Title Page
ABSTRACT
Contents
LIST OF ABBREVIATIONS 13
CHAPTER 1. INTRODUCTION 18
1.1. Introduction/background to study problem 18
1.2. The research questions 21
1.2.1. Research hypothesis 22
1.2.2. Clarification of terms 22
1.3. Research Objectives 23
1.4. Significance of the study 23
1.5. Justification of the Study 24
1.5.1. Review of water resources in Nigeria 24
1.5.2. Review of water policies in Nigeria 26
1.5.3. The situation in Abuja, Nigeria 28
1.6. Present study coverage 32
CHAPTER 2. RELEVANT LITERATURE REVIEW 33
2.1. Definition of a watershed 33
2.2. Watershed contamination sources 35
2.2.1. Point Sources 35
2.2.2. Non-point sources 35
2.3. Conceptual framework: 37
2.4. Achieving water quality through watershed protection approach 39
2.5. The watershed model 41
2.6. Water quality standards 42
2.7. Factors affecting water quality in surface and groundwater 43
2.8. Watershed governance concept 44
2.9. Korea watershed policies and best practices 45
2.9.1. Best water environment practices in Korea 46
2.9.2. Watershed structure in South Korea 51
2.9.3. Water management policy structure in Korea: 52
CHAPTER 3. RESEARCH METHODOLOGY 56
3.1. Methodology employed 56
3.2. Study area 56
3.2.1. Gachang dam 57
3.2.2. Gongsan dam 58
3.3. Research design framework 59
3.3.1. Explanation of the research design framework 60
3.4. Data capture/acquisition 60
3.5. Sampling points 60
3.5.1. Components of the sample 60
3.6. Selection and harmonization of water quality elements for assessment 61
3.7. Data classification 61
3.7.1. Monthly distribution of elements for each of the six selected samples and for eight years in Gachang dam 61
3.7.2. Mean monthly distribution of samples elements for the years under review 63
3.7.3. Yearly mean distribution of water quality variables 64
Chapter 4. DATA ANALYSIS, RESULTS AND DISCUSSION 66
4.1. Introduction 66
4.2. The mean monthly physical/chemical characteristics of water quality variables 66
4.2.1. Water temperature 66
4.2.2. Hydrogen Ion Concentration (pH) 68
4.2.3. Biochemical Oxygen Demand (BOD mg/L) 70
4.2.4. Chemical Oxygen Demand (COD mg/L) 72
4.2.5. Suspended Solids (mg/L) 74
4.2.6. Total Phosphorous (mg/L) 77
4.3. The yearly mean physicochemical characteristics and variation of water quality variables 79
4.3.1. Statistical tools for comparison/hypothesis testing 79
4.3.2. Normality test results for yearly mean variables 80
4.3.3. Mean yearly variationof watertemperaturebetween Gachang and Gongsan dam watersheds 82
4.3.4. Mean yearly variation in Hydrogen Ion Concentration (pH)between Gachang and Gongsan dam watersheds 83
4.3.5. Mean yearly variation in BOD between Gachang and Gongsan dam watersheds 84
4.3.6. Mean yearly variation in CODbetween Gachang and Gongsan dam watersheds 86
4.3.7. Mean yearly variation in Suspended Solidsbetween Gachang and Gongsan dam watersheds 87
4.3.8. Mean yearly variation in Total Phosphorusbetween Gachang and Gongsan dam watersheds. 89
4.4. Examining land use effects on water quality conditions in the two dams/watersheds 90
4.4.1. Land use effects in Gachang watershed (Dae-il and O-ri settlements combined) 92
4.4.2. Land use effects in Gongsang watershed (Mu-tae and Gongsan settlements combined) 94
4.4.3. Contrasting upstream activities in the two watersheds 96
4.4.4. Contrasting downstream activities in the two watersheds 99
Chapter 5. CONCLUSION AND RECCOMENDATIONS 102
5.1. Conclusions 102
5.2. Recommendations 103
5.3. Limitations of the present study 107
REFERENCES 109
APPENDICES 120
초록 137
Table 2.1. Grade Level Index 50
Table 2.2. Paradigm shift in water quality management. 55
Table 3.1. pH Sample point 1. 62
Table 3.2. pH Sample point 2 62
Table 3.3. Mean monthly distribution of hydrogen ion concentration. 63
Table 3.4. YEARLY MEAN WATER QUALITY VARIABLES... 64
Table 3.5. YEARLY MEAN WATER QUALITY VARIABLES FOR... 65
Table 4.1. Normality test statistics. 80
Table 4.2. Normality test results for z-values and Shapiro-Wilk's sig.... 81
Table 4.3. Distribution of land uses in Gachang watershed area. 92
Table 4.4. Distribution of land uses in Gongsan watershed area. 94
Figure 1.1. Map of Nigeria showing eco-climatic zones of Nigeria. 25
Figure 1.2. Hydrological Map of Nigeria. 26
Figure 1.3. Satellite image of Jabi Lake. 29
Figure 1.4. Urban encroachment around Jabi Lake Abuja. 29
Figure 1.5. Entry point of raw water from Gurara River into Lower Usuma Dam. 30
Figure 1.6. Pastoral activities near Lower Usuma Dam. 31
Figure 1.7. Agricultural support activity near Lower Usuma Dam. 31
Figure 2.1. Watershed interactions. 34
Figure 2.2. Social, Economic, and Environmental Considerations to... 41
Figure 2.3. Watershed Non-point source model. 42
Figure 2.4. Location of the Nakdong River Basin in South Korea. 52
Figure 3.1. Map showing the location of Daegu (shaded) South Korea. 57
Figure 3.2. Location of Gachang Dam. 58
Figure 3.3. Location of Gongsan Dam. 58
Figure 3.4. Research Design framework. 59
Figure 4.1. Mean monthly temperature (2010-2017)_Gachang Dam. 67
Figure 4.2. Mean monthly temperature (2010-2017)Gongsan Dam. 68
Figure 4.3. Mean monthly pH from 2010 to 2017 for Gachang Dam. 69
Figure 4.4. Mean monthly pH from 2010 to 2017 for Gongsan Dam. 70
Figure 4.5. Mean monthly BOD_Gachang Dam. 71
Figure 4.6. Mean monthly BOD_Gongsan Dam. 72
Figure 4.7. Mean monthly COD_Gachang Dam. 73
Figure 4.8. Mean monthly COD_Gongsan Dam. 74
Figure 4.9. Mean monthly Suspended Solids_Gachang Dam. 75
Figure 4.10. Mean monthly Suspended Solids_Gongsan Dam. 76
Figure 4.11. Mean monthly T_P in Gachang Dam. 77
Figure 4.12. Mean monthly T_P in Gongsan Dam. 78
Figure 4.13. Mean yearly variation in temperature (℃) from 2010-2017. 82
Figure 4.14. Mean yearly variation in pHfrom 2010-2017. 83
Figure 4.15. Mean yearly variation in BOD (mg/L) from 2010-2017. 84
Figure 4.16. Mean yearly variation in COD (mg/L)from 2010-2017. 86
Figure 4.17. Mean yearly variation in Suspended solids from 2010-2017. 87
Figure 4.18. Mean yearly variation in Total phosphorous (mg/L) from2010-2017. 89
Figure 4.19. Dams and Watershed settlements locations. 91
Figure 4.20. Bar graph showing land use distribution in Gachang dam watershed area. 93
Figure 4.21. Bar graph showing land use distribution in Gongsan dam watershed area. 96
Figure 4.22. Upstream water color in Gachang watershed 97
Figure 4.23. Residential area in upstrean Gachang watershed 97
Figure 4.24. Farming activities in upstream Gachang watershed 98
Figure 4.25. Gachang Dam 98
Figure 4.26. Upstream water color in Gongsan watershed 98
Figure 4.27. Residential area inupstream Gongsan watershed 99
Figure 4.28. Large scale paddy and Farming activities in upstream Gongsan... 99
Figure 4.29. Construction works in downstream Gongsan watershed 100
Figure 4.30. Downstream factory sites in Gongsan watershed 100
Figure 4.31. Downstream Livestock and farm fields in Gongsan watershed 101
Figure 4.32. Downstream residential area in Gongsan watershed 101
Figure 4.33. Downstream water color and appearance in Gongsan watershed. 101