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[[Overview of Africa Groundwater Atlas | Africa Groundwater Atlas]] >> [[Hydrogeology by country | Hydrogeology by country]] >> Hydrogeology of Somalia
 
[[Overview of Africa Groundwater Atlas | Africa Groundwater Atlas]] >> [[Hydrogeology by country | Hydrogeology by country]] >> Hydrogeology of Somalia
 
[[File:CC-BY-SA_logo_88x31.png | frame | This work is licensed under a [https://creativecommons.org/licenses/by-sa/3.0/ Creative Commons Attribution-ShareAlike 3.0 Unported License]]]
 
 
In history, the area of present-day Somalia was the site of several powerful empires, and an important commercial centre, including trading in spices with merchants from India. Islam arrived before the 9th century, and Islamic sultanates dominated the region into European colonial times, making treaties with European forces from the 17th century onwards. In the late 19th century Britain and Italy gained control of British Somaliland in the south and Italian Somaliland in the north, respectively. Ethiopia and France also laid claims to part of present-day Somalia. Italian Somaliland was taken by Britain in 1941, later becoming a UN trusteeship under Italian administration. In 1960 the two regions united to become the independent Somali Republic.
 
 
Initially under a civilian government, a coup in 1969 was followed by military or one-party rule through the 1970s and 80s. Military conflict with Ethiopia in the 1970s was a foreshadowing of the Somali civil war that began in 1991, during which time Somalia was viewed as a ‘failed state’. With no central governmental authority for several years, many areas returned to customary or religious law. Parts of the south were held by various Islamic groups; Somaliland in the north declared itself an independent state; and Puntland in the northeast declared itself an autonomous region within Somalia. Transitional institutions were established from 2000 in parts of the country, but much of the south remained under the control of various groups, including Al-Shabaab. Various attempts at peace talks, coalition government and other transitional governance, at the same time as military operations, continued throughout the 2000s, until a transitional federal government was formed in 2012. However, there is significant ongoing instability. Somaliland is a self-declared sovereign state currently recognised by the internationally community as an autonomous territory, and Puntland also considers itself an autonomous state. These two regions remain slightly more stable than the still-contested southern zones, including the capital, Mogadishu.
 
 
Although Somalia remains poor, with a low GDP per capita, the war did not have as drastic effect on the economy as may have been expected. In part this is because the maintenance of traditional governance in some regions made private sector activity possible, often funded by remittances from the extensive Somali diaspora. Such activities include communications, money transfer and transport industries. Agriculture, mainly livestock, dominates the economy: most of the population are nomadic or semi-nomadic pastoralists. As well as livestock – often to Gulf states – other key exports include fish, charcoal and bananas. Recent developments have included fish and meat processing and other manufacturing plants.
 
 
A semi-arid to arid country, Somalia has very restricted water resources. There are only two permanent rivers, both in the south. Elsewhere, all rivers are ephemeral, flowing only for hours or days. Groundwater is the sole water resource for most of the country, in rural and urban areas. However, because of low rainfall and widely deep groundwater tables, accessing groundwater is difficult, and expensive, in much of the country.
 
  
  
 
==Authors==
 
==Authors==
  
'''Hussein Gadain''', Food and Agriculture Organisation of the United Nations, Kenya
+
Hussein Gadain, Food and Agriculture Organisation of the United Nations, Kenya
  
'''Dr Zoran Stevanovic''', University of Belgrade, Serbia
+
Zoran Stevanovic, University of Belgrade, Serbia
  
'''Dr Kirsty Upton''' and '''Brighid Ó Dochartaigh''', British Geological Survey, UK
+
Kirsty Upton and Brighid Ó Dochartaigh, British Geological Survey, UK
  
'''Dr Imogen Bellwood-Howard''', Institute of Development Studies, UK
 
 
Please cite this page as: Gadain, Stevanovic, Upton, Ó Dochartaigh and Bellwood-Howard, 2018.
 
 
Bibliographic reference: Gadain H, Stevanovic Z, Upton K. Ó Dochartaigh BÉ and Bellwood-Howard, I. 2018. Africa Groundwater Atlas: Hydrogeology of Somalia. British Geological Survey. Accessed [date you accessed the information]. http://earthwise.bgs.ac.uk/index.php/Hydrogeology_of_Somalia
 
 
==Terms and conditions==
 
 
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 [[Africa Groundwater Atlas Terms of Use | Terms of use]] for more information.
 
  
 
==Geographical Setting==
 
==Geographical Setting==
  
[[File: Somalia_Political.png | right | frame | Somalia. 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 | geography resource page]].]]
+
[[File: Somalia_Political.png | right | frame | Map of Somalia (For more information on the datasets used in the map see the [[Geography | geography resources section]])]]  
  
 
===General===
 
===General===
 +
  
 
{| class = "wikitable"
 
{| class = "wikitable"
 
|-
 
|-
|Capital city || Mogadishu
+
|Estimated Population in 2013* || 10,495,583
 +
|-
 +
|Rural Population (% of total) (2013)* || 61.4%
 +
|-
 +
|Total Surface Area* || 627,340 sq km
 +
|-
 +
|Agricultural Land (% of total area) (2012)* || 70.3%
 
|-
 
|-
|Region || Eastern Africa
+
|Capital City || Mogadishu
 
|-
 
|-
|Border countries || Ethiopia, Djibouti, Kenya
+
|Region || Eastern Africa
 
|-
 
|-
|Total surface area* || 637,660 km<sup>2</sup>  (63,766,000 ha)
+
|Border Countries || Ethiopia, Djibouti, Kenya
 
|-
 
|-
|Total population (2015)* || 10,787,000
+
|Annual Freshwater Withdrawal (2013)* || 3,298 Million cubic metres
 
|-
 
|-
|Rural population (2015)* || 6,388,000 (59%)
+
|Annual Freshwater Withdrawal for Agriculture (2013)* || 99.48%
 
|-
 
|-
|Urban population (2015)* || 4,399,000 (41%)
+
|Annual Freshwater Withdrawal for Domestic Use (2013)* || 0.45%
 
|-
 
|-
|UN Human Development Index (HDI) [highest = 1] *|| No data
+
|Annual Freshwater Withdrawal for Industry (2013)* || 0.06%
  
 
|}
 
|}
  
<nowiki>*</nowiki> Source: [http://www.fao.org/nr/water/aquastat/data/query/index.html?lang=en FAO Aquastat]
+
<nowiki>*</nowiki> Source: World Bank
  
  
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The little seasonal variation in climate is largely related to changes in wind patterns. There is a main monsoonal wet season in April and May, and a smaller wet season in October and November.  
 
The little seasonal variation in climate is largely related to changes in wind patterns. There is a main monsoonal wet season in April and May, and a smaller wet season in October and November.  
  
[[File: Somalia_ClimateZones.png | 375x365px |Koppen Geiger Climate Zones]][[File: Somalia_ClimatePrecip.png | 375x365px |Average Annual Precipitation]][[File: Somalia_ClimateTemp.png | 375x365px |Average Temperature]]
 
  
[[File: Somalia_pre_Monthly.png| 255x124px| Average monthly precipitation for Somalia showing minimum and maximum (light blue), 25th and 75th percentile (blue), and median (dark blue) rainfall]] [[File: Somalia_tmp_Monthly.png| 255x124px| Average monthly temperature for COUNTRY showing minimum and maximum (orange), 25th and 75th percentile (red), and median (black) temperature]] [[File: Somalia_pre_Qts.png | 255x124px | Quarterly precipitation over the period 1950-2012]] [[File: Somalia_pre_Mts.png|255x124px | Monthly precipitation (blue) over the period 2000-2012 compared with the long term monthly average (red)]]
+
<gallery widths="375px" heights=365px mode=nolines>
 +
File: Somalia_ClimateZones.png |Koppen Geiger Climate Zones
 +
File: Somalia_ClimatePrecip.png |Average Annual Precipitation
 +
File: Somalia_ClimateTemp.png |Average Temperature
 +
</gallery>
 +
 
 +
Rainfall time-series and graphs of monthly average rainfall and temperature for each individual climate zone can be found on the [[Climate of Somalia | Somalia Climate Page]].  
  
More information on average rainfall and temperature for each of the climate zones in Somalia can be seen at the [[Climate of Somalia | Somalia 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 | climate resource page]].
+
[[File: Somalia_pre_Monthly.png| 255x124px| Average monthly precipitation for Somalia showing minimum and maximum (light blue), 25th and 75th percentile (blue), and median (dark blue) rainfall]] [[File: Somalia_tmp_Monthly.png| 255x124px| Average monthly temperature for COUNTRY showing minimum and maximum (orange), 25th and 75th percentile (red), and median (black) temperature]] [[File: Somalia_pre_Qts.png | 255x124px | Quarterly precipitation over the period 1950-2012]] [[File: Somalia_pre_Mts.png|255x124px | 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 | climate resources section]].
  
 
===Surface water===
 
===Surface water===
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{|
 
{|
 
|-
 
|-
 +
|
 +
| [[File: Somalia_Hydrology.png | frame | centre| Surface Water Map of Somalia (For more information on the datasets used in the map see the [[Surface water | surface water resources section]])]]
 +
|}
  
|Somalia has only two permanent rivers, the Juba and the Shabelle, both of which begin in the Ethiopian Highlands and flow southwards. In the north of the country, the arid and semi-arid climate means that all rivers are ephemeral and flashy, with water flowing for only a few hours to days after rainfall events, and there are no river gauging stations in these rivers.  
+
Somalia has only two permanent rivers, the Juba and the Shabelle, both of which begin in the Ethiopian Highlands and flow southwards. In the north of the country, the arid and semi-arid climate means that all rivers are ephemeral and flashy, with water flowing for only a few hours to days after rainfall events, and there are no river gauging stations in these rivers.  
  
 
Before the civil war in 1991, the Ministry of Agriculture was mandated to operate river flow and climate gauging stations. Daily river level readings date back to 1951 for the two furthest upstream stations on the two rivers at the border with Ethiopia, although these records include many gaps. Data were not collected at other stations until 1963, when a network of gauging stations was established and data was collected until 1991 with few discharge measurements for rating curve establishment. During the subsequent civil war, the hydrometric network fell into complete disrepair, with no monitoring and collection of water level data until early 2000s. In 2001, FAO established the Somali Water and Land Information Management under the [http://www.faoswalim.org FAO/SWALIM] project.  
 
Before the civil war in 1991, the Ministry of Agriculture was mandated to operate river flow and climate gauging stations. Daily river level readings date back to 1951 for the two furthest upstream stations on the two rivers at the border with Ethiopia, although these records include many gaps. Data were not collected at other stations until 1963, when a network of gauging stations was established and data was collected until 1991 with few discharge measurements for rating curve establishment. During the subsequent civil war, the hydrometric network fell into complete disrepair, with no monitoring and collection of water level data until early 2000s. In 2001, FAO established the Somali Water and Land Information Management under the [http://www.faoswalim.org FAO/SWALIM] project.  
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Data on current and historical river flows for the Juba and Shabelle rivers, including data availability for both pre-war (1951 to 1990) and post war (2000s-date) periods, is acceessible through the [http://www.faoswalim.org/water/water-resources/surface-water FAO/SWALIM website]
 
Data on current and historical river flows for the Juba and Shabelle rivers, including data availability for both pre-war (1951 to 1990) and post war (2000s-date) periods, is acceessible through the [http://www.faoswalim.org/water/water-resources/surface-water FAO/SWALIM website]
 
| [[File: Somalia_Hydrology.png | frame | centre| Major surface water features of Somalia. Map developed from World Wildlife Fund HydroSHEDS; Digital Chart of the World drainage; and FAO Inland Water Bodies. For more information on the map development and datasets see the [[Surface water | surface water resource page]].]]
 
 
|
 
 
|}
 
 
 
  
 
===Soil===
 
===Soil===
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|[[File: Somalia_soil.png | frame | Soil Map of Somalia, from the European Commission Joint Research Centre: European Soil Portal. For more information on the map see the [[Soil | soil resource page]].]]
+
|[[File: Somalia_soil.png | frame | Soil Map of Somalia (For map key and more information on the datasets used in the map see the [[Soil | soil resources section]])]]
 
|
 
|
 
|}
 
|}
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| [[File: Somalia_LandCover.png | frame | Land Cover Map of Somalia, from the European Space Agency GlobCover 2.3, 2009. For more information on the map see the [[Land cover | land cover resource page]].]]
+
| [[File: Somalia_LandCover.png | frame | Land Cover Map of Somalia (For map key and more information on the datasets used in the map see the [[Land cover | land cover resources section]])]]
|
 
|}
 
 
 
 
 
===Water statistics===
 
 
 
{| class = "wikitable"
 
| ||2003||2011||2012||2014||2015
 
|-
 
|Rural population with access to safe drinking water (%) || ||8.8 ||  || ||
 
|-
 
|Urban population with access to safe drinking water (%) ||69.6 || ||  || ||
 
|-
 
|Population affected by water related disease || No data || No data || No data || No data || No data
 
|-
 
|Total internal renewable water resources (cubic metres/inhabitant/year) || || ||  ||556.2 ||
 
|-
 
|Total exploitable water resources (Million cubic metres/year) || No data || No data || No data || No data || No data
 
|-
 
|Freshwater withdrawal as % of total renewable water resources ||22.44|| || || ||
 
|-
 
|Renewable groundwater resources (Million cubic metres/year) || || ||600 || ||
 
|-
 
|Groundwater produced internally (Million cubic metres/year) || || ||  ||3,300 ||
 
|-
 
|Fresh groundwater withdrawal (primary and secondary) (Million cubic metres/year) ||131|| || || ||
 
|-
 
|Groundwater: entering the country (total) (Million cubic metres/year) || 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
 
|-
 
|Industrial water withdrawal (all water sources) (Million cubic metres/year) ||2|| || || ||
 
|-
 
|Municipal water withdrawal (all water sources) (Million cubic metres/year)  ||15 || || || ||
 
|-
 
|Agricultural water withdrawal (all water sources) (Million cubic metres/year) ||3,281 || || || ||
 
|-
 
|Irrigation water withdrawal (all water sources) <sup>1</sup> (Million cubic metres/year) || No data || No data || No data || No data || No data
 
|-
 
|Irrigation water requirement (all water sources) <sup>1</sup> (Million cubic metres/year) ||263 ||  || || ||
 
|-
 
|Area of permanent crops (ha) || || ||  ||25,000||
 
|-
 
|Cultivated land (arable and permanent crops) (ha) || || ||  ||1,125,000 ||
 
|-
 
|Total area of country cultivated (%) || || ||  || 1.764||
 
|-
 
|Area equipped for irrigation by groundwater (ha) ||10,000|| ||  || ||
 
|-
 
|Area equipped for irrigation by mixed surface water and groundwater (ha) || No data || No data || No data || No data || No data
 
 
 
 
|}
 
|}
 
These statistics are sourced from [http://www.fao.org/nr/water/aquastat/main/index.stm 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 [http://www.fao.org/nr/water/aquastat/data/query/index.html?lang=en Aquastat Main Database].
 
 
<sup>1</sup> More information on [http://www.fao.org/nr/water/aquastat/water_use_agr/index.stm irrigation water use and requirement statistics]
 
 
  
 
==Geology==
 
==Geology==
  
This section provides a summary of the geology of Somalia. More detail can be found in the references listed at the bottom of this page. Many of these references can be accessed through the [http://www.bgs.ac.uk/africagroundwateratlas/index.cfm Africa Groundwater Literature Archive].
+
This section provides a summary of the geology of Somalia. More detail can be found in the references listed at the bottom of this page. ''Many of these references can be accessed through the [http://www.bgs.ac.uk/africagroundwateratlas/index.cfm Africa Groundwater Literature Archive].''
  
The geology map on this page shows a simplified overview of the geology at a national scale (see [[Geology | the Geology resources page]] for more details).  
+
The geology map on this page shows a simplified version of the geology at a national scale (see [[Geology | the Geology resources page]] for more details). ''The map is available to download as a shapefile (.shp) for use in GIS packages.'' A more detailed geological map at 1:1,500,000 is also published (see Geology: key references, below).
  
[https://www.bgs.ac.uk/africagroundwateratlas/downloadGIS.html '''Download a GIS shapefile of the Somalia geology and hydrogeology map'''].
 
  
A more detailed geological map at 1:1,500,000 has also been published (see Geology: key references, below).
+
[[File: Somalia_Geology2.png | centre| border| 400px]]
 
 
 
 
[[File:Somalia_Geology4.png | center | thumb| 400px | Geology of Somalia 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 | geology resource page]]. [https://www.bgs.ac.uk/africagroundwateratlas/downloadGIS.html Download a GIS shapefile of the Somalia geology and hydrogeology map].]]
 
  
 
{| class = "wikitable"
 
{| class = "wikitable"
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|-
 
|-
 
|Volcanic basaltic rocks
 
|Volcanic basaltic rocks
||Pliocene - Pleistocene  
+
||Pleistocene  
 
||These basaltic lavas were deposited in different periods. They followed existing topographical depressions and uneven basin floors. Several lava flows have tuff intercalations in some places.   
 
||These basaltic lavas were deposited in different periods. They followed existing topographical depressions and uneven basin floors. Several lava flows have tuff intercalations in some places.   
 
form a cover
 
form a cover
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|Iskushuban Formation; Mudug Formation; Daban Formation; Hafun Series  
 
|Iskushuban Formation; Mudug Formation; Daban Formation; Hafun Series  
 
||Tertiary (Oligocene to Miocene)
 
||Tertiary (Oligocene to Miocene)
||Thick, extensive, complex series of sedimentary rocks, including soft limestones, conglomerates and sandstones, of various origins including marine, lagoonal and continental.  
+
||Thick, extensive, complex series of sedimentary rocks.  
  
 
The Miocene Iskushuban Formation comprises marl, sandstone, gypsum, coal, limestone and fine grained conglomerate.  
 
The Miocene Iskushuban Formation comprises marl, sandstone, gypsum, coal, limestone and fine grained conglomerate.  
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The Oligocene/Miocene Mudug Formation comprises marly and biogenic limestones, calcarenites and sandstones
 
The Oligocene/Miocene Mudug Formation comprises marly and biogenic limestones, calcarenites and sandstones
  
The Oligocene/Eocene Daban Formation comprises siltstones, sandstones, conglomerates, gypsum and limestones.   
+
The Oligocene Daban Formation comprises siltstones, sandstones, conglomerates, gypsum and limestones.  
||In total, 500 to over 2000 m thick. Individual formations are from 40 to 500 m thick.
+
   
 +
||500 m to over 2000 m thick
 +
 
 
|-
 
|-
 
|Auradu Formation; Taleex Formation; Karkar Formation
 
|Auradu Formation; Taleex Formation; Karkar Formation
||Tertiary (Palaeocene-Eocene)
+
||Tertiary (Eocene)
||Limestone and evaporitic rocks.
+
||Limestone and evaporitic rocks. The Auradu and Karkar formations are limestone; the Taleex Formation was formed in typical arid climate conditions, and includes evaporitic gypsum and anhydrite as well as limestones and dolostones. The limestones are karstic.  
 
+
||Average thicknesses of the formations are: Karkar - 300 m; Taalex - 250 m; and Auradu - 200-400 m
The uppermost Karkar Formation crops out in the north and includes limestones, marls and dolomites, with some gypsum.
 
 
 
The Taleex Formation covers a large area in the centre of the country and in the north, and consists largely of gypsum and anhydrite, with limestones and dolomites.  
 
 
 
The Auradu Formation, in the centre of Somalia, is fractured karstic limestone with marl and dolomitic strata (United Nations 1989).
 
||The total thickness of all units is from 700 to 1200 m. Average thicknesses of the formations are: Karkar - 200 to 300 m; Taalex - 250 m; and Auradu - 200-400 m.
 
 
|-
 
|-
 
!colspan="4"| Mesozoic sedimentary
 
!colspan="4"| Mesozoic sedimentary
 
|-
 
|-
|Yessoma, Fer Fer and Belet Uen formations
+
|
 
||Upper Cretaceous
 
||Upper Cretaceous
||The Yessoma Formation consists of Nubian-type sandstones with thin limestones. The Belet Uen and Fer formations consist of gypsum, marls and dolomites.
+
||Yessoma Formation - Nubian-type sandstones with thin limestones.
||The Yessoma Formation is from 100 to over 1000 m thick. The Fer Fer and Belet Uen formations are approximately 50 to 350 m thick.
+
||From 100 m to over 1000 m thick
 +
 
 
|-
 
|-
 
|
 
|
||Cretaceous undifferentiated (mostly Lower to Middle Cretaceous)
+
||Cretaceous undifferentiated
||Sandstones, conglomerates, limestones and evaporitic rocks, including gypsum. These rocks occur in parts of southern Somalia, where they are dominated by calcareous and evaporitic rocks; and as scattered small outcrops in the north near the coast, where they are typically sandstones with conglomerates in the west, and limestones in the east.
+
||Sandstones, conglomerates, limestones and evaporitic rocks. These rocks occur in the northern part of southern Somalia, where they are dominated by calcareous and evaporitic rocks; and as scattered small outcrops in the north near the coast, where they are typically sandstones with conglomerates in the west, and limestones in the each.
||Probably between approximately 100 to 900 m thick.
+
||
 +
 
 +
 
 +
 
 
|-
 
|-
|Hamanlei, Garba Harre, Uegit, Anole, Iscla Baidoa, Bihendula and Adigral formations, and other unnamed formations
+
|Hamanlei Formation
 
||Jurassic
 
||Jurassic
||In the north, largely marine and clastic limestones, with less common shales and sandstones. The limestones are often karstic. In the south of the country, thought to be largely sandstones with some limestones.  
+
||Marine and clastic limestones, shales and sandstones. The limestones are karstic.
 
||Thickness varies, mainly due to lateral facies change, from 220 m (at Gowan) to 1000 m (at Bixinduule, between Sheekh and Berbera)
 
||Thickness varies, mainly due to lateral facies change, from 220 m (at Gowan) to 1000 m (at Bixinduule, between Sheekh and Berbera)
  
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==Hydrogeology==
 
==Hydrogeology==
  
This section provides a summary of the hydrogeology of the main aquifers in Somalia.  More information is available in the references listed at the bottom of this page. Many of these references can be accessed through the [http://www.bgs.ac.uk/africagroundwateratlas/index.cfm Africa Groundwater Literature Archive].
+
This section provides a summary of the hydrogeology of the main aquifers in Somalia.  More information is available in the references listed at the bottom of this page. ''Many of these references can be accessed through the [http://www.bgs.ac.uk/africagroundwateratlas/index.cfm 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 [[Aquifer properties| the Aquifer properties resource page]] for more details). ''The map is available to download as a shapefile (.shp) for use in GIS packages.''
  
The hydrogeology map on this page shows a simplified overview of the type and productivity of the main aquifers at a national scale (see the [[Africa Groundwater Atlas Hydrogeology Maps | Hydrogeology map resource page]] for more details).
+
[[File: Somalia_Hydrogeology2.png| centre| border| 400px]]
 
 
[https://www.bgs.ac.uk/africagroundwateratlas/downloadGIS.html '''Download a GIS shapefile of the Somalia geology and hydrogeology map'''].
 
 
 
[[File:Somalia_Hydrogeology4.png | center | thumb| 450px | Hydrogeology of Somalia at 1:5 million scale. For more information on how the map was developed see the [[Africa Groundwater Atlas Hydrogeology Maps | Hydrogeology map]] resource page. [https://www.bgs.ac.uk/africagroundwateratlas/downloadGIS.html Download a GIS shapefile of the Somalia geology and hydrogeology map].]].
 
  
 
'''Summary'''
 
'''Summary'''
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Groundwater quality is a major issue. Most groundwater sources have salinity levels above 2,000 µS/cm. Many of the shallow wells are also unprotected and vulnerable to microbiological and other contamination (FAO/SWALIM 2012).
 
Groundwater quality is a major issue. Most groundwater sources have salinity levels above 2,000 µS/cm. Many of the shallow wells are also unprotected and vulnerable to microbiological and other contamination (FAO/SWALIM 2012).
  
A number of studies have laid down a good base for further hydrogeological works (see Hydrogeology: key references, below and other references in the [https://www.bgs.ac.uk/africaGroundwaterAtlas/atlas.cfc?method=listResults&title_search=&author_search=&category_search=&country_search=SO&placeboolean=AND&singlecountry=1 Africa Groundwater Literature Archive]). Numerous NGOs have also worked in the region and supported urban centres and local rural and semi-urban communities by drilling water wells or conducting geophysical surveys. However, although many water projects have been implemented or supported in the region, water well drilling has commonly been conducted without adequate project feasibility studies, and to date, no systematic data collection has been carried on groundwater exploitation, capacity, and especially on groundwater level fluctuations. However, during the last few years,the [http://www.faoswalim.org/ FAO/SWALIM] project (Somalia Water and Land Information Management) has done extensive work relating to water resources, including preparing more accurate and adequate hydrogeological maps of the northern part of Somalia, which are essential for planning any groundwater exploration and exploitation (FAO/SWALIM 2012).  
+
A number of studies have laid down a good base for further hydrogeological works (see Hydrogeology: key references, below and other references in the [http://www.bgs.ac.uk/africagroundwateratlas/searchResults.cfm?title_search=&author_search=&category_search=&country_search=SO&placeboolean=AND&singlecountry=1 Africa Groundwater Literature Archive]). Numerous NGOs have also worked in the region and supported urban centres and local rural and semi-urban communities by drilling water wells or conducting geophysical surveys. However, although many water projects have been implemented or supported in the region, water well drilling has commonly been conducted without adequate project feasibility studies, and to date, no systematic data collection has been carried on groundwater exploitation, capacity, and especially on groundwater level fluctuations. However, during the last few years,the [http://www.faoswalim.org/ FAO/SWALIM] project (Somalia Water and Land Information Management) has done extensive work relating to water resources, including preparing more accurate and adequate hydrogeological maps of the northern part of Somalia, which are essential for planning any groundwater exploration and exploitation (FAO/SWALIM 2012).  
  
  
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====Unconsolidated====
 
====Unconsolidated====
 
{| class = "wikitable"
 
{| class = "wikitable"
|Named Aquifers||General Description||Water quality issues||Recharge
+
|Named Aquifers||General Description||Water quantity issues||Water quality issues||Recharge
 
|-
 
|-
 
|Alluvial terrace deposits - Pleistocene to Holocene/Recent
 
|Alluvial terrace deposits - Pleistocene to Holocene/Recent
Line 316: Line 240:
 
Generally unconfined, but where covered or associated with Quaternary volcanic basalts, they can be confined, sometimes with considerable artesian pressure (e.g. in the Xunboweyle area). In unconfined aquifers the water table is typically 2 to 3 m deep throughout the year, related to seasonal flows along riverbeds. In deeper confined, artesian aquifers in older deposits, the piezometric head does not fluctuate much throughout the year.  
 
Generally unconfined, but where covered or associated with Quaternary volcanic basalts, they can be confined, sometimes with considerable artesian pressure (e.g. in the Xunboweyle area). In unconfined aquifers the water table is typically 2 to 3 m deep throughout the year, related to seasonal flows along riverbeds. In deeper confined, artesian aquifers in older deposits, the piezometric head does not fluctuate much throughout the year.  
  
Thickness varies from a few metres to over 100 m. At Geed Deeble (source for the Hargeysa water supply), the tapped aquifer depth is over 150 m. Boreholes are typically between 10 m and 50 m deep.  
+
Vary from a few metres to over 100 m thick. At Geed Deeble (source for the Hargeysa water supply), the tapped aquifer depth is over 150 m. Boreholes are typically between 10 m and 50 m deep.  
 
+
||In Somaliland in the north of Somalia, dynamic (sustainable) groundwater reserves in the major alluvial aquifers are estimated at an average flow of ~30 m³/sec.  
In Somaliland in the north of Somalia, dynamic (sustainable) groundwater reserves in the major alluvial aquifers are estimated at an average flow of ~30 m³/sec.  
 
 
||Generally low levels of mineralisation, with TDS below 1000 mg/l, and of moderate to good drinking water quality. Water from shallow dug wells and some springs often has a conductivity in the range 2000 to 4000 microS/cm, but other samples of shallow groundwater in the western part of northern Somalia have conductivity values of less than 1500 microS/cm.
 
||Generally low levels of mineralisation, with TDS below 1000 mg/l, and of moderate to good drinking water quality. Water from shallow dug wells and some springs often has a conductivity in the range 2000 to 4000 microS/cm, but other samples of shallow groundwater in the western part of northern Somalia have conductivity values of less than 1500 microS/cm.
 
||High infiltration capacity  
 
||High infiltration capacity  
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|-
 
|-
 
|Alluvial sediments filling major valleys and plateaus - Pleistocene to Holocene/Recent
 
|Alluvial sediments filling major valleys and plateaus - Pleistocene to Holocene/Recent
||Low to high productivity, depending on local lithology, thickness and lateral extent.
+
||Low to moderate productivity  
 +
 
 +
||
 +
||
 
||
 
||
||Direct rainfall recharge, and indirect recharge from infiltration of river water
 
 
|}
 
|}
  
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====Volcanic====
 
====Volcanic====
 
{| class = "wikitable"
 
{| class = "wikitable"
|Named Aquifers||General Description||Water quality issues||Recharge
+
|Named Aquifers||General Description||Water quantity issues||Water quality issues||Recharge
 
|-
 
|-
 
|Pleistocene basaltic lava flows
 
|Pleistocene basaltic lava flows
 
||These are a potential aquifer in some areas. They contain groundwater only where fractured and/or weathered, or in lenses of pyroclastic material between lava flows. They typically have low to moderate permeability, but are locally highly fractured, increasing permeability. However, they occur primarily as elevated plateaus, and are often unsaturated. In some areas, such as Agabar and Las Dhure, they are found in the lowlands and may be saturated, and in this case are likely to be unconfined. Boreholes drilled in these areas have intersected water-bearing zones composed of sand/pyroclastic lenses and weathered basalt.  
 
||These are a potential aquifer in some areas. They contain groundwater only where fractured and/or weathered, or in lenses of pyroclastic material between lava flows. They typically have low to moderate permeability, but are locally highly fractured, increasing permeability. However, they occur primarily as elevated plateaus, and are often unsaturated. In some areas, such as Agabar and Las Dhure, they are found in the lowlands and may be saturated, and in this case are likely to be unconfined. Boreholes drilled in these areas have intersected water-bearing zones composed of sand/pyroclastic lenses and weathered basalt.  
 +
||
 
||
 
||
 
||In some areas, vertical fractures resulting from cooling of the basalts may occur, and are likely to form primary recharge routes.   
 
||In some areas, vertical fractures resulting from cooling of the basalts may occur, and are likely to form primary recharge routes.   
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Key references for this aquifer are Faillace and Faillace 1986, FAO/SWALIM 2012 and German Agro-Action 2005.
 
Key references for this aquifer are Faillace and Faillace 1986, FAO/SWALIM 2012 and German Agro-Action 2005.
 
 
==== Sedimentary - Intergranular and Fracture Flow====
 
{| class = "wikitable"
 
|Named Aquifers||General Description||Water quality issues||Recharge
 
|-
 
|Upper Cretaceous Yessoma Formation (Nubian sandstone)
 
||The Yessoma Formation is of Nubian sandstone type and can form a high productivity aquifer. The coarsest grained part of the formation occurs between 140 m and 180 m depth. Calculated aquifer transmissivity is around 2 x 10<sup>-3</sup> m²/sec (220 m²/day), with an average specific capacity of 7.5 m³/hour/m. Most boreholes penetrating the formation can sustain a yield of more than 30 m³/hour.
 
||Groundwater of good quality is generally supplied by dug wells in the weathered part of the aquifer.
 
||Recharge is estimated to be approximately in the range of 3 to 5% of annual rainfall (Van der Plac 2001).
 
|-
 
|Jurassic sandstones
 
||Jurassic sedimentary rocks in the south of Somalia are likely to be dominated by sandstone. Their groundwater potential is not well known. Groundwater storage and flow may be by both intergranular and fracture flow. Low to moderate yields may be possible.
 
||
 
||
 
|}
 
  
 
==== Sedimentary - Fracture Flow====
 
==== Sedimentary - Fracture Flow====
 
{| class = "wikitable"
 
{| class = "wikitable"
|Named Aquifers||General Description||Water quality issues||Recharge
+
|Named Aquifers||General Description||Water quantity issues||Water quality issues||Recharge
 
|-
 
|-
 
|Tertiary: Iskushuban Formation (Miocene); Mudug Formation (Oligocene/Miocene); Daban Formation (Oligocene)
 
|Tertiary: Iskushuban Formation (Miocene); Mudug Formation (Oligocene/Miocene); Daban Formation (Oligocene)
Line 370: Line 280:
  
 
Boreholes in the Oligocene/Miocene Mudug Formation are drilled to 180 to 220 m deep, and provide yields of 3 to 5 l/s for drawdowns in the range 3 to 24 m. Transmissivity values of 3.1 x 10<sup>-3</sup> to 2.9 x 10<sup>-4</sup> m²/sec were calculated.
 
Boreholes in the Oligocene/Miocene Mudug Formation are drilled to 180 to 220 m deep, and provide yields of 3 to 5 l/s for drawdowns in the range 3 to 24 m. Transmissivity values of 3.1 x 10<sup>-3</sup> to 2.9 x 10<sup>-4</sup> m²/sec were calculated.
 +
||
 
||
 
||
 
||Recharge is estimated to be approximately in the range of 3 to 5% of annual rainfall (Van der Plac 2001).
 
||Recharge is estimated to be approximately in the range of 3 to 5% of annual rainfall (Van der Plac 2001).
 +
 +
|-
 +
|Upper Cretaceous Yessoma Formation (Nubian sandstone)
 +
||The Yessoma Formation is of Nubian sandstone type and forms a high productivity aquifer. The coarsest grained part of the formation occurs between 140 m and 180 m depth. Calculated aquifer transmissivity is around 2 x 10<sup>-3</sup> m²/sec (220 m²/day), with an average specific capacity of 7.5 m³/hour/m. Most boreholes penetrating the formation can sustain a yield of more than 30 m³/hour.
 +
||
 +
||Groundwater of good quality is generally supplied by dug wells in the weathered part of the aquifer.
 +
||Recharge is estimated to be approximately in the range of 3 to 5% of annual rainfall (Van der Plac 2001).
 +
 
|-
 
|-
 
|Cretaceous undifferentiated: sandstones, conglomerates, limestones and evaporitic rocks
 
|Cretaceous undifferentiated: sandstones, conglomerates, limestones and evaporitic rocks
 
||Little is known about the aquifer properties of these rocks.
 
||Little is known about the aquifer properties of these rocks.
 +
||
 
||
 
||
 
||
 
||
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==== Sedimentary - Karstic====
 
==== Sedimentary - Karstic====
 
{| class = "wikitable"
 
{| class = "wikitable"
|Named Aquifers||General Description||Water quality issues||Recharge
+
|Named Aquifers||General Description||Water quantity issues||Water quality issues||Recharge
 
|-
 
|-
 
|Eocene Karkar, Taalex and Auradu limestones
 
|Eocene Karkar, Taalex and Auradu limestones
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The depth to water table in unconfined parts of these aquifers is usually between 5 and 15 m throughout the year.
 
The depth to water table in unconfined parts of these aquifers is usually between 5 and 15 m throughout the year.
  
Fresh groundwater reserves in the Auradu aquifer in the Somaliland and Puntland regions are estimated as equivalent to an average flow of 63.4 m³/sec. The estimated fresh groundwater reserve in the Karkar aquifer is lower at approximately 10 m³/sec.
+
||Fresh groundwater reserves in the Auradu aquifer in the Somaliland and Puntland regions are estimated as equivalent to an average flow of 63.4 m³/sec. The estimated fresh groundwater reserve in the Karkar aquifer is lower at approximately 10 m³/sec.
 
||Groundwater in the Karkar karst aquifer is slightly mineralised, with an SEC (conductivity) value typically between 1500 and 1800 micromhos/cm.  
 
||Groundwater in the Karkar karst aquifer is slightly mineralised, with an SEC (conductivity) value typically between 1500 and 1800 micromhos/cm.  
  
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|-
 
|-
 
|Jurassic limestones
 
|Jurassic limestones
||The Jurassic limestones in the north of the country have the greatest potential for groundwater development in the country. There is usually pure limestone in the upper part of the formation, with marly levels and calcareous sandstones in the lower part. The upper parts in particular are usually characterised by a high degree of fracturing and probably karstic cavities, and groundwater circulation probably develops mainly in this zone. The limestones can be highly permeable, with a transmissivity value from one test borehole at Borama of 3.1 x 10<sup>-3</sup> m²/sec (270 m²/day).
+
||The Jurassic limestones have the greatest potential for groundwater development in the country. There is usually pure limestone in the upper part of the formation, with marly levels and calcareous sandstones in the lower part. The upper parts in particular are usually characterised by a high degree of fracturing and probably karstic cavities, and groundwater circulation probably develops mainly in this zone. The limestones can be highly permeable, with a transmissivity value from one test borehols at Borama of 3.1 x 10<sup>-3</sup> m²/sec (270 m²/day).
  
 
The depth to water table in unconfined parts of the aquifer is usually between 5 and 15 m throughout the year.
 
The depth to water table in unconfined parts of the aquifer is usually between 5 and 15 m throughout the year.
  
Groundwater reserves in the Jurassic limestone aquifer in the Awadal region are estimated as equivalent to an average flow fo 18.9 m³/sec.
+
||Groundwater reserves in the Jurassic limestone aquifer in the Awadal region are estimated as equivalent to an average flow fo 18.9 m³/sec.
 
||Groundwater in the Jurassic aquifer is generally of bicarbonate type with low levels of mineralisation, with SEC (conductivity) commonly in the range 600 microS/cm to 1200 microS/cm.   
 
||Groundwater in the Jurassic aquifer is generally of bicarbonate type with low levels of mineralisation, with SEC (conductivity) commonly in the range 600 microS/cm to 1200 microS/cm.   
  
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====Basement====
 
====Basement====
 
{| class = "wikitable"
 
{| class = "wikitable"
|Named Aquifers||General Description||Water quality issues||Recharge
+
|Named Aquifers||General Description||Water quantity issues||Water quality issues||Recharge
 
|-
 
|-
 
|
 
|
 
||Forms a low productivity aquifer or an aquitard, depending on the development of permeability by weathering/fracturing.  
 
||Forms a low productivity aquifer or an aquitard, depending on the development of permeability by weathering/fracturing.  
 +
||
 
||Groundwater has low to moderate mineralisation, with conductivity often between 300 mS/cm and 1400 mS/cm, up to a maximum of 3570 mS/cm in some shallow wells. More than 70% of analysed waters have good characteristics according to WHO standards for drinking water in arid regions.  
 
||Groundwater has low to moderate mineralisation, with conductivity often between 300 mS/cm and 1400 mS/cm, up to a maximum of 3570 mS/cm in some shallow wells. More than 70% of analysed waters have good characteristics according to WHO standards for drinking water in arid regions.  
 
||  
 
||  
 
|}
 
|}
 +
  
 
==Groundwater Status==
 
==Groundwater Status==
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==References==
 
==References==
 
 
The following references provide more information on the geology and hydrogeology of Somalia.
 
The following references provide more information on the geology and hydrogeology of Somalia.
These, and others, can be accessed through the [https://www.bgs.ac.uk/africaGroundwaterAtlas/atlas.cfc?method=listResults&title_search=&author_search=&category_search=&country_search=SO&placeboolean=AND&singlecountry=1 Africa Groundwater Literature Archive]
+
These, and others, can be accessed through the [http://www.bgs.ac.uk/africagroundwateratlas/searchResults.cfm?title_search=&author_search=&category_search=&country_search=SO&placeboolean=AND&singlecountry=1 Africa Groundwater Literature Archive]
  
 
===Geology: key references===
 
===Geology: key references===
  
 
Abbate E, Sagri M & Sassi FP (with the collaboration of Aden IH, Arush MA, Yusuf OS). 1994. The geological map of Somalia 1:1,500,000. University of Florence, SELCA, Florence   
 
Abbate E, Sagri M & Sassi FP (with the collaboration of Aden IH, Arush MA, Yusuf OS). 1994. The geological map of Somalia 1:1,500,000. University of Florence, SELCA, Florence   
 +
  
 
===Hydrogeology: key references===
 
===Hydrogeology: key references===
Line 521: Line 443:
 
FAO/SWALIM. 2011. Water sources inventory for northern Somalia, Technical Report No. W-12, January 2009, Nairobi
 
FAO/SWALIM. 2011. Water sources inventory for northern Somalia, Technical Report No. W-12, January 2009, Nairobi
  
FAO-SWALIM  (Balint Z, Stevanovic Z, Gadain H et al.). 2012. [http://www.faoswalim.org/content/w-20-hydrogeological-survey-and-assessment-selected-areas-somaliland-and-puntland-report-no Hydrogeological Survey and Assessment of Selected Areas in Somaliland and Puntland]. Technical Report No. W-20, FAO-SWALIM (GCP/SOM/049/EC) Project, Nairobi, Kenya.
+
FAO-SWALIM  (Balint Z, Stevanovic Z, Gadain H et al.). 2012. Hydrogeological Survey and Assessment of Selected Areas in Somaliland and Puntland. Technical Report No. W-20, FAO-SWALIM (GCP/SOM/049/EC) Project, Nairobi, Kenya. http://www.faoswalim.org/content/w-20-hydrogeological-survey-and-assessment-selected-areas-somaliland-and-puntland-report-no
  
 
German Agro-Action. 2005. Inception Report of the integrated water resource management plan - Community based natural resource management in the Dur-Dur watershed, Awdal Region, Somaliland, EC: 424-NGO-AG02-03; GAA: SOM 1003
 
German Agro-Action. 2005. Inception Report of the integrated water resource management plan - Community based natural resource management in the Dur-Dur watershed, Awdal Region, Somaliland, EC: 424-NGO-AG02-03; GAA: SOM 1003
Line 539: Line 461:
  
 
UNICEF. 1983-1986. Rural water supply and sanitation  programme in the  Northern  Regions",  Internal  Reports,  Hargeysa
 
UNICEF. 1983-1986. Rural water supply and sanitation  programme in the  Northern  Regions",  Internal  Reports,  Hargeysa
 
United Nations. 1989. [https://www.bgs.ac.uk/africaGroundwaterAtlas/atlas.cfc?method=ViewDetails&id=AGLA060020 Groundwater in Eastern, Central and Southern Africa: Somalia]. United Nations Department of Technical Cooperation for Development. Natural Resources/Water Series No. 19, ST/TCD/6.
 
  
 
Van der Plac MC. 2001. Burao water supply project XB=SOM-00-X01, Hydrogeological Site Investigations, Togdheer Region (Somaliland), UNCHS (Habitat)  
 
Van der Plac MC. 2001. Burao water supply project XB=SOM-00-X01, Hydrogeological Site Investigations, Togdheer Region (Somaliland), UNCHS (Habitat)  
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Return to the index pages:
+
==Return to the index pages==
 
[[Overview of Africa Groundwater Atlas | Africa Groundwater Atlas]] >> [[Hydrogeology by country | Hydrogeology by country]] >> Hydrogeology of Somalia
 
[[Overview of Africa Groundwater Atlas | Africa Groundwater Atlas]] >> [[Hydrogeology by country | Hydrogeology by country]] >> Hydrogeology of Somalia
  
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[[Category:Hydrogeology by country|s]]
 
[[Category:Hydrogeology by country|s]]
 
[[Category:Africa Groundwater Atlas]]
 

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