Data Sources & Methodology
Transparent scientific methodology and open data sources
About Our Methodology
The Centre for Blue Economy Africa ESG Platform employs rigorous scientific methodologies and leverages multiple authoritative data sources to provide accurate, timely, and actionable insights on Ghana's water resources and environmental health. Our approach combines remote sensing, ground-truth validation, statistical analysis, and community engagement.
Primary Data Sources
Satellite Data Sources
Sentinel Hub (ESA Copernicus Programme)
- Satellites: Sentinel-1 (SAR), Sentinel-2 (Optical)
- Resolution: 10-20 meters
- Frequency: 5-day revisit time
- Applications: Land cover change, water body monitoring, vegetation health
- Access: Copernicus Open Access Hub
NASA Earthdata (EOSDIS)
- Instruments: MODIS, Landsat-8, VIIRS, ASTER
- Resolution: 30-250 meters
- Frequency: Daily to 16-day revisit
- Applications: Water quality, temperature, chlorophyll concentration
- Access: NASA Earthdata Portal
Google Earth Engine
- Data: 40+ years of historical imagery
- Capabilities: Petabyte-scale geospatial analysis
- Applications: Time-series analysis, change detection, trend analysis
- Access: Earth Engine Platform
OpenAerialMap
- Data: High-resolution aerial imagery
- Coverage: Community and drone-based imagery
- Applications: Detailed site-specific analysis
- Access: OpenAerialMap
Ground-Based Monitoring
Ghana Water Resources Commission (WRC)
- Water quality monitoring data
- Flow rate measurements
- Hydrological assessments
- Licensed water abstraction records
Environmental Protection Agency (EPA Ghana)
- Environmental impact assessments
- Pollution monitoring reports
- Compliance and enforcement data
- Air quality measurements
Water Research Institute (WRI-CSIR)
- Laboratory water quality analysis
- Heavy metal contamination studies
- Biological monitoring
- Research publications
Community Monitoring Network
- 85 community monitoring stations
- Citizen science observations
- Local ecological knowledge
- Real-time field reports
Socioeconomic Data
Ghana Statistical Service
- Population and demographic data
- Economic indicators
- Employment statistics
- Household surveys
Ministry of Fisheries and Aquaculture Development
- Fish catch statistics
- Fisheries licensing data
- Aquaculture production records
- Market price information
Ghana Health Service
- Waterborne disease incidence
- Health facility records
- Epidemiological surveillance
- Community health assessments
Field Surveys & Interviews
- Community consultations
- Focus group discussions
- Key informant interviews
- Participatory assessments
Analytical Methodology
1. Satellite Image Processing
Image Acquisition & Preprocessing
- Automated download of Sentinel-2 and Landsat-8 imagery
- Atmospheric correction using Sen2Cor algorithm
- Cloud masking and quality filtering
- Geometric and radiometric calibration
Spectral Indices Calculation
| Index | Formula | Application |
|---|---|---|
| NDVI | (NIR - Red) / (NIR + Red) | Vegetation health and forest cover |
| NDWI | (Green - NIR) / (Green + NIR) | Water body identification |
| MNDWI | (Green - SWIR) / (Green + SWIR) | Water extraction and turbidity |
| Turbidity Index | Red / Blue ratio | Suspended sediment concentration |
Change Detection
- Pixel-based change detection algorithms
- Object-based image analysis (OBIA)
- Time-series trend analysis using Mann-Kendall test
- Land cover classification using Random Forest algorithm
2. Water Quality Assessment
Field Sampling Protocol
- Monthly sampling at 85 fixed monitoring stations
- Quarterly sampling at 200+ supplementary sites
- Standard sampling procedures following APHA guidelines
- Chain of custody protocols for sample integrity
Laboratory Analysis
| Parameter | Method | Standard |
|---|---|---|
| pH | Electrometric | APHA 4500-H+ B |
| Turbidity | Nephelometric | APHA 2130 B |
| Dissolved Oxygen | Winkler titration / Electrochemical | APHA 4500-O C |
| Heavy Metals | ICP-MS / AAS | APHA 3120 / 3111 |
| Total Suspended Solids | Gravimetric | APHA 2540 D |
Water Quality Index (WQI) Calculation
We employ the weighted arithmetic Water Quality Index method:
WQI = Σ(Wi × Qi) / ΣWi
Where:
- Wi = Weight of parameter i
- Qi = Quality rating of parameter i
- Quality scale: 0-25 (Excellent), 26-50 (Good), 51-75 (Poor), 76-100 (Very Poor)3. ESG Metrics Framework
Environmental Indicators
- Water Quality Index: Composite of 10 parameters (pH, turbidity, DO, heavy metals, etc.)
- Forest Cover: NDVI-based classification with >0.4 threshold
- Biodiversity Health: Species richness and abundance indices
- Air Quality: PM2.5, PM10, and gaseous pollutants
Social Indicators
- Community Health: Disease incidence, mortality rates, healthcare access
- Employment Rate: Labor force participation in sustainable livelihoods
- Education Access: School enrollment and completion rates
- Food Security: Dietary diversity and household food insecurity access scale
Governance Indicators
- Policy Compliance: Adherence to environmental regulations
- Enforcement Rate: Percentage of violations addressed
- Transparency: Open data availability and accessibility
- Stakeholder Engagement: Community participation in decision-making
4. Galamsey Impact Assessment
Site Identification
- Machine learning classification of mining areas using satellite imagery
- Ground-truthing through field surveys and drone imagery
- Community reporting and verification
- Integration with mining licensing database
Impact Quantification
- Buffer analysis (500m, 1km, 5km) around mining sites
- Water quality degradation assessment in downstream areas
- Forest loss quantification using before-after analysis
- Socioeconomic impact surveys in affected communities
Severity Classification
| Severity | Criteria |
|---|---|
| High | Heavy metal levels >10x WHO standards, forest loss >50%, multiple water bodies affected |
| Medium | Heavy metal levels 5-10x WHO standards, forest loss 25-50%, 1-2 water bodies affected |
| Low | Heavy metal levels <5x WHO standards, forest loss <25%, localized impact |
5. Data Quality Assurance
Validation Procedures
- Cross-validation with multiple data sources
- Inter-laboratory comparison testing
- Field verification of satellite-derived products
- Statistical outlier detection and review
Accuracy Assessment
- Satellite classification accuracy: >85% overall accuracy
- Laboratory QA/QC: <10% relative percent difference on duplicates
- Spatial accuracy: <10m positional error
- Temporal consistency checks and trend validation
Uncertainty Quantification
- Monte Carlo simulation for composite indices
- Confidence intervals for trend estimates
- Sensitivity analysis for model parameters
- Transparent reporting of data gaps and limitations
Open Data Policy
We are committed to open science and transparent data sharing. All data products and analytical results are available under Creative Commons CC-BY 4.0 license, with appropriate attribution requirements.
Data Access
Direct Download
Download processed datasets in CSV, GeoJSON, and Shapefile formats
API Access
RESTful API for programmatic access to real-time and historical data
Analysis Scripts
Open-source code repository with all analytical scripts and workflows
Key References & Standards
Standards & Guidelines
- WHO (2017). Guidelines for drinking-water quality, 4th edition
- APHA (2017). Standard Methods for the Examination of Water and Wastewater, 23rd edition
- GRI (2021). GRI Standards: Universal Standards
- EPA Ghana (2019). Environmental Assessment Regulations
Scientific Literature
- Owusu-Nimo et al. (2018). Impact of illegal mining on water quality in Ghana. Environmental Monitoring
- Agyei et al. (2020). Satellite-based assessment of mining impacts. Remote Sensing Applications
- Mensah et al. (2019). Heavy metal contamination in Ghanaian water bodies. Environmental Science
- Boateng et al. (2021). Alternative livelihoods for mining communities. Development Studies
Questions About Our Methodology?
For detailed technical questions, data access inquiries, or collaboration opportunities, please contact our research team.