Peri-urban land use change in the Lagos megacity

S. Dekolo1,2, I. Nwokoro1 & L. Oduwaye1

1Department of Urban and Regional Planning, University of Lagos, Nigeria2Department of Urban and Regional Planning, Lagos State Polytechnic, Nigeria

• This presentation examines the use of remote sensing to monitor spatio-temporal land-use and land-cover changes for Ikorodu, one of the largest peri-urban local government in the Lagos Megacity with the use of LANDSAT Multi-temporal images for a period spanning two decades (i.e., 1990 to 2011). Policy implications are also discussed.

Overview

INTRODUCTION

The expansion of Lagos like most cities in developing countries is characterized by sporadic, sprawling and spatially extensive development.

The consequences are more obvious in its peri-urban areas, which suffer from problems of climate change, poverty, stagnation, lack of tenure, lack of infrastructure, land speculation, pollution, natural resource depletion and diminution of agro-ecological and rural lands.

Land use and land cover changes due to city expansion have serious ecological repercussions and pose a great deal of challenge to environmental sustainability at local and global scales.

Introduction

•Achieving environmental sustainability requires a better understanding of the land use change processes, analysis of past and current trends of land use change, and the effect of urban expansion.

•Remote sensing, guarantees timely and accurate detection of land use and land cover changes.

Remote Sensing is the science and art of obtaining information about an object, area, or phenomenon through the analysis of data acquired by a device that is not in contact with object, area, or phenomenon under investigation.

Most contemporary land use studies employ remote sensing imagery from multispectral sensors; the foremost task is the observation of spectral characteristics of measured electromagnetic radiation from a target or landscape. Since the launch of the first LANDSAT (ERTS-1) in 1972, there has been a better understanding of the Earth and its terrestrial ecosystems, as well as its land processes. This has had an enormous impact in global research, providing researchers with real-world data and access to greatly enhanced spatial and analytical tools. Today, remote sensing image data of the Earth’s surface acquired by spacecraft platforms is readily available in a digital format.

Remote sensing and Land Use Studies

• The city of Lagos grew from a small fishing settlement (the Lagos Island), which later became the seat of the British Colonial government in 1861. The censuses 1871 and 1911 shows that the city’s population had doubled from 28,520 to 73,770; by 1963 the population has increased to 1.4 Million people with its urban population put at 46% .

• The 1991 census By 1991 puts its population at 5.6 Million and 9.1 million the following 2006 census. Today, it is a megacity and one of the largest conurbations in the world. Its continuous expansion has led to the annexure of rural communities and the loss of forest and agricultural lands to built-up areas.

The Study Area

Population Growth of Lagos

Lago

s Div

isio

n

Ikej

a Div

isio

n

Bada

gry

Divisio

n

Ikor

odu

Divisio

n

Epe

Divisio

n

Tota

l Lag

os S

tate

04,000,0008,000,000

Census 1963-2006

Census-1963 Census-1991 Census-2006

Comparing the growth of Lagos with other Nigerian Cities

1 2 3 4 5 6 7 8 9 10 11 12 13 140

2000

4000

6000

8000

10000

12000

14000

16000

Abuja 2971

Benin City 1755

Ibadan 3752

Ilorin 1123Kaduna 2083

Kano 4487

Lagos 14134

Maiduguri 1301Ogbomosho 1386Port Harcourt 1479Zaria 1293

Nigerian Cities with Poplation 750,000 or More in 2007

PO

PU

LATIO

N (

‘000)

1900-1980 1980-2006

Spatial Growth of Lagos

Ikorodu Division

Ikorodu in the Lagos settingThe study area Ikorodu is a Nigerian local government area (municipality) and the only surviving administrative area of Lagos State since its creation in 1968.

It has an area of approximately 396.5 km2, Ikorodu is spatially located approximately 36km North of Lagos. Since the 1960s,

Ikorodu was known for extensive farmlands and that is why it derived its name from ‘Oko-Odu’ meaning vegetable farm.

RESEARCH METHODOLOGY

•In this research, multispectral and multi temporal images were used. Landsat TM (Thematic Mapper) for 1990 and Landsat ETM+ (Enhanced Thematic Mapper plus) for 2000 and 2011.

Acquisition

Date

Satellite

Number

Sensor Type WRS Path/Row UTM Zone Datum Spatial

Resolution (m)

03/01/2011 Landsat 7 ETM+ 191/55 31 N WGS84 28.5-30

06/02/2000 Landsat 7 ETM+ 191/55 31 N WGS84 28.5-30

27/12/1990 Landsat 4 TM 191/55 31 N WGS84 28.5-30

Data used

•Unsupervised ISODATA clustering and post classification method was used.•In order to facilitate land use change detection in this research, five classes of land uses were generated Urban/built-up, Forested Land, Agricultural Lands, Wetlands, Water Bodies. Level 1 of classes will be used to generate change statistics, while level 2 will be basically description of classes

Level 1 Level 2 (Description)1. Urban or Built-up Land Residential, Commercial,

Industrial, Institutional, Transportation/Communication/Utilities, Mixed uses

2Agricultural Land Cropland, Grazing , Agricultural Tree Crop Plantation, Arable Crop Plantation

3.Forest Land Riparian Forest, Forest Plantation, Disturbed Forest, Mangrove Forest

4. Wetlands Forested Freshwater Swamp, Non-Forested Freshwater Swamp

5. Water Bodies Ocean, Rivers and Streams, Lakes, Bays and Estuaries, Ponds

LULC Classification

Research Workflow

RESULTS AND DISCUSSION

1990

Multispectral/ Multi-temporal Composite Imagery

Overall accuracy for 1990, 2000 and 2011 are 62.45%, 91.41% and 88.62% respectively

Unsupervised ISODATA Cluster Classified Raster

20112000

Image Classification for Ikorodu 1990-2011

  1990 2000 2011 1990-2000

Change (%)

2000-2011

Change (%)

1990-2011Change

(%)

1990-2011

Growth/Decline

(%)

Land-Use Clusters

Area(Ha)

% Area(Ha)

% Area(Ha)

%

Urban/Built-up 2320.74 4.49 6116.40 11.79 16749.81 32.38 +7.30 +20.59 +27.89 +671.74

Agric. Land 13533.48 26.16 10934.91 21.08 5679 10.98 -5.08 -10.10 -15.18 -58.03

Forestland 22126.77 42.77 20794.14 40.08 15612.66 30.18 -2.69 -10.3 -12.59 -29.44

Wetlands 2694.78 5.20 2526.30 4.87 2525.67 4.87 -0.33 0 -0.33 -6.28

Water Bodies 11060.55 21.38 11506.32 22.18 11169.18 21.59 +0.80 -0.59 0.21 +9.82

Total 51736.32 100 51878.07 100 51736.32 100        Population 184,674 248,529 838,332 34.58 112.42 237.38  

Built-up (m2/pers)

125.67 246.10 199.80 96 19 59

Vegetn. (m2/pers)

2076.90 1378.32 284.10 -34 -79 -86

Land Use/Land Cover Change Statistics for Ikorodu (1990-2011)

Land Use in Ikorodu (1990-2011)

All values in Percentage

Urban/Built-up

Agric. Land

Forestland

Wetlands

Water Bodies

0 5 10 15 20 25 30 35 40 45

4.49

26.16

42.77

5.2

21.38

11.79

21.08

40.08

4.87

22.18

32.38

10.98

30.18

4.87

21.59

2011 2000 1990

Percentage Change

1990 2000 2011

-20

-10

0

10

20

30

40

Urban/Built-up

Agric. Land

Forestland

Wetlands

Water Bodies

• The result of the classified land use/cover maps produced for the study area shows a total built-up area of 2320.74 hectares in 1990, this increased to 6116.40 hectares by 2000 and finally 16749.81 in 2011.

• This represents a 672% growth of built up area in the past two decades, which is three times the population growth that increased from 184,674 to 838,332, i.e., a growth of 237%.

• On the other hand, there was a consistent loss of forest and agricultural land. 58% of forestland was lost to urban expansion; there was a decrease from 22126.77 hectares in 1990 to 20794.14 by 2000 and further to 15612.66 hectares in 2011. 29% of agricultural land was lost in the past two decades; the table shows a reduction from 13533.48 hectares of agricultural land in 1990 to 5679 hectares by 2011. Adding the loss of wetlands, this is 6.28%, the total vegetation cover lost to built-up areas for the study period sums up to 94%

Land Use Change Analysis

• Comparing the rate of change in built-up per capita and vegetation per capita is a simple criteria for evaluating growth.

• The study also shows that between 1990 and 2000 the built-up per capita index increase by 96% (i.e. 126m2 to 246m2), however, this rate dropped by 19% in 2011.

• The 86% decrease in vegetation per capita from 2076.9 sqm in 1990 to 284sqm in 2011 is a clear indication of a sprawling development pattern in the study area.

Growth Pattern and Sprawl Measurement

CONCLUSION

The study examined the land use/cover change and urban growth of Ikorodu, one of the most important and fastest growing peri-urban towns in the Lagos megacity.

There has never been a comprehensive plan to guide development in Ikorodu until now. This explains the sprawling fractal that has been created.

There is a consistent loss of forest and agricultural land use to urban development in the past two decade. This is a major challenge inhibiting sustainability and will transcend from local to global scales.

Loss of farmlands (farm settlements established by the Western Nigeria government and other farms) poses a threat to rural livelihood and may lead to food insecurity in the future

Peri-urban dynamics in Lagos has its consequence as persistent loss of forest and agricultural resources, environmental pollution and degradation, which seems unnoticed due to lack of spatial technologies and spatial data infrastructures that are adequately integrated in our land-use planning framework must be addressed to prevent a trend leading to a mega-slum and ecocide.

There is need for timely and accurate data management of land based resources in our cities

It is also suggested that GIS and remote sensing technology be adopted by land managers in the city’s municipalities or local government councils as well as other government and non-governmental agencies dealing with land use management.

Recommendations and Policy Implications

Spatial Data Infrastructure need to be developed from the grass root level and at departmental levels of governments.

The GIS and remote sensing programmes in land use planning schools needs to be strengthened and a constructivism approach adopted in the instruction.

There is need for urgent preparation and implementation of an Ikorodu Master Plan.

• This research was conducted as part of a M.Phil Research at the Department of Urban and Regional Planning, University of Lagos.

• Further work will be done by determining the drivers of these changes and modeling the future changes of the Megacity. It is hoped that these findings will be presented in future conferences.

Further Work