FloodWatch Ghana: Flood Risk Intelligence for Greater Accra (v0.1)

FloodWatch Ghana is an open-source flood risk intelligence system for Greater Accra, built to help planners, emergency responders, and researchers understand which parts of the city are most at risk from flooding — and why.

The system pulls together five satellite and geospatial datasets — terrain elevation (NASA SRTM), monthly precipitation (NASA GPM IMERG), terrain slope, land cover imperviousness (ESA WorldCover 2021), and proximity to water bodies (OpenStreetMap) — normalises them, and combines them into a single composite risk score for every 30-metre pixel across the region. The output is published as a live interactive web map that updates monthly as new rainfall data arrives from NASA's GPM satellite.

Version 0.1 was validated against the May 18, 2025 Greater Accra flood event — 132mm of rainfall in a single day, 4 deaths, and over 3,000 people displaced. All 7 districts that flooded were correctly identified as high risk by the model (Recall: 1.00, F1: 0.44).

This archive contains the full data processing pipeline (Python), the risk model, the frontend web map (HTML/CSS/JS), validation results, and methodology documentation. Greater Accra is the pilot — the pipeline is designed to scale to other regions of Ghana and West Africa.