Difference between revisions of "Hydrogeology of Cote d'Ivoire"

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'''Most of the textual information on this page was taken from the chapter on Côte d'Ivoire in the report
 
'''Most of the textual information on this page was taken from the chapter on Côte d'Ivoire in the report
[http://www.bgs.ac.uk/africagroundwateratlas/fulldetails.cfm?id=AGLA060034 ‘Groundwater in North and West Africa’] (UN 1988). This information is outdated. If you have more recent information on the hydrogeology of Cote d'Ivoire, please get in touch.'''  
+
[http://www.bgs.ac.uk/africagroundwateratlas/fulldetails.cfm?id=AGLA060034 ‘Groundwater in North and West Africa’] (UN 1988). Some of this information is outdated. If you have more recent information on the hydrogeology of Cote d'Ivoire, please get in touch.'''  
  
 
==Compilers==
 
==Compilers==
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There are four main rivers in Côte d'Ivoire: the Cavally, Sassandra, Bandama and Comoé, all of which flow from north to south, into the Atlantic Ocean. There are also several smaller coastal rivers, which also generally flow from north to south into the Atlantic, but some discharge into lagoons before they reach the coast. In the north, there are several tributaries of the Niger and the Black Volta rivers. The Niger tributaries flow northwards towards Mali.
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The highest river flows occur from April to October, with lowest flows in January and February.
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There are a number of dams on some of the major rivers, related to hydroelectric schemes.
  
  
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Equatorial
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The south of the country is equatorial with forest; the centre is dominated by tropical forest; and the north is dominated by savannah vegetation.
tropical Forest
 
savannah
 
  
 
| [[File:Côte d'Ivoire_LandCover.png | frame | Land Cover Map of Côte d'Ivoire (For map key and more information on the datasets used in the map see the [[Land cover | land cover resources section]])]]
 
| [[File:Côte d'Ivoire_LandCover.png | frame | Land Cover Map of Côte d'Ivoire (For map key and more information on the datasets used in the map see the [[Land cover | land cover resources section]])]]
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==Geology==
 
==Geology==
  
This section provides a summary of the geology of Côte d'Ivoire. More information is available in the report [ADD LINK UN] (1988) (see References section, below).
+
This section provides a summary of the geology of Côte d'Ivoire. More information is available in the report [http://www.bgs.ac.uk/africagroundwateratlas/fulldetails.cfm?id=AGLA060034 ‘Groundwater in North and West Africa: Côte d'Ivoire’] (UN 1988). (see References section, below).
  
 
The geology map shows a simplified version of the geology at a national scale (see [[Geology | the Geology resources page]] for more details).
 
The geology map shows a simplified version of the geology at a national scale (see [[Geology | the Geology resources page]] for more details).
  
  [[File:Côte d'Ivoire_Geology.png | right]]
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  [[File:Côte d'Ivoire_Geology.png | center]]
  
 
{| class = "wikitable"
 
{| class = "wikitable"
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|Key Formations||Period||Lithology
 
|Key Formations||Period||Lithology
 
|-
 
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!colspan="4"|Geological Environment 1
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!colspan="4"| Coastal sedimentary basin
 
|-
 
|-
|Name of formation1
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|Continental Terminal;
||Time period
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||Cretaceous to Quaternary
||Description
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||Coastal sedimentary rocks and unconsolidated sediments form a wedge which narrows towards the north, where it terminates at the edge of the basement rock, less than 35 km from the coast. The basin is crossed from west to east by a fault with a displacement of several thousand metres, which separates two distinct zones:
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- to the north is a shallower basin where the sedimentary infill is not usually more than 300 m thick
 +
 
 +
- to the south is a deep basin, where the sedimentary infill reaches 4,000 to 5,000 m thick.
 +
 
 +
There is a series of lagoons, part of an ancient hydrographic system, which have very thick mud deposits and are now submerged.
 +
 
 +
The upper part of the sedimentary basin infill, especially in the 'low plateau' areas south of the lagoons, close to the shore, are Quaternary formations with a sand-clay continental formation about 20 m thick overlying a series of marine clays interbedded with sands, together about 10 m thick.
 +
 
 +
The lower part of the sedimentary infill comprises detrital continental Tertiary (Miocene-Pliocene) formations - mostly coarse sands -  and, in the deepest areas, Upper and Middle Cretaceous marine formations, mostly sand/sandstone and clay. Together, these form the Continental Terminal formation. In places this lies directly on basement rock; in others, there is an underlying layer of Palaeocene (mostly limestone) or Maastrichtian (sand/sandstone) rocks.
 
|-
 
|-
|
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!colspan="4"|Basement (West African Shield)
||
 
||
 
 
|-
 
|-
!colspan="4"| Geological Environment 2
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|Birrimian
 +
||Middle and Upper Precambrian; Proterozoic
 +
||Metamorphic rocks, mainly of sedimentary origin. These are generally schists, with meta-sandstones and meta-conglomerates in places. In places there are granitic intrusions, accompanied by volcano-sedimentary formations of tuffs, breccias, green rocks and schists of Proterozoic age. These form bands running from north-northeast to south-southwest, and are heavily folded, sometimes vertical.
 
|-
 
|-
|
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|Prebirrimian
||
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||Lower Precambrian
||
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||The oldest basement formations include crystalline gneiss, granites and migmatites. They are most common in the west of the country (although migmatites are found everywhere).
|-
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|
 
||
 
||
 
|-
 
!colspan="4"| Geological Environment 3
 
|-
 
|
 
||
 
||
 
|-
 
|
 
||
 
||
 
 
|}
 
|}
  
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The hydrogeology map shows a simplified version of the type and productivity of the main aquifers at a national scale (see [[Aquifer properties| the Aquifer properties resource page]] for more details).  
 
The hydrogeology map shows a simplified version of the type and productivity of the main aquifers at a national scale (see [[Aquifer properties| the Aquifer properties resource page]] for more details).  
  
  [[File:Côte d'Ivoire_Hydrogeology.png]] [[File: Hydrogeology_Key.png | 500x195px]]
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  [[File:Côte d'Ivoire_Hydrogeology.png]] [[File: Hydrogeology_Key.png | center | 500x195px]]
  
  

Revision as of 13:19, 9 September 2015

Africa Groundwater Atlas >> Hydrogeology by country >> Hydrogeology of Côte d'Ivoire

Most of the textual information on this page was taken from the chapter on Côte d'Ivoire in the report ‘Groundwater in North and West Africa’ (UN 1988). Some of this information is outdated. If you have more recent information on the hydrogeology of Cote d'Ivoire, please get in touch.

Compilers

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

Geographical Setting

Côte d'Ivoire is in west Africa with a southern coast on the Gulf of Guinea. The country is largely flat, less than 500 m, with local relief. The west of the country is more hilly, with parts rising above 500 m, to a maximum of about 1200 m elevation. The south has many low lying areas and a few isolated or groups of low hills rising to around 650 m elevation.

Map of Côte d'Ivoire (For more information on the datasets used in the map see the geography resources section)

General

Estimated Population in 2013* 20,316,086
Rural Population (% of total) (2013)* 47.2%
Total Surface Area* 318,000 sq km
Agricultural Land (% of total area) (2012)* 64.8%
Capital City Yamoussoukro
Region Western Africa
Border Countries Liberia, Guinea, Mali, Burkina Faso, Ghana
Annual Freshwater Withdrawal (2013)* 1549 Million cubic metres
Annual Freshwater Withdrawal for Agriculture (2013)* 38.4%
Annual Freshwater Withdrawal for Domestic Use (2013)* 41.1%
Annual Freshwater Withdrawal for Industry (2013)* 20.5%
Rural Population with Access to Improved Water Source (2012)* 67.8%
Urban Population with Access to Improved Water Source (2012)* 91.5%

* Source: World Bank


Climate

The southern coastal zone has an equatorial climate with the highest rainfall, at around 2,400 mm/year, and rainfall is fairly evenly distributed throughout the year. The centre of the country has a tropical climate, with average annual rainfall of around 1,000 to 1,400 mm, and two wet seasons: the main one starting in December and the smaller one from August to October. The north is drier, with average annual rainfall betweewn 400 and 1,000 mm, concentrated in a short rainy season from July to September.

Average monthly precipitation for Côte d'Ivoire showing minimum and maximum (light blue), 25th and 75th percentile (blue), and median (dark blue) rainfall Average monthly temperature for Côte d'Ivoire 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

There are four main rivers in Côte d'Ivoire: the Cavally, Sassandra, Bandama and Comoé, all of which flow from north to south, into the Atlantic Ocean. There are also several smaller coastal rivers, which also generally flow from north to south into the Atlantic, but some discharge into lagoons before they reach the coast. In the north, there are several tributaries of the Niger and the Black Volta rivers. The Niger tributaries flow northwards towards Mali.

The highest river flows occur from April to October, with lowest flows in January and February.

There are a number of dams on some of the major rivers, related to hydroelectric schemes.


Surface Water Map of Côte d'Ivoire (For more information on the datasets used in the map see the surface water resources section)

Soil

Soil Map of Côte d'Ivoire (For map key and more information on the datasets used in the map see the soil resources section)

Land cover

The south of the country is equatorial with forest; the centre is dominated by tropical forest; and the north is dominated by savannah vegetation.

File:Côte d'Ivoire LandCover.png
Land Cover Map of Côte d'Ivoire (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 Côte d'Ivoire. More information is available in the report ‘Groundwater in North and West Africa: Côte d'Ivoire’ (UN 1988). (see References section, below).

The geology map shows a simplified version of the geology at a national scale (see the Geology resources page for more details).

Côte d'Ivoire Geology.png
Geological Environments
Key Formations Period Lithology
Coastal sedimentary basin
Continental Terminal; Cretaceous to Quaternary Coastal sedimentary rocks and unconsolidated sediments form a wedge which narrows towards the north, where it terminates at the edge of the basement rock, less than 35 km from the coast. The basin is crossed from west to east by a fault with a displacement of several thousand metres, which separates two distinct zones:

- to the north is a shallower basin where the sedimentary infill is not usually more than 300 m thick

- to the south is a deep basin, where the sedimentary infill reaches 4,000 to 5,000 m thick.

There is a series of lagoons, part of an ancient hydrographic system, which have very thick mud deposits and are now submerged.

The upper part of the sedimentary basin infill, especially in the 'low plateau' areas south of the lagoons, close to the shore, are Quaternary formations with a sand-clay continental formation about 20 m thick overlying a series of marine clays interbedded with sands, together about 10 m thick.

The lower part of the sedimentary infill comprises detrital continental Tertiary (Miocene-Pliocene) formations - mostly coarse sands - and, in the deepest areas, Upper and Middle Cretaceous marine formations, mostly sand/sandstone and clay. Together, these form the Continental Terminal formation. In places this lies directly on basement rock; in others, there is an underlying layer of Palaeocene (mostly limestone) or Maastrichtian (sand/sandstone) rocks.

Basement (West African Shield)
Birrimian Middle and Upper Precambrian; Proterozoic Metamorphic rocks, mainly of sedimentary origin. These are generally schists, with meta-sandstones and meta-conglomerates in places. In places there are granitic intrusions, accompanied by volcano-sedimentary formations of tuffs, breccias, green rocks and schists of Proterozoic age. These form bands running from north-northeast to south-southwest, and are heavily folded, sometimes vertical.
Prebirrimian Lower Precambrian The oldest basement formations include crystalline gneiss, granites and migmatites. They are most common in the west of the country (although migmatites are found everywhere).


Hydrogeology

This section provides a summary of the hydrogeology of the main aquifers in Côte d'Ivoire. More information is available in the report [ADD LINK UN] (1988) (see References section, below).

The hydrogeology map 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).

Côte d'Ivoire Hydrogeology.png

Hydrogeology Key.png


Unconsolidated

Named Aquifers Period General Description Water quality

Sedimentary - Intergranular Flow

Named Aquifers Period General Description Water quality

Sedimentary - Intergranular & Fracture Flow

Named Aquifers Period General Description Water quality

Sedimentary - Fracture Flow

Named Aquifers Period General Description Water quality

Basement

Named Aquifers Period General Description Water quality


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 Cote d'Ivoire.

These, and others, can be accessed through the Africa Groundwater Literature Archive

United Nations. 1988. Groundwater in North and West Africa: Côte d'Ivoire. United Nations Department of Technical Cooperation for Development and Economic Commission for Africa, Natural Resources/Water Series No.18, ST/TCD/5


Return to the index pages

Africa Groundwater Atlas >> Hydrogeology by country >> Hydrogeology of Cote d'Ivoire