ABSTRACT
Implications of dam development on soil, water, vegetation and socio-economic characteristics were investigated in the study. Soil studies involved collection of samples at 0-15cm and 15-30cm depths prior to excavation (control sample), from epicenter of location where overburden were heaped (point A) and 2m away from overburden (point B). Samples were analyzed for pH, OC, OM, N, P, K, Ca, Mg, Na, ECEC, Fe, Mn, Zn and Cu). Water samples were collected upstream, inside dam and downstream and analyzed for pH, Cl, K, Na, Ca, conductivity, turbidity, total solids, total dissolved solids, dissolved oxygen, biological oxygen demand, NO3, Fe, Mn, Zn and Cu. Vegetation study involved dividing the 200m X 200m dam area into 4 transects within which sampling was done using improvised quadrat of 3 different sizes. Questionnaire and interviews were used to elicit responses from inhabitants of the area on the socio-economic implications of the dam project. Soil analysis results showed changes due to heaping of overburden on top soil. pH, N, P, K, Ca, Mg, Na, OC, OM, Fe, Zn, Mn and Cu at 0-15cm depth before dam construction were 5.05, 0.2mg/kg, 49.1mg/kg, 0.17mg/kg, 4.2cmol/kg, 2.3cmol/kg, 0.16cmol/kg, 2.62%, 4.51%, 3.52mg/kg, 4.41mg/kg, 1.36mg/kg and 0.54mg/kg respectively before construction, while after construction values (from point A) increased to 6.0, 0.18mg/kg, 42.5mg/kg, 0.21mg/kg, 4.75cmol/kg, 2.8cmol/kg, 0.39cmol/kg, 2.02%, 3.5%, 7.79mg/kg, 6.43mg/kg, 2.55mg/kg and 2.48mg/kg respectively because of dam construction. This translates to about 50% significant change in soil characteristics. Water analysis results also showed some changes attributable to dam development as pH, K, Na, Ca and Mg, concentrations changed from 6.55, 3.42mg/l, 133.3mg/l, 27mg/l, 14mg/l respectively before dam development to 6.73, 5.94mg/l, 3.0mg/l, 102.17mg/l, 28.06mg/l (inside dam) after dam development. Fe, Mn, Zn and Cu concentrations also increased even above permissible limit for these metals in drinking water. Prior to dam construction, phanerophytes dominated the landscape, but after dam construction, many of these trees and shrubs were removed giving way to abundant species of chamaephytes. Total species, number of individual species, density and species’ richness index before dam construction were 25, 2712, 0.0678 and 24.873 respectively which changed to 38, 2041, 0.0511 and 37.868 after dam construction resulting in a 25% loss in vegetation cover. Socio-economic analysis showed that dam construction affected the number of lands available for farming and other purposes. Its construction caused noise and increased concentration of dust particles. Majority of Ishiagu residents use Ivo river as the major source of water while Oviaovia and Ngele-Okwe streams are utilized by about 40% of residents especially those residing in Obinagu and Amagu villages. ARCC dam construction affected soil, water, vegetation and livelihoods of residents of the study area. Recommendations were made for sustainability of the project and protection of both environment and livelihoods from permanent or irreversible degradation.
TABLE OF CONTENTS
Title page ii
Declaration iii
Certification iv
Dedication v
Acknowledgements vi
Table of Contents vii
List of Tables x
List of Figures xi
List of Plates xii
Abstract xiii
CHAPTER
1 – INTRODUCTION 1
1.1
Background of the Study 1
1.2
Statement of the Problem 2
1.3 Aim and Objectives of the Study 3
1.4 Scope of the Study 4
1.5 Significance of the Study 4
1.6 Justification of the Study 5
CHAPTER 2 – LITERATURE REVIEW 6
2.1 History
of Dam Development 6
2.1.1 Types of dam 7
2.1.2 Utility of dams 14
2.2 Institutions
Related to Dam development 17
2.2.1 International commission on large dams 17
2.2.2 World register of dams 18
2.2.3 World commission on dams 19
2.2.4 World bank group 19
2.3 Dam
Development in Nigeria 20
2.3.1 Policies and institutions related to dam development in Nigeria 21
2.3.2 Role of dams in economic development of Nigeria 29
2.3.3 Challenges of dam management in Nigeria 32
2.4 Implications
of Dam Development 35
2.4.1 Alteration of flow regime 36
2.4.2 Biodiversity 37
2.4.3 Water quality 40
2.4.4 Sedimentation 41
2.4.5 Greenhouse gases emission 42
2.4.6 Socio-economic and cultural heritage 42
2.4.7 Health 43
CHAPTER 3 – METHODOLOGY 44
3.1 Description
of Study Area 44
3.1.1 Location 44
3.1.2 Climate 44
3.1.3 Soil and relief 44
3.1.4 Vegetation 45
3.1.5 Economic activities 45
3.2 Dam
Specifications 47
3.3 Methodology 49
3.3.1 Assessing ecological features of study area 49
3.3.2 Assessing implications of dam development on soil properties 50
3.3.3 Investigating Implications of dam development on water quality 54
3.3.4 Assessing implications of dam development on vegetation 59
3.3.5 Assessing social, economic and health implications of dam
development 59
3.4
Data Analysis 60
CHAPTER 4 – RESULTS AND DISCUSSION 61
4.1
Ecological Features of Study Area 61
4.1.1 Rainfall 61
4.1.2 Temperature 62
4.1.3 Relative humidity 63
4.1.4 Flora 64
4.1.5 Fauna 66
4.2 Implications
of Dam Development on Soil 67
4.2.1 pH 69
4.2.2 Phosphorus 69
4.2.3 Nitrogen 70
4.2.4 Organic carbon and organic matter 71
4.2.5 Calcium 71
4.2.6 Magnesium 72
4.2.7 Potassium 73
4.2.8 Sodium 74
4.2.9 Cation exchange capacity 74
4.2.10 Iron 75
4.2.11 Manganese 76
4.2.12 Zinc 76
4.2.13 Copper 76
4.3 Implications
of Dam Development on Water 78
4.3.1 pH 78
4.3.2 Chloride 79
4.3.3 Potassium 79
4.3.4 Sodium 80
4.3.5 Calcium and magnesium 80
4.3.6 Electric conductivity 81
4.3.7 Turbidity 81
4.3.8 Total suspended solids 81
4.3.9 Total dissolved solids 82
4.3.10 Dissolved oxygen 83
4.3.11 Biological oxygen demand 83
4.3.12 Nitrate 83
4.3.13 Iron 84
4.3.14 Manganese 84
4.3.15 Zinc 85
4.3.16 Copper 85
4.4 Implications
of Dam Development on Vegetation 87
4.5 Social,
Economic and Health Implications of Dam Development 92
4.5.1 Land ownership and use 93
4.5.2 Health 93
4.5.3
Water use 96
4.5.4
Benefits of ARCC construction 98
CHAPTER 5 – CONCLUSION AND
RECOMMENDATIONS 99
5.1 Conclusion 99
5.2 Recommendations 100
References 101
LIST OF TABLES
3.1: Distribution of questionnaire for assessing economic,
social and health
implications of ARCC dam development 60
4.1:
Mean annual rainfall (mm) of Ishiagu (2000-2017) 61
4.2:
Mean annual temperature (0C) of Ishiagu (2000-2017) 62
4.3:
Mean annual relative humidity (%) of Ishiagu (2000-2017) 63
4.4:
Families of different plant species and composition in ARCC 64
4.5:
Fauna occurring in African Resource and Conservation Center 66
4.6:
Properties of excavated soil overburden 67
4.7: Soil properties at different
depths before and after heaping of overburden 68
4.8: Summary
of implications of dam development on Soil 77
4.9: Properties of water collected
upstream, inside dam and downstream 78
4.10:
Summary of implications of dam development on water 86
4.11: Plant
species occurring at the site before and after dam development 87
4.12:
Species’ life form classification before dam development 88
4.13:
Species’ life form classification after dam development 88
4.14:
Respondents’ social, economic and health characteristics 92
LIST OF FIGURES
2.1 Utility
of dams by purpose 14
3.1: Map of
Ebonyi state showing local government areas
46
3.2:
Ishiagu community in Ivo LGA of Ebonyi State 46
4.1:
Bimodal pattern of monthly rainfall distribution (mm) in Ishiagu 61
4.2:
Mean monthly temperature (0C) of Ishiagu 62
4.3:
Mean monthly relative humidity (%) of Ishiagu 63
LIST OF PLATES
3.1:
Dam at various stages of development (1)
47
3.2:
Dam at various stages of development (2)
48
3.3:
Dam at various stages of development (3) 48
3.4:
Excavated parent rock material as overburden on top soil 50
4.1:
Vegetation loss due to dam development 91
4.2:
Phanerophytes lost due to dam development 91
4.3: Construction activities at ARCC generating dust and
noise 96
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND OF THE STUDY
The environment provides support for
all living things by supplying many essential material resources, goods and services.
For ages, humans have used natural resources from the environment to improve
living conditions. However, its use has not been without considerable
alteration or outright damage to the environment. Water is essential natural
resource that has been harnessed and greatly utilized for various purposes by
humans. Water is very vital for good health and life sustenance, ranking second
only to air. It is so important that water shortage or scarcity makes life
miserable and even generate conflicts when communities struggle for control and
utilization of water resources (Ukiwe et
al., 2012). Interventions necessary for supplying, storing and distributing
water has been described as the driver of civilizations and human development
over the ages (Nestmann and Stelzer, 2007) resulting in the development of many
dams for harnessing and better utilization of water resources. Dam construction
dates back to more than 5000 years ago and in modern times, has witnessed
tremendous increase promoted by technical improvements in cement concrete
technology.
Dam construction usually triggers
changes in natural ecosystems arising from activities carried out at
pre-development stage, development stage and post-development stage. These
activities include initial earthworks that involve removal of vegetation, soil
excavation and movement of soil materials from excavation point to a dump site,
diversion of water flow, and construction of a barrier across the water body,
water impoundment and storage resulting from the dam barrier. Implications of
these activities on environmental components could be direct, indirect or
cumulative; which could either be positive or negative; random or predictive;
local or widespread, temporary or permanent; short or long term. Knowledge of
project implications is only possible through environmental assessment which provides a comprehensive net appraisal of any project,
forecasting possible implications of the project on the environment and other
important variables that deals with the preservation, conservation, protection
and sustenance of all forms of life on earth. Such assessment helps to
create a healthy balance between human needs and environmental protection for
sustainable development. In environmental assessment of dam, implications of
dam development on soil, water, aquatic and terrestrial lives, vegetation and
landscape, human livelihoods, culture and health are usually assessed. This
study investigated the implications of the African Resource and Conservation
Center earthen dam on soil, water, vegetation and livelihoods of those resident
in the study area.
African Resource and Conservation
Center is a 250 hectare facility being developed to conserve wildlife and
biodiversity, promote natural beauty and aesthetics, tourism and hospitality.
It is located in an area where underground water is difficult to access due to
characteristic hard pan, impervious soils with high crusting (Ogbodo, 2011;
Nwite et al., 2014) requiring river
basin interventions in form of dam construction to augment natural water
supplies.
1.2
STATEMENT OF THE PROBLEM
Interventions in nature aims at
improving living standards and general welfare of humans. Such interventions
and development geared towards improving living conditions would only be
sustainable if resources are utilized without degrading or irreversibly
destroying the environment. The African Resource and Conservation Center, is
being developed to conserve wildlife and biodiversity as well as promote
tourism. A dam was constructed to make sufficient water available for the
Center since underground water is relatively difficult to access. The project
involves damming of Oviaovia and Ngele-Okwe streams to impound and store
water. The dam is in the final phase of completion but before going into
operation, an assessment of possible environmental implications on soil, water,
vegetation, socio-economic, health and culture of the residents of the area
where the dam is proposed was undertaken. Several activities such as excavation
and removal of vegetation is capable of altering partially or completely, soil
and vegetation characteristics of an area affecting flora and fauna. Damming of
Oviaovia and Ngele-Okwe streams is likely to change the natural flow of the
streams, subsequently affecting water quality at both dam upstream and
downstream. Also, the construction of the dam would likely lead to a change in
land use of the area as original owners of the land are displaced from their
parcel of land used for farming several activities such as farming, hunting,
grazing, collection of herbs and firewood. These issues are not isolated as
various studies have shown the extent to which dam construction can cause
significant changes in soil, water, vegetation, and even socio-economic and
health characteristics of an area (McCartney et al., 2001; Dukiya, 2013; Zemba et al., 2016). It is on this
premise that an assessment of environmental implications of the African
Resources and Conservation Center dam on soil, water, vegetation, livelihoods
and other vulnerable components was carried out to forestall any permanent or
irreversible degradation of the environment.
1.3 AIM AND
OBJECTIVES OF THE STUDY
The study determined the
implications of the African Resources and Conservation Center dam development
on the environment. Specifically, it
- described
the ecological features of the area where the dam is being developed.
- assessed the implications of
dam development on soils characteristics.
- examined the implications of
dam development on water quality.
- investigated the implication of
dam development on vegetation of the area.
- assessed the implications of dam development on
socio-economic, health and culture variables of residents of the area.
1.4 SCOPE OF
THE STUDY
This study assessed the implications
of dam development on soil, water, vegetation and socio-economic
characteristics of Ishiagu, where the dam was developed. It highlights various dam construction activities already
going on in the Center, the possible implications of such construction
activities and dam development as well as what should be done to avoid, reduce
or minimize negative implications of the dam development on the environment,
public health, livelihoods and property.
1.5 SIGNIFICANCE OF THE STUDY
A healthy environment is something
that help life flourish and its importance can never be over emphasized.
Sustainable development puts into consideration the present and future needs of
generations living and those yet unborn. Sustainable development ensures that
while efforts are made at present to improve living conditions and overall
welfare of humans presently, future needs and potentials to meet such needs are
not jeopardized. Providing water continuously to meet water demand for various
purposes by humans, require interventions in natural water resources in form of
dams and man-made reservoirs to store water and make it available when and
where necessary. This ensures the attainment, protection and preservation of
the fundamental human right of access to clean water as natural water supplies
may be insufficient.
An assessment of the environmental
implications of the ARCC dam provides a basis for proactive measures and
reaching sound decisions aimed at checking and preventing irreversible
degradation of the environment.
1.6
JUSTIFICATION OF THE STUDY
Human population increase,
development, expanding economies, declining groundwater and decreasing surface
water quality prompt the need for interventions in water resources management
(Nestmann and Stelzer, 2007). One way humans have managed water resources is
through dam construction which is capable of altering the environment. The
implications of the changes in soil and riparian vegetation brought about by
the development is worthy of consideration. Ongoing dam construction at African
Resources and Conservation Center, Ishiagu could substantially lead to
degradation of the environment since environmental components such as water,
soil, vegetation and livelihoods are affected. For instance, excavation works
and heaping of overburden on top soil can change both physical and chemical
properties of soil; water in the dam reservoir is also capable of changing
water properties and quality upstream and downstream. In like manner,
vegetation removals partially or completely alters and change both flora and
fauna attributes of the area. It is through an environmental assessment that
possible risks associated with dam development are identified, minimized or
completely prevented to ensure protection and conservation of the environment
for sustained productivity.
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