ONLINE E-WASTE COLLECTION SYSTEM project Report (Approved)
Complete Project Work
1. APPLICATION OF GEOGRAPHIC INFORMATION SYSTEM IN
MAPPING OPTIMAL SITE SELECTION FOR SOLID WASTE
COLLECTION POINT AND DISPOSAL IN NEW OWERRI, IMO
STATE
BY
OKEKE CHIKA M.
20081614735
A PROJECT SUBMITTED IN PARTIAL FULFILMENT
OF THE REQUIREMENTS FOR THE AWARD OF
BACHELOR OF TECHNOLOGY (B.TECH) DEGREE IN
GEOLOGY
DEPARTMENT OF GEOSCIENCES
SCHOOL OF SCIENCE
FEDERAL UNIVERSITY OF TECHNOLOGY
OWERRI
MARCH, 2014
2. ii
DECLARATION
I hereby declare that this project work titled “Application of Geographic
Information System in Mapping Optimal Site Selection for Solid Waste Collection
Point and Disposal in New Owerri, Imo State” was undertaken by the researcher
and has not been presented anywhere for any academic award.
Previous works of other authors used here has been duly acknowledged and
referenced.
………………………………. ..……………………..
OKEKE CHIKA M. DATE
20081614735
3. iii
CERTIFICATION
This is to certify that this study entitled "Application of Geographic Information
System in mapping optimal site selection for solid waste collection point and
disposal in new Owerri, Imo State" was done by Okeke Chika Marcyprian
with the registration number 20081614735 and a final year student of Department
of Geosciences in the school of science, Federal University of Technology Owerri.
…………………………. …………………
Dr. C.C.Z. Akaolisa Date
(Supervisor)
…………………………. …………………
Prof. K.K. Ibe Date
(Head of Department)
…………………………. …………………
Prof. F.O.U. Osuala Date
(Dean, School of Science)
…………………………. …………………
External Examiner Date
4. iv
DEDICATION
This work is dedicated to the glory of the Almighty God for his mercies and
kindness towards its success.
Also, to my lovely father Mr. Marcel Okeke and mother Mrs. Edith Okeke.
5. v
ACKNOWLEDGEMENT
My profound gratitude goes to my supervisor Dr. C.C.Z Akaolisa of my department
for his encouragement, gracious time and constructive criticism structured towards
achieving an effective and successful project.
I also want to acknowledge my course adviser Dr. Alex Opara for his good advice
to me towards my academics in order to reach a goal of being an outstanding
student in my department. I will not fail to thank the Head of my Department, Prof.
K.K Ibe and other lecturers of my department for devoting their crucial time in
bringing me up to the real world of Geosciences.
I express my thanks to my guardian Mr. Albert C. Ndubizu, the General Manager of
Imo State Geographic Information Agency for releasing the GIS software needed
for the success of this work. My thanks also go to Okorondu Ugochukwu Victor
and to my fellow students in my department for their kind gestures and ceaseless
time in assisting me towards the success of this work.
I express my gratitude to surveyor Mr. Chinedu and his team from Imo State
Ministry of Land and Survey for releasing the layout maps of all the areas in the
study area. Also, not left behind are surveyor Mr. Marcel and town planner Mr. O.
Akolan of Owerri Capital Development Authority for their assistance in releasing
information and in decoding land use features on Owerri Master Plan map.
Finally, I am deeply recognizing the assistance of Chief Chris Onwuegbuchulam
(Ministry of Environment) despite his ill health and limit time painstakingly taught
and gave me an overview of how I will go about this project so as to achieve an
effective and successful work.
May God Almighty Bless You All.
6. vi
ABSTRACT
In Nigeria, waste disposal have been a problem both in the urban and rural areas.
Wastes are indiscriminately dumped on open plots of land and particularly along
streets rendering the roads impassable and reducing the aesthetic value of the area.
Optimum selection of waste collection points is therefore necessary in other to
prevent the indiscriminate dumping of waste which is hazardous to human health
and also to effectively and efficiently manage the solid waste to promote hygienic
environment. Site evaluation for waste disposal describes the important criteria used
in evaluating land for waste disposal. The factors to be considered in such
evaluations include: climate, topography, drainage, soil properties, groundwater and
surface water. GIS consists of a set of computerized tools and procedures that can
be used to effectively store, retrieve, overlay, correlate, manipulate, analyze, query,
display (both graphically and numerically) and disseminate land related
information. This study used Geographic Information Systems (GIS) as a solution
to select suitable locations for solid waste collection points and disposal land use
option in New Owerri. A total of 5 thematic maps determinants obtained from
different sources were employed for GIS operation. These include road map, river
map and (3) different land use maps (residential, commercial and public use land
uses) of the study area. These maps are the thematic data layers for GIS operation
and were collected as existing maps from different sources to serve the purpose of
manipulation and analyses so as to procure the most suitable site for collection point
of solid waste generated in New Owerri, Imo State. The maps were scanned,
digitized, georeferenced, and polygonized using AutoCAD drawing capabilities to
convert them into vector format and later exported to arc view 3.2a software for
analysis. The final analysis like buffering, overlay by union, clipping and query
operations display areas of preferred collection point for solid waste generated in
New Owerri, Imo State.
7. vii
TABLE OF CONTENT
PAGE
Title Page - - - - - - - - - - - i
Declaration - - - - - - - - - - - ii
Certification - - - - - - - - - - iii
Dedication - - - - - - - - - - iv
Acknowledgement - - - - - - - - - v
Abstract - - - - - - - - - - - vi
Table of Content - - - - - - - - - - vii
List of Figures - - - - - - - - - - xi
List of Tables - - - - - - - - - - xiv
List of Plates - - - - - - - - - - xv
Chapter One
1.0 Introduction - - - - - - - - - 1
1.1 Statement of the Problem - - - - - - - 3
1.2 Location of the Study Area - - - - - - - 4
1.3 Physiography of the Study Area - - - - - - 6
1.4 Hydrogeology of the Study Area - - - - - - 7
1.5 Aim of Study - - - - - - - - - 8
1.6 Objectives of Study - - - - - - - - 8
1.7 Scope of Study - - - - - - - - - 9
1.8 Significant of the Study - - - - - - - - 9
1.9 Limitation - - - - - - - - - - 9
Chapter Two
2.0 Geology of the Study Area - - - - - - - 12
2.1 Stratigraphy Of The Study Area - - - - - - - 13
9. ix
3.6.2 Criteria for Selecting Suitable Solid Waste Collection Points - - 43
3.6.3 Cartographic Modelling - - - - - - - - 44
3.7 Spatial Analyses Performed - - - - - - - 47
3.7.1 Digital Mapping Processes on Map of New Owerri - - - 47
3.7.2 Buffering Operation - - - - - - - - 50
3.7.2.1 Analysis of Buffering Operation - - - - - - 51
3.7.3 Overlay Operations - - - - - - - - 55
3.7.3.1 Analysis of Overlay Operation - - - - - - 56
3.7.4 Polygon Clipping Operations - - - - - - - 65
3.7.4. 1 Analysis of Clipping Operation - - - - - - 65
3.8 Spatial Query/Search - - - - - - - - 68
3.8.1 Single Criteria Query - - - - - - - - 68
3.8.2 Multi Criteria Queries - - - - - - - - 79
3.8.2.1 Input for Multi-Criteria Queries - - - - - - 79
3.8.2.2 Output for Multi-Criteria Queries - - - - - - 80
3.9 Interpretation of Results - - - - - - - 88
Chapter Four
Setting Criteria for the Selection of the Most Final Suitable Disposal Sites for
Solid Waste Generated From the Collection Points
4.0 Research Methodology, Results and Interpretation - - - 98
4.1 Soil Types in Owerri West - - - - - - - 98
4.2 Soil Sampling - - - - - - - - - 99
4.3 Land Use (LU) And Land Cover (LC) Study in Owerri - - - 100
4.3.1 Methodology Of The Land Use And Land Cover Study - - - 102
4.3.2 Results And Interpretation Of The Land Use And Land Cover Study - 102
10. x
4.4 Owerri West Land Capability Indices Determination For
Solid Waste Disposal Land Use Option - - - - - 104
4.4.1 Laboratory Analysis of the Soil Samples - - - - - 104
4.4.2 Results and Interpretation of the Soil Sample - - - - 104
4.5 Owerri West Soil Erodibility Indices Determination
For Solid Waste Disposal Land Use Option - - - - 109
4.5.1 Laboratory Analysis Of The Soil Samples - - - - - 109
4.5.2 Erosion Prediction - - - - - - - - 109
4.5.3 Results And Interpretation - - - - - - - 110
4.6 Determination Of Soil Textural Characteristics
For Solid Waste Disposal Land Use Option at Avu Dumpsite - - 112
4.6.1 Soil Sampling at Avu Dumpsite - - - - - - 112
4.6.2 Laboratory Analysis of the Soil Samples at Avu Dumpsite - - 112
4.6.3 Results and Interpretation from the Soil Analysis at Avu Dumpsite - 113
Chapter Five
5.0 Discussion, Conclusion and Recommendation - - - - 118
5.1 Discussions - - - - - - - - - - 118
5.2 Conclusions - - - - - - - - - - 120
5.3 Recommendations - - - - - - - - - 122
5.4 Design Of A Modern Sanitary Landfill For The Area - - - 124
References - - - - - - - - - - 125 - 129
Appendixes - - - - - - - - - - 130 - 137
11. xi
LIST OF FIGURES
PAGE
Figure 1.1 Location Map of the Study Area - - - - - - 5
Figure 2.1 Geology Map of Imo State Showing the Study Area - - - 18
Figure 2.2 Geology Map of the Study Area - - - - - 19
Figure 2.3The Functional Elements of Solid Waste Management System - 23
Figure 3.1Designs and Construction of Phases of Spatial Database - - 27
Figure 3.2 An Entity Relationship Diagram Representing the
Spatial Data Structure for Vector Maps - - - - - 29
Figure 3.3 layout of composite map of the study area (New Owerri) - - 44
Figure 3.4 Cartographic model of the study - - - - - 46
Figure 3.5 Georeferenced New Owerri Map in an AutoCAD Environment - 48
Figure 3.6 Digitized map of New Owerri in an AutoCAD environment - 49
Figure 3.7 Layout of shape file of imported digitized Map of
New Owerri In Arcview 3.2a - - - - - - 50
Figure 3.8layout of the buffer of otamiri river and nworie stream - - 51
Figure 3.9 Layout of buffer of roads in New Owerri area - - - 52
Figure 3.10 Layout of buffer of public use theme in New Owerri area - 53
Figure 3.11 Layout of buffer of commercial land use theme in
New Owerri area - - - - - - - 54
Figure 3.12 Layout of buffer of residential land use theme in
New Owerri area - - - - - - - - 55
Figure 3.13 Layout of union of residential and public land use theme - - 57
Figure 3.13.1 Layout of shape file of union of residential and public
Land use theme - - - - - - - - 58
Figure 3.14 Layout of the union of residential and public and
Commercial land use theme - - - - - - 59
12. xii
Figure 3.14.1 Layout of shape file of the union of residential and public and
Commercial land use theme - - - - - - 60
Figure 3.15 layout of union of buffered road and river - - - - 61
Figure 3.15.1 layout of shape file of union of road and river - - - 62
Figure 3.16 layout of union of residential and public and commercial
and river and road land use (final union) - - - - 63
Figure 3.16.1 layout of shape file of final union - - - - - 64
Figure 3.17 layout of result of clipping operation (candidate site) - - 66
Figure 3.17.1 layout of shape file of clipping operation - - - - 67
Figure 3.18 query input and output of 10m from road - - - - 69
Figure 3.18.1 layout of result of road query in shape file - - - - 70
Figure 3.19 query input and output of 20m from residential - - - 71
Figure 3.19.1 layout of result of residential land use query in shape file - 72
Figure 3.20 query input and output of 40m from public land use - - 73
Figure 3.20.1layout of result of public land use query in shape file - - 74
Figure 3.21 query input and output of 20m from commercial land use - 75
Figure 3.21.1 layout of result of commercial land use query in shape file - 76
Figure 3.22 query input and output of river - - - - - 77
Figure 3.22.1 layout of result of river query in shape file - - - - 78
Figure 3.23 query input and output for suitable site within residential
and commercial land use - - - - - - 80
Figure 3.24 layout of suitable site within residential and commercial land use 81
Figure 3.25 query input and output for suitable site within residential
and public land use - - - - - - - 82
Figure 3.26 layout of suitable site within residential and public
Land use - - - - - - - - - 83
13. xiii
Figure 3.27 query input and output of suitable site within public and
Commercial land use - - - - - - - 84
Figure 3.28 layout of suitable site within public and commercial land use - 85
Figure 3.29 layout of union of suitable site within residential and
Commercial and public land use - - - - - 86
Figure 3.30 layout of most suitable site - - - - - - 87
Figure 4.1 Unified soil classification system-plasticity chart - - - 108
Figure 4.2Particle size distribution curve for Avu dumpsite soil - - - 117
14. xiv
LIST OF TABLES
PAGE
Table 2.1 Stratigraphic Units of the Niger Delta Basin - - - - 14
Table 2.2 Generalized Stratigraphy of the Study Area, Imo State - - 14
Table 3.1 logical design of data structure - - - - - - 30
Table 3.2 Physical design showing attribute table of land use map - - 31
Table 4.1 LU and LC Classes in 1986 - - - - - - - 103
Table 4.2 LU and LC Classes in 2000 - - - - - - - 104
Table 4.3 Summary of Laboratory, Field and Literature Data - - - 107
Table 4.4 Average erodibility index (K) of project locations and
predicted soil losses for the various communities
using Hudson (1995) equation - - - - - - - 110
Table 4.5 Standard erodability indices - - - - - - 112
Table 4.6: Summary of mean concentration of elements of soil samples
from Avu Dumpsites and its corresponding crustal abundance - - 116
15. xv
LIST 0F PLATES
PAGE
Plate 1 An overview of Avu dumpsite in Owerri, Imo State - - - 11
Plate 2 Polluted surface water due to leachate from solid waste dumpsite - 11
Plate 3 picture showing georeferencing and digitizing of scanned map - 37
Plate 4 picture showing analysis of the operation performed using
ArcView 3.2a software - - - - - - - - 38
Plate 5: A modern sanitary landfill designed to replace Avu open dumpsite - `124
16. 1
CHAPTER ONE
1.0 INTRODUCTION
According to World Health Organization (WHO); solid waste is defined as useless,
unwanted or discarded materials arising from domestic, trade, commercial,
industrial and agricultural as well as from public services. Solid wastes are grouped
into two viz: biodegradable and non-biodegradable wastes. The biodegradable
wastes are the wastes that can easily be decomposed by the action of anaerobic
bacteria. Examples are organic matter such as food, fruit and vegetable waste. The
non-biodegradable wastes on the other hand are those that cannot easily be
decomposed by the action of the anaerobic bacteria. Examples are glass waste,
metal waste, rubber waste, plastic waste, medical waste, electronic waste (e-waste).
The collection and disposal of solid waste is today a major public health issue and a
vital factor affecting the quality of our Nigerian cities. It is one of the most intrinsic
causes of environmental problems today found mainly in the deterioration of
environmental parameters (air, land and water quality); which leads to destruction
of the aesthetic beauty of the environment, traffic jam, flooding, and environmental
air pollution. The increase in the volume of solid waste being generated daily in
most Nigerian cities especially in Owerri municipal is due to rapid population
growth of migrant population, urbanization and general economic growth (NEST
1991). In many Nigerian cities, the volume of solid waste generated has
overwhelmed the capacity of urban administrators to plan for its collection and
disposal.
The purpose of land use planning is to make the best, most sensible, practical, safe
and efficient use of each parcel of land. Mapping of a land unit for a particular
purpose is an aspect of Land use planning which ensures maximum and safe
utilization of land. Problems of improper waste disposal are always associated with
over population in developing countries of the world. This condition usually causes
17. 2
environmental degradation leading to contamination/pollution of the environment.
In Owerri Municipality, solid wastes are mainly deposited in to open dumps and
landfills. This is because landfills are the simplest, cheapest and most effective
method of disposing wastes. For instance, wastes dumped at the Avu landfill in
Owerri West on the Port Harcourt highway are mainly solid wastes. The landfills
are poorly conceptualized in design with no adequate engineered systems to contain
landfill emissions. They are indiscriminately sited within the municipality without
regard to the nature of soil, hydrogeology and proximity to living quarters.
Also in Owerri Municipal, major solid waste generated is from residential and
commercial activities. The volume has recently grown above planned limits,
becoming a threat to the initial sufficient and effective collection and disposal of
solid waste. The unimaginable rapid population growth together with the poor and
unsustainable planning has given the municipality less significant and no suitable
solid waste collection point. Solid waste are disposed of indiscriminately; often on
open spaces such as markets places, road sides “as in Aladimma” and area A of
World Bank dump, in between dual major roads “as in Douglas Road dump”,
streets, river banks, gutters etc., and during heavy rain falls. This causes traffic jam,
imposes threats to the health of man and his environment at large.
However, the advent of Geographic Information System (GIS) in Nigeria has paved
way for the analysis of points for the collection and disposal of solid waste after
considering certain factors and criteria. GIS role in solid waste management is as
large as its many aspects of planning and operation which is dependent on the
spatial data.
1.1 STATEMENT OF THE PROBLEM
Owerri has experienced rapid population and industrial growth since it became the
capital state of Imo in 1976. The population and industrial growth have elevated the
18. 3
generation of solid waste. The increase in the volume of solid waste being
generated daily in most Nigerian cities especially in Owerri municipal is due to
rapid population growth of migrant population, urbanization and general economic
growth (NEST 1991). The volume of this solid waste generated has overwhelmed
the capacity of urban administrators to plan for its collection and disposal. It is one
of the most intrinsic causes of environmental problems today found mainly in the
deterioration of environmental parameters (air, land and water quality); which leads
to destruction of the aesthetic beauty of the environment, traffic jam, flooding, and
environmental air pollution. In Owerri Municipality, solid wastes are mainly
deposited in to open dumps and landfills. This is because landfills are the simplest,
cheapest and most effective method of disposing wastes. For instance, wastes
dumped at the Avu landfill in Owerri West on the Port Harcourt highway are
mainly solid wastes.
However, new Owerri is an emerging town from Owerri municipal with some
areas densely populated producing large and voluminous waste that are dumped
illegally on untied roads (area A of world bank) and on open spaces. This attitude
although is less expensive, imposes higher cost to the society through pollution of
air, water and land and may extend to flooding due to blockage of drainage channel.
There has not being suitable points for collection and disposal of waste generated
by people living in this area. The efficacy of selecting solid waste collection points
anddisposal sitesare based on the consideration of three relevant issues namely;
Social, Environmental and Economic factors. It is important to determine best waste
collection and disposal points based on the efficient consideration of the above
three factors. Having seen that the problem of solid waste collection and disposal
are spatial problems too, it is therefore the aim of this project to apply GIS in
resolving it for new Owerri.
19. 4
1.2 LOCATION OF THE STUDY AREA
The study area is New Owerri within Owerri Metropolis, Imo State. New Owerri by
land mass covers over 55% of Owerri metropolis area. It is located on the south
west part of Imo State in the dug deltaic formation of the Niger Delta basin, south
eastern Nigeria. The area is bounded by longitudes7o
00’
E and 7o
05’
20’’
E and
latitudes 5o
27’
4’’
N and 5o
32’
20’’
N. New Owerri is bound in the north by New
Road, Irete, in the east by Old Owerri (along Nworie River), in the south by Nekede
(along Otamiri) area and in the west by Umuguma. New Owerri comprises World
Bank areas, Federal Low Cost Housing Estate area, Concord Hotel area, the new
State Secretariat area, Federal Secretariat area, Nekede extension, zoo area,
Umugwueze and UmuejechiNekede area, New Industrial Layout and other layouts
identified as Area A, B, C to Y and more.
21. 6
1.3 PHYSIOGRAPHY OF THE STUDY AREA
The prevalent climatic condition in the area is marked by two main regimes: the
rainy and the dry seasons. The rainy season is from April to October during which
the temperature varies from 25℃ to 29℃, and this season is associated with the
prevalent moisture-laden south-west trade wind from the Atlantic Ocean. The wet
season is also characterized by double maximum rainfall during which the first peak
occur in July and the second occurs in September with a mean annual rainfall of
2152 mm (Ezeigbo, 1990). The dry season starts in November, when the dry
continental north- eastern wind blows from the Mediterranean Sea across the Sahara
desert and Samarian desert and down to the southern part of Nigeria. Due to
vagaries of weather, the August break sometimes occurs in July or early September.
Humidity is usually low and clouds are absent, during the dry season. The effect of
the harsh north easterly wind, also called Harmattan, is felt within the period. The
average monthly temperatures are high throughout the year. It has a mean annual
rainfall of about 2250-2500 mm. The mean temperature is 25-27°C.
The area lies within the tropical rain forest belt of Nigeria. The natural vegetation in
greater part of the area had been replaced by derived savanna grassland interspersed
with oil palm trees due to anthropogenic activities and also most vegetative cover
has been removed due to human activities such as farming and construction of civil
structures. The topography is fairly low and with comparatively few undulations. Its
average elevation is about 12.2m above sea level. The area is well drained by rivers
Otamiri, Nworie and seasonal Okitankwo an offshoot of Imo River.Owerri
Municipal inhabitants are mainly traders, few artisans, civil servants and farmers
who are predominantly natives.
22. 7
1.4 HYDROGEOLOGY OF THE STUDY AREA
The geology of an area to some extent controls the occurrence and types of the
aquifer found on the area. The study area is outcropped by the Oligocene Benin
Formation which is known as the ‘coastal plain-sand’ (Fig1.3). It consists mainly of
sands, sandstone and gravel with clays occurring in lenses. The sands and
sandstones ranges from fine to coarse grained and is largely unconfined, with
thickness ranging from 2.0 m to 2100.0 m (Avbovbo, 1978). The environment of
deposition is partly lagoonal and partly fluvio- lacustrine/deltaic (Reyment, 1965).
The formation which dips south westward starts as a thin edge layer at its contact
with the Ogwashi - Asaba Formation in the northern part of the area, and thickens
southwards to about 1000.0 m in Owerri area. The Benin Formation is composed
mainly of high resistant fresh water-bearing continental sands and gravels with
minor clay intercalations (Onyeagocha, 1980). The sediments represent upper
deltaic plain deposits. The Formation is generally water bearing and hence it is the
main source of portable ground water in the municipality. The aquifers are
recharged mainly by surface precipitation and nearby drainages sediments
deposition and groundwater flow are generally in the NW – SE trend, in line with
the regional trend of the basin. The sandy unit which constitutes about 95% of the
rock in the area is composed of over 96% of quartz (Onyeagocha, 1980).
1.5 AIM OF STUDY
The aim of this work is to apply Geographic Information System (GIS) to determine
optimum collection points and most suitable sites for the final disposal of the solid
waste in New Owerri, Imo State.
23. 8
1.6 OBJECTIVES OF STUDY
The objectives of this work is to generate a database by creating different layers
(roads, stream and land use) to serve the purpose of manipulation and analyses to
procure the collection point and most suitable disposal site for the solid waste
generated in New Owerri, Imo State. These objectives are as follows:
1. Designing and creation of digital spatial database “Owerri street guide map” of
the study area (data conversion from analogue to digital format).
2. Georeferencing and digitization of digital data.
3. Identification of roads, rivers and different land uses within the study area.
4. Creation of topological relationship between geographic feature and their
attributes.
5. Performing spatial analysis such as converting layers to shape files,
polygonizing, buffering, overlaying union and interception, erasing and
querying in order to get the most suitable collection points.
6. Setting criteria for the selection of the most final suitabledisposal sites for solid
waste generated from the collection points. These criteria are as follows:
a. Land use and land cover study in owerri.
b. Determination of land capability indices for solid waste land use option in
owerri west.
c. Geotechnical study of soil erodobility indices of land use determinant in
owerri west.
d. Geotechnical study on soil textural characteristics of Avu dumpsite.
24. 9
1.7 SCOPE OF STUDY
This study is limited to the new Owerri municipal inside Owerri municipal, Imo
State. It focuses on site selection for solid waste collection and disposal, having
considered the existence of waste dumpsite at the eastern and northern part of the
town,
1.8 SIGNIFICANT OF THE STUDY
To promote the health of man and his environs through a GIS technology approach
to solid waste management for efficient and effective determination of most suitable
point for collection and disposal of solid waste generated in new Owerri. In
addition, to achieve sustainable developmental objectives as well as certifying the
saying the health is wealth and a healthy person is wealthy as well.
1.9 LIMITATION
1. The map of street guide otherwise called master plan of Owerri has not been
updated since 1976 that the state was created. Thus, the recently developed
path of new Owerri has its features and roads not named in the map, making
field work a difficult task toward attribute data acquisition.
2. Majority of the southern, western and part of the northern side of new Owerri
are still big forest, this makes identification of a tangible point for
georeferencing difficult.
3. The study area was too large consisting of over 30 layouts at a scale of
1:20,000 each which made its mapping a difficult task.
25. 10
4. The large size of the study area made the spatial analysis to be poorly visible
in project presentation.
5. Financial constraints for the procurement of the necessary hardware and
software required for the project as well as expatriate consultancy.
6. The problem of mobility during field observation and acquisition of
geographic data.
7. Problem of securing data from virus and other hardware and software
problems.
8. Access to data, lack of up-to-date data and incomplete data.
26. 11
Plate 1: An overview of Avu dumpsite in Owerri, Imo State
Plate 2: Polluted surface water due to leachate from solid waste dumpsite
27. 12
CHAPTER TWO
2.0 GEOLOGY OF THE STUDY AREA
Geologically, the study area is underlain by a sequence of sedimentary rocks. The
lithological and geologic setting of the study area controls the occurrence and flow
of the ground water. Moreover, the area is underlain by the coastal plain sands of
the Benin Formation (Simpson, 1955), ranging from Miocene to recent in age
(Reyment, 1965). The Benin Formation is made up of thick friable sands with
minor intercalations of clay beds and lenses. The sand units are medium to coarse
grained, pebbly, poorly-sorted and locally contain lenses of fine-grained sandstone
and sandy clay (Short and Stauble, 1967; Onyeagocha, 1980).
The grains of the Formation are sub-angular to well-rounded. The colour of the
sands and the sandstones are white or yellowish brown as a result of Alumonite
coatings. Lignite occurs in the streaks or finely dispersed fragments; haematite
grains and feldspars are common. The clay is grayish brown, sandy or silky and
contains some plant remains and dispersed lignite. The sands and the sandstones
units of the formation are deposits of upper continental deltaic plain environment
(Short and Stauble, 1967)
Petrographic analysis of the rocks shows that the quartz makes up about 95 to 98%
of all the grains (Onyeagocha, 1980). Benin Formation has variable thickness and it
has been shown that the average thickness of the formation at the area is about
800m (Avbovbo, 1978).
However, in some places enclosed by the study area, the Formation is overlain by a
considerable thickness of red earth composed of iron stained regolith formed by
weathering and subsequent ferruginization of the weathered materials. The Benin
Formation is conformably underlain by the Ogwashi - Asaba formation. The
28. 13
Ogwashi -Asaba formation consists of a lignite series and predominantly made up
of sands with minor shale units. Its average thickness is 200m. The age is partly
Oligocene (Kogbe, 1974).
2.1 STRATIGRAPHY OF THE STUDY AREA
The stratigraphy of southeastern Nigeria has been studied in details by Uma and
Egboka (1985). The Stratigraphic succession of rocks in the study area (Table 2.1)
consists of Imo-Shale-Formation, being the oldest formation and followed by
Ameki Formation, Ogwashi-Asaba Formation while the youngest is the Benin
Formation (Uma and Egboka, 1985). The coastal plain sand belonging to the Benin
Formation extends to a considerable depth in the area and with good hydraulic
properties for groundwater development. The formation consists predominantly of
very thick coastal sand, sandstone, clays and sandy clays occur in lenses. The Benin
Formation is in part cross-stratified with the forset beds alternating between coarse
and fine-grained sands. Petrographic study on several thin sections (Onyeagocha,
1980) shows that quartz makes up more than 95% of all grains. Groundwater occurs
abundantly in the coastal plain sands (Benin Formation) and the static water level
(SWL) ranges from 8.0 – 65.0 meters depending on the location and the time of the
year. The Benin Formation is a good aquifer with an average annual replenishment
of about 2.8 billion cubic meters per year (Onyegocha, 1980). In most areas, the
sandy components form more than 90% of the sequence of the layers therefore
permeability, transmissivity and storage coefficient are very high.
29. 14
Table 2.1: Stratigraphic Units of the Niger Delta Basin (After Short and
Stauble, 1967)
Outcropping Units Subsurface Units Present-day Equivalents
Benin Formation Benin Formation Continental (fluviatile) deposits
mainly sandstones
Ogwashi–Asaba
Formation
Agbada Formation Mixed continental brackish water
Ameki Formation Marine deposits, sandstones and
clays
Imo Shales Akata Formation Marine deposits, mainly clays
Table 2.2: Generalized Stratigraphy of the Study Area, Imo State (After Uma
and Egboka, 1985).
Age Formation Maximum
approximated
Thickness (m)
Lithology
Miocene - Recent *BeninFormation 2000 Unconsolidated, yellow and white
sandstones occasionally pebbly
with lenses of grey sand clay.
Oligocene - Miocene Ogwashi – Asaba
Formation
500 Unconsolidated, sandstones with
carbonaceous mudstones, sandy
clays and lignite seams.
Eocene Ameki Formation 1460 Sandstones with grey argillaceous
sandstones shalesand thin
limestone units.
Paleocene Imo Formation 1200 Blue to dark grey shale and
30. 15
subordinate sandstones. It includes
three sandstone members, the
Igbabu, Ebenebe and Umunna
sand.
Upper Maastrichtian Nsukka Formation 350 White to grey coarse-medium
grained sandstone: carbonaceous
shales, sandy shales, subordinate
coals and thin limestones.
Lower Maastrichtian Ajali Sandstone 3504 Medium-coarse grained cross
bedded sandstones, poorly
consolidated with subordinate
white and pale grey shale.
All other Formations except the Benin formation were included to give a general
overview of the geology of the area (Imo State). However, all the depths of interest
in this project work terminated in the Benin formation.
A striking feature in the geology map is the similarity in the pattern of surface
outcrops of the Formations. Almost all the Formations at the study are occurring
along the NW – SE bands that were grossly parallel to the regional strike. The rock
units also get younger southwestward, a direction that is parallel to the regional clip
of the Formation.
The Ajali sandstone (Maastrichtian) is the oldest exposed geologic Formation in
the Imo River Basin. It outcrops along a NW – SE (2 to 4km wide) band at the
northeastward margin of the basin. The Formation consists of thick friable poorly
consolidated sandstones, typically white in colour but sometimes iron-stained.
There is a marked banding of coarse and fine grained layers and the sands grains
31. 16
and layer fragments are sub-angular with a spores cement of white clay (Reyment,
1965). Unit of this sandstone are typical cross-bedded and both the major and
foreset bedding planes are frequently lined with very thin white clay streaks. The
maximum thickness of the Formation within the Imo basin is about 300m (Uma,
1986).
The Nsukka Formation conformably overlies the Ajali sandstones and occupies a
relatively broader stretch of land west of the area underlain by the Ajali sandstone.
The Nsukka Formation dips at 2o
to 7o
to the west and southwest with an average
dips at 6o
SW but may decrease to about 1o
or 2o
especially increase north of the Imo
basin. The rock unit consists of an alternating succession of sandstones, dark shales
and sandy shales with thin coal seams at various horizons. The basal units of the
Formation consist of fine – medium grained loosely-consolidated sandstones. The
Imo Formation consist of a thick sequence of blue and dark grey shales with
occasional bands of clay iron stone and subordinate thin sandstone (Sward and
Casey, 1961).
The Imo Formation dips at relatively higher angles of 17o
to 25o
to the southwest
and south and it include the sandstone members: the Igbabu, Ebenebe and Umuna
sandstones with the last two outcropping at the Imo River Basin. The Imo
Formation is succeeded vertically by the younger Ameki Formation (Eocene),
which consist of a series of highly fossiliferous grayish-green sandy-clay with
calacareous concretions and white clayey sandstones. It has two lithological groups
recognized in parts, the lowers with fine to coarse sandstones and intercalations of
calcareous slide and thin shelly limestone and the upper with coarse, cross-bedded
sandstone, bands of fine, grey-green sandstone and sandy clay (Reyment, 1965).
The Ameki Formation constitutes the main bulk of Eocene strata overlying the
Imo Formation and the thickness may attain as much as 1400 meters in some
32. 17
places. The Ameki Formation is in turn succeded by the Ogwashi/Asaba Formation.
It is Oligocene to Miocene in age consisting of variable sequence of clay,
sandstones grills and thick seams of lignite alternating with grity clay (Desauvagie,
1974). A characteristics feature of the Formation within the Imo Basin is the up dip
and down dip pinch outs and the thickness of the lignite seams is more than 6m in
some area (Reyment, 1965). This Formation is only known from isolated outcrops
and in boreholes.
The Ogwashi/Asaba Formation is overlain by the Benin Formation which is the
youngest Formation (Miocene to Recent) in the Imo Basin. It occupies the middle
and lower regions and directly overlies more than half of the Basin.
The Benin Formation is made up of very friable sands with minor intercalations of
clays. It is mostly coarse-grained, pebbly, poorly-sorted and contains pods and
lenses of fine grained sands, sandy clays and clays (Whiteman, 1982 and Umu and
Egboka 1985). The Formation is in part cross-stratified and the foreset beds
alternate between coarse and fine grained sands. The dominance of sandy horizon in
the Benin Formation is also indicated by the logs of boreholes drilled through the
Formation. The strata logs of more than 85% of the over 400 water wells examined
indicated sand horizons of more than 90% with sandy clays making up the rest.
35. 20
2.2 PREVIOUS WORK
A Geographic Information System (GIS) is basically an organized collection of
computer hardware, software, geographic data and personal, designed to efficiently
capture, store, manipulate, analyze and display all forms of geographically
referenced information (ESRI, 1991). GIS acts as a decision support system by
facilitating the management, manipulation and analysis of spatial-temporal data. For
example:
Iro (2009) applied GIS in mapping Otamiri River water shed in Owerri, Imo state.
Olajide (2007) applied GIS in mapping solid waste disposal point in Ogbomosho
North Local Government, Oyo State.
Awosan (2006) applied GIS in mapping solid waste collection point in Ajoda New
Town, Ibadan”. GIs applications are dimensionless ranging from micro level to
macro level planning (Burroughs, 1986 and Nnabugwu, 2007). However, the
boundless capabilities are limited by one’s ability to visualize its implications. GIS
is used extensively in government business and research for a wide range of
applications including environmental resource analysis, land use planning, location
analysis, tax appraisal, utility and infrastructure planning, real estate analysis,
marketing and demographic analysis, location analysis or site selection, water
quality management, agriculture and forest managements, etc (Mather, 1991,
Nnabugwu, 2003 and Olajide, 2007).
Kufoniyi, (1998) stressed that the solution of environmental problem relies on the
use of appropriate tool for managing urban areas. Hence, GIS becomes the efficient
tool for such task. He further stated that a well-designed GIS has capability of
providing new flexible form of output such as customized maps, quick and easy
36. 21
access to large volume of data, the ability to merge one dataset with another and the
means to analyze spatial characteristics of data.
Jeffery and John (1989) reported that “Site selection using a GIS” is a classical case
of land capability analysis. Since, solid waste generation is a land-based activity,
hence, proper analysis, visualization and mapping of the volume, frequency, variety
and distribution of solid waste generation is best handled with GIS technology.
Njoku (2010), stated that spatial decision making problems such as site selection
requires the consideration of multiple and conflicting criteria and objectives,
therefore a solution method that contributes towards consensus building is required,
supporting decision making in a spatial context is the implication in the use of GIS.
A land suitability modeling can be presented using environmental, economic and
other location criteria through the use of a GIS. Selection of suitable sites for a
research center according to ESRI (1996) identified the following techniques;
- Preparing data for analysis - Creating buffer zones
- Using boundary operations - Performing polygon overlay
- Manipulating tabular data - displaying spatially referenced data.
From the foregoing review, GIS is observed to be an efficient tool for land
suitability analysis selection. It has the capability of accepting data from diverse
source integrating them with other useful in formations and performing query and
carry out spatial analysis. Thus, with these capabilities, this study intends to exploit
GIS in mapping out solid waste collection and disposal points in new Owerri.
Hornsfal et al (1999) defined solid waste as non-liquid, non-soluble material arising
from human and animal activities, which are discarded as being useless or
37. 22
unwanted. They range from municipal garbage to industrial solid waste that
contains complex and hazardous substances.
Anderson (1982) sees solid waste as any garbage, refuse, sludge from waste
treatment plant or any pollution control facility or any other discarded material
resulting from industrial, commercial, mining and agricultural operation and
community activities.
Olarjinde (2007) describes solid waste as substances or objects discarded as
worthless or unwanted, defective or of no further value for manufacturing or
production process.
Similarly, NEST (1997) in the same opinion added that these unwanted materials
are disposed off according to the provision of natural law. Sridhar (1996), defined
solid waste as any unavoidable material resulting from domestic and individual
material which must be disposed off.
However, the rate of solid waste generation increases with increase in
industrialization, population growth, urbanization, and technological advancement,
(Njoku 2010).
38. 23
Fig 2.3The Functional Elements of Solid Waste Management System
Nwadike (2004) in his work defined solid waste collection as the gathering of solid
waste and the hauling of collected waste to approved site for processing or disposal.
Most of the operational cost in solid waste management is in collection Salvato
(1991). He puts the cost estimate to represent about 80% of the total cost in disposal
by sanitary landfill and 60% when incineration is used. In view of the cost
involved, Ogedengbe (1998) was of the opinion that three fundamental questions
often arise namely ;(a)Who shall collect the waste? (b) How should to be collected?
And(c) When should collection be done? He added that to address the above
questions, a municipal authority may use direct labour (i.e. staff), contract it to a
private organization or leave it in the hands of individual households who would be
expected to make their own contract agreements with private companies.
According to Nkwocha, (2002), various types of collection system are used in
municipal for collection of solid waste generated. They can be classified into; (a)
Waste Bins, (b) Waste Bags and (c) Collection Vehicles. Based on mode of
operation, there are two categories of collection vehicle system namely;
Waste Generation
Storage
Collection
Disposal
Transfer and Transport Processing and
Recovery
39. 24
(i) Hauled Container System HCS; in this method, the container used for
storage of solid waste are hauled to the processing or disposal site, emptied and
returned either to their original location or another location. HCS are of two types;
tilt-frame HCS and Trash trailer HCS.
(ii) Stationery Container System SCS; these are collection system in which the
container used for the storage of solid waste remain at the point of generation,
except when moved for collection of solid waste. The two types of SCS are; theone
in which self-loading compactors are used and the one in which manual loading
vehicles are used.
According to Peary et al., (1986) and Nwadike, (2004), solid waste collection routes
are routes laid out to enable the workforce and equipment to function effectively.
The layout of collection route follows a four-step process;first, location maps are
prepared on large scale showing the area to be serviced. Also, the following are
plotted for each solid waste pick-up; location point, number of containers,
collection frequency and the estimated quantity of solid waste to be collected at
each pick-up location if a stationery container system is used. Second, data
summaries are prepared containing the estimated quantity of solid waste that can be
collected at each pick-up location serviced daily and the determined number of
location that will be serviced during each pick up cycle.Third, the preliminary
collection routes are laid out starting from dispatched stations or where the
collection vehicles are parked to the last location nearest to the disposal
point.Fourth, a balanced route is developed incorporating the haul distance for each
route after preliminary route has been laid out. Also, the labour requirement per
day, work times per day, and the lost solid waste transfer and transport locations are
determined.
40. 25
According to (Okorie, Nwagwo, 1993 and Nkwocha, 2002), the four main methods
adopted by local government and state waste management agencies in Nigeria are
house-to-house, communal depots, curbside collection and block collection method.
41. 26
CHAPTER THREE
DESIGNING, CREATION AND ANALYSIS OF DIGITAL SPATIAL
DATABASE
3.0 RESEARCH METHODOLOGY, RESULTS AND INTERPRETATION
3.1 DATABASE DESIGN
Database design otherwise known as data modeling is the process of defining
features to be included in the database, their attributes and relationships, and their
internal representation. Database is the core or heart of any GIS operations. It
allows system to meet up with the information or needs of the people (purpose) for
which a GIS project is carried.
Kufoniyi (1998) defined database design as the process by which real word entities,
their attributes and relationships are analyzed and modeled in such a way that
maximum benefits are derived using the minimum sets of data. Database design
passes through the following phases;
(i) Conceptualization design (ii) Logical design and
(iii) Physical design.
Below is the diagram showing the phases of database design.
42. 27
Fig: 3.1Designs and Construction of Phases of Spatial Database (Kufoniyi, 1998)
3.1.1 VIEW OF REALITY
View of reality is the mental abstraction of reality for a particular relevance to the
application or group application at hand. It is simply the perception of reality as
they actually existed. E.g. the roads, rivers and land uses are seen on the study area
as they actually existed. View of reality forms the bases of which observed features
are represented in the stages of data modeling.
Reality
View of Reality
View of Reality
View of Reality
Construction
Phase
Spatial Database
Conceptual Design
Logical Design
Physical Design
43. 28
3.1.2 CONCEPTUALISATION OF REALITY
This is also called external view. It is concerned with the way in which the data is
viewed by end users (individual perception of reality). At this stage of the database
design, decisions are made on how the view of reality will be represented in a
simplified manner and still satisfy the information requirement of the user.
Conceptual design is a concise describes the data types, relationships and
constraints expressed using the concepts provided by the high level data model. The
objective however is to determine the basic entities, the spatial relationships
between them and their attributes and how they will be modeled in such a way as to
satisfy desired need.
In this project, the vector model was adopted for use as Linear (1 – D), area (2 – D)
objects depending on the features geometric structure). The location of objects in
the data are given as X and Y coordinates, they are adopted for use and their
represented relatives were treated as points, lines and polygon feature class. The
entities or layers generated in this project were;
- Land use layer (polygon) - Road layer (line)
- River layer (line) and - Ward boundary layer
(polygon)
44. 29
As used in Fig. 3.2, the term area feature is used to describe a homogenous extent of
the earth bounded by one or more features, such as land use. A linear feature is a
geographic feature that can be represented by a line or set of lines such as road or
river. Area and Linear features are represented by arcs. In the same vein an arc is
an ordered string of vertices that begin at one location and end at another, connected
by line. The vertices at each end point of an arc are called nodes, which are the
beginning and ending locations of an arc.
45. 30
3.1.3 LOGICAL DESIGN
Logical design otherwise called data structure describes how entities and their
attributes are represented or simply the recording pattern of data in computer
system.
The conceptual data model in Fig. 3.2 was translated into a relational logical design
data structure as below;
Table 3.1 logical design of data structure
Entity Attribute field
Road Rd-id Rd-type Rd-name Rd-length
Boundary Bndry-id Bndry-name Bndry-area
Land use Ld-id Ld-type Ld-status Ld-area Ld-pop
dsty
River Rv-id Rv-name Rv-length
3.1.4 PHYSICAL DESIGN
This is an implementation stage in which the internal data structure and
organization for the database were specified. It is also referred to as a high-level
representation of data sets and the representation is guided by well spelt-out
constraints. At this stage, the field name, data types and width are specified. The
representation of features is determined by the type of software used. Arcview 3.2a
software used in this project represented lines, point object and areas as polygons.
46. 31
Table 3.2 physical design showing attribute table of land use map
Table
Name
Attribute Description Data Type Data
Width
Road Rd-id
Rd-type
Rd-length
Rd-name
Road unique identifier
Road type
Road length in meters
Road name
Numeric
String
Numeric
String
3
9
8
30
Boundary Bndry-id
Bndry-
name
Bndry-area
Boundary identifier
Boundary name
Boundary area in
hectares and square
meters
Numeric
String
Numeric
1
30
8
Land use Ld-id
Ld-type
Ld-status
Ld- pop
dsty
Land use identifier
Land use type
Land use status
Land use population
density
Numeric
String
String
string
3
30
25
15
River Rv-id
Rv-length
Rv-name
River unique identifier
River length
River name
Numeric
Numeric
string
1
8
20
47. 32
3.2 DATA ACQUISITION
The main data required for this project are land related data such as maps,
coordinate values, name and length of roads, status of land uses, etc.
3.2.1 DATA SOURCE
Generally, there are two types of data namely; primary and secondary data.
The data source for this project relies mainly on secondary data; they are:
A. Owerri Street Guide map and Owerri master plan collected from state
ministry of land and survey, new secretariat, Owerri. This contains the land
use data at a scale of 1: 20,000, map of Imo state showing Owerri municipal
area and Owerri west area.
B. Other secondary sources includes documented materials such as magazines,
newspapers, libraries, written texts, related journals, maps and satellite
imagery of the study area gotten from Google Earth in the internet.
Also, the firsthand information obtained from the study area arecalled primary data.
They include:
A. The Geographical coordinates of three points using Google earth software,
B. The name of the areas and streets, the length of roads as well as a ground
thruthing field observation embarked upon to confirm the features on the
maps.
3.2.2 DATA CONVERSION
The maps used in this project were in analogue format. They were however
converted into digital format through the process of vectorization (scanning with
scanner and georeferencing and digitizing with auto cad software). The digitization
of the map produced the following layers;
48. 33
(i) Land use (ii) Road and (iii) River.
3.2.3 GEOMETRIC DATA ACQUISITION
Geometric data were acquired through the use of Google earth software from
internet to supply the coordinate values of points in the study area (in geodetic
format). The geographical co-ordinates were converted to rectangular (using the
Geo-calc software) which is the acceptable referencing system for geo-referencing
maps in the AutoCAD software.
The coordinate points are as follows:-
(i) First reference point (Assumpta Cathedral Owerri)
N 060
27’ 16.95”
E 070
03’ 15.32”
(ii) Second reference point (Imo Concorde Hotel)
N 060
28’ 21.63”
E 070
03’ 10.65”
(iii) Third reference point (junction between NMT1 and WMT2 Highway
along Umuguma)
N 050
25’ 45.64”
E 060
55’ 52.83”
3.2.3.1 GEOREFERENCING
This is the process of bringing the scanned map into its true earth (location)
coordinate on the computer system using an acceptable referencing system. The
Universal Traverse Mercator (UTM) with referencing to Mina datum was used. The
49. 34
geographical co-ordinates obtained with Google Earth software were converted to
rectangular (using the Geo-calc software) which is the acceptable referencing
system for geo-referencing maps in the AutoCAD software. Thus, each image was
corrected for scale and station and geo-referenced using the following converted
coordinate points.
i) First reference point (Assumpta Cathedral) East
X 2 61755.320 E
Y 615970.756 N
ii) Second reference point (Imo Concorde Hotel) South
X 271595.728 E
Y 614230.920 N
iii) Third reference point (junction between NMT1 and WMT2 Arterial
Highway along Umuguma) West
X 267170.976 E
Y604796.745 N
3.2.3.2 DIGITIZING
This is the systematic extraction of important features from the map to be used in
GIS spatial analysis. The features on the map were digitized as points, lines and
polygons and were classified into themes for proper identification, differentiation,
thematic map creation and other analytical operations. The onscreen digitizing was
50. 35
done with the use of AutoCAD Land Development 2i where the map was digitized
into the following layers;
(i) Land use - Commercial
- Residential
- Public (including recreational, administrative,
reserve and religious land uses)
(ii) Road (iii) River and (iv) Boundary layers.
3.2.4 ATTRIBUTE DATA ACQUISITION
The attribute data were collected through primary and secondary data sources.
They are for residential, commercial and public use land uses, roads, river and
boundary. “The attribute tables for the various land use types mentioned above are
shown on appendix ii below”
Thus, in the process of carrying out the project, the following operations were
performed for efficient and effective actualization of this plan;
1. Procurement of digital map of new Owerri from internet and coordinate
points with the aid of Google Earth software which is to be combined with
analogue maps of the same area gotten from Ministry of Land and Survey
and Owerri Capital Development Authority (OCDA), all from Imo State.
2. Conversion of procured geodetic (geographic) angle from Google Earth
software to Rectangular (projections) coordinates with the aid of
Geocalculator software for georeferencing in AutoCAD.
3. Conversion of analogue map to digital map followed by georeferencing and
digitization in AutoCAD which is exported into Arcview software.
51. 36
4. Design and creation of database that will support the integration of record of
land use, rivers and road network of the area, which will permit updating and
retrieval of information pertaining to the study area.
5. Collection and structuring of the attribute data using Arcview 3.2a software.
6. Performing analysis using Arcview 3.2a software.
Plate 3: picture showing georeferencing and digitizing of scanned map
52. 37
Plate 4: picture showing analysis of the operation performed using ArcView
3.2a software.
53. 38
3.3 SYSTEM DESIGN
3.3.1 HARDWARE REQUIREMENT
Ahp pavilion v4225nr personal computer (laptop) was used with the following
configurations;
1. Intel ® Celeron (PM) CPU, rated at 3.2 window experience index (named Xp
window 7), manufactured at Haiter,
2. 5.12MB of RAM of 32-biting operating system type,
3. A mustakAz Scanner
4. A HP DeskJet D1560 Printer
3.3.2 SOFTWARE REQUIREMENTS
The following software was used for this project;
- Microsoft Window XP Professional window 7 viena, Service
pack 3, version2008-2009.
- Arc View GIS Version 3.2a for spatial analysis of site selection.
- AUTOCAD Land Development 2i for georeferecing and
digitizing the scanned map
- GEO CALC (Geographic Calculator 3.09) Software for
conversion of coordinates from geographical to rectangular and
vice – verse.
- Google Earth Software for acquiring satellite imageries and
geographical coordinates.
54. 39
3.4 DATABASE CREATION
This is the construction phase of obtaining GIS database after three levels of design
phase. It involved the organization of the data in the forms that were compatible
with the relevant software. The analogue map digitized in AutoCAD was exported
to Arc View where area features were polygonized. Both acquired spatial and
attribute data were used in creating the database. The process went thus;
Launch Arc View 3.2a, click “Open theme”, icon table was displayed. Click “edit
menu”, select “start editing”, select “add field”. A dialogue box was displayed.
Input name, i.e. land use area, land use type, land use status etc., input data type i.e.
string, number or Boolean as appropriate then click “edit menu”. Select “add
record” and type in the entire attribute in the table and click “edit menu” and finally
“stop editing”.
3.5 DATABASE MAINTENANCE
This is an aspect of database management system concerned with the maintenance
of data to retain its value. It involves management of quality, integrity and security
aspect of the database.
3.5.1 DATA QUALITY
This is the application of quality assurance and quality control measures while
carrying out the project to ensure high confidence limit in the guaranteeing of the
work. The measures include;
1. The hard copy map was obtained from the state ministry of land and survey,
new secretariat, Owerri, Imo State.
2. The georeference points (coordinates) were collected directly from internet
with Google Earth software etc.
55. 40
3.5.2 DATA SECURITY
Security measures adopted in this project includes;
1. Data were properly protected in the system with the use of password codes,
2. Backups were put in place to protect the data from being lost as well as
devices being used,
3. Data transfer and transaction were done with utmost care.
3.5.3 DATA INTEGRITY
This ensures the consistency and correctness of data stored in a database, the data
integrity adopted for this project is the domain integrity were the data type, width
and decimal of attribute were all specified.
3.6 SPATIAL DATA ANALYSIS, RESULT PRESENTATION AND
INTERPRETATION
3.6.1 INTRODUCTION
Spatial analyses are the operations performed on spatial data to find solutions to
spatial problems. It involves the organization of database into layers for the purpose
of providing rapid access to the data that might be required for geographic analysis.
By applying the abstraction process, real world entities were stimulated into the
computer. The process involved;
(i) Identifying the spatial feature form the real world that are of interest in the
context of an application and choosing how to represent them in the conceptual
model.
56. 41
(ii) Representing the conceptual model by an appropriate spatial data model.
(iii) Selecting an appropriate spatial data structure to store the model within the
computer.
For this research work, spatial analyses were performed to locate the best locations
for solid waste collection within New Owerri in Owerri, Imo State. Investigation
from local authority and field survey revealed that there were no standard criteria
for ascertaining and zoning of solid waste collection points in Imo State. For this
reason, the user-based criteria based on the United Nations (UN) standard criteria
requirement was adopted for this research work.
The spatial operations used in the spatial analysis include buffering, overlay
(union), clipping and querying of data to arrive at the needed goal, the entities of
interest, (i.e. Roads, rivers and other land uses) were buffered. The buffering cut
across the study area at 100meters away from the features of interest at a distance
10meters per-ring, generating 10 rings on around the feature. This was done to take
care of the situation at hand as well as future expansions.
3.6.2 CRITERIA FOR SELECTING SUITABLE SOLID WASTE
COLLECTION POINTS
In selection of solid waste collection points, the following selection criteria set
based on the United Nations Standard Criteria Requirement was adopted. They are;
- The collection point should be 10m away from roads (for easy collection and
to prevent road blockage).
- The collection point should not be less than 70m away from water bodies e.g.
rivers.
57. 42
- They should be 40m away from public use areas
- They should be 20m away from commercial areas.
- They should be 20m away from residential areas (thus within the proximity
of prospective users).
- A collection point must be at least 100m away from one another.
- The population density must determine the number of collection points
within each layout.
- It must be along the road/street junctions
(Source: www.gisdevelopment.net)
59. 44
3.6.3 CARTOGRAPHIC MODELLING
A cartographic model is a set of interacting, ordered map operation that act on raw
data as well as a derived and intermediate map data to stimulate a spatial decision
making process (Michael, 1997). It is simply a graphical representation of data and
analytical procedures employed in building up a spatial database. It is also the
process of linking or organizing basic analysis operations in a logical sequence such
that the output from one is the input to the next. In this project, the cartographic
model revealed the step by step procedures of combining declared data (themes) to
generate the product i.e. the most suitable sites.
One unique aspect of GIS is its capabilities of carrying out analysis on real word
data, it allows for analysis of an existing database on geographic relationships. GIS
analysis used in this project includes buffering, overlay operations (unioning),
clipping and spatial queries. These operations were carried out to analyze all the
established criteria necessary for the location of solid waste collection points.
(i) Buffering of roads, rivers, residential, commercial and public use land uses
(buffer of 100m at an interval of 10m).
(ii) Union of buffered results
(iii) Clipping of unioned results with boundary
(i) Single and multi-criteria queries.
60. 45
Fig. 3.4 Cartographic model of this study
Res + Pub. Use
Residential use
layer
Residential
theme
Buffered
residential
Commercial
theme
River layerRoad layerPublic use
layer
Boundary
layer
Public theme Commercial
theme
Road theme River theme
Boundary
theme
Buffered
public
Buffered
commercial
Buffered road Buffered river
Union
union Com + Pub +
residential
Union
Road + river
Union
Com + pub + res + road + river Clip
Query 1
Query (2)
Candidate site
Base map
Scanned land use map
Georeferenced
Digitized
Residential Commercial Public road
Possible areas Possible areas Possible areas Possible areas
Pub &com
use
comcomm.
Res&pub useCom & res use
Suitable site Suitable site Suitable site
Union
Most suitable site
61. 46
3.7 SPATIAL ANALYSES PERFORMED
3.7.1 DIGITAL MAPPING PROCESSES ON MAP OF NEW OWERRI
Owerri street guide map was scanned and imported into the AutoCAD land
development software where it was georeferenced and digitized. Arcview GIS 3.2a
was launched and the digitized map was exported from Auto CAD to Arc view. The
road, boundary, rivers, residential, public and commercial layers were converted to
shape files after which the various entities were polygonized with Arcview script.
Thus, all the features were converted from polylines to polygons which are the
acceptable shapes for spatial analysis in the Arcview environment.
63. 48
Fig 3.6 Digitized map of new Owerri in an AutoCAD environment
2013, Field Work
64. 49
Fig 3.7 layouts of shape file of imported digitized map of new Owerri in Arcview
3.2a
65. 50
3.7.2 BUFFERING OPERATION
One important spatial operation is the determination of spatial proximity or
nearness of various geographic features. The operation performed by the buffer
command generates one or more polygons surrounding geographic features and the
polygon is called BUFFER ZONE. In this study, buffering operation of 100m at an
interval of 10m was carried out on all the entities.
3.7.2.1 ANALYSIS OF BUFFERING OPERATION
Make the theme (feature) to be buffered e.g. river theme active click the ‘theme’
menu on the toll bar and select ‘create buffer’. A dialogue box is shown. Click
‘next’ and select ‘as multiple rings’ then input the number of rings, distance
between rings and units. Click next and on the new dialogue box, click on ‘yes’ for
dissolve barriers between buffers?’ Also select ‘only outside the polygon’, then
save in a new theme and click finish. The new theme will definitely show.
66. 51
FIG 3.8 TO FIG 3.12SHOWS ALL THE BUFFERING OPERATIONS
PERFORMED.
Fig 3.8layout of the buffer of otamiri river and nworie stream
70. 55
Fig3.12 layout of the buffer of residential land use in New Owerri
3.7.3 OVERLAY OPERATIONS
This is a GIS analytical tool used to merge two themes representing different data
sets to generate a new set of information. Topological overlay can be used for
different objectives such as theme updating, feature extracting, merging adjacent
themes and merging feature attributes.
The concept of overlay is by combining two or more themes (features), usually in
preparation for further analysis. For this research, overlay by union of entities was
applied. Overlay by union is used to combine features of an input theme with the
71. 56
polygons from an overlay theme, to produce an output theme that contains the
attributes and full extent of both themes.
For this project, the following overlay operations were performed;
(i) First Overlay: The buffered residential land use theme was overlaid (unioned)
with the buffered public use land use theme to have another output theme called
union of residential and public use land uses.
(ii) Second Overlay: The buffered commercial theme was overlaid with union of
residential and public use theme to produce a new output theme called; union of
commercial, public use and residential land uses.
(iii) Third overlay: The buffered road theme was overlaid (unioned) with the
buffered river theme to have another output theme called union of road and river.
(iv) Fourth overlay: The unioned road and river were overlaid with the union of
commercial, public use and residential land uses, to produce a new output theme
called; final union made up of the union of commercial, public use, residential,
river and roads theme.
3.7.3.1 ANALYSIS OF OVERLAY OPERATION
Click on ‘view’ on the tool bar menu and select ‘geo processing wizard’. A
dialogue box is shown; select ‘union two themes’ and click next on the new
dialogue box, specify the two themes involved e.g. buffer of commercial layer and
buffer of public use layer. Specify the output file and click ‘finish’. The new theme
will definitely show.
72. 57
FIG 3.13 TO FIG 3.16 SHOWS ALL THE OVERLAY BY UNION
OPERATIONS PERFORMED.
Fig 3.13 layout of the union of residential and public land use
73. 58
Fig 3.13.1 shape filelayout of the union of residential and public use theme
74. 59
Fig 3.14 Layout of union of buffered commercial, public use and residential land
uses
75. 60
Fig 3.14.1 shape file layoutof the union of residential and public use and
commercial land use
78. 63
Fig 3.16 layout of the union of public, commercial and residential land use and road
and river i.e. final union
79. 64
Fig 3.16.1 shape file layout of the final union of public, commercial and residential
land use and road and river
Boundary shape1.shp
Final union.shp
1000 0 1000 2000 3000 Meters
N
EW
S
shapefile of union of road, river, residential, com mercial and public land use
field work, 2010field work, 2010
276000
276000
277000
277000
278000
278000
279000
279000
280000
280000
281000
281000
282000
282000
602000 602000
603000 603000
604000 604000
605000 605000
606000 606000
607000 607000
608000 608000
609000 609000
2013, Field Work
80. 65
3.7.4 POLYGON CLIPPING OPERATIONS
This is the spatial extraction of those features from one coverage that resides
entirely within a boundary defined by features in another coverage (called clip-
coverage). In line with analysis for this study, the boundary of the study area was
clipped with the theme; union of commercial, public use, residential and roads to
produce the candidate site for further research.
3.7.4. 1 ANALYSIS OF CLIPPING OPERATION
Click on ‘view’ on the tool bar menu and select ‘geo-processing wizard’ A dialogue
box is shown. Select ‘clip one theme based on another’ and click on ‘next’. On the
new dialogue box, select the input theme i.e. union of commercial, public use,
residential, river and roads, as well as the polygon overlay theme i.e. boundary
layer. Specify the output file and click ‘finish’. The new theme will definitely show.
82. 67
Fig 3.17.1 shape file of the candidate’s site layout of result of the clipping operation
83. 68
3.8 SPATIAL QUERY/SEARCH
This is the major analytical operation carried out on the attribute table of various
entities. The spatial search was performed by querying the database. It is the
process of acquiring information from a GIS by asking spatial questions from the
geographic data.
Spatial query is the process of selecting features based on location or spatial
relationship (e.g. selecting all areas 20m from residential areas). Database querying
is achieved through a query expression built to precisely define what to be selected.
Query expressions can either be single or multiple criteria.
In this project, the single criteria query was carried out after buffering and the
resultant output ( in shape file) were unioned, and clipped to form a candidate shape
file which was queried multiply to obtain most suitable sites for the present need
only.
However, the future need were also incorporated by overlaying the buffered land
use theme without querying and clipping the final union to form a candidate site to
be queried either singly or multiply to obtain desired result.
3.8.1 SINGLE CRITERIA QUERY
Single criteria query was used to determine the possible areas for solid waste
collection points for all the land uses including roads. This didn’t produce the final
result but gave an insight to the possible areas where the collection containers can
be placed. This was done using the set criteria as stated in 4.2. It was inputted into
the query builder as follows; 10m from roads (Roads=10m) for easy collection and
to prevent road blockage, 20m from residential areas (Res=20m) and 20m from
commercial areas as well (com=20m) so it will be within the proximity of users and
84. 69
40m from public use (public use =40m) so it wouldn’t constitute nuisance to people
using public facilities.
POSSIBLE AREAS FOR ROADS
(Rd Dist.=10m)
Fig 3.18 Query input and output of 10m from road
94. 79
3.8.2 MULTI CRITERIA QUERIES
Multi criteria queries were used to determine the suitable sites as well as the most
suitable sites for solid waste collection within New Owerri area. This query
combines more than one entity in a particular land uses to select the suitable sites
within the land thereof. Three multiple criteria query was carried out in this project.
(i) First; identification of most suitable points within residential and
commercial area at 20m interval respectively
(ii) Second; identification of suitable points on areas within residential and
public land use at 20m and 40m interval respectively.
(iii) Third; identification of most suitable points on areas with commercial
and public land use at 20m and 40 interval respectively
The result of this query shows sites that are suitable for users at the same time in the
two land uses. The result is a union of points or areas where the land uses meet /
intersect with the set criteria in place within a particular land use type.
3.8.2.1 INPUT FOR MULTI-CRITERIA QUERIES
- First: Res_Buff DIST = 20 and Com_BuffDIST=20 and RdDIST = 10
- Second: Res_BuffDIST=20 and Pub_BuffDIST = 40 and RdDIST = 10
- Third: comm._BuffDIST=20 and Pub_BuffDIST=40 and RdDIST = 10
95. 80
3.8.2.2OUTPUT FOR MULTI-CRITERIA QUERIES
- SUITABLE SITES WITHIN RESIDENTIAL AND COMMERCIAL
Fig 3.23 Query input and output for suitable sites within residential and commercial
land use
96. 81
Fig 3.24 Layout of suitable sites within residential and commercial land use
97. 82
- SUITABLE SITES WITHIN RESIDENTIAL AND PUBLIC USE
Fig 3.25 Query input and output for suitable sites within residential and public use
99. 84
- SUITABLE SITES WITHIN COMMERCIAL AND PUBLIC USE
Fig 3.27 Query input and output for suitable sites within commercial and public use
100. 85
Fig 3.28 Layout of suitable sites within commercial and public use land use
101. 86
Fig 3.29 Layout of union of suitable sites within commercial, residential and public
use land uses
According to the map sourced from State Ministry of Land & Survey and Owerri
Capital Development Authority, New Owerri area is characterized mainly by
residential areas, public use areas as well as commercial areas.
Thus, there is need to make available more waste bins for these areas, especially the
high density residential areas.
Afterwards, points that were within 100m proximity were expunged using the
measure tool on ArcView window.
103. 88
3.9 INTERPRETATION OF RESULTS
Figures 4.22, 4.24 and 4.26 were overlaid to have a combined suitable sites (fig.
4.27), which again was queried to have the suitable sites, after which points that
were within 100m proximity were expunged using the measure tool on ArcView
window (as seen in figure 4.28) thus giving the most suitable sites for locating solid
waste collection points in New Owerri.
In Fig 4.28, the collection points were identified as points in relation to their
coordinate values and layout. The following coordinate values represent the
locations specified by the Geographic Information Systems as well as the attributes
of the points. Thus, in all the sited collection points, the distances to similar land
use type are the same as stated in the criteria with respective distances of;
road=10m, commercial land use=20m, public land use=40m, river >70m and
residential land use=20m.
INDUSTRIAL LAYOUT
This has nine collection points with respective coordinate values of:
278421.01E&609192.64N, 278897.32E&608762.14N,
279053.03E&608606.42N, 279282.03E&608285.83N, 279126.31E&608029.36N,
278851.52E&608837.00N, 278411.85E&607827.84N, 277770.67E&607827.84N,
277092.85E&607837.00N
AMAKAOHIA POCKET LAYOUT
This has five collection points with respective coordinate values of:
278824.04E &609320.88N, 279098.83E & 609063.41N, 279300.35E &
608872.05N, 280042.29E &608991.13N, 280427.00E &609046.09N
104. 89
ARUGO LAYOUT
This has four collection points with respective coordinate values of:
279.538.50E & 608340.79N, 279987.33E & 608716.34N, 280060.61E &
608020.20N, 280616.19& 608203.39
UMUJECHI NEKEDE VILLAGE LAYOUT/NEW OWERRI SOUTH
This has four collection points with respective coordinate values of:
280332.46E&603065.10N, 280550.21E&603255.63N,
280822.39E&603037.88N, 280631.86E&602847.35N.
UMUGWULE NEKEDE VILLAGE/NEW OWERRI SOUTH
This has only one collection point of 279965.00E & 602888.18N.
UMUMBAZU NEKEDE VILLAGE/NEW OWERRI SOUTH
This has two collection points with respective coordinates of:
279992.22E&602262.14N and 279651.98E&601758.59.
PUBLIC BUILDING/NEW OWERRI SOUTH
This has only one collection point with coordinate values of
279189.26E&602670N.
AREA H LAYOUT
This has four collection points with respective coordinate value of:
280196.36E&604017.76N, 280060.27E&603677.52N, 280278.02E&603691.13N,
280880.21E&603772.79N.
105. 90
AREA G LAYOUT
This has five collection points with respective coordinate values of:
280550.21E&604412.43N, 280836.00E&604439.65N, 280754.35E&604276.34N,
281121.80E&604249.12N, 280890.44E&603936.10N.
AREA F LAYOUT
This has three collection points with respective coordinate value of:
281257.96E&604453.26N, 281475.65E&604589.35N and
281217.07E&604439.65N.
AREA E LAYOUT
This has three collection points with respective coordinate values of:
280659.08E&605310.26N, 280509.38E&605092.90N and
280550.21E&604725.45N.
AREA C LAYOUT
This has four collection points with respective coordinate values of:
280904.05E&605378.70N, 280890.44E&605092.90N, 281366.77E&605378.70N
281462.04E&604956.81N.
COMMERCIAL DISTRICT LAYOUT
This has nine collection points with respective coordinate values of:
278222.99E&604548.53N, 278359.09E&604181.07N,
278616.67E&604279.34N, 278944.29E&604834.32N, 279325.36E&605011.25N,
279393.41E&604861.54N, 279760.86E&605160.95N, 280101.10E&605065.68N
280169.14E&605297.04N.
106. 91
AREA R LAYOUT
This has three collection points with respective coordinate values of:
279338.97E&603364.51N, 279883.34E&603595.87N and
279230.09E&603677.52N.
AREA P LAYOUT
This has two collection points with respective coordinate values of:
279447.84E&604643.79N and 278989.86E&604317.17N.
AREA B LAYOUT
This has five collection points with respective coordinate values of:
279815.30E&604902.37N, 279842.52E&604643.79N, 279651.98E&604398.82N,
280196.36E&604521.31N 279937.78E&604289.95N.
AREA U LAYOUT
This has only one collection point with coordinate value of
278495.18E&603105.93N.
AREA U’A LAYOUT
This has only one collection point with coordinate value of
279053.17E&603282.85N.
AREA T LAYOUT
This has three collection points with respective coordinate values of:
278168.56E&603759.18N, 278359.09E&603976.93N and
278386.31E&603677.52N.
107. 92
FEDERAL MINISTRY OF WORKKS & HOUSING/SITE SERVICES
SCHEME LAYOUT
This has three collection points with respective coordinate values of:
276630.69E&603078.71N, 277351.99E&602929.00N and
277351.99E&603364.51N.
AREA V LAYOUT
This has two collection points with respective coordinate values of:
277488.09E&603881.66N and 277841.93E&604126.63N.
AREA W LAYOUT
This has two collection points with respective coordinate values of:
277773.06E&602888.18N and 278073.29N
SECRETARAIT LAYOUT
This has only one collection point with coordinate value of
279284.53E&605174.56N.
PUBLIC BUILDING/EXHIBITION GROUND LAYOUT NEW OWERRI
WEST
This has five collection points with respective coordinate values of:
277134.24E&604984.03N, 276889.27E&604371.60N, 276739.57E&603745.57N,
277365.60E&604357.99N, 277814.71E&604602.96N.
AREA A LAYOUT
This has seven collection points with respective coordinate values of:
108. 93
278862.98E&606194.71N, 279487.80E&606246.77N,
279088.61E&605925.68N, 279591.94E&606055.86N, 279574.59E&605582.29N,
279279.53E&605778.16N,
AREA N LAYOUT WORLDBANK
This has ten collection points with respective coordinate values of:
278.584.25E&606168.18N, 278406.47E&605895.21N,
278876.21E&606001.81N, 278434.20E&605775.09N, 278819.13E&605771.83N,
278533.69E&605629.93N, 278027.90E&605678.86N, 278848.49E&605595.68N,
278598.93E&605504.34N and 278414.62E&605435.83N.
PUBLIC BUILDING LAYOUT
This has fifteen collection points with respective coordinate values of:
279661.35E&608077.86N, 279826.25E&607366.25N, 279140.68E&607791.48N,
278741.49E&607678.66N, 278889.01E&607531.13N, 279010.51E&607305.50N,
278481.14E&607192.69N,278463.79E&608858.89N,
278524.54E&606923.67N, 278377.01E&607522.46N, 278229.48E&607175.33N,
278298.90E&606845.56N,277760.86E&607366.25N,
277717.47E&607062.52N, 277396.38E&607123.26N.
WORLD BANK AREA M LAYOUT
This has nine collection points with respective coordinate values of:
278437.75E&606672.00N, 278472.47E&606481.08N, 278533.21E&606316.20N,
278281.55E&606177.35N, 278706.77E&606264.13N, 278186.09E&606426.37N,
278264.19E&606602.58N, 277977.81E&606455.05N, 278047.24E&606307.52N
109. 94
AREA S LAYOUT
This has four collection points with respective coordinate values of:
277514.05E&606459.65N, 277342.80E&606199.93N, 277476.94E&606051.51N,
277808.34E&605874.56N
AREA X LAYOUT
This has eight collection points with respective coordinate values of:
276540.80E&606511.02N, 276809.08E&606462.50N, 277228.64E&606448.23N,
276869.02E&606302.67N, 277094.49E&606237.03N, 276786.25E&606128.57N,
277017.43E&606125.72N, 276820.50E&605831.75N
ONITSHA YOUTH CENTRE LAYOUT
This has seven collection points with respective coordinate values of:
280052.92E&607407.97N, 280297.30E&607270.24N, 280306.18E&607074.74N,
280488.36E&607123.61N, 280417.26E&606919.22N, 280634.98E&607012.53N,
280266.20E&606483.79N,
AREA D LAYOUT
This has three collection points with respective coordinate values of:
279525.29E&606379.38N, 279736.35E&605940.61N, 280114.02E&606368.27N,
AREA L LAYOUT
This has six collection points with respective coordinate values of:
110. 95
279158.73E&607079.18N, 279069.87E&606834.80N, 278831.05E&606640.41N,
278814.38E&606462.69N, 279180.95E&606623.75N, 279375.34E&606529.33N,
NEW D LAYOUT
This has six collection points with respective coordinate values of:
277417.06E&605509.23N, 277768.06E&605494.16N, 278010.96E&605306.59N,
277668.17E&605206.70N, 277425.57E&605175.36N, 277222.93E&605149.62N,
AREA Y LAYOUT
This has four collection points with respective coordinate values of:
277277.16E&605700.16N, 277162.99E&605646.23N, 277157.28E&605417.90N,
276754.85E&605489.25N,
FEDERAL LOW COST HOUSING ESTATE TAN2
This has six collection points with respective coordinate values of:
277812.93E606580.51N, 277700.11E&606481.08N, 277865.00E&606402.98N,
277804.25E&606272.81N, 277847.64E&606125.28N, 277891.03E&605943.04N
FEDERAL LOWCOST HOUSING ESTATE TAN1
This has six collection points with respective coordinate values of:
278003.85E&605726.09N, 278151.38E&605804.19N, 278029.88E&605647.98N,
278246.83E&605658.66N, 278246.83E&605457.07N, 278116.66E&605465.74N
The available portions specified by the system are the most suitable sites. Thus, the
local government can now use their discretion to place the waste bins (containers) at
111. 96
strategic points as specified. If the bins are properly placed at these points, New
Owerri territory will be;
- A healthy environment for the inhabitants.
- Void of health hazards associated with indiscriminate dumping of solid
wastes.
- Made a clean area in contrast to other cities of Nigeria and in line with the
state governments’ programme of ensuring a “clean and green” city.
- Void of induced flooding caused by blocking of drainage as a result of
indiscriminate dumping of solid wastes.
- Made a model area in terms of efficient and effective solid waste
management.
112. 97
CHAPTER FOUR
SETTING CRITERIA FOR THE SELECTION OF THE MOST FINAL
SUITABLE DISPOSAL SITES FOR SOLID WASTE GENERATED FROM
THE COLLECTION POINTS
4.0 RESEARCH METHODOLOGY, RESULTS AND
INTERPRETATION
These criteria for determining the most final suitable sites for disposal of solid
waste are as follows:
a. Land use and land cover study in owerri.
b. Determination of land capability indices for solid waste land use option in
owerri west.
c. Geotechnical study of soil erodobility indices of land use determinant in
owerri west.
d. Geotechnical study on soil textural characteristics of Avu dumpsite.
4.1 SOIL TYPES IN OWERRI WEST
Owerri West Local Government Area with its headquarters at Umuguma is located
between latitudes of 5o
23’
and 5o
34W and between longitudes of 6o
5o
’ and 7o
E,
and has 15 autonomous communities namely Obinze, Avu, Nekede, Ihiagwa,
Amakohia Ubi, Ndegwu, Okuku, Eziobodo, Oforola. Ohi, Umuguwaand Orogwe,
Okolochi, Emeabiam and Irete.
With the soil map of Imo State, using the United States Department of Agriculture
(Peech et al. 1947) and Food and Agricultural Organization of the United Nations
(FAO 1976) classification systems, there are three classes of soil in Imo State.
They are Ferralitic soils from the coastal plain sand and the escapement are
occupying an area of about 7,798 square kilometers, which is 61% of the total area
113. 98
of flat to undulating topography characterized by good drainage. Hydromorphic
soils from plateau and Cross-River plain are occupying an area of about 31% of the
total landmark and have developed along the escapement found in the Northeastern
part of the State.
Alluvial soils occupy about 8% of the total area of the state and are found along the
low terrace of the Cross-River and Orashi River. They are poorly drained and are
subject to permanent or periodic flooding.
The communities living in these areas hardly go through each year without adverse
effect of soil erosion especially that due to water.
4.2 SOIL SAMPLING
A total of 19 soil samples each were collected for the study in determining the land
capability indices and soil erodobilty indices in Owerri west; and also the soil
textural characteristics of the refuse dumpsite in Avu.
15 soil samples each were collected at 15 (fifteen) autonomous communities in
owerri west L.G.A from pits dug at a depth of 5 meters using auger to determine the
land capability and soil erodobility indices. These autonomous communities are
Obinze, Avu, Nekede, Ihiagwa, Amakohia Ubi, Ndegwu, Okuku, Eziobodo,
Oforola, Ohi, Umuguma, Orogwe, Okolochi, Emeabiam and Irete.
2 (two) soil samples were also collected at the vicinity of Avu dumpsites between
1.0 – 2.5 meters depth to determine the textural characteristics of the soil while
additional 2 (two) samples at the same depth range were collected far away from
the dumpsite, to serves as control samples. Sampling tools were washed with water
and dried before the next sample was collected. They were placed in polythene
bags, and transported to laboratory for analysis. Method of random sampling was
adopted in which 19 (nineteen) soil samples covering the entire soil types of the
area were collected.
114. 99
4.3 LAND USE (LU) AND LAND COVER (LC) STUDY IN OWERRI
Land use study is the act of planning to make the best, most sensible, practical, safe
and efficient use of each parcel of land. On the other hand, LU refers to the manner
in which these biophysical assets are used by people [for details, see Cihlar and
Jansen, 2001]. Land use and land cover dynamics has been common place around
Owerri and environs. Owerri and environs are characterized by natural and
man-made problems and rapid land use and cover changes such as flooding,
erosion, induced soil infertility and degradation, deforestation, etc. This study
examines the application of multi-temporal remotely-sensed data in the detection of
static LU and LU changes between 1986 and 2000. The study provides temporal
empirical comparative assessment of TM 86 and ETM+ 2000, while identifying the
primary drivers of the intra-class dynamics during the periods in order to predict
what types will dominate the area in the future.
The study area, Owerri metropolis is a closely-settled built-up area and the
administrative capital of Imo State of Nigeria. The pre-1976 Owerri comprised
largely pockets of rural settlements of predominantly subsistence farmers. It lies
between latitude 50
25’N and 50
34’ N and longitude 60
7’E and 70
06’E covering an
area of approximately 5,792.72 km2. The 1991 population of Owerri was 289, 721
[NPC 1991]. In 1998, the projected population was put at 353, 665 people [Imo
State Government, 2000] While in 2006, the population was 401, 873 [NPC 2006].
The area is within the humid tropics and is characterized by high temperature and
rainfall regimes with a mean maximum temperature of about 320o
C and a mean
minimum of about 210o
C.
Recent studies (Nnaji, 1998, 1999 and FGN, 2003) however reported declining
trend in rainfall characterized by large spatial and temporal variations. The area lies
in the rainforest belt of Southeastern Nigeria characterized by low- land tropical
rainforest, which has virtually given way to secondary forest re-growths of mostly
115. 100
tree crops and shrubs separated by crops at various stages of growth. In the area,
vegetation plays the dual role of humus supply and protection of the soil from the
ubiquitous soil erosion.
Owerri and environs are within the densely populated region of Southeastern
Nigeria. In spite of the increasing population which presses on land availability,
market gardening is largely practiced. The growth rate of the population growth,
its size structure, density, spatial distribution and urbanization characteristics
are critical factors of the environment likely to affect LU and LC dynamics.
Being the administrative capital of Imo State, associated infrastructure, education
opportunities and employment potentials in the city attracts growing migrants from
distant and adjourning towns and villages. The emergence of small and medium
sized agro-husbandry industries in the peripheral, semi urban villages have attracted
urban sprawl and rapid socio-economic activities. Hence, subsistence agriculture,
petty trading, white collar jobs (paid employment), artisanship characterize and
significantly influence the contemporary LU and LC patterns. This has exerted
great pressure on the ecological resources, even without any eco-conservations
efforts.
Similarly, soil erosion, flooding, increasing soil infertility resulting in bare surfaces
also contributed in shaping these patterns.
4.3.1 Methodology of the land use and land cover study
The study was undertaken with 1:100,000 administrative map of Imo State covering
the study area which was obtained from the Ministry of Lands and Urban
Development, Owerri Nigeria. The map was used for the enhancement of LU and
LC classification, orientation and geometric registration of the imageries during
interpretation. The satellite imageries were obtained from the National Space
Research and Development Agency [NASRDA] Abuja, Nigeria. The LU and LC
116. 101
patterns represented on the map were used as the starting point of the contemporary
LU and LC classification in the present study. This done, the regularity of LU and
LC conversion of the different classes were analyzed.
4.3.2 Results and interpretation of the land use and land cover study
The results of the study revealed significant shift between the two periods. The
imageries proved very useful and effective in the accurate mapping of ground
features. The bare/eroded surfaces class gave the highest PAVM value of 65.7%
followed by water body 44.9. The major LU and LC classes identified in the study
are: built-up area, poorly dispersed forest vegetation, cultivation, bare/eroded
surfaces and water body. The variants of forest vegetation was the dormant LU and
LC type in 1986 and 2000 and covered a total area of 2,792.72km2
, especially
around the out-lying peri-urban areas. Land areas and features were assigned
different spectral signatures to represent changes from one class to the other. The
largest inter-class change occurred between the cultivation and the forest vegetation
classes. The forest vegetation class has the largest unchanged portion among the
classes.
Simple percentages were used to show the differences and to represent the relative
amount of the LU and LC classes as a percentage of the total area. The strength of
their differences is shown using the Percentage Absolute Variations of Mapping
[PAVM] values expressed as:
𝑃𝐴𝑉𝑀 =
(𝐴1 − 𝐴2) × 100
(𝐴1 + 𝐴2)
Where A1 = Landsat TM 86 map percentage of the LU and LC classes within the
study area.
A2 = the absolute differences in values between A1 and A2
The values show that there was an overall change of about 26.9% between the data
sets. The forest vegetation showed the lowest (4.31%), while the eroded/bare
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surfaces showed the highest change of 65.74%. This portrays the ability of the two
imageries to accurately map identical features.
Table 4.1: LU and LC Classes in 1986
LANDSAT TM 86 [19th
December
1986]
Area in km2
Bare/Eroded surface 21.96
Cultivation 891.94
Forest Vegetation 1, 431.25
Built-up 438.04
Water Body 9.53
Total 2, 792.72
Table 4.2: LU and LC Classes in 2000
LANDSAT ETM+ [of 12th
December
2000]
Area in km2
Bare/Eroded surface 4.54
Cultivation 680.40
Forest vegetation 1,560.00
Built-up 543.88
Water Body 3.62
Total 2,792.72
118. 103
4.4 OWERRI WEST LAND CAPABILITY INDICES DETERMINATION
FOR SOLID WASTE DISPOSAL LAND USE OPTION
4.4.1 Laboratory Analysis of the Soil Samples
The collected soil samples were subjected to the following analysis using specified
equipment. Atterberg limits, (using Cassagrande apparatus), particle size
distribution, (using British electric shaker machine), porosity and permeability
(using permeameter), consolidation settlement using (consolidometer), shear
strength (using triaxial shear box) and finally compressive strength. Analysis were
done using ASTM D, 4318-98(2000) and ASTM, 1988 standard specifications. All
analytical procedures are shown in (Robert et al 2001).
4.4.2 Results and Interpretation of the soil sample analysis
The average results of laboratory, filed and literature studies are shown in Table 3.
The table is a reference guide in the rating of the basic determinants of land use
factors. From the table, while the forralithic soil is poorly graded, the
hydromorphic and ferralithic soil are well graded. Forralithic soil and lithosoil
tilt towards Sandy clay while that of ferralithic and hydromorphic soils tilt
towards silty clay.
Soils that tilt towards sand have high shear and compressive strength , while those
tilting towards silt have high attenuative power in handling waste effluents,
Gauley and Krone (1966), Krynine and Jude (1957). The result shows that while the
clay fraction of hydromorphic soil is 13% that of ferralithic soil is 13.5%. From
these, the activity indices of ferralithic and hydromorphic soils were calculated to
be 1.84 and 2.02, while their liquidity indices, were calculated as -0.24 and -0.41.
This was obtained using the relation according to Robert et al (2001):
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…………(1)
and
………(2)
Where PI is plasticity Index, W natural moisture content and PL is Plastic Limit.
The result of this calculation indicates that the two soils hydromorphic and
ferralithic soils are expansive and weak, therefore unsuitable for residential and
industrial buildings, (Robert, 2001).
Permeability and porosity result show that the permeability and porosity of
hydromorphic soil is measured 1.97 x 10-2
cm/sec and 0.31 that of ferralithic
soilis measured 1.89 x 10-2
cm/sec and 0.30, while lithosoil has 1.70 x 10-2
and
0.30; the Forralithic soil also has 1.70 x 10-2
and 0.30.
Where τ is shear strength, C = cohesion, δn = effective stress on soil and ө =
Frictional angle based on total stress analysis. Employing equation 3 and
parameters C and tan ө from graph of shear versus Normal stress, the shear
strength for hydromorphic, forralithic, ferralithic and lithosoils are
85.56KN/m2
, 96.09KN/m2
, 87.82KN/m3
and 88.36 KN/m3
respectively.
The shear strength of hydromorphic and ferralithic soils are lower than forralithic
andlithosoils, also the angle of internal friction is high for forralithic soils indicating
a high shear strength (Aria, 2003).
Hydromorphic and ferralithic soils show high cohesion, there is likelihood of shear
failure when subjected to load like industrial buildings, since saturated clays fail if
subjected to vibration, (Aria 2003).
The result of compressive strength shows that forralithic soil has compressive
strength of 9.10KN/m2
with test load of 14.43KN/m2
, ferralithic soil 2.10 KN/m2
test load 20.16 KN/m2
. Hydromorphic soil 2.176KN/m2
test load 56.0 KN/m2
while
lithosoil has 3.24KN/m2
with test load of 21.34 KN/m2
.
