Hydrogeology of Guinea Bissau
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Present-day Guinea Bissau was once part of the Gabu kingdom and the ancient Mali empire. From the 15th century, the coast became a centre of slave trading by Portuguese merchants, which, as well as inland areas, became fully colonised by the Portuguese in the 19th century. An armed rebellion against colonial rule from the 1950s led to independence in 1974. The rebels were allied to an extent with independence fighters from another Portuguese colony, Cape Verde, although the two countries never unified. Since independence, Guinea Bissau has experienced constant political change, with a succession of coups.
Guinea Bissau adopted the CFA currency in 1997. There is some potential for mineral exploitation and possibly offshore hydrocarbon exploitation, but their development has been impeded by political instability and armed conflict. The economy remains dominated by agriculture and fishing, with cashew nuts and groundnuts the most important export crops. GDP and HDI remain some of the lowest world-wide. Illegal drug trafficking is significant, with the country used as a transit point for drugs between South America and Europe.
A tropical country with high but seasonal rainfall, Guinea Bissau has relatively abundant seasonal surface water resources, but dry season water supplies are largely sourced from groundwater.
Dr Kirsty Upton and Brighid Ó Dochartaigh, British Geological Survey, UK
Dr Imogen Bellwood-Howard, Institute of Development Studies, UK
Please cite this page as: Upton, Ó Dochartaigh and Bellwood-Howard, 2018.
Bibliographic reference: Upton, K, Ó Dochartaigh, B É and Bellwood-Howard, I. 2018. Africa Groundwater Atlas: Hydrogeology of Guinea Bissau. British Geological Survey. Accessed [date you accessed the information]. http://earthwise.bgs.ac.uk/index.php/Hydrogeology_of_Guinea_Bissau
Terms and conditions
|Border countries||Senegal, Guinea|
|Total surface area*||36,130 km2 (3,613,000 ha)|
|Total population (2015)*||1,844,000|
|Rural population (2015)*||962,000 (52%)|
|Urban population (2015)*||882,000 (48%)|
|UN Human Development Index (HDI) [highest = 1] (2014)*||0.4196|
* Source: FAO Aquastat
More information on average rainfall and temperature for each of the climate zones in Guinea Bissau can be seen at the Guinea Bissau climate page.
These maps and graphs were developed from the CRU TS 3.21 dataset produced by the Climatic Research Unit at the University of East Anglia, UK. For more information see the climate resource page.
|Rural population with access to safe drinking water (%)||60.3|
|Urban population with access to safe drinking water (%)||98.8|
|Population affected by water related disease||No data||No data||No data||No data||No data||No data|
|Total internal renewable water resources (cubic metres/inhabitant/year)||8,677|
|Total exploitable water resources (Million cubic metres/year)||No data||No data||No data||No data||No data||No data|
|Freshwater withdrawal as % of total renewable water resources||0.5573|
|Renewable groundwater resources (Million cubic metres/year)||350|
|Groundwater produced internally (Million cubic metres/year)||14,000|
|Fresh groundwater withdrawal (primary and secondary) (Million cubic metres/year)||31|
|Groundwater: entering the country (total) (Million cubic metres/year)||No data||No data||No data||No data||No data||No data|
|Groundwater: leaving the country to other countries (total) (Million cubic metres/year)||No data||No data||No data||No data||No data||No data|
|Industrial water withdrawal (all water sources) (Million cubic metres/year)||11.9|
|Municipal water withdrawal (all water sources) (Million cubic metres/year)||34.1|
|Agricultural water withdrawal (all water sources) (Million cubic metres/year)||144|
|Irrigation water withdrawal (all water sources) 1 (Million cubic metres/year)||No data||No data||No data||No data||No data||No data|
|Irrigation water requirement (all water sources) 1 (Million cubic metres/year)||26.3|
|Area of permanent crops (ha)||250,000|
|Cultivated land (arable and permanent crops) (ha)||550,000|
|Total area of country cultivated (%)||15.22|
|Area equipped for irrigation by groundwater (ha)||530|
|Area equipped for irrigation by mixed surface water and groundwater (ha)||7,371|
These statistics are sourced from FAO Aquastat. They are the most recent available information in the Aquastat database. More information on the derivation and interpretation of these statistics can be seen on the FAO Aquastat website.
Further water and related statistics can be accessed at the Aquastat Main Database.
1 More information on irrigation water use and requirement statistics
The geology map below shows a simplified version of the geology of Guinea Bissau at 1:5 million scale (see the Geology resources page for more details).
A more detailed geology map of Guinea Bissau is available to view and interrogate online at the Visualizador de Mapas geoPortal (published 2014). This map was created by the Uidade de Informacao Geocientifica of the Portugese National Laboratory of Energy and Geology (LNEG).
This report provides more information on the Geology of Guinea Bissau (Geologia da Guiné-Bissau) (Alves 2010).
Guinea-Bissau can be divided into an eastern zone with predominantly Paleozoic and some Precambrian rocks, and a western zone with mainly late Mesozoic to Cenozoic sediments. The sedimentary facies of the Paleozoic are mainly clastic, with carbonates occurring only in the Silurian. The Cretaceous to Cenozoic sediments are mainly of marine origin (University of Guelph).
|Quaternary||Coastal sediments, including beach sands; river and coastal alluvium. Including sands, silts, and clays.|
|Upper Cretaceous - Tertiary sedimentary|
|Maastrichtian, Palaeocene-Eocene, Oligocene, Miocene||A sequence of largely marine sedimentary rocks, including limestones, marls, clays, silts, sands and phosphates. Drilling investigations have proved a ~5m thick phosphate layer in the Palaeocene-Eocene sequence, with 25-50m of overlying sediments.|
|Little is known of the igneous rocks in Guinea-Bissau.|
|Devonian||Shales and sandstones, including the Upper Devonian Bafata Group, and Lower Devonian sandstones in the Cusselinta-Saltinho area.|
|Silurian||Rocks of the Buba Group, including sandstones with some organic rich/carbonaceous black shales.|
|Cambrian-Ordovician||Sandstones, shales, conglomerates and rare limestones.|
|Precambrian metamorphic complex|
|Neoproterozoic||A volcanic and metasedimentary complex, including schists, quartzites and metavolcanic rocks.|
The hydrogeology map below shows a simplified version of the type and productivity of the main aquifers at a national scale (see the hydrogeology map resource page for more details).
More information on the hydrogeology of Guinea Bissau is available in the report United Nations (1988) (see References section, below).
For further information about transboundary aquifers, please see the Transboundary aquifers resources page.
References with more information on the geology and hydrogeology of Guinea Bissau can be accessed through the Africa Groundwater Literature Archive.
Alves PH. 2010. Geologia da Guiné-Bissau. X Congresso de Geoquimica dos Paises de Lingua Portuguesa, XVI Semana de Geoquimica. LNEG – Laboratório Nacional de Energia e Geologia / IICT – Instituto de Investigação Científica Tropical
University of Guelph. Rocks for Crops.
WES. Guinea Bissau: Country Profile. Water, Environment and Sanitation (WES), UNICEF.
United Nations. 1988. Groundwater in North and West Africa: Guinea-Bissau. United Nations Department of Technical Cooperation for Development and Economic Commission for Africa.