IGRAC supported the inventory of hydrogeological maps in Africa, which is accessible in a dedicated section of the Africa Groundwater Atlas. The inventory contains more than 100 maps, at the sub-national, national and regional/continental scale. Links are provided for the maps that are available online.
Importance of hydrogeological maps and current challenges
Hydrogeological maps play a valuable role in improving the planning and implementation of groundwater resource development, and monitoring, evaluating and managing water supplies.
Most countries in Africa have a national hydrogeological or groundwater map, although not all - even those countries that depend significantly on groundwater resources (e.g. Mali). There is much room for the development of new national hydrogeological maps where these are not yet available.
In many countries that do have a national hydrogeological map, this is decades old, and often based on limited information available at the time of making. In most countries, much more hydrogeological data and information has been collected in the years since the national map was created, and there is great scope for updating older national maps with new and more extensive data.
Many older hydrogeological maps are also hard to access. They were made in the pre-GIS, and often even in the pre-computer, era. They are usually available only as hard (paper) copies, which may be out of print, expensive or otherwise difficult to acquire for general use.
The way forward
There is a growing demand for easily accessible - which today means digital – country-scale maps to support effective groundwater resource planning and management - maps that provide a reliable, up to date overview of national groundwater resources. There is potential for digitizing and georeferencing existing maps to make them more widely available: scanned pdfs available to view and download online; and georeferenced maps available to be viewed in interactive online viewers, and even to download in a format that is compatible with modern GIS software for subsequent use and analysis. Examples of where existing maps have been digitally georeferenced and made available to view online are eSwatini and Lesotho. Another approach to making national scale hydrogeological maps more widely available is the Africa Groundwater Atlas Country Hydrogeology Maps, which provide simple overviews of aquifer type and productivity for most countries in Africa, and are available to download as digital shapefiles for use in GIS.