Land Capability Index Mapping for Waste Disposal Landuse Option Using Geographic Information System (GIS) in Enugu Area, South Eastern Nigeria

doi:10.4236/jgis.2012.45049

Journal of Geographic Information System, 2012, 4, 444-461

http://dx.doi.org/10.4236/jgis.2012.45049 Published Online October 2012 (http://www.SciRP.org/journal/jgis)

Land Capability Index Mapping for Waste Disposal

Landuse Option Using Geographic Information System

(GIS) in Enugu Area, South Eastern Nigeria

Augustine Onunkwo-Akunne, Samuel Okechukwu Onyekuru, Godwin Ifedilichukwu Nwankwor

Department of Geology, Federal University of Technology Owerri, Owerri, Nigeria

Email: [email protected]

Received January 2, 2012; revised February 5, 2012; accepted March 14, 2012

ABSTRACT

The projected 300% growth rate in the population of Enugu area and its environs by the year 2020 and the expected

increase in waste generation necessitated the need to map out areas for waste disposal for future utilization and as a

protective strategy for the environment in Enugu area. Land capability index mapping using Geographic Information

System (GIS) is one of the appropriate tools required for solving this problem. A total of 12 landuse determinants were

selected as thematic data layers, and as basic factors influencing the choice of waste disposal landuse option in the area.

The themes (thematic maps) generated from field/laboratory measurements and from literature, include slope, water

table, surface and subsurface water conditions, elevation, geology, soil, drainage and geo-structural stability (fault, ero-

sion, landslide and flooding) maps. The maps were scanned, digitized, georeferenced, and polygonized using autocard

drawing capabilities to convert them into vector format and later exported to arc view software for analysis. The final

processing using overlay model builder yields layers that display areas of preferred waste disposal sites in a map form,

which generally shows areas of varying suitability (suitable, moderately (low) suitable and unsuitable). The waste dis-

posal map of Enugu area shows that blocks 1 (Obeagu area) and 3 (Ebe/Nsude areas) represent suitable and unsuitable

areas, respectively, while block 2 (Ngwo area) has low suitability for waste disposal.

Keywords: Landuse; Thematic Maps; Waste Disposal; Land Capability

1. Introduction

The purpose of landuse planning is to make the best,

most sensible, practical, safe and efficient use of each

parcel of land [1]. Mapping of a land unit for a particular

purpose is an aspect of Landuse planning which ensures

maximum and safe utilization of land. Enugu area under

investigation is presently witnessing high rate of popula-

tion growth. Accordingly, a projection of the population

of Enugu area is pegged at approximately 300%, giving

rise to a population figure of about 3,237,298 people by

the year 2020, [2]. Problems of improper waste disposal

are always associated with over population in developing

countries of the world. This condition usually causes en-

vironmental degradation leading to contamination/pollu-

tion of the environment. It is therefore, necessary to map

out areas of varying capabilities for waste attenuation

and containment in the Enugu area for future utilization

and as a protective strategy for the environment.

Site evaluation for waste disposal involves the under-

standing of basic soil components and properties, mecha-

nisms operating in the soil and limitations of the mecha-

nisms in terms of pollutant loading rates. It also 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, slope, surface water, fault and flood poten-

tial [3-11].

The application of Geographic Information System

(GIS) in the evaluation of land has widely been ac-

claimed to facilitate efficient decision making and plan-

ning of land use options, [12]. 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, [13].

This approach is applied in the determination of areas

with varying degrees of suitability for waste disposal

land use option in the Enugu area and environs.

1.1. Location of Study Area

The study area is located within Latitudes 6˚16'N and

6˚31'N and Longitudes 7˚20'E and 7˚41'E covering an

C

A. ONUNKWO-AKUNNE ET AL. 445

areal extent of about 630 km2

(Figure 1). The area is also

located within the rain forest belt of Nigeria and has an

average annual rainfall of about 1100 mm a year, [14].

1.2. Topography of the Study Area

The most striking feature within the study area is Enu-

gu-Awgu escarpment. This escarpment is part of the

Nsukka–Okigwe Cuesta, which was formed by the resis-

tant sandstones of the lower part of the Ajali Sandstone

and the Mamu Formation (Figure 1), [15]. The elevation

of the escarpment ranges from 450 m to about 530 m,

while the slopes range between 3% and 6% in the dip

slope part to between 55% and 65% along the scarp face,

[16]. Terminating at the foot of the escarpment to the east

is the extensive undulating Cross River Plain, underlain

by the Enugu Shale.

1.3. Drainage

The Enugu-Awgu escarpment forms the most important

watershed separating the Cross River system to the east

from a network of streams flowing westwards towards

the Anambra Basin, [14]. The escarpment is also in-

dented with river valleys, which form the source of

streams rising at about the 305 m elevation and flowing

down into deep canyons and v-shaped gullies incised in

the weakly bedded and friable sandstones and sands of

the Ajali and Mamu Formations, [17]. The rivers and

rivulets give rise to dendritic drainage pattern, usually

developed in rocks with uniform resistance to weathering

and erosion, [18].

1.4. Geology

The study area lies in the Anambra Basin of southeastern

Nigeria. The basin is of Cretaceous to Tertiary age,

[15,19]. Five formations that underlie the study area in-

clude: Ezeaku Formation (Turonian), Awgu Ndiabo Shale

(Santonian), Asata-Nkporo/Enugu Shale (Campanian-

Maastrichtian), Mamu Formation (middle Maastrichtian)

and Ajali Sandstone (late Maastrichtian). The strati-

graphic succession is shown in Figure 2 and Table 1.

The formations are conformable, although minor discor-

dance may be present, but there is no evidence of any

prolonged break in sedimentation, [20].

1.5. Hydrogeology

The major water bearing units (aquifers) occur in the

Ajali Sandstone that underlie areas to the west of the

study area, with a generally deep static water table of

about 30 to 40 m deep, [21]. Aquifers also occur within

the Mamu Formation, while some aquitards occur within

the Enugu Shale, [18]. The aquitards, are fractured and

are tapped by hand dug wells which show high coliform

counts, [22]. In the eastern part of Enugu area, the static

water table occurs at an average depth of 5 to 9 m mak-

ing the area vulnerable to pollution. The generalized

depth to water table in the area is shown in Figure 3. It

shows that depth to water table decreases from west to

east. At the western section, the water table is at an av-

erage depth of 60 m and at the eastern section towards

the Cross River plain, the water table is very close to the

ground surface averaging about 9 m deep.

Figure 1. Location map showing Enugu area and environs.

A. ONUNKWO-AKUNNE ET AL.

446

Figure 2. Geological map of Enugu area and environs.

Table 1. Generalized sedimentary sequences in southeastern Nigeria [15].

Age Formation Lithology

Maastrichtian 6.5 - 6.8 Ma Ajali Formation Friable sandstone with cross bedding.

Mamu Formation Alternating sequence of sandstone clay stone and shale with coal seams.

Campanian 78 - 82 Ma Nkporo. Enugu Shale Dark grey shale with clayey shale with clay lenses.

Santonian 78 - 82 Ma Awgu Formation Bluish grey shale with clay lenses.

Turonian 82 - 92 Ma Ezeaku Formation Black shale with clay and limestone lenses.

Figure 3. Water table map of the study area.

A. ONUNKWO-AKUNNE ET AL.

447

1.6. Soils 2.2. Laboratory Studies

The main soil types in the area are ferralithic and hy-

dromorphic soils, which are derived from the Ajali Sand-

stones and Enugu Shales underlying the area. The soils

derived from Enugu Shale are expansive and have hy-

draulic conductivity values of about 10–5 m/s, [23]. These

soils can be grouped into four classes (based on weath-

ering conditions): Ferralithic Soil (deep, friable and po-

rous), hydromorphic soil (saline soil), lithosoil (thin soils

mostly found on hill slopes) and forralithic soils, (Figure

4), [7].

Laboratory investigations carried out on the soils in-

cluded: particle size analysis, porosity, permeability and

Atterberg limit tests.

Samples for particle size distribution analysis were

first thoroughly disintegrated by alternate cycles of wet-

ting and drying. The disintegrated material was sieved

through 3.35 mm, 0.425 mm to 0.075 mm sieve meshes

after thoroughly shaking the samples with a standard

electric sieve shaker. The percentage by weight of soil

particles retained on each sieve mesh, were plotted

against sieve mesh size to obtain the size distribution

pattern of each sediment sample. The particle size distri-

bution of sediments less than 0.075 mm was determined

using the hydrometer method in accordance with [24] BS

standard. Only hydromorphic and ferralithic soils were

investigated using this method. The hydrometer analysis

is based on Stroke law and indicates the percentage of

clay fraction present in a sample of soil.

2. Materials and Methods

Data required for the analysis of land use options for

Enugu Area is divided into primary and secondary data

types. The primary data involved information obtained

from field and laboratory studies, while secondary data

included information obtained from literature and raw

data collated from ministries, parastatals, universities and

companies. The porosity and permeability of the soils were also

determined as one of the necessary parameters used in

delineating potential of an area for waste disposal lan-

duse option. The tests were carried out on the hydro-

morphic, ferralithic and forralithic soils using falling

head method.

2.1. Soil Sampling

Soil samples were taken randomly from two horizons at

Owa, Enugu, Ugwuafor and Agbani. Sampling was car-

ried out by pitting to a fairly considerable depth of 5 and

5.8 m horizons. Collection was made on fresh samples,

while indurated surfaces, humus sections and gravely

beds were avoided. The collected soils were preserved in

polythene bags and taken to the laboratory for necessary

soil tests in accordance with [24] BS standard.

3. Results and Data Analysis

The results of particle size distribution of 3 samples rep-

resenting the different soil types in Enugu area is pre-

ented in Tables 2-4 and Figures 5-7. The results s

Figure 4. Soil map of Enugu area.

A. ONUNKWO-AKUNNE ET AL.

448

Table 2. Grain size data for ferralithic soil.

Sieve Size (mm) Mass retained Cumulative mass retained (g) % Cum-mass retained % Passing

5.56 0 0 0 100

3.35 0.2 0.2 0.04 99.96

2.0 2.1 2.3 0.46 99.54

1.18 33.1 35.4 7.08 92.92

0.6 60.8 96.2 19.24 80.76

0.425 98.6 194.8 38.96 61.04

0.5 97.8 292.6 58.52 41.48

0.212 84.0 377.6 75.52 14.48

0.15 85.6 463.2 92.64 7.36

0.075 32.8 496.0 99.20 0.8

Received 3.4 499.4 99.98 0.02

Table 3. Grain size data for forralithic soil.

Sieve Size (mm) Mass retained Cumulative mass retained % Cum-mass retained % Passing

3.35 0 0 0 100

2.0 0.2 0.2 0.04 99.56

1.18 2.8 3.0 0.6 99.4

0.6 8.7 11.7 2.34 97.66

0.425 19.1 30.8 6.16 93.84

0.3 21.7 52.5 10.5 89.5

0.212 56.0 108.5 21.7 78.3

0.15 153.2 261.7 52.34 47.3

0.075 191.0 452.7 90.54 9.46

Received 47.0 495.7 99.94 0.06

Table 4. Grain size data for hydromorphic soil.

Sieve Size (mm) Mass retained(g) Cumulative mass retained (g) % Cum-mass retained % Passing

28.0 0 10 0 100

19.0 18.4 18.4 374 96.26

14.0 6.2 24.6 5.00 95.00

10.0 27.3 51.9 10.55 89.45

5.6 76.6 131.5 26.75 73.25

3.35 81.3 212.8 43.26 56.12

2.0 70.6 283.4 57.65 42.35

1.18 57.3 340.9 67.34 30.66

0.6 30.5 371.4 75.34 24.46

0.425 13.4 384.8 78.28 21.72

0.3 10.5 395.6 80.41 19.59

0.212 6.3 401.6 81.69 18.31

0.15 26.3 427.9 87.04 12.96

0.075 36.3 464.2 94.43 5.57

Received 17.7 481.9 98.03 1.97

A. ONUNKWO-AKUNNE ET AL. 449

Figure 5. Grain size distribution of the forralithic soil (Owa).

Figure 6. Grain size distribution of the ferralithic soil (Ugwuafor).

Figure 7. Grain size distribution of the hydromorphic soil (Enugu).

A. ONUNKWO-AKUNNE ET AL.

450

show that forralithic soils can be grouped as sandy clay

soils while hydromorphic and ferralithic soils are silty

clay soils.

The plots of hydrometer analysis for the two soil types

(ferralithic and hydromorphic soils) are shown in Fig-

ures 8(a) and (b), which show that the clay fraction of

the hydromorphic soil is 13% and that of ferralithic soil

is 13.5% in the analyzed samples.

The result of the falling head test for some of soil

types in the study area is shown in Table 5. The For-

ralithic and hydromorphic soils have higher porosity and

permeability which corroborates the work of [25].

(a)

(b)

Figure 8. (a) Plot of grain size analysis result using hydrometer for ferralithic soil; (b) Plot of grain size analysis result using

hydrometer for hydromorphic soil.

A. ONUNKWO-AKUNNE ET AL. 451

Table 5. Permeability and porosity of soils in Enugu area.

Soil Type Pe rm eabi lity (cm/s) Porosity (%)

Hydromorphic Soil 1.97 × 10–2 31

Ferralithic Soil 1.89 × 10–2 30

Forralithic Soil 1.92 × 10–2 31

Similarly, the following physical properties of litho-

soils that also underlie part of the study area have also

been defined, [16]: shear strength = 88.36 N/m2, porosity

= 30% and permeability is 1.70 cm/s, soil group is silty

sand.

3.1. Engineering Classification of Soils

The Unified Soil Classification System (USCS; Table 6)

used particle size distribution and Atterberg Limit Data

(Tables 7-9) to describe two main soil groups in the

study area: coarse and fine grained soils. The plasticity

chart (Figure 9) also used grain size distribution and

Atterberg limit data (Tables 7-9) to characterize three

classes of soils in the study area (Forralithic Soil, Hy-

dromorphic Soil and Ferralithic Soil): Forralithic soils,

plotted on CL-ML field (Figure 9) representing silty clay

and poorly graded soils. Hydromorphic soil plotted on

SP-CL field which is silty clay and poorly sorted soils.

Ferralithic soil plotted on SW-CL field which is silty clay

and well sorted soils.

3.2. Thematic Maps

Twelve thematic maps generated from the various field

and laboratory operations and from literature were em-

ployed as basic landuse determinants in the study area.

The maps are the themes that form data layers for Geo-

graphic Information System (GIS) operation. The the-

matic maps were first scanned at 150 dpi (dot per inch)

esolutions, digitized, polygonized and georeferenced r

Table 6. Unified soil classification system.

Major

Divisions Subdivisions USCS

Symbol Typical Names

Laboratory

Classification

Criteria

Remarks

GW Well Graded Gravels, or gravel-

sand mixtures with little or no fines Less than 5% fines C ≥ –4 and 1 ≤ C ≤ 3

GP Poorly Graded Gravels, or

gravely sands, little or no fines Less than 5% fines Does not meet C and or

C criteria listed above

GM Silty Gravels and sand mixtures More than 12% fines Minus No. 40 Soils plot

above A Line

Gravels (More than

50% Retained on

No. 4 Sieve

GC Silty Gravels, Gravels and clay

Mixtures More than 12% fines Minus No. 40 Soils plot

above A Line

SW Well graded Sands or Gravelly

Sands, little or no fines Less than 5% fines C ≥ –6 and 1 ≤ C ≤ 3

SP Poorly Graded Sands or Gravelly

Sands little or no fines Less than 5% fines Does not meet C and or

C criteria listed above

SM Silty Sands, Sand Silt Mixtures More than 12% fines Minus No. 40 Soils plot

above A Line

Coarse Grained

Soil (More than

50% Retained

on No. 200

Sieve

Sands (50% or

more of coarse

fraction passing

No. 4 Sieve)

SC Clayey Sands, Clay-Sand

Mixtures More than 12% fines Minus No. 40 Soils plot

above A Line

ML Inorganic silts, rock, flour, silts

of low plasticity Inorganic soil PL < 4 or Plots below A

Line

CL Inorganic Clays of low plasticity

(Gravel Clays, Sandy Clays, etc. Inorganic soil PL > 7 or Plots above A

Line

Silts and Clays

(Liquid Limit <

50%)

OL Organic Silts, Organic Clays

of low plasticity Organic soil LL (Oven-Dried) LL

(Not Oven Dried) 0.75

MH Inorganic silts, micaceous silts,

silts of high plasticity Inorganic soil Plots below A Line

CH Inorganic highly plastic Clays,

fat clays, silty clays, etc. Inorganic soil Plots on or above A line

Fine Grained

Soils (50% or

more passes

No. 200 Sieve

Silts and Clays

(Liquid Limit 50%

or more)

OH Organic Silts and Organic Clays

of high plasticity Organic soil LL (Oven-Dried) LL

(Not Oven Dried) 0.75

Peat Highly Organic PT

Peat and other highly

organic soils

Primary organic

matter, dark in colour

A. ONUNKWO-AKUNNE ET AL.

452

Table 7. Soil parameters determined for forralithic soils.

US Sieve % passing Atterberg limits

N04 (3.35) 99.96

N010 (2.0) 99.54

N040 (0.425) 01.04

N0100 (0.15) 7.36

N0200 (0.075) 0.8

LL = 26.06%

PL = 19.75%

PI = 6.31%

Table 8. Soil parameters determined for hydromorphic

soils.

US Sieve % passing Atterberg limits

N04 (3.35) 100

N010 (2.0) 99.6

N040 (0.425) 93.8

N0100 (0.15) 47.3

N0200 (0.075) 9.5

LL = 43.3%

PL = 16.89%

PI = 26.46%

Table 9. Soil parameters determined for ferralithic soils.

US Sieve % passing Atterberg limits

N04 (3.35) 56.12

N010 (2.0) 42.35

N040 (0.425) 21.96

N0100 (0.15) 12.96

N0200 (0.075) 5.57

LL = 39.84%

PL = 14.70%

PI = 25.14%

Figure 9. Unified soil classification system-plasticity chart.

with 4 control points of 6˚16'N and 6˚31'N (Latitude) and

7˚20'E and 7˚41'E (Longitude). The digitized thematic

maps include: elevation map, slope map, soil depth map,

drainage map, soil class map, surface water map, depth

to water table map, erosion map, escarpment map, fault

map, flood/landslide map and geologic map of the study

area (Figures 10-21). These data base (thematic maps)

were modified using excel statistical software and geo-

graphic calculator and arranged as distinct layers. Data

analysis also involved conversion of the collected eleva-

tion values and coordinates to national grid. With the aid

of the topographic map of Enugu area and the Geo-

graphic Positioning System (GPS), the 3D Digital Ter-

rain Model (DTM) of the study area was developed in

Arc view by the extrapolation of elevation values at 100

m range (Figure 22). The DTM of the area revealed de-

tailed picture of the drainage pattern that aided selection

of waste disposal sites free from environment of internal

drainage, [3].

3.3. Organization of Geographic Input Data

and the Establishment of GIS Data Layers

The thematic data layers used in this work are relevant

for waste disposal land use option (Table 10). The scale

values of the tables are the capability ratings assigned to

each environmental factor based on a scale of 0 - 2, to

make up three classes of landuse representing zones of

unsuitable (0), low suitability (1) and suitable (2). A zero

(0) capability value renders the land of any area very

unsuitable as the capability values of other landuse fac-

tors within the same polygon remains zero irrespective of

their high suitability values, [26].

3.4. Overlay Process

The input themes (thematic layers) were overlaid using

computer iterative technique starting from theme I to 12

(Figure 23). This operation was done by the selection of

a model builder from the operational table (Table 10)

using the Arc view software. Individual themes are added

to one another using the matrix operation of the form:

1

12

T Scale Value:

T









This operation produced a waste disposal land use map

(Figure 24). The waste disposal map shows that areas 1

(Obeagu area) and 3 (Ebe/Nsude areas) represent suitable

and unsuitable areas, respectively, while 2 (Ngwo area)

has low suitability for waste disposal.

4. Discussion

The result of the overlay operations produced the pre-

ferred areas for waste disposal land use option. The map

shows various areas of capabilities for waste disposal

designated as areas 1, 2 and 3 representing suitable, un-

suitable and low suitability, respectively. The study

shows that area 1 (Obeagu area) occupies 60% of the

land area that is suitable for waste disposal. This means

that the greater percentage of Enugu area is suitable for

A. ONUNKWO-AKUNNE ET AL. 453

Figure 10. Digitized elevation map of Enugu area.

Figure 11. Digitized slope map of the study area.

A. ONUNKWO-AKUNNE ET AL.

454

Figure 12. Soil-depth maps of the study are a .

Figure 13. Digitized and polygonized soil drainage maps.

A. ONUNKWO-AKUNNE ET AL. 455

Figure 14. Digitized and polygonized soil class map.

Figure 15. Digitized and polygonized surface water map.

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456

Figure 16. Digitized and polygonized wate r table map.

Figure 17. Digitized and buffered gully erosion map.

A. ONUNKWO-AKUNNE ET AL. 457

Figure 18. Digitized and polygonized esc ar pment map.

Figure 19. Digitized and buffered fault map.

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458

Figure 20. Digitized geological map of Enugu area and environs.

Figure 21. Digitized, buffered, landslide and flooded area.

A. ONUNKWO-AKUNNE ET AL. 459

Figure 22. Digital terrain model map of Enugu area.

Table 10. Organization of thematic data layers for w aste disposal landuse option.

Input Theme Percentage

Influence Input

Field Input Label Scale Value Remarks

Slope Theme 1

(Layer 1) 10%

1

2

3

0-9(Gentle Slope)

9-19( sloppy)

> 19 ( steep)

2

1

0

Down migration of

leachate

Elevation Theme 2

(Layer 2) 6%

Used in the derivation of

DEM for slope

computation

Soil Depth Theme 3

(Layer 3) 5%

1

2

3

Deep

Shallow

2

1

Attenuation of pollutants

Geology Theme 4

(Layer 4) 20%

1

2

3

4

5

Ajali FM

Mamu FM

Asata/Nkporo

Awgu-Ndi Abo

Ezeaku

2

1

2

1

Based on geological

characteristics e.g.

Fractured rocks enhance

the migration of pollutants

Drainage Theme 5

(Layer 5) 10%

1

2

3

Moderate

Well Drained

1

2

Poorly Drained soil can

lead to reducing

conditions

Soil Class Theme 6

(Layer 6) 5%

1

2

3

4

Sandy (Foralithic)

Clayey Sand (Hyromorphic)

Silty Sand (Lithosoil)

Sandy Clay (Ferralithic)

1

2

0

1

Based on soil

Engineering classification

Surface Water

Theme 7 (Layer 7) 8% Buffered 1000 m (1 km)

Depth To Water Table

Theme 8 (Layer 8) 9%

1

2

3

Very Shallow

Shallow

Deep

1

2

3

Can be polluted when

shallow

Erosion Theme 9

(Layer 9) 8% 1

2

Buffered

Active

Non Active

0

Can distribute wastes GIS

Buffer  (1 km)

Escarpment Theme 10

(Layer 10) 4%

Scarp

Crest

Dip

0

1

2

Escarpment is

characterized by high

slope.

Flooded/Land Slide

Theme 11 (Layer 11) 5% 1

2

Buffered

Active

Non Active

0

Reducing condition

distribution of wastes and

leachate Buffer 1 km)

Fault Theme 12

(Layer 12) 10% 1

2

Buffered

Active

Non Active

0

Can create pathway for

leachate migration to

ground water. GIS buffer

 (1 km)

Total 100%

A. ONUNKWO-AKUNNE ET AL.

460

Figure 23. Overlay model for waste disposal land use.

Figure 24. Suitability map for waste disposal land use option in Enugu area.

waste disposal except Enugu Metropolis. The western

quadrant is suitable due to low water table conditions,

considerable soil thickness of about 19 m and very high

sorption capacities due to the presence of fines in the

samples. Areas of low suitability for waste disposal

(Area 2: Ngwo area) occupy 20% of the land area, and

falls mainly around the escarpment and the eastern end of

the map. The low suitability in Area 2 is a function of

steep slopes of around 50%, seepage at the foot of the

escarpment due probably to high pore water pressure,

and very shallow water table conditions. The unsuitable

zones for waste disposal—Area 3 (Ebe/Nsude areas) also

occupy about 20% of the land area and correspond to

fault zones, scarp face terrain, flood and landslide prone

areas.

If a terrain is suitable for waste disposal, such a land

has an advantage over unsuitable areas as leachates are

easily attenuated by natural processes, hence the envi-

ronment is protected and safe for man to live. Natural

protection also saves huge costs required in waste man-

agement, especially in constructing engineered systems

in areas that have high suitability for residential land use

A. ONUNKWO-AKUNNE ET AL. 461

but low suitability for waste disposal landuse option. In

such areas the international standard practice of leachate

treatment, containment and discharge into the environ-

ment should be observed.

The area at Ugwuaji off Enugu-Port Harcourt ex-

pressway presently mapped out and used by Enugu State

Environmental Sanitation Authority (ESESA) for the

disposal of the wastes falls in one of the areas of high

suitability of the present study. This implies that its pre-

sent position is well cited. Most industries and residential

buildings within Enugu Metropolis also correspond to

areas of low suitability for waste disposal.

5. Conclusion

This study has shown that the area suitable for waste

disposal practices in Enugu Area cover the greater per-

centage of the land unit and are found within the western,

central and to a reasonable extent, the eastern blocks.

Some of the available lands were adjudged unsuitable

due to faults, erosion, landslides, floods and scarp face.

This study is therefore expected to form the basis for

future landuse management for enhanced sustainable

development and better planning of Enugu area and en-

virons.

REFERENCES

[1] L. V. Dutra and R Hober, “Primary Forest and Landcover

Contextual Brazil Proceedings on International Geo-

sciences and Remote Sensing Symposium,” USA, 1998,

pp. 5-35.

[2] “Nigerian Population Census,” Enugu State Government

Gazette, 2006.

[3] C. C. Raymond, “Land Application of Wastes,” John

Wiley and Sons Publishers, Hoboken, 1979, pp. 150-160.

[4] S. A. Griffiths, “Land Treatment of Leachate for Munici-

pal Landfills Nayea Publications,” 1981, pp. 210-216.

[5] P. N. Gauley and R. B. Korne, “Soil Mantle as a Waste

Treatment System,” University of California, Berkely,

1966, pp. 120-131.

[6] W. R. Aria, “Principles of Geotechnics, Environmental

Protection Service,” Harwood Academic Publishers, New

York, 2003, pp. 85-124

[7] R. Davis and G. Rogers, “Landfill Evaluation and Siting

Study New Jersey,” John Wiley and Sons Publishers,

Hoboken, 1975, pp. 240-285.

[8] P. Crynine, “Land Disposal of Solid Wastes CBS Pub-

lishers and Distributors,” New Deihi, 1977, pp. 850-930.

[9] C. B. Hunt, “Geology of Soils, Their Evolution, Classifi-

cation and Uses,” W. H. Freeman, San Francisco, 2002,

pp. 130-172.

[10] M. J. Hammer, “Water and Waste Water Technology,”

2nd Edition, Wiley publisher’s, New York, 2003, pp

230-238.

[11] P. C. Sidle, “Relative Importance of Factors Influencing

Landsliding in Coastal Alaska,” Proceedings of Annual

Engineering Geology and Soil Engineering Symposium,

Juneau, 1985, pp. 34-38.

[12] D. A. Holland and S. L. Smith, “The Effect of Changing

Grid in the Creation of Laser Scanner, Digital Surface

Models in Geo-Computation,” Oxford University Press,

Oxford, 2003, pp. 230-240.

[13] V. C. Kang, “Introduction to Geographic Information

System,” Tata McGraw-Hill Publishing Company Ltd.,

New Delhi, 2002, pp. 20-25.

[14] N. P. Iloeje, “A New Geography of Nigeria,” Revised

Edition, Williams Clowes Ltd., London, 1981, pp. 85-

120.

[15] R. A. Reyment, “Aspect of the Geology of Nigeria,”

Ibadan University Press, Ibadan, 1965, pp. 22-38.

[16] G. E. K Ofomata, Technical Report on Feasibility Study

of Erosion Vulnerability Areas in the Eastern Part of Ni-

geria Ethiope Publishing House, Britain, 1985, pp. 35-37.

[17] L. C. Amajor, “Sedimentary Facies Analysis of the Cam-

pano-Maestritchtian Ajali Sandstone Okigwe Area Nige-

ria,” 20th Annual Conference of Nigeria Mining and Geo-

sciences Society, Vol. 13, Nsuka, 1984, p. 11.

[18] B. C. E. Egboka, “Water Resources Problem in the Enugu

Area of Enugu State,” Nigerian Journal of Mining Geol-

ogy, Vol. 20, 1993, pp. 1-6.

[19] R. C. Murat, “Stratigraphy and Paleogeography of Creta-

ceous and Lower Tertiany in Southern—Nigeria, African

Geology,” Ibadan University Press, Ibadan, 1972, pp.

251-266.

[20] A. Simpson, “The Nigerian Coal Field: The Geology of

Part of Onitsha, Owerri and Benue Provinces,” Geology

Survey Nigeria Bulletin, 1954, p. 24.

[21] G. I. Nwankwo, B. C. Egboka and I. P. Orajaka,

“Groundwater Occurrence and Flow Patterns in the

Enugu Coal-Mine Areas, Anambra State, Nigeria,” Hy-

drological Sciences Journal, Vol. 33, No. 5, 1988, pp.

465-485. doi:10.1080/02626668809491275

[22] E. C. Ezeanyim, “Hydrogeology of Enugu Area and En-

virons,” Master’s Thesis, University of Nigeria, Nsukka,

1988.

[23] B. C. E. Egboka and F. O. Onyebueke, “NAH Journal on

Acute Hydro-Geological Problems, VIS a VIS Planning

and Management of Developing Economy. A Case Study

of Enugu Area, Nigeria,” 1999.

[24] “Annual Book of ASTM Standard Vol. 04, Soil and Rock

Standard Practice for Particle Size Analysis and Deter-

mination of Soil Constants,” West Conshokockem, 2000,

pp. 8-9.

[25] Chengliu and Evett, “Soil Properties,” 2nd Edition, Pren-

tice Hall Inc., Englewood Cliffs, 2000, p. 28.

[26] F. J. Chapin, “Urban Land Use Planning,” University of

Illinois Press, Champaign, 1965, pp. 34-48.

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