Hydrogeology of Djibouti

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Djibouti, located where the Red Sea joins the Gulf of Aden and the Indian Ocean, at a crossroads linking Africa to the Middle East, and at the mouth of the Suez Canal, has always been a trading hub. The area of present-day Djibouti was once part of a series of ancient kingdoms with strong links to ancient Ethiopia and Egypt. Its proximity to the Arabian Peninsula meant Islam was adopted early. It was later colonised by France in the late 19th century, and the construction of railroads to Ethiopia meant it became an important regional port. It won independence as the Republic of Djibouti in 1977. The independent country’s first president remained in power until 1999. In the 1990s, the country experienced a civil war that ended in a power sharing agreement in 2000. Since 2000, there have been periodic episodes of civil unrest and a number of contested elections, but overall Djibouti is perceived internationally as having being relatively politically stable.

This, combined with Djibouti’s strategic location, have led to it being the site of a number of military bases for foreign personnel, as well as continuing to have regionally important ports, which bring in the majority of national revenue. It is a hub for international naval forces combating piracy in one of the world's busiest shipping routes. Foreign relations are therefore very important to the country’s economic stability. The Djibouti franc is pegged to the USD. The economy is dominated by the service sector, which accounts for 80% of GDP, with commercial activities focused on the country’s free trade policies and transport links. Industry, including fishing and fish processing, and growing salt production, accounts for around 17% of GDP. The desert environment limits agricultural production, which accounts for only 3% of GDP. Rural people traditionally relied on nomadic pastoralism, but rural populations are now small: three quarters of Djibouti's inhabitants live in cities. Its limited natural resources mean that Djibouti relies heavily on energy and food imports. Despite the importance of services to the economy, there is very high unemployment. Nevertheless, relative political stability also means that the country has become an important country of passage for refugees, asylum seekers and economic migrants from surrounding countries.

Djibouti is an arid country with very limited surface water resources. Over 90% of water supplies come from groundwater. In many areas, groundwater levels are deep and/or groundwater has high levels of mineralisation, making it unsuitable for drinking or agriculture. There have been periodic droughts in recent years, with corresponding reduced recharge and falling groundwater levels.


Compilers

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 BÉ and Bellwood-Howard, I. 2018. Africa Groundwater Atlas: Hydrogeology of Djibouti. British Geological Survey. Accessed [date you accessed the information]. http://earthwise.bgs.ac.uk/index.php/Hydrogeology_of_Djibouti

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The Africa Groundwater Atlas is hosted by the British Geological Survey (BGS) and includes information from third party sources. Your use of information provided by this website is at your own risk. If reproducing diagrams that include third party information, please cite both the Africa Groundwater Atlas and the third party sources. Please see the Terms of use for more information.

Geographical Setting

Djibouti. Map developed from USGS GTOPOPO30; GADM global administrative areas; and UN Revision of World Urbanization Prospects. For more information on the map development and datasets see the geography resource page

General

Capital city Djibouti
Region East Africa
Border countries Eritrea, Ethiopia, Somalia
Total surface area* 23,200 km2 (2,320,000 ha)
Total population (2015)* 887,900
Rural population (2015)* 192,100 (22%)
Urban population (2015)* 695,800 (78%)
UN Human Development Index (HDI) [highest = 1] (2014)* 0.4704

* Source: FAO Aquastat


Climate

Djibouti's climate is of tropical dry type, with a cool season (22-30 °C) from October to April and a warm season (30-40 °C) from May to September. Average annual evapotranspiration is estimated at 2,000 mm. Average annual rainfall is very low and erratic.

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.

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

Surface water

Djibouti has no perennial rivers. The hydrographic system is divided into two zones, one draining towards the Red Sea or the Gulf of Aden, the other towards the western plains of the country. Rainfall is low and erratic, usually occurring as heavy storm events that often cause flooding. Ephemeral rivers flow after rainfall events. There are two significant hypersaline lakes that are the focal points for internal drainage basins - Lake Assal in central Djibouti and Lake Abhe in the southwest on the border with Ethiopia. Lake Assal is 174 m below sea level (Schlüter 2006).

Soil

Soil Map of Djibouti, from the European Commission Joint Research Centre: European Soil Portal. For more information on the map see the soil resource page

Land cover

Land Cover Map of Djibouti, from the European Space Agency GlobCover 2.3, 2009. For more information on the map see the land cover resource page


Water statistics

1989 1998 2000 2013 2014 2015
Rural population with access to safe drinking water (%) 64.7
Urban population with access to safe drinking water (%) 97.4
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) 337.9
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 6.267
Total renewable groundwater (Million cubic metres/year) 15
Exploitable: Regular renewable groundwater (Million cubic metres/year) No data No data No data No data No data No data
Groundwater produced internally (Million cubic metres/year) 15
Fresh groundwater withdrawal (primary and secondary) (Million cubic metres/year) 18
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) 0
Municipal water withdrawal (all water sources) (Million cubic metres/year) 16
Agricultural water withdrawal (all water sources) (Million cubic metres/year) 3
Irrigation water withdrawal (all water sources)1 (Million cubic metres/year) 2.5
Irrigation water requirement (all water sources)1 (Million cubic metres/year) 0.8
Area of permanent crops (ha) 0
Cultivated land (arable and permanent crops) (ha) 2,000
Total area of country cultivated (%) 0.0862
Area equipped for irrigation by groundwater (ha) 670
Area equipped for irrigation by mixed surface water and groundwater (ha) 0

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

Geology

The geology map shows a simplified version of the geology at a national scale. More information is available in the report UN (1989) (see References section, below).



Geology of Djibouti at 1:5 million scale. Based on map described by Persits et al. 2002 / Furon and Lombard 1964. For more information on the map development and datasets see the geology resource page

Summary

Most of Djibouti is composed of Cenozoic sedimentary and volcanic rocks, with recent unconfined alluvial sediments in wadis. Structurally, the country forms a triangular depression caused by the general tectonic trends of the Great Rift Valleys of East Africa. These run N-S and NW-SE and have created a complex fragmented relief, composed of high blocks and subsidence zones, in which there are sometimes lakes (Schlüter 2006).

Geological Environments
Period Description
Unconsolidated sedimentary
Quaternary
Volcanic
Quaternary (Pleistocene) Mainly basaltic lavas, subordinate ignimbrites and rhyolites (Schlüter 2006).
Tertiary (Miocene) Mainly silicic massifs, lava flows and domes, and ignimbrites (Schlüter 2006).
Consolidated sedimentary
Jurassic-Cretaceous A small outcrop area of continental conglomerates and sandstones of the Amba Aradam Sandstones.

Hydrogeology

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 Djibouti is available in the report United Nations (1989) (see References section, below).

Hydrogeology of Djibouti at 1:5million scale. For more information on how the map was developed see the hydrogeology map resource page

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Hydrogeology Key.png

Summary

Fractured igneous volcanic aquifers are the main aquifer type in Djibouti. Shallow unconsolidated alluvial aquifers in wadis are a locally important aquifer.

The high evapotranspiration combined with intermittent and usually heavy rainfall rainfall events mean that a very low proportion of rainfall infiltrates directly as groundwater recharge. However, indirect recharge infiltrating from ephemeral river flows is an important recharge source.

Groundwater levels fluctuate naturally on a seasonal basis, with many shallow wells drying up during the dry season. Extended droughts have caused longer term declines in groundwater levels.


Groundwater Status

Groundwater quantity

Over-abstraction of groundwater is a recognised problem in a number of different parts of Djibouti. The estimated level of over-abstraction in 2005 was 15 million m3/year (FAO AQUASTAT 2005).

Groundwater quality

Groundwater salinity is widely high: in 2005, more than half of Djibouti's boreholes were recorded as showing salinity of more than 900 mg/l, and sometimes up to 1,200 mg/l. At this time, only groundwater in the northwest of the country was recorded as having ionic levels below the standards of use for irrigation. High levels of boron are the most common (FAO AQUASTAT 2005).

Where groundwater is used for agriculture, high evapotranspiration rates and mineralised irrigation returns have contributed to rising salinity (FAO AQUASTAT 2005). In coastal zones, salinity is exacerbated by over-abstraction that draws down water levels and induces sea water intrusion(Ahmed et al. 2018).

Rapid urbanisation with a lack of adequate sanitation is contributing to groundwater quality degradation in urban areas (Ahmed et al 2017).

Groundwater use and management

Groundwater use

Groundwater is the main source of water for most of the country, for domestic and agricultural use.

Most irrigation using groundwater is small scale, because there are few locations with high yielding aquifers. Most farmers use small volumes of groundwater from shallow hand dug wells or boreholes in alluvium in wadis, where the shallow alluvial aquifer is recharged periodically by ephemeral river flows after rainfall events. The use of groundwater for irrigation has led to problems of increased salinity, both in shallow alluvial and deeper volcanic rock aquifers.

Groundwater management

The key institutions responsible for groundwater resources include (FAO AQUASTAT):

  • the Ministry of Agriculture, Livestock and the Sea (MAEM), which among its other mandates is responsible for water resources studies and exploitation.
  • The Water Directorate, part of the MAEM, which was created in 2001 with responsibility for water resources services. The Water Directorate has national and regional sub-divisions.
  • The National Water Board of Djibouti (ONED), which manages hydraulic works for water supplies in the main urban areas, under the supervision of the MAEM.
  • The National Water Resources Council (NECC) was established in 1989, responsible for coordinating and planning all actions in this area as part of a water master plan.
  • The National Fund for Water (FNE) was created in 2001 to provide funding for the maintenance of rural water supply pumping stations, the meteorological network, drought relief and the creation of urban water supplies.
  • The Centre for Research and Studies of Djibouti (CERD) is responsible for scientific research relating to the management of drinking water and the exploration of new water resources.

Key water legislation includes a Water Code (1996) and a Water Master Plan, adopted in 2000.

In 1993, an inventory of water points was drawn up. In 2000, there were 600 (partially functional) water points and 56 rural pumping stations throughout the country - see the table, below (FAO AQUASTAT 2005).


Table - Inventory of water points in Djibouti in 1993 (from FAO AQUASTAT 2005)

District Borehole Well Spring Guelta1 Pond
Djibouti 40 2
Ali-Sabieh 47 52 1
Dikhil 34 68 25 16 3
Tadjourah 30 23 43 7
Obock 17 50 13 1
Total 168 195 82 24 3

1 A guelta is a pocket of water that forms in drainage canals or wadis.

Transboundary aquifers

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

References

Other references with information on the geology and hydrogeology of Djibouti may be accessible through the Africa Groundwater Literature Archive.


Ahmed IM, Le Coz M, Jalludin M, Sardini P and Razack M. 2018. Assessment of Groundwater Resources in a Complex Volcanic Reservoir with Limited Data Sets in a Semi-Arid Context Using a Novel Stochastic Approach. The Goda Volcanic Massif, Republic of Djibouti. Journal of Water Resource and Protection 10, 106-120. doi 10.4236/jwarp.2018.101007

Ahmed AH, Rayaleh WE, Zghibi A and Ouaddane B. 2018. Assessment of chemical quality of groundwater in coastal volcano-sedimentary aquifer of Djibouti, Horn of Africa. Journal of African Earth Sciences 131, 284-300. doi 10.1016/j.jafrearsci.2017.04.010

Awaleh MO, Baudron P, Soubaneh YD, Boschetti T, Hoch FB, Egueha NM, Mohamed J, Dabar OA, Masse-Dufresne J and Gassani J. 2017. Recharge, groundwater flow pattern and contamination processes in an arid volcanic area: Insights from isotopic and geochemical tracers (Bara aquifer system, Republic of Djibouti). Journal of Geochemical Exploration 175, 82-98. doi 10.1016/j.gexplo.2017.01.005

Bundesanstalt für Geowissenschaften und Rohstoffe. 1982. Inventory and development of the water resources of the Republic of Djibouti. Report prepared by W. Müller, for project No. 78.2233.1, German Hydrogeological Cooperation. Hanover, Germany.

FAO AQUASTAT. 2005. Djibouti. FAO AQUASTAT.

Jalludin M and Razack M. 1994. Analysis of pumping tests in fractured basalts with regards to tectonics, hydrothermal effects and weathering, Republic of Djibouti. Journal of Hydrology, 155, 237-250. doi 10.1016/0022-1694(94)90167-8.

Jalludin M and Razack M. 2004. Assessment of hydraulic properties of sedimentary and volcanic aquifer systems under arid conditions in the Republic of Djibouti (Horn of Africa). Hydrogeology Journal, 12, 159-170. doi 10.1007/s10040-003-0312-2.

JICA. 2014. The Republic of Djibouti: the Master Plan Study for sustainable irrigation and farming in southern Djibouti. Final Report. JICA, December 2014.

Muller, W. 1982. The water resources of the Republic of Djibouti, possibilities and limits of regional development.

Schlüter T. 2006. Geological Atlas of Africa. Springer, Berlin-Heidelberg-New York.

United Nations. 1989. Groundwater in Eastern, Central and Southern Africa: Djibouti. United Nations Department of Technical Cooperation for Development.

UNHCR. 2013. Djibouti. UNHCR Global Appeal 2012-2013

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