Evaluating the role of rainwater harvesting systems in enhancing water security against climate variability and galamsey mining impacts in Ghana’s Gold Belt using SPI analysis|RISS 상세보기

다국어 초록 (Multilingual Abstract)

This study evaluates the potential of Rainwater Barrel Sharing Networks (RBSN) as a localized adaptation measure for improving water security in Obuasi, Ghana, under projected climate change scenarios. Obuasi, representative of Ghana’s gold-belt region which includes other mining areas such as Tarkwa Nsuaem and Daboya was selected because it combines a bimodal rainfall regime with severe surface-water contamination from artisanal mining (galamsey), creating both hydrological opportunity and socio-environmental urgency. Using historical rainfall data and future projections under the Shared Socioeconomic Pathways (SSP1–2.6 and SSP5– 8.5), the study applied the Standardized Precipitation Index (SPI) to assess rainfall variability and the Vulnerability–Reliability–Resiliency (VRR) and Storage– Reliability–Yield (SRY) frameworks to evaluate RBSN performance. Results show that RBSN reliability increases with storage capacity but varies under different emission scenarios. Under SSP1–2.6, reliability levels of 80–90 percent are achieved with storage of 10–12 m³ at a demand ratio of 0.6, supported by stable rainfall patterns. Under SSP5–8.5, more erratic rainfall requires storage expansion to 14–16 m³ to maintain comparable reliability, though resiliency decreases and vulnerability rises due to longer dry spells. The SRY analysis identifies 0.6 as the optimal demand threshold, balancing yield and storage efficiency while avoiding over-design or under-use. Beyond technical performance, RBSN offers dual benefits for Obuasi by reducing reliance on polluted surface water and enhancing resilience to droughts intensified by mining-induced land degradation. The study concludes that RBSN represent a viable and context-sensitive climate-adaptation strategy for Ghana’s mining zones when designed around local rainfall characteristics, managed collectively at the community level, and integrated into national water-governance frameworks. Policymakers are encouraged to embed RBSN within Ghana’s National Climate Adaptation Plan and support implementation through incentives, technical training, and public education to promote long-term, climate-resilient water management.

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국문 초록 (Abstract)

초록

본 연구는 기후 변화 시나리오 하에서 가나 오부아시(Obuasi)의 물 안보 향상을 위한 지역 맞춤형 적응 대책으로서 레인배럴 공유 네트워크(Rainwater Barrel Sharing Networks, RBSN)의 가능성을 평가하였다. 오부아시는 타르크와 은수암(Tarkwa Nsuaem)과 다보야(Daboya) 등 다른 광산 지역을 포함하는 가나 금광 지대의 대표 도시로, 이중 우기(bimodal rainfall regime)를 지니면서도 불법 소규모 채광(갤럼시, galamsey)로 인한 심각한 수질 오염이 공존하는 지역이다. 이러한 수문학적 잠재력과 사회·환경적 긴급성이 결합된 사례로서 본 연구의 주요 대상지로 선정되었다.
연구는 새로운 기후시나리오로 제시되는 공유사회경제경로(Shared Socioeconomic Pathways, SSP1–2.6 및 SSP5–8.5) 하의 과거 및 미래 강우 자료를 활용하여 표준강수지수(Standardized Precipitation Index, SPI)로 강우 변동성을 분석하고, Vulnerability–Reliability–Resiliency(VRR) 및Storage–Reliability–Yield(SRY) 분석 틀을 적용하여 RBSN의 성능을 평가하였다. 분석 결과, RBSN의 신뢰도는 저장 용량이 증가할수록 향상되지만, 배출 시나리오에 따라 차이를 보였다. SSP1–2.6에서는 안정적인 강우 패턴을 배경으로 저장용량 10–12m³/m2, 해당 기간 일평균 강우량 대비 수요비율 0.6일 때 약 80–90%의 신뢰도를 달성하였다. 반면 SSP5–8.5에서는 강우의 불규칙성이 커져 동일한 신뢰도를 유지하기 위해 14–16m³/m2의 저장용량이 필요하였으며, 건기 장기화로 인해 복원력은 감소하고 취약도는 증가하였다. SRY 분석에서는 수요비율 0.6이 산출 효율성과 저장 안정성 간의 균형을 이루는 최적 설계 기준으로 나타났다.
기술적 성능을 넘어, RBSN은 오부아시의 수질 오염 저감과 가뭄 대응력 강화라는 이중 효과를 제공한다. 분산형 빗물 저장 시스템을 통해 오염된 지표수 의존도를 줄이고, 채광으로 인한 토양 훼손 및 홍수 피해를 완화할 수 있다. 연구는 RBSN이 지역 강우 특성에 기반한 설계, 공동체 중심의 관리, 국가 물 관리 체계와의 통합을 전제로 할 때, 가나의 광산 지역에서 실현 가능한 기후 적응 전략임을 입증하였다. 따라서 정책 입안자들은 RBSN을 가나 국가 기후변화 적응계획(National Climate Adaptation Plan)에 포함하고, 인센티브 제공, 기술 교육, 대중 인식 제고를 통해 장기적이고 회복력 있는 물 관리 체계를 구축할 것을 제안한다.

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초록 본 연구는 기후 변화 시나리오 하에서 가나 오부아시(Obuasi)의 물 안보 향상을 위한 지역 맞춤형 적응 대책으로서 레인배럴 공유 네트워크(Rainwater Barrel Sharing Networks, RBSN)의 가능성을 평...

목차 (Table of Contents)

CHAPTER 1 1
INTRODUCTION 1
1.1 Background of Study 1
1.2 Problem Statement 2
1.3 Justification of Study 3

CHAPTER 1 1
INTRODUCTION 1
1.1 Background of Study 1
1.2 Problem Statement 2
1.3 Justification of Study 3
1.4 Research Aim and Objectives 3
1.5 Research Questions 4
1.6 Significance of Study 4
1.7 Scope of Study 5
CHAPTER TWO. 6
LITERATURE REVIEW 6
2.1 Conceptual and Theoretical Foundations 6
2.1.1 Water Security and Adaptive Capacity 6
2.1.2 Integrated Water Resources Management (IWRM) in Ghana 6
2.1.3 Resilience Theory in Water Systems 7
2.1.4 The Vulnerability, Resiliency, and Reliability (VRR) Framework 7
2.1.5 Adaptive Management under Uncertainty 7
2.1.6 Shared Socioeconomic Pathways (SSPs) and Climate Futures 8
2.2 Climate Variability Analysis Tools and Indices 10
2.2.1 Standardized Precipitation Index (SPI) Applications in Ghana 10
2.2.2 Comparative Drought Indices (SPEI, PDSI, RAI) 10
2.3 Illegal Mining (Galamsey) and Water Insecurity in Ghana 11
2.3.1 Geographic Distribution of Galamsey in Ghana’s Gold Belt 11
2.3.2 Hydrological Impacts of Galamsey (Pollution, Sedimentation, Turbidity) 12
2.3.3 Socio-Economic Drivers of Galamsey 12
2.3.4 Governance and Policy Responses 13
2.3.5 Climate Variability and the Double Exposure Context 13
2.4 Rainwater Barrel Sharing Network (RBSN) in Ghana and Beyond 14
2.4.1 Historical and Global Applications of RBSN 14
2.4.2 RBSN in Ghana: Pilots and Community Adoption 14
2.4.3 Evaluating RBSN Using VRR Metrics 14
2.4.4 International Lessons from Asia, India, Brazil, and South Korea 15
2.4.5 Barriers to RBSN Adoption in Ghana 15
2.5 Integrating Climate Variability, Galamsey, and RBSN 16
2.5.1 Double Exposure in Gold Belt Communities 16
2.5.2 Overlaying SPI and Galamsey Hotspots 16
2.5.3 VRR Analysis of RBSN under SSP Scenarios 17
2.5.4 International Lessons from Mining-Affected Regions 17
2.5.5 The Role of Storage-Reliability-Yield (SRY) Graphs 17
2.6 Identified Research Gaps 19
2.6.1 Theoretical Gaps 19
2.6.2 Methodological Gaps 19
2.6.3 Contextual Gaps 19
2.6.4 Scenario Gaps 20
2.6.5 Integration Gaps 20
2.7 Summary of Literature Review 20
CHAPTER 3 22
RESEARCH METHODOLOGY 22
3.1 Introduction to Methodology 22
3.1.1 Justification of Methodology 23
3.2 Study Areas 25
3.2.1 Geographic Location and Extent 25
3.2.2 Climate and Rainfall Patterns 26
3.2.3 Hydrological Characteristics 27
3.2.4 Socio-Economic Context (Mining and Agriculture) 27
3.3 Data Sources and Collection 28
3.3.1 Meteorological Data (Rainfall) 28
3.3.2 Hydrological and Water Resources Data 29
3.3.4 Socio-Economic and Galamsey Data 29
3.3.5 Rainwater Harvesting Data (Household and Community Systems) 29
3.4 Climate Modeling and SPI Analysis 30
3.4.1 Tools and Software (MATLAB Application) 30
3.4.2 Data Pre-Processing and Normalization 30
3.4.2 Data Cleaning 31
3.4.2 Data Conversion 31
3.4.2 SPI Calculation (1-, 3-, 6-, 12-Months Timescales) 31
3.4.2 Validation of SPI with Historical Events 32
3.4.2 Integration of SSP Scenarios (1-2.6, 2-4.5, 3-7.0, 5-8.5) 32
3.5 Rainwater Harvesting System (RBSN) Performance Evaluation 33
3.5.1 Reliability of RBSN 34
3.5.2 Resiliency of RBSN 34
3.5.3 Vulnerability of RBSN 35
3.5.4 Storage-Reliability-Yield (SRY) Analysis 35
3.5 Limitations of the Methodology 36
CHAPTER FOUR 38
RESULTS AND DISCUSSION 38
4.1 Introduction 38
4.3 Annual Maximum Daily Rainfall 39
4.3.1 Obuasi (Ashanti Region Hotspot) 40
4.3.2 Tarkwa Nsuaem (Western Region Hotspot) 42
4. 3.3 Daboya (Northern Region Hotspot) 44
4.3.4 Comparative Synthesis Across Study Locations 46
4.3.4 Transition to SPI-Based Drought Assessment 47
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4.4 Standardized Precipitation Index (SPI) Analysis 48
4.4.1 Obuasi (Historical SPI Results) 49
4.4.2 Obuasi SPI under SSP1-2.6 50
4.4.3 Obuasi SPI under SSP5-8.5 52
4.4.4 Tarkwa Nsuaem (Historical SPI Results) 55
4.4.5Tarkwa Nsuaem SPI under SSP1-2.6 56
4.4.6 Tarkwa Nsuaem SPI under SSP5-8.5 58
4.4.7 Daboya Historical SPI (12-Months) 61
4.4.8 Daboya under SSP1-2.6 62
4.4.9 Daboya SSP5-8.5 Scenario 64
4.5 Selection of Ideal Location for Rainwater Harvesting Systems 78
4.4 Rainwater Sharing Barrel Network (RWSBN) Performance Assessment (Obuasi Case Study) 81
4.4.1 Monthly Average Rainfall Comparison 81
4.4.1 Reliability 84
4.4.2 Resiliency 87
4.4.3 Vulnerability 90
4.4.4 Storage-Reliability-Yield (SRY) Analysis 93
4.4.5 Storage Requirements Across Scenarios 96
4.4.6 Synthesis for Obuasi 98
4.4.7 Policy Implications for RBSN in Ghana 99
4.6 Key Findings and Reflections 100
CHAPTER 5 102
CONCLUSION 102
5.1 Summary of Findings 102
5.2 Contributions of the Study 102
5.3 Limitations of the Study 103
5.4 Policy Implications 104
5.5 Recommendations for Future Research 104
5.6 Closing Reflections 105
REFERENCES 106