Continental hydrogeological maps of Africa

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Africa Groundwater Atlas >> Resource pages >> Groundwater and Hydrogeological Maps of Africa >> List of Continental Groundwater and Hydrogeological Maps of Africa


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This page provides information on groundwater and hydrogeological maps that cover the whole continent of Africa, with links to where they can be accessed online if available. There are two lists with summary information: first on continental scale maps that cover Africa alone, and then on global scale maps that include Africa. Below this are more details of selected key maps. The maps are all listed in reverse order of age, with newest maps first.

If you know of maps that aren't described here but should be, please let us know! Email us: AfricaGWAtlas@bgs.ac.uk


List of Maps covering Africa alone

This lists maps that cover the whole continent of Africa, but no other area. They are listed in reverse order of age. Some of these are 'traditional' style hydrogeological maps, showing an assessment of groundwater resource potential that can be based on various hydrogeological parameters. Others are 'thematic' maps that highlight particular aspects of groundwater, such as recharge or transboundary aquifers.


Map Title Date Scale Publishing Organisation Format Where to find
Groundwater recharge for Africa 2021 BGS Pdf image in article The map is presented and described in detail in MacDonald et al. 2021.
Groundwater resources map of Africa 2018 BGR / WHYMAP Paper , pdf View scanned map, with marginalia, at WHYMAP.
Transboundary aquifers of Africa 2018 IGRAC and UNESCO-IHP GIS; pdf View digital version in IGRAC portal; View pdf version.
Transboundary Aquifer Map for Africa 2013 IWMI View low resolution image at CGIAR The map is described in detail in this report
Groundwater (aquifer) productivity for Africa 2012 nominal 1:20 million BGS xyz tab-delimited text file (convertible to GIS raster/grid) Download GIS map
Groundwater storage for Africa 2012 nominal 1:20 million BGS xyz tab-delimited text file (convertible to GIS raster/grid Download GIS map
Depth to groundwater for Africa 2012 nominal 1:20 million BGS xyz tab-delimited text file (convertible to GIS raster/grid) Download GIS map
Groundwater resources map of Africa 2008 WHYMAP pdf View pdf map.
Carte hydrogeologique de l’Afrique 2008 1:10 million BRGM View image on project webpage
International Hydrogeological Map of Africa / Carte Hydrogeologique Internationale de l’Afrique 1992 1:5 million Organisation Africaine de Cartographie et de Télédétection (OACT) View scanned image at WHYMIS
Major Hydrogeological Formations (after Geological Map of Africa, 1:5,000,000) 1988 1:5 million United Nations View scanned image at WHYMIS



List of Maps of the World that include Africa

This lists global maps that include Africa. They are listed in reverse order of age.

Map Title Date Scale Editors Publishing Organisation Format Where to find
World Karst Aquifer Map 2017 WHYMAP Vector shapefile; webmap service; view online; pdf poster; printed map Download shapefile or poster pdf; web map service; view online on WHYMAP Viewer; for a printed copy contact whymap@bgr.de
Global transboundary aquifer (TBA) maps 2009, 2012, 2014, 2015, 2017 IGRAC and UNESCO-IHP Shapefile; view online; printed map on poster IGRAC online portal
Global Groundwater vulnerability to floods & droughts 2015 1: 25 million WHYMAP Vector shapefile; webmap service; view online; pdf poster; printed map Download shapefile or poster pdf; web map service; view online on WHYMAP Viewer; for a printed copy contact whymap@bgr.de
Groundwater and river basins of the world 2012 WHYMAP Vector shapefile; webmap service; view online; pdf poster; printed map Download shapefile or poster pdf; web map service; view online on WHYMAP Viewer; for a printed copy contact whymap@bgr.de
Groundwater resources of the world 2008 1:25 million & 1:40 million WHYMAP Vector shapefile; webmap service; view online; pdf poster; printed map Download shapefile or poster pdf; web map service; view online on WHYMAP Viewer or IGRAC online portal; for a printed copy contact whymap@bgr.de


Details of selected continental scale maps of Africa

Groundwater Resources Map of Africa

BGR/UNESCO. 2018. Groundwater Resources Map of Africa. 1:12,500,000. BGR Hannover / UNESCO Paris.

What the map shows

The map shows the current status on groundwater resources mapping in Africa, and is presented with accompanying marginalia including hydrogeological cross sections, transboundary aquifer maps, and information from regional hydrogeological studies.

The map of groundwater resources shows a background of country political borders, with a number of overlaid hydrogeological themes:

  • Hydrogeological/aquifer categories. Three categories are distinguished: major groundwater basins; areas with complex hydrogeological structure; areas with local and shallow aquifers.
  • Recharge zones. Five zones are distinguished: very high, high, medium, low and very low, ranging from over 300 mm/year to zero.
  • Special groundwater features, including known areas of saline groundwater, natural groundwater discharge areas in arid regions, areas of known groundwater over abstraction, and areas of groundwater mining.
  • Additional hydrological features (major rivers and lakes) and selected cities including those largely dependent on groundwater

Purpose, uses and limitations of the map

The map was designed to be used as a planning tool to support the long term sustainable development and management of groundwater resources in Africa. The information on the map supports integrated management of water resources at regional level, and allows for further specific analysis, such as assessing the potential vulnerability of groundwater resources to pollution or to changes in groundwater recharge due to global climate change.

How the map was developed

The map was developed within WHYMAP (the World-wide Hydrogeological Mapping and Assessment Programme), a joint consortium programme whose objective is to summarise groundwater information on a global scale in map form. The first edition of the map was published in 2008. A second edition was produced for the 7th Africa Water Week in Libreville, Gabon, in 2018. It contains hydrogeological sections of regional aquifers as well as regional and transboundary hydrogeological surface information on the composition of geological units and their respective groundwater yield. Recharge was estimated for WHYMAP by University of Frankfurt, derived from the global hydrological model WaterGAP, the Global Runoff Data Centre (GRDC), the Global Precipitation Climatology Centre (GPCC), as well as numerous international experts and institutes. The map legend uses the International Standard Legend for Hydrogeological Maps (SLHyM) and a harmonisation methodology developed on the basis of the International Hydrogeological Map of Europe (IHME1500).

Links

An image of the 2018 edition of the printed map, with marginalia, is available to view at WHYMAP.

An image of the 2008 edition of the printed map is available to view at WHYMAP.

Quantitative Digital Groundwater Maps of Africa

British Geological Survey (BGS). 2012. Quantitative groundwater maps for Africa. 1:20,000,000 (nominal scale).

What the maps show

  • Aquifer productivity: estimated relative aquifer productivity, based on typical potential yields of properly located and constructed boreholes. 6 categories ranging from Very High (>20 l/s) to Very Low (<0.1 l/s).
  • Groundwater storage: 6 categories based on water depth in mm, from 0 to >50,000 mm.
  • Depth to groundwater: 6 categories from <7 to >250 m.

Purpose, uses and limitations of the maps

These maps were developed primarily to highlight areas in Africa that are more likely to be resilient to climate change, and areas where sufficient groundwater resources may be available to help adaptation to climate change. They were developed using the best available data at a continental scale for Africa. An assessment of confidence levels for the maps was made based on the availability and spatial distribution of the hydrogeological maps and reviewed groundwater studies from which hydrogeological information was obtained. For much of eastern and southern Africa, both good quality national hydrogeological maps and information from many individual groundwater studies are available. The lack of good quality hydrogeological maps in North and West Africa is compensated for by the availability of many individual studies, which vary from local to regional scale. In Central Africa, however, both maps and study information are scarce.

How the maps were developed

The three maps each show a different aspect of the spatial distribution of key hydrogeological and groundwater properties:

  • aquifer productivity (the potential for groundwater abstraction);
  • groundwater storage; and
  • depth to groundwater level.

The maps were developed in GIS and designed to be made available digitally for use in GIS. They were developed using a continental scale geological basemap at 1:5,000,000 scale originally published by UNESCO (Furon and Lombard, 1964) and digitised and made available through the USGS (Persits et al., 1997).

Some geological units were subdivided using more detailed information from regional and national geological maps and from geological studies: Precambrian basement rocks were subdivided into three categories (metasedimentary, craton and mobile belts); and sedimentary rocks were subdivided into major sedimentary basins. The resulting new digital basemap was attributed with hydrogeological information extracted from available regional, national and sub-national hydrogeological maps across Africa, which were scanned and georeferenced for use in GIS. Further detailed information used to refine this initial hydrogeological characterisation was extracted from a literature review of 250 published journal papers and reports on groundwater studies in Africa; and from a database of water borehole yields in basement rocks across Africa. Final drafts of the maps were peer reviewed by experts in African groundwater.

The hydrogeological parameters used in the maps were selected in part to reflect the availability of data. Key quantitative hydrogeological properties (including transmissivity, effective porosity and groundwater level) are scarce in much of Africa. These were subsititude by various proxy data, which have been shown to be effective surrogates in data poor areas elsewhere (e.g. Graham et al., 2009):

  • typical borehole yields of effectively sited boreholes. This was interpreted as aquifer productivity, and used as surrogate for transmissivity.
  • A qualitative assessment of the groundwater flow and storage characteristics of different aquifers. This was used as a proxy for effective porosity.

Interim internal maps were also produced in GIS showing aquifer flow and storage type (with 5 categories: intergranular, fracture, mixed intergranular and fracture, karst, and fracture/weathered), and aquifer saturated thickness (with 4 categories from <25 m to >250 m).

Links

The maps are available as three separate digital, GIS-enabled files that can be freely downloaded from BGS.


More information on the development of the map can be seen at BGS

and in this article:

MacDonald, A M, Bonsor, H C, Ó Dochartaigh, B E, Taylor, R G. 2012. Quantitative maps of groundwater resources in Africa. Environmental Research Letters 7, 024009. doi:10.1088/1748-9326/7/2/024009

Carte hydrogéologique de l'Afrique

BRGM. 2008/2016. Carte hydrogéologique de l’Afrique. 1:10,000,000.

What the map shows

The map shows a background of country political borders, and overlaid on this:

  • Hydrogeological units. Eleven units are differentiated based on lithostratigraphy
  • Recharge zones. Seven zones are differentiated. Recharge is estimated based on modelling by Döll, 2005.
  • Major sedimentary basins. Boundaries of sedimentary basins (particularly in north Africa?), which contain multi-layered and/or deep aquifer systems.
  • Groundwater flow directions from deep confined aquifers.
  • Main hydrographic basins.

How the map was developed

An initial digital map at 1:10,000,000 was produced in GIS in 2003-2005 through “SIG Afrique”, a geological information network involving eleven African countries and BRGM. In 2008, after a validation workshop with several international experts, the map was published with funding from the French Ministry of Foreign Affairs. It was developed by combining two categories of information (geological data and water recharge indicators) to locate and estimate the scale of water resources in outcropping geological formations. It identifies potential aquifers and their groundwater potential depending on their inferred porosity and on the climatic zone as shown by the estimated recharge. An updated version was published in 2016, in parallel with an updated edition of the underlying 1:10,000,000 scale geological map (Thiéblemont et al. 2016).

Links

The map is available to view online at BRGM.

The map is described in detail in this report:

Seguin, J.J. et Gutierrez, A. 2016. Les ressources en eau du continent africain: rareté et abundance. Géosciences N°21: L’Afrique, Terre de Connaissances. Septembre 2016.

More details of map development can be seen in this presentation from the SiGAfrique project.

Information on the new edition of the 1:10,000,000 scale geological map; it can be viewed in OneGeology and downloaded as a pdf (large file) (Thiéblemont et al. 2016).

International Hydrogeological Map of Africa / Carte Hydrogeologique Internationale de l’Afrique

African Organisation for Cartography and Remote Sensing / Organisation Africaine de Cartographie et de Télédétection (AOCRS / OACT). 1988-1992. Carte hydrogéologique internationale de l'Afrique / International hydrogeological map of Africa. 1:5,000,000.

What the map shows

The map shows a background of topographic data, with a number of overlaid hydrogeological themes:

  • Lithology of geological units. Ten categories are distinguished.
  • Aquifer classes. Three categories are distinguished: continuous aquifers, discontinuous aquifers and non-aquifers.
  • Estimated recharge. The continuous and discontinuous aquifer classes are each subdivided into three subclasses according to the estimated recharge to each aquifer (high (>100 mm/yr) and regular, medium and regular, or low (<10 mm/yr) and irregular).
  • Additional information on surface water hydrology, groundwater quality, hydrodynamics, artificial works and geology, shown using point and line symbols.

How the map was developed

Map development was launched by the Organisation of African Unity at the beginning of the 1980s, after the Lomé summit of African Heads of States (Gilbrich & Struckmeier, 2014). The map was produced by the African Organisation for Cartography and Remote Sensing / Organisation Africaine de Cartographie et de Télédétection (AOCRS / OACT), based in Algiers. Scientific coordination and map editing were done by M. Safar-Zitoun, C. Fezzani and A.C. Nouiouat, and also involved almost 100 scientists from 41 African countries and some twenty from outside Africa. UNESCO and aid agencies from Germany, France, Switzerland and Yugoslavia provided financial input and expertise. The topographic base for the hydrogeological map was provided by the French National Geographic Institute (IGN) and the Commission for the Geological Map of the World (CGMW) via a project called the Geological Map of Africa.

After the preparation of a feasibility study and agreement of a common legend for the map, drafts of the five final map sheets were produced, region by region, and finalised during a series of workshops. Most of the sheets are accompanied by explanatory brochures describing the hydrogeological conditions of the sheet areas in French and/or English.

Links

African Organisation for Cartography and Remote Sensing / Organisation Africaine de Cartographie et de Télédétection (AOCRS / OACT). Edited by Safar Zitoun & Nouiouat. 1988-1992. Carte hydrogéologique internationale de l'Afrique / International hydrogeological map of Africa. Algiers, Institut national de cartographie, 1:5,000,000. 1 map on 6 sheets; colour.

A scanned image of the map is available to view at WHYMAP.


Africa, Major Hydrogeological Formations

United Nations. 1988. Africa, major hydrogeological formations (after Geological Map of Africa 1:5,000,000). ca.1:20,000,000.

What the map shows

The map shows a background of country political borders, over which two main hydrogeological themes are overlaid:

  • Hydrogeological/aquifer categories. Three top level categories are distinguished: aquifers with interstitial porosity; aquifers with fracture and channel porosity; and formations with little or no porosity except locally in certain favourably situated weathered or fissured zones. Each top level category is subdivided into four sub-categories according to geological rock type.
  • Isohyet showing where annual rainfall is less than 100 mm.

Links

United Nations Department of Technical Cooperation for Development. 1988. Africa, major hydrogeological formations (after Geological Map of Africa 1:5,000,000). 1 map: colour; 44 x 55 cm. New York.

A scanned image of the map is available to view at WHYMAP.

A separate scan of the map legend.

General References

Gilbrich, W H, and Struckmeier, W F. 2014. 50 Years of Hydro(geo)logical Mapping Activities. German Federal Institute for Geosciences and Natural Resources (BGR) and UNESCO International Hydrological Programme (UNESCO-IHP).


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