Difference between revisions of "Hydrogeology of Burkina Faso"

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||Cenozoic - Tertiary
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||Cenozoic  
 
||Mainly sandstones, with interbedded mudstones.
 
||Mainly sandstones, with interbedded mudstones.
 
||Unconformably overlie Proterozoic to Palaeozoic sedimentary dolomites and other formations in the Gondo plain in the north of the country,
 
||Unconformably overlie Proterozoic to Palaeozoic sedimentary dolomites and other formations in the Gondo plain in the north of the country,
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||Proterozoic (Late Precambrian) to Palaeozoic
 
||Proterozoic (Late Precambrian) to Palaeozoic
 
||These are consolidated, indurated sedimentary rocks, sometimes metamorphosed. They occur along the northwest and north, and in the extreme southeast of the country. They include sandstone-quartzites and conglomerates at the base, which are overlain by largely sandstone formations, interbedded with schists and rare dolomitic limestones in the west of the country. At the top of the sequence are mixed formations including argillaceous schists; quartzitic sandstones; interbedded limestones and dolomites; breccias; and marbled conglomerates. In the southeast are sandstone facies (eg the Gobinangau Sandstone) with pelitic schists and calcareous and phosphated strata.  
 
||These are consolidated, indurated sedimentary rocks, sometimes metamorphosed. They occur along the northwest and north, and in the extreme southeast of the country. They include sandstone-quartzites and conglomerates at the base, which are overlain by largely sandstone formations, interbedded with schists and rare dolomitic limestones in the west of the country. At the top of the sequence are mixed formations including argillaceous schists; quartzitic sandstones; interbedded limestones and dolomites; breccias; and marbled conglomerates. In the southeast are sandstone facies (eg the Gobinangau Sandstone) with pelitic schists and calcareous and phosphated strata.  
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||Precambrian
 
||Precambrian
 
||Birrimian, Eburnean and PreBirrimian: igneous and metamorphic rocks: granites, gneisses, schists, quartzites and greenstones.  
 
||Birrimian, Eburnean and PreBirrimian: igneous and metamorphic rocks: granites, gneisses, schists, quartzites and greenstones.  
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====Unconsolidated====
 
====Unconsolidated====
 
{| class = "wikitable"
 
{| class = "wikitable"
|Named Aquifers||General Description||Water quantity issues||Water quality issues||Recharge
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|Named Aquifers||General Description||Water quantity issues||Water quality issues
 
|-
 
|-
 
|Alluvium   
 
|Alluvium   
||Alluvial deposits in river valleys and floodplains can have high permeability and storage capacity, where they are dominated by coarse grained sand and gravel. Where they are underlain by permeable bedrock - eg sandstones or weathered basement - groundwater in the alluvial deposits is often in hydraulic continuity with groundwater in the underlying bedrock aquifer.  
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||Alluvial deposits in river valleys and floodplains can have high permeability and storage capacity, where they are dominated by coarse grained sand and gravel. Alluvium can be up to 60 m thick. Where they are underlain by permeable bedrock - eg sandstones or weathered basement - groundwater in the alluvial deposits is often in hydraulic continuity with groundwater in the underlying bedrock aquifer.  
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==== Sedimentary - Intergranular Flow====
 
==== Sedimentary - Intergranular Flow====
 
{| class = "wikitable"
 
{| class = "wikitable"
|Named Aquifers||General Description||Water quantity issues||Water quality issues||Recharge
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|Named Aquifers||General Description||Water quantity issues||Water quality issues
 
|-
 
|-
 
|Continental Terminal
 
|Continental Terminal
||This aquifer has variable lithology and irregular structure, with non-continuous layers. Unconfined. Typically 10 m thick at its edges, ranging up to 100 m thick in the centre of the aquifer in the plain of Gondo.  
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||This aquifer has variable lithology and irregular structure, with non-continuous layers. Where it is overlain by unconsolidated alluvial aquifers, groundwater is often in hydraulic continuity across both aquifer layers. The aquifer is largely unconfined.
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The Continental Terminal aquifer ranges in thickness from 10 m thick at its edges, up to 100 m thick in the centre of the aquifer in the plain of Gondo.  
  
 
The water table can range from 10 m to more than 90 m below the ground surface. Borehole depths typically range from 40 m to 120 m.
 
The water table can range from 10 m to more than 90 m below the ground surface. Borehole depths typically range from 40 m to 120 m.
 
||This aquifer is generally used for rural water supplies.
 
||This aquifer is generally used for rural water supplies.
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||  
 
||  
 
|}
 
|}
 
  
  
 
==== Sedimentary - Fracture Flow====
 
==== Sedimentary - Fracture Flow====
 
{| class = "wikitable"
 
{| class = "wikitable"
|Named Aquifers||General Description||Water quantity issues||Water quality issues||Recharge
+
|Named Aquifers||General Description||Water quantity issues||Water quality issues
 
|-
 
|-
|Consolidated Sedimentary rocks of Proterozoic to Palaeozoic age
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|Proterozoic to Palaeozoic (meta)sedimentary rocks
||The upper layers are unconfined. Lower formations can be confined if overlain by dolerite intrusion or a clayey layer.
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||Sandstones, dolomites and limestones form aquifer layers within this sequence. The aquifer layers range from 50 to 1000 m thick. Upper aquifer layers are typically unconfined. Lower aquifer formations can be confined if overlain by dolerite intrusion or a clayey layer.
  
 +
These rocks can be overlain by up to 60 m of alluvium, and groundwater is often in hydraulic continuity with the unconfined upper bedrock aquifer layers, with the water table ranging from 10 m to 60 m below the ground surface. In confined aquifer layers, borehole water levels are typically less than 5 m below the ground surface, and in some cases are artesian.
  
 
||The aquifer is used for water supply in rural and urban areas (70% of abstraction from the aquifer); and also for mineral water and other commercial/industrial use (25%) and other uses.
 
||The aquifer is used for water supply in rural and urban areas (70% of abstraction from the aquifer); and also for mineral water and other commercial/industrial use (25%) and other uses.
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====Crystalline Basement====
 
====Crystalline Basement====
 
{| class = "wikitable"
 
{| class = "wikitable"
|Named Aquifers||General Description||Water quantity issues||Water quality issues||Recharge
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|Named Aquifers||General Description||Water quantity issues||Water quality issues
 
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|Granites, gneisses, schists, quartzites and greenstones.
 
|Granites, gneisses, schists, quartzites and greenstones.
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In some areas, fractured zones form aquifers, sometimes underlying, and associated with, weathered zones. These fractured aquifer zones can range from 10 m to 80 m thick, and the water table can range from 20 m to 60 m below the ground surface. Boreholes abstracting from this aquifer are between 40 and 150 m deep.
 
In some areas, fractured zones form aquifers, sometimes underlying, and associated with, weathered zones. These fractured aquifer zones can range from 10 m to 80 m thick, and the water table can range from 20 m to 60 m below the ground surface. Boreholes abstracting from this aquifer are between 40 and 150 m deep.
 
||Groundwater from crystalline basement aquifers is dominantly used for rural water supplies (70%), with other uses being for mineral water and other commercial/industrial use (25%) and a small amount of abstraction for agriculture (2%).
 
||Groundwater from crystalline basement aquifers is dominantly used for rural water supplies (70%), with other uses being for mineral water and other commercial/industrial use (25%) and a small amount of abstraction for agriculture (2%).
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||  
 
||  
 
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Revision as of 09:49, 1 July 2015

Africa Groundwater Atlas >> Hydrogeology by country >> Hydrogeology of Burkina Faso

Authors

Youssouf Koutoube,

Kirsty Upton, Brighid Ó Dochartaigh, British Geological Survey, UK


Geographical Setting

Map of Burkina Faso (For more information on the datasets used in the map see the geography resources section)

General

Much of Burkina Faso is a largely flat plain with an average altitude of 400 m above sea level, which is cut into by valleys and flood plains.

Estimated Population in 2013* 16,934,839
Rural Population (% of total) (2013)* 71.8%
Total Surface Area* 273,600 sq km
Agricultural Land (% of total area) (2012)* 44.1%
Capital City Ouagadougou
Region Western Africa
Border Countries Benin, Cote d'Ivoire, Ghana, Mali, Niger, Togo
Annual Freshwater Withdrawal (2013)* 818 Million cubic metres
Annual Freshwater Withdrawal for Agriculture (2013)* 51.4%
Annual Freshwater Withdrawal for Domestic Use (2013)* 45.9%
Annual Freshwater Withdrawal for Industry (2013)* 2.7%
Rural Population with Access to Improved Water Source (2012)* 75.8%
Urban Population with Access to Improved Water Source (2012)* 97.5%

* Source: World Bank


Climate

Burkina Faso can be divided into three climate zones, with rainfall decreasing from south to north. There is a distinct dry season during winter months, and wet season during summer months.

Rainfall time-series and graphs of monthly average rainfall and temperature for each individual climate zone can be found on the Burkino Faso Climate Page.


Average monthly precipitation for Burkina Faso showing minimum and maximum (light blue), 25th and 75th percentile (blue), and median (dark blue) rainfall Average monthly temperature for Burkina Faso showing minimum and maximum (orange), 25th and 75th percentile (red), and median (black) temperature Quarterly precipitation over the period 1950-2012 Monthly precipitation (blue) over the period 2000-2012 compared with the long term monthly average (red)

For further detail on the climate datasets used see the climate resources section.

Surface water

The centre, south and west of Burkina Faso are drained by tributaries of the Volta system, including the Nakambe, Mouhoun and Comoé rivers. The north and east are drained by rivers of the Niger basin. Many of the smaller rivers are ephemeral, drying during the dry season. There are a number of natural lakes. Many valleys are dammed to store wet season rainfall: in 2001 there were approximately 2000 reservoirs with a total storage volume estimated at 2.66 billion cubic metres (Obuobie and Barry 2012)



Surface Water Map of Burkina Faso (For more information on the datasets used in the map see the surface water resources section)

Soil

Soil Map of Burkina Faso (For map key and more information on the datasets used in the map see the soil resources section)

Land cover

Land Cover Map of Burkina Faso (For map key and more information on the datasets used in the map see the land cover resources section)


Geology

This section provides a summary of the geology of Burkina Faso. More detail can be found in the references listed at the bottom of this page. Many of these references can be accessed through the Africa Groundwater Literature Archive. The geology map on this page shows a simplified version of the geology at a national scale (see the Geology resources page for more details). The map is available to download as a shapefile (.shp) for use in GIS packages.

Burkina Faso Geology.png
Geological Environments
Key Formations Period Lithology Structure
Unconsolidated
Quaternary Detrital deposits: dominantly alluvium in river valleys; some lake deposits.
Continental Terminal
Cenozoic Mainly sandstones, with interbedded mudstones. Unconformably overlie Proterozoic to Palaeozoic sedimentary dolomites and other formations in the Gondo plain in the north of the country,
Proterozoic to Palaeozoic (meta)sedimentary
Bandiagara and Koutiala sandstones, Toun schists, Bobo sandstone, Gobinangou Sandstone Proterozoic (Late Precambrian) to Palaeozoic These are consolidated, indurated sedimentary rocks, sometimes metamorphosed. They occur along the northwest and north, and in the extreme southeast of the country. They include sandstone-quartzites and conglomerates at the base, which are overlain by largely sandstone formations, interbedded with schists and rare dolomitic limestones in the west of the country. At the top of the sequence are mixed formations including argillaceous schists; quartzitic sandstones; interbedded limestones and dolomites; breccias; and marbled conglomerates. In the southeast are sandstone facies (eg the Gobinangau Sandstone) with pelitic schists and calcareous and phosphated strata.
Crystalline Basement
Precambrian Birrimian, Eburnean and PreBirrimian: igneous and metamorphic rocks: granites, gneisses, schists, quartzites and greenstones.

Hydrogeology

This section provides a summary of the hydrogeology of the main aquifers in Burkina Faso. More information is available in the references listed at the bottom of this page. Many of these references can be accessed through the Africa Groundwater Literature Archive. The hydrogeology map on this page shows a simplified version of the type and productivity of the main aquifers at a national scale (see the Aquifer properties resource page for more details). The map is available to download as a shapefile (.shp) for use in GIS packages.

Burkina Faso Hydrogeology.png Hydrogeology Key.png


Unconsolidated

Named Aquifers General Description Water quantity issues Water quality issues
Alluvium Alluvial deposits in river valleys and floodplains can have high permeability and storage capacity, where they are dominated by coarse grained sand and gravel. Alluvium can be up to 60 m thick. Where they are underlain by permeable bedrock - eg sandstones or weathered basement - groundwater in the alluvial deposits is often in hydraulic continuity with groundwater in the underlying bedrock aquifer.

Sedimentary - Intergranular Flow

Named Aquifers General Description Water quantity issues Water quality issues
Continental Terminal This aquifer has variable lithology and irregular structure, with non-continuous layers. Where it is overlain by unconsolidated alluvial aquifers, groundwater is often in hydraulic continuity across both aquifer layers. The aquifer is largely unconfined.

The Continental Terminal aquifer ranges in thickness from 10 m thick at its edges, up to 100 m thick in the centre of the aquifer in the plain of Gondo.

The water table can range from 10 m to more than 90 m below the ground surface. Borehole depths typically range from 40 m to 120 m.

This aquifer is generally used for rural water supplies.


Sedimentary - Fracture Flow

Named Aquifers General Description Water quantity issues Water quality issues
Proterozoic to Palaeozoic (meta)sedimentary rocks Sandstones, dolomites and limestones form aquifer layers within this sequence. The aquifer layers range from 50 to 1000 m thick. Upper aquifer layers are typically unconfined. Lower aquifer formations can be confined if overlain by dolerite intrusion or a clayey layer.

These rocks can be overlain by up to 60 m of alluvium, and groundwater is often in hydraulic continuity with the unconfined upper bedrock aquifer layers, with the water table ranging from 10 m to 60 m below the ground surface. In confined aquifer layers, borehole water levels are typically less than 5 m below the ground surface, and in some cases are artesian.

The aquifer is used for water supply in rural and urban areas (70% of abstraction from the aquifer); and also for mineral water and other commercial/industrial use (25%) and other uses.

Crystalline Basement

Named Aquifers General Description Water quantity issues Water quality issues
Granites, gneisses, schists, quartzites and greenstones. The upper part of the aquifer is weathered, and can be in hydraulic continuity with overlying alluvial aquifers (see Unconsolidated, above). The weathered zone can be 10 m to 80 m thick. The water table in the weathered zone can lie between 5 m and 30 m below the ground surface. Boreholes are typically from 40 m to 80 m deep. Groundwater in the weathered zone aquifer is typically unconfined.

In some areas, fractured zones form aquifers, sometimes underlying, and associated with, weathered zones. These fractured aquifer zones can range from 10 m to 80 m thick, and the water table can range from 20 m to 60 m below the ground surface. Boreholes abstracting from this aquifer are between 40 and 150 m deep.

Groundwater from crystalline basement aquifers is dominantly used for rural water supplies (70%), with other uses being for mineral water and other commercial/industrial use (25%) and a small amount of abstraction for agriculture (2%).

Groundwater Status

Groundwater quantity

Groundwater quality

Groundwater use and management

Groundwater use

Groundwater management

Groundwater monitoring

Transboundary aquifers

For further information about transboundary aquifers, please see the Transboundary aquifers resources page


References

The following references provide more information on the geology and hydrogeology of Burkina Faso. These, and others, can be accessed through the Africa Groundwater Literature Archive.


Geology: key references

Castaing C, Billa M, Milési J P, Thieblemont D, Le Metour J, Egal F, Donzeau M et al. 2003. Notice explicative de la carte géologique et minière à 1/1 000 000ème du Burkina Faso. Proj. SYSMIN 7

Hottin G et Ouédraogo OF. 1975. Notice explicative de la carte géologique à 1/1 000 000 de la - IWACO ·1989· Etude du bilan du Burkina Faso. Rapport intermédiaire de la deuxième phase 1987-1990. Tome 2 : inventaire des ressources en eau

Sattran V et Wenmenga U. 2002. Géologie du Burkina Faso (Czech Edition), 10 dec 2002, République de Haute-Volta, Edition BRGM, 56p

Hydrogeology: key references

Ministère de l'eau. 1993. Notice explicative de la carte hydrogéologique du Burkina Faso échelle 1:5OO.OOO, feuille Ouagadougou - DEP du Ministètre de l'eau, Assistance technique : IWACO B.V., Financement: Burkina FasolPays-Bas, 4Sp. + cartes

Ministère de l'eau. 1988. Rapport de fin de projet : travaux et résultats hydrogéologiques - projet d'hydraulique villageoise Yatenga II, CCE, FED, Convention n034981BF, 48 p+annexes

Ministère de l'eau. 1990. Etude des ressources en eau souterraine du Yatenga - CIEH, série hydrogéologie, 138p.

Ministère de l'environnement et de l'eau. 1998. Politique et stratégies en matière d'eau 126p.

Obuobie E and Barry B. 2012. Burkina Faso, in Groundwater Availability and Use in Sub-Saharan Africa; a review of fifteen countries. Pavelic et al. (Eds).

UN. 1988. Burkina Faso, in Ground water in North and West Africa. Natural Resources/Water Series No. 18, ST/TCD/5. Department of Technical Co-operation for Development and Economic Commission for Africa.

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Africa Groundwater Atlas >> Hydrogeology by country >> Hydrogeology of Burkina Faso