📡 Data & IoT

Open Cities Accra - Community Flood-Risk Mapping into OpenStreetMap

Between June 2018 and February 2020 the Humanitarian OpenStreetMap Team, Mobile Web Ghana and OSM Ghana surveyed four flood-prone neighbourhoods on Accra's Odaw river - Alogboshie, Akweteyman, Alajo and Nima - into OpenStreetMap: buildings, drainage networks, roads, waste dumping sites and services. The World Bank paid. The data fed Ghana's GARID flood programme, and it is still in OpenStreetMap today.

Completed 📅 2018–2020 ◆ Source-checked

🤖 AI-generated summary of the sources below — how this works · 🔎 Last verified 2026-08-01

📡 Data & IoT Flood resilience Open data Citizen participation

📊 Impact

HOT reports roughly 36,000 buildings, 98 km of roads and paths, 1,500 drain points, 83 km of drain segments and hundreds of solid-waste dumping sites mapped across the four communities, with over 110 mappers and 30 government staff trained. Those are operator figures; no independent evaluation was found. The data's survival was checked directly rather than assumed: an Overpass query of the OpenStreetMap database on 1 August 2026, over a bounding box covering Alogboshie and Akweteyman, found building outlines rising from 82 on 1 June 2018 to 16,321 on 1 March 2020, and standing at 17,773 today, alongside 439 mapped drain and ditch segments.

🎓 Lesson

Open data outlives the grant that made it; the obligation to act on it never existed. The buildings and drains are still in OpenStreetMap six years after the money stopped. The flood programme they were collected for had rehabilitated 0.10 km of a planned 6 km of drainage after six years, and its US$7 million early-warning equipment was still being reported as non-operational in 2026.

Evidence🏛️ Official

Scale🏘️ District

FundingWorld Bank / GFDRR Open Data for Resilience Initiative, under Open Cities Africa

📖 Terms in this entry: Civic participation platform · Digital identity · Digital twin

Sources

↗ HOT - Open Cities Africa, Accra City Project (Ghana)Operator page for the Open Cities Africa city grant specifically: 11 June 2018 to 28 February 2019, three communities (Alogboshie, Akweteyman, Alajo), building footprints only in Alogboshie, plus drainage networks, flood history, roads, water points, solid waste points and facilities. Lists Mobile Web Ghana, OSM Ghana, GFDRR, the World Bank and OpenDRI as partners. Read as the sub-phase, not the whole engagement - see the next source.

↗ HOT - Supporting the Greater Accra Resilient and Integrated Development Project to protect communities from floodingPublished 9 July 2020; describes the full Accra engagement from June 2018 to February 2020 across four communities (Nima added) and carries every output figure used here. Names the beneficiary as Ghana's Ministry of Inner-Cities and Zongo Development and the wider GARID project. Its end date and community count differ from the project page above; this desk reads the two as whole-engagement versus sub-phase rather than as a contradiction.

↗ GARID project website - republication of the HOT postThe receiving programme acknowledging the mapping on its own site: same June 2018 to February 2020 window, same four communities, same World Bank funding line.

↗ OpenStreetMap / Overpass API - persistence check (desk query, 1 Aug 2026)Not a published source but a reproducible measurement, and the only way to test the continuity claim. Bounding box covering Alogboshie and Akweteyman. Building ways: 82 at the 2018-06-01 snapshot, 16,321 at 2020-03-01, 17,773 live today; 439 drain and ditch ways live today. This proves the data exists and was created inside the project window, not that every object was drawn by a project mapper.

↗ IMANI Africa - GARID: the bigger question is not the delay (July 2026)Independent Ghanaian policy think tank; the counterweight. Only 0.10 kilometres of the planned six kilometres of drainage rehabilitation had been completed. Also establishes that GARID itself is a concessional World Bank loan, distinct from the grant money that paid for this survey.

↗ Graphic Online - GARID coordinator on the $7 million flood alert systemReturned 403 to automated fetch; described from search results corroborated across two independent queries. Two and a half years after handover of US$7m of equipment to four national institutions, the flood early warning system was still not operational. Contested - one search result cites a World Bank assessment describing it as operational - so the entry says reported non-operational rather than asserting it.

This overview was generated with AI from the public sources listed above and checked against them before publication. It has not had a complete human fact-check — treat it as a starting point and follow the sources.

Continue exploring

Compare this project

🇰🇪 Map Kibera — Residents Surveying an Informal Settlement into OpenStreetMap · Nairobi Residents mapping their own settlement in 2009 against a donor flood-risk programme in 2018 - both end with data nobody must act on. 🇹🇿 Ramani Huria Community Flood Mapping · Dar es Salaam Same funder, method and years; Dar mapped about half a city's wards, Accra four neighbourhoods on one river. 🇳🇬 Lagos State Parametric Flood Insurance Policy · Lagos Two ways to spend donor money on the same hazard: map the floodplain, or buy an automatic payout against it.

Explore the wider context

🏙️ Urban digital twins compared 🌊 Flood resilience guide 🏙️ Accra city profile 📡 Data & IoT projects

📎 Cite this project

1001 Smart Cities (2026). “Open Cities Accra - Community Flood-Risk Mapping into OpenStreetMap” — Accra, Ghana. The Smart City Atlas. https://1001smartcities.org/projects/accra-open-cities-mapping/ (last verified 2026-08-01). Data: CC BY 4.0.

The underlying data is free to reuse with attribution — see the open data page.

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