A new tool to map floods around the world, especially those that occur in the Global South, has been launched through a partnership between Google, MapBox, and other players working with a UN University group based in Canada.

The World Flood Mapping Tool uses the Google Earth engine combined with nearly 40 years of satellite data, which provides enough geospatial information to do flooding analysis on a global scale. The free, publicly available flood maps take the view to street level at a resolution of 30 meters, the project managers said.

Among case studies used to develop the project were the 2015 floods affecting Mozambique and Malawi, after tropical cyclones Bansi and Chedza hit the region. More than 530,000 people were affected in what quickly led to a cholera outbreak, as well as displacement and other cascading effects.

The new online tool adds available layers for population, buildings and land use. It can be used for community planning, zoning, insurance assessments and more, say the creators at the UN University’s Institute for Water, Environment and Health.

Potential supply chain issues can be identified, as well as emergency relief routes during disasters because flood impacts are updated more quickly. Hamid Mehmood, a GIS and remote sensing specialist at UNU-INWEH who led the tool’s development, says that a UNU-INWEH survey showed a majority of flood forecasting centers in flood-prone countries cannot run complex flood forecasting models in-house.

Reliable information about flood risk is especially valuable in Africa and Southeast Asia, where urban areas are expected to grow 80% by 2030. Some 1.5 billion people are at risk of floods now, but that number is only expected to grow with coming climate change impacts.

Image: OCHA file