (Smith and Ward, 1998). Moreover,

despite the negative impact of flood such as

damage to properties, loss of life, loss of jobs or

income, discontinuous of the network of social

contact as expected, and effect on constant access

to education, adequate health and food services, and

there can still be series of positive flood impacts,

for example, increased fertility of agricultural land

(Parker et al., 1987). Vulnerability, is a critical

measure of extent of poverty, though closely

associated with poverty, but refers to quality of

being weak and unable to protect oneself from

attack and lack of security (Idowu, 2011). With

every day increase in number of people living in

urban area worldwide, the number of people that

will be vulnerable or be at risk to flood hazards is

likely to increase. With an increase in disasters be it

small or large will endanger developmental gains

and make the implementation of the Millennium

Development Goals difficult (UN-ISDR, 2008).

Flood is said to be the most sufficiently great effect

of climate change on the poor people (Idowu,

http://www.ijsk.org/

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2011). It occurred as a result of increased in

precipitation thereby damaging infrastructures such

as roads, drainage systems, culverts, houses and

water supply that may resulted in cumulative

effects on many parts of the study area. Charveriat

(2000) stated it that in Asia, natural disasters

affected about 3.76 billion people between the year

1970 and 1999 and as well as the countries in the

regions of Caribbean and Latin America were

affected by earthquakes, droughts and floods,

windstorms, however, floods had the highest

increasing cost. According to the World Bank

(2001), the potential impacts of climate change on

human health would increase vulnerability and

climate change and will have both direct and

indirect adverse effects on human health. With

climate change, weather is less predictable, heavy

storm rainfalls is more likely to occur as rains more

uncertain. Unpredictable rainfall is shown both by

observations, like the large inconstant in the levels

of Lake Victoria in Africa since 1980, and by the

experiences of prolong urban overcrowded

residents, who give account greatly of constant

storms producing floods since 1990 (Action Aid

International, 2006).

Floods and wind storms from long term

data on natural disasters suggest that flooding are

the most common causes of natural disaster

globally over the past 10 decades (Few et al, 2004).

According to the International Federation of Red

Cross and Red Crescent Societies, in a decade from

1993 to 2002 flood disasters “affected more people

worldwide (140 million per year on average) than

every other natural or technological disasters put

together” (IFRC, 2003). As the world urban areas

keep increasing, flood disasters are reportedly keep

increasing and having negative impacts on poor

people (Alam et al., 2008) and the development of

an urban area in general. Moreever, the urban flood

risk research was strongly influenced by the

concept of floods within the natural, rural

environment (Zevenbergen, 2007). Vulnerability is

a term that can be used in various ways, especially

in describing a condition of susceptibility shaped by

exposure, sensitivity and resilience (Kasperson et

al., 1995). As stated by many researchers, the

effects of flood are not all that negative, but also

have its positive impact on the environment.

Although flooding, generally, is a bane of most of

the people, but can be beneficial. In a real sense,

nature benefits more from natural floods than not

having them at all (Abowei and Sikoki, 2005).

The advantageous effect of flood is at the

time river overflows, and the overflows water

subsided and return back to its normal flow, then

the deposited materials will make the land more

fertile and richer in nutrient. Therefore, the organic

materials and deposited minerals by the river water

keep the soil fertile and productive for agricultural

purposes (Abowei and Sikoki, 2005). However, in

Ibadan metropolis the cause of floods is mainly as a

result prolonged rainfall and poor urban drainage

systems which is similar to most third world

countries around the world. In most of these

vulnerable countries, disaster management is

usually centralized on disaster response and relief,

and rehabilitation activities. Several studies suggest

that a paradigm shift is needed from disaster

response and relief to disaster risk and reduction in

vulnerability (Birkmann, 2006; Yodmani, 2001).

Therefore, the city of Ibadan in southwest Nigeria

has a history of flood disasters with the most recent

occurred on the 26th of August 2011. This occurred

after Ona-Ara River, when its flood plains and that

of Eleyele Lake over flooded after 14 hours of non-

stop rainfall. As a result of this disaster, there was

destruction of over five thousand households, about

2,500 hectares of farmlands, roads and about 10,

bridges which was affected (Ikhuoria et al, 2012).

According to Ashiru (2015) stated that the highest

height ever for a flood point in Ibadan was recorded

at Moniya. This study, therefore, this study

examined the flood vulnerability, its relationship

with land use and topographic information

assessment in Ibadan metropolis, Oyo State,

Nigeria

2. STUDY AREA

Ibadan is one of the oldest and largest cities in

Africa, the capital of Oyo State, Nigeria. It consists

of eleven local government areas (LGAs) generally

called Ibadan metropolis. In 1856, the population

was estimated at 60,000, 200,000 in 1890, over

238,000 in 1921, and more than 386,000 in 1931

(Mabogunje 1962). Ibadan consists of the densely

populated (urban core) and its less-populated (Peri-

Urban areas). The Urban core (inner part) consists

of Ibadan North, Ibadan North East, Ibadan North

West, Ibadan South East and Ibadan South West.

The Peri-Urban areas (outer part) consist of

Akinyele, Egbeda, Ido, Lagelu, Ona-Ara, Oluyole.

The Peri-urban areas are zones of transition from

rural to urban land uses located between the outer

limits of urban and regional centers and the rural

environment. The typical West African monsoon

climate which consists of the rainy (March-

September) and dry (October-February) seasons


May. 2020. Vol. 16, No.1 ISSN 2311-2484


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occurred in the study area and drained by Ogunpa

and Ona-Ara rivers and their tributaries.

The floods in the city over the years occurred as a

result of long term rainfall leading to inundation of

river channels and streams. Dense networks of

streams and rivers in the urban and peri-urban

neighbourhoods of the metropolis sustained the

floods. Figure 1 describes the study area. Table 1, 2

and 3 showed the Demographic Features,

geographic locations coordinates and ranking

scheme for raster layers of Local Government

Areas in Ibadan.

Figure 1. Digitized Map of Ibadan metropolis

Table 1. Demographic Features of Local Government Area’s in Ibadan

S/No. Local Government Area Population (2006

census)

Area in km2 Population Density

Person/km2 (2006

census)

1 Ibadan North 306,795 145.58 2,107

2 Ibadan North East 330,399 81.45 4,057

3 Ibadan North West 152,834 31.38 4,870

4 Ibadan South East 266,046 80.45 3,307

5 Ibadan South West 282,585 124.55 2,269

Sub-Total (urban core) 1,338,659 463.33 2,889

6 Akinyele 140,116 427.26 495

7 Egbeda 129,461 136.83 2,058

8 Ido 53,584 865.49 119

9 Lagelu 68,901 283.92 521

10 Ona-Ara 123,048 369.37 549

11 Oluyole 91,527 577.1 459

Sub-Total (Peri urban core) 1,211,934 2,659.97 456

Grand Total 2,550,593 3,123.30 816.63

Source: Provisional Figure released by the National Population Commission (2007)

Table 2. Geographical Location coordinates of Local Government Areas in Ibadan S/No LGA Area(in Sqkm) Geographic

Longitude

Geographic Latitude Height above MSL

(metres)

1 Ibadan N 306,795 3.911° 7.412° 209

2 Ibadan NE 330,399 3.931° 7.374° 216

3 Ibadan NW 152,834 3.878° 7.401° 216

4 Ibadan SE 266,046 3.905° 7.335° 179

5 Ibadan SW 282,585 3.864° 7.354° 173

6 Akinyele 140,116 3.916° 7.561° 258

7 Egbeda 129,461 4.059° 7.391° 212

8 Ido 53,584 3.712° 7.507° 210

9 Lagelu 68,901 4.047° 7.495° 221

10 Oluyole 91,527 3.877° 7.184° 159

11 Ona-Ara 123,048 4.040° 7.251° 154

Source: authors compiled from the Google earth updated 2019


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Table 3. Presentation of ranking scheme for raster

layers

S/N Class Rank

1 The least vulnerable areas 1

2 Areas of low vulnerability 2

3 Moderately vulnerable areas 3

4 Highly vulnerable areas 4

5 Areas of the highest vulnerability 5

Source: Authors compiled (2019)

3. DATA AND METHODS

3.2 Method

The topographic map at a scale of 1:50,000

prepared by Ibadan Urban Flooding Management

Project which weas obtained from the Surveyor

General office of Oyo State (OSGOY) Secretariat

Ibadan and was used to assess the flood

vulnerability in the study area. From the

topographic map, attribute such as names of places,

drainage network, roads and other cultural features

of the study area was extracted.

Shuttle Radar Topographic mission (SRTM)

obtained from National Aeronautics and Space

Administration (NASA) website consisting one

image scene of 4,100 x 4,200 lines with a 30m

spatial resolution over a 60 x 60 kilometres swath

width which was obtained in 2017 and referenced

to the WGS84/EGM96 Geoid was used for the

delineation of floodplains in the study area.

This image was used for the delineation of

floodplains in the study area. Land Use Map was

derived from the reclassification of a 2018 medium

resolution landsat satellite image of Nigeria from

the Regional Centre for Training in Aerospace

Surveys (RECTAS) consisting of seven (7) spectral

bands in which land use map of Ibadan was derived

with the use of ArcGIS 10.2.1 software.

Geology Map acquired from geological surveys

department which was modified at a small scale to

define the geomorphology of the study area, was

used in determining areas whose surfaces will be

likely to retain surface runoff and hence cause

secondary flooding. Building footprints and the

road network was extracted from the Quick bird

satellite imagery obtained from archives of

Regional Centre for Training in Aerospace Surveys

(RECTAS).

It consists of three (3) spectral bands and a ground

resolution of 0.6m. Land sat ETM image was

acquired from the GLCF website with a ground

resolution of 30m. All the bands contain the visible,

near infrared (NIR), middle infrared and far

infrared spectral regions of electromagnetic

spectrum (EMS).

i. Band 2 (0.59-0.65µm) is the red wavelength

band. With band 2, chlorophyll absorption region

is sensed thereby aiding in plant species

differentiation. It is also useful for cultural feature

identification.

ii. Band 3 (0.72-0.86µm) is the near infrared

wavelength (NIR) which is useful in the

determination of vegetation types, vigour and

biomass content. With band 3, water bodies’ can

be delineats and can also aid soil moisture

discrimination.

iii. Band 4 (1.51-1.74µm) is the first of the two

bands in the middle infrared wavelength.

It is indicative of vegetation moisture content and

soil moisture. In the temperate region, with band 4,

it is easy to differentiate snow from clouds. The

three bands were composite together to single band

which was used for drainage mapping and

determination of the dominant land use land cover

types. Geology Map was acquired from geological

surveys department and was modified at a small

scale to define the geomorphology of the study

area, this was usefully in determining areas whose

surfaces will be likely to retain surface runoff and

hence cause secondary flooding. Figure 2 showed

the topographic map sheet and the overlaid

Quickbird satellite imagery of the study area.

Figure 2a. Topographic map sheet of the study area


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Figure 2b. Overlaid Quickbird Satellite image

4. RESULTS AND DISCUSSIONS

The results below presents the analysis derived from

various method of data acquisition from different

source. Figure 3-13 presents the analysis carried out.

Figure 3a. Map showing Landuse map of Ibadan

Figure 3b. Map showing reclassed land-use

Figure 3 (a & b) above described the major Urban

areas as the most vulnerable to floods because they

have the highest percentage of impervious surfaces

and they also have the highest human and housing

population. Vulnerability in this regard decreases

away from the urban centre with the lowest

vulnerability being in thickly forested areas where

the soil is still held together by the natural

vegetation. Areas where agriculture is being

practiced are given a moderate value because even

though such areas are not at great risk such as the

urban areas but the soil in this areas have been

tampered with and they are not as firm as they

should be. They can easily be eroded and deposited

thus facilitating flooding. Land use was classified

into five classes and is as follows;

Plantations and forest were classified as areas with

the least vulnerability to flood. Grasslands were

classified as low vulnerability area to flood. Areas

were rain-fed agriculture is practiced was classified

as areas with moderate vulnerability to flood.

Minor urban areas and places away from the city

centre were classified as high vulnerability area to

flood. Major urban areas and water bodies were

classified as areas with the highest vulnerability to

flood.


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Figure 4a. Geology map of Ibadan

Figure 4b. Map of re-classed geology

Figure 5. Map showing an overlay of geology

and land-use datasets

The re-classed datasets of geology, land use, slope

and drainage buffer were overlaid on each other.

Percentage influences were ascribed to each of the

datasets in the following manner; Geology dataset

was ascribed a percentage influence of 10%, Land

use dataset was ascribed a percentage influence of

20%, Slope dataset was ascribed a percentage

influence of 30%, Drainage dataset was ascribed a

percentage influence of 40%, thus making a total of

100%. Three sets of overlay operation were carried

out so as to make the procedures more explicit and

the result more visual. The first was the overlay of

the geology and land use. This was done using a

ratio of 33:67 respectively that corresponds to the

intended percentage influence of 10% and 20%

respectively

Figure 6a. Digital Elevation Model of study area

Figure 6b. Aspect/flow direction of the DEM


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The digital elevation model of Ibadan was derived

from the Shuttle Radar Topography Mission

(SRTM) satellite image. The highest point within the

study area was identified to be 428metres and the

lowest point was 54metres above sea level as

represented in Figure 6 (a & b)

Figure 7. contour map derived from the DEM

From the DEM in figure 7 above, a contour map

with 50m interval was derived which showed places

of equal height/elevation. The result from the

contour showed that Ona-Ara, Oluyole and part of

Ido have lower equal terrain which ranges from 100-

150m. 200m elevation exists in all local government

areas. While larger percentage in Akinyele, part of

Lagelu and Ibadan North terrain has equal height of

250m. Part of Akinyele and Ido has elevation of

300m and above. It is possible for a low land (low

terrain) area to experience flood more than in high

land (high terrain) areas.

Figure 8a. Map of Ibadan showing slope

Figure 8b. Map of Ibadan showing re-classed slope

The result from (figure 8a) showed an area with

slope values. Slope values that are ranges from 0 to

4.4 were classified as least area vulnerable to flood,

values ranges from 4.4 to 8.0 was classified as low

area vulnerable to flood, values range from 8.1 to

14.0 was classified as moderate area vulnerable to

flood, values range from 14.1 to 20.0 was classified

as high areas vulnerable to flood and values range

from 20.01 and above was classified as the highest

areas vulnerable to flood.

Figure 9. Vulnerability map of Ibadan showing an

overlay of Geology, Land-use and slope datasets


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Figure 9 above showed overlay map of Geology

map, land use map and slope map. This was done

using a 50:50 ratio respectively that corresponds to

the intended percentage influence of 10%, 20% and

30% for geology, land use and slope datasets

respectively.

Figure 10a. Map Showing River buffers of 100-400m Figure 10b. Rasterized and re-classed buffer

The drainage network in Ibadan was buffered (figure

10a) with a distance of 100, 200, 300, 400 and

beyond 400 metres away from the channel. It is

logical that the nearer a feature is from a river

channel, the higher the vulnerability of it being

flooded. Therefore, the buffer zone of 100 metres

was ascribed to be of the highest vulnerability and

areas away from the 400 metre buffer were ascribed

to be of the lowest. For the reclass analysis (figure

10b) the highest value of 5 was ascribed to the

100metre buffer, a value of 4 was ascribed to the



400metre buffer and the lowest value of 1 was

ascribed to areas beyond the 400meter buffer.

Figure 11. Vulnerability map of Ibadan showing susceptible buildings and susceptible roads

Figure 11 above showed the Buildings vulnerable to

flood. The total area covered was calculated. Total


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land area of 16.386299km2 has the highest

vulnerability to flood. Total land area of

227.589014km2 has a high vulnerability to flood.

Total land area of 513.198588 km2 has a moderate

vulnerability to flood. total land area of 809.141458

km2 has a low vulnerability to flood. A total land

area of 5.953924km2 has the least vulnerability to

flood. The result showed the number of buildings in

each vulnerability region, a total of 19,922 buildings

fell under areas with the highest vulnerability to

flood. A total of 103,930 buildings are of high

vulnerability to flood, a total of 159,902 buildings

are of moderate vulnerability to flood, a total of

24,692 buildings are of low vulnerability to flood

and a total of 21 buildings fell under areas with the

lowest vulnerability to flood. A total of 1663 roads

fell under areas vulnerable to flood.

Figure 12. Map of Ibadan showing watershed

Figure 12 above showed the watershed map and was

created from a series of images derived from the

digital elevation model of Ibadan. The watershed

map ranges in value from point from 70, the highest

point within the catchment area of the drainage basin

to zero, the lowest point within the drainage basin.

Figure 13. Map showing Ibadan flood plain

Figure 13 above showed that the flood point was

207metres above sea level; which implied that

places below this height are within the flood plain.

This height was regarded as the benchmark for

delineating the drainage basin or flood plain.

Table 4. Summary of the flood result and analysis

Flood analysis Percentages (%)

Area vulnerable to flood 82.75

Area located within the

flood plain

85

Dense drainage network 62

Risk analysis 54

Source: Authors compiled

5. CONCLUSION

Flood vulnerability has been assessed and it

revealed from the findings that larger percentage of

the study area is vulnerable to flood which takes

82.75% of the study area, this is due to the increase

in population and increase rate of infrastructure

such as Institutional, Industrial, residential/built-up,

Commercial, and a dense road network. Over 85%

in the study area is found within the floodplain;

therefore, leads to increase in the flood

vulnerability of the study area. This is especially

aided by the dense drainage network (62%) within

the area and the susceptibility of the underlying

sedimentary rock formations (alluvium) in a large

expanse of the area. Moreover, risk analysis

showed that about 54% of the study area was at risk

of been flooded due to their improper flow of water

to streams, rivers or dams. It showed that land use

has a direct relationship with flood vulnerability of

the study area, with the urban area taking up all the

institutional, industrial, built-up/residential, and

Commercial areas. A highly developed and

commercialised area shows presence of pavements

and impervious surfaces. All these prevent water

percolation into the ground, hence leading to high

amount of surface run-off leading to environmental

risk. Therefore, the pair wise comparism analysis of

the various spatial data layers and proximity

analysis to the major source of flooding

(river/streams) within the study area indicated that

only a peripheral of the city has the least

vulnerability to flooding, areas like Oluseyi,

Oremeji Agugu, Olorunsogo, Cocacola, IITA,

Ojoo, Shasa, Sagbe, Agbowo, Yemetu, Obasa,

Elewure, part of Old Ife road and Iwo Road among

others are highly vulnerable to flooding. On the

other hand, Akinyemi, Ring road, Ojaba-Mapo

Hall, New Garage, Lekan Salami stadium, Eleyele,

Bere, Challenge and Ring Road among others are

moderately vulnerable to flooding.


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RECOMMENDATIONS

The findings of this study could be integrated

within a spatial enabled decision support system,

especially as disaster risk reduction is concerned.

This is especially critical for Ibadan city which

seems to have a history of flooding for over 50

years. This will serve as a basis for advising

residents in locating basic infrastructure within the

high risk zones. Also, the response mechanism

could be efficient, through the adoption of the

findings of this study; especially for best route,

relief sites (higher ground) etc in the event of future

flood occurrence. Consequently, all stakeholders in

the disaster management cycle should be

acquainted with this methodology and results in

order to mitigate the impact of floods in the future.

REFERENCES

1. J. Abowei, and F. Sikoki, “Water Pollution

Management and Control”. Double Trust

Publications Co., Port Harcourt, 2005. pp 236

2. Action Aid International (AAI), “Climate

change, urban flooding and the rights of the urban

poor in Africa: Key findings from six African

cities”. (Available on

http://www.actionaid.org/docs/urban%20flooding

%20africa%20report.pdf Accessed 12/03/2008),

2006.

3. K. Alam, M. Herson, and I. O‟Donnel, “Flood

Disasters: Learning from Previous Relief and

Recovery Operations”. Prevention Consortium and

ALNAP, 2008.

4. A. Ashiru, “Spatial variation in the resillence to

flooding”. Thesis submitted to the department of

Geography, University of Ibadan. Ibadan, Nigeria,

2015)

5. J. Birkmann, “Measuring vulnerability to

promote disaster-resilient societies: Conceptual

frameworks and definitions. In: Measuring

Vulnerability to Natural hazards-Towards Disaster

Resilient Societies”, edited by: Birkmann, J.,New

York, United Nations University, 2006, pp. 9–54.

6. C. Charvériat, “Natural Disasters in Latin

America and the Caribbean: An Overview of Risk”.

Inter-American Development Bank. Working Paper

434. 2000.

7. R. Few, M. Ahern, F. Matthies, and S. Kovats,

“Floods, health and climate change: A strategic

review” Tyndall Centre Working Paper No. 63.

8. Google earth satellite imagery (2018). updated

Google earth Pro, 2004.

9. E. O. Idowu, “Effect of Climate Change (Flood)

On Housing for The Urban Poor in Ilaje Somolu

Local Government”, Unpublished B.Sc.

Dissertation, Department of Urban and Regional

Planning, University of Lagos, 2011.

10. IFRC, “World Disaster Report 2003 (Geneva:

IFRCRCS); at: www.ifrc.org, 2003, Pp 11.

11. Kasperson et al. “Research and Assessment

Systems for Sustainability: Framework for

Vulnerability”, The George Perkins Marsh Institute

at Clark University and The Stockholm

Environment Institute, 2001.

12. A. L. Mabogunje, “The Residential Districts of

Ibadan, Nigeria. Geographical Review, Vol. 52, No.

1, January 1962, 2007.

13. Munich Re Topics, “Natural catastrophes in

2002”. Review, 2002.

14. National Population Commission, “National

Population Census of Nigeria”, National Bureau of

Statistics, Abuja, 2007.

15. G. M. H. Parker, Y. Garcia, Fukushima, and W.

Yu, “Experiments on turbidity currents over an

erodible bed”. Journal of Hydraulic Research,

25(1), 1987, 123-147.

16. Smith, K. (1996). Environmental Hazards.

Assessing Risk and Reducing Disaster. London,

Routledge.

17. K., Smith, and R. Ward, “Floods Physical

Processes and Human Impact”, Published by John

& Wiley and son Ltd. Conneil, Bangkok, Thailand,

1998.

18. UN-International Strategy for Disaster

Reduction (UN-ISDR), “Disaster Risk Reduction

Strategies and Risk Management Practices: Critical

Elements for Adaptation to Climate Change”

Submission to the UNFCCC Adhoc Working Group

on Long Term Cooperative Action. 2008, Available

at: www.unisdr.org/.../risk-

reduction/climatechange/.../ IASC-

ISDR_paper_cc_and_DDR.pdf

19. World Bank, “World Bank Development

Indicators”. Washington DC, World Bank, 2001.

20. S. Yodmani, “Disaster Risk Management and

Vulnerability Reduction: Protecting the Poor”,

2001.

21. C. Zevenbergen, “Adapting to Change:

Towards Flood Resilient Cities”. Inaugral Address

by Chris Zevenbergen in Delft, The Netherlands,

December 14, 2007. UNESCO-IHE (Institute for

Water Education), 2007.


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