Hydrogeology of Tunisia

Africa Groundwater Atlas >> Hydrogeology by country >> Hydrogeology of Tunisia

Authors

Amira Mekni, INAT, Tunisia

Safouan Ben Ammar, ISTEUB, Tunisia

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

Geographical Setting

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

General

Tunisia has a long coastline onto the Mediterranean Sea. In the north of the country is the Tunisian Dorsale mountain chain, which rises to 1,554 m. In the centre of the country are a series of east-west trending depressions, called chotts. The south of Tunisia is dominated by the Sahara.

Estimated Population in 2013*	10,886,500
Rural Population (% of total) (2013)*	33.5%
Total Surface Area*	155,360 sq km
Agricultural Land (% of total area) (2012)*	64.9%
Capital City	Tunis
Region	Northern Africa
Border Countries	Algeria, Libya
Annual Freshwater Withdrawal (2013)*	2850 Million cubic metres
Annual Freshwater Withdrawal for Agriculture (2013)*	76.0%
Annual Freshwater Withdrawal for Domestic Use (2013)*	12.8%
Annual Freshwater Withdrawal for Industry (2013)*	3.9%
Rural Population with Access to Improved Water Source (2012)*	90.5%
Urban Population with Access to Improved Water Source (2012)*	100%

* Source: World Bank

Climate

Tunisia has a semi-arid Mediterranean climate in the north; arid in the centre, and desert (Saharan) in the south. Rainfall distribution is determined by the direction of the prevailing winter winds (north-west) and the presence of high ground, and is heaviest in the north (over 400 mm/year and up to 1,500 mm/year in the far northwest), declining towards the centre (150 to 300 mm/year) and becoming very light in the south (less than 150 mm/year and less than 50 mm/year in the far south), with some years of no rain.

• 
  Koppen Geiger Climate Zones
• 
  Average Annual Precipitation
• 
  Average Temperature

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

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

Surface water

The main permanent surface watercourses which drain to the sea are in the north, mostly rising in the northwest and flowing eastwards. In the arid central reason, surface watercourses are ephemeral, flowing only for a few days or weeks a year. In the south, surface flows are rare and small. None of these central and southern ephemeral flows reach the sea; instead, surface water infiltrates over plains or in inland depressions (sabhkas).

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

Soil

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

Land cover

Land Cover Map of Tunisia (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 Tunisia. 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.

Geological Environments

Key Formations	Period	Lithology	Structure
Geological Environment 1
Name of formation1	Time period	Description	Structure
Geological Environment 2
Geological Environment 3

Hydrogeology

This section provides a summary of the hydrogeology of the main aquifers in Tunisia. 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.

File:COUNTRY Hydrogeology.png 

Unconsolidated

Named Aquifers	General Description	Water quantity issues	Water quality issues	Recharge

Sedimentary - Intergranular Flow

Named Aquifers	General Description	Water quantity issues	Water quality issues	Recharge

Sedimentary - Intergranular & Fracture Flow

Named Aquifers	General Description	Water quantity issues	Water quality issues	Recharge

Sedimentary - Fracture Flow

Named Aquifers	General Description	Water quantity issues	Water quality issues	Recharge

Basement

Named Aquifers	General Description	Water quantity issues	Water quality issues	Recharge

Groundwater use and management

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

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Africa Groundwater Atlas >> Hydrogeology by country >> Hydrogeology of Tunisia