Hydrogeology of Democratic Republic of the Congo

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The Democratic Republic of Congo (DRC) is the largest country in sub-Saharan Africa. Between the 14th and 19th centuries, the kingdom of Kongo included much of the western part of present-day DRC, while in the centre and east of the country the kingdoms of Luba and Lunda ruled from the 16th and 17th to the 19th centuries. The region was made a personal colony of the Belgian King Leopold II in 1885, called the Congo Free State, and exploited for its natural resources, particularly rubber, through plantation agriculture using forced labour. During this time a large proportion of the Congolese population died as a result of exploitation and disease. Belgium annexed the territory as the Belgian Congo in 1908. Independence was gained in 1960 as the Republic of Congo, also known as Congo-Leopoldville; this was later changed to Zaire in 1971 and the Democratic Republic of the Congo in 1997.

Since independence, the DRC has experienced extensive political, civil and military conflict, with civil wars, involvement in conflict in neighbouring countries, including Rwanda, coup d’etats and widespread internal unrest. The second Congo war, from 1998 to 2003, has been called the deadliest global conflict since the Second World War, killing between 2.5 and 5.5 million people and involving nine countries. The official end of this conflict did not end unrest or instability. Human rights organisations warn that the most recent political unrest in 2016 and 2017 has sparked a new rise in conflict that risks spreading across the country again.

The DRC has one of the lowest GDPs per capita in the world. It has vast mineral resources, including cobalt, diamonds, copper, gold, uranium and oil, which generated up to 70% of export revenue in the 1970s and 80s, but revenues are vulnerable to price fluctuations in global markets, and foreign investment in the mining industry is hard to attract in the climate of instability and poor infrastructure. Control over natural, especially mineral, resources has played a part in conflict in the country, and a large proportion of DRC’s mineral exports is thought to be illegally traded. Small scale artisanal mining is also important to the informal economy. The dense forest that covers much of the country is a rich timber resource, but, along with very poor infrastructure, also impedes transportation. The DRC obtains electricity from hydroelectric stations on the Congo River, as well as some coal and oil. Subsistence agriculture supports most of the population; commercial plantation is beginning to expand again after declining during the Congo wars, and supports key the export crops of coffee and rubber.

With high rainfall and major perennial rivers, the DRC is a water-rich country, but water supply infrastructure is poor. Despite the abundance of surface waters, most of the population relies on groundwater for water supplies.


Authors

Josué Bahati Chishugi, Département de Géologie, Universite Officiellé de Bukavu, DR Congo

Juvenal Birikomo, REGIDESO, DR Congo

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: Chishugi, Birikomo, Upton, Ó Dochartaigh and Bellwood-Howard, 2018.

Bibliographic reference: Chishugi JB, Birikomo J, Upton K, Ó Dochartaigh BÉ and Bellwood-Howard, I. 2018. Africa Groundwater Atlas: Hydrogeology of the Democratic Republic of the Congo. British Geological Survey. Accessed [date you accessed the information]. http://earthwise.bgs.ac.uk/index.php/Hydrogeology_of_Democratic_Republic_of_the_Congo

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Geographical Setting

The central part of the country is a large basin ranging in altitude from 350 to 700 m above sea level, with broad steep-sided valleys. To the east of this basin is a mountain ridge from 2300 to 3800 m above sea level that marks the edge of the East African Rift. To the south are the high Kasai and Shaba plateaus, from 1000 to 2000m above sea level. To the west are the Mayumbe hills, around 750 m in elevation, with narrow cols and valleys. To the north the basin is bounded by the watershed of the Oubangui river. The coastal area in the west, on the Atlantic Ocean, contains largely low land and sandy beaches, or cliffs.

Democratic Republic of the Congo. 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 Kinshasa
Region Central Africa
Border countries Republic of the Congo, Central African Republic, South Sudan, Uganda, Rwanda, Burundi, Tanzania, Zambia, Angola
Total surface area* 2,000,000 km2 (200,000,000 ha)
Total population (2015)* 77,267,000
Rural population (2015)* 46,992,000 (61%)
Urban population (2015)* 30,275,000 (39%)
UN Human Development Index (HDI) [highest = 1] (2014)* 0.4331

* Source: FAO Aquastat

Climate

The Democratic Republic of the Congo lies on the equator. Average temperatures across much of the country are around 25 degrees C, except in the eastern mountains where average temperatures are around 20 degrees C. There is much cloud cover over much of the year, with the maximum sunshine in the dry season.

Average annual rainfall for the whole country is over 1,200 mm, rising to more than 2,000 mm in the central basin, and falling to a minimum of around 850 mm at the western coast. There is a single rainy season, from September to June in the south and from February to November in the north; and a single dry season, in June and July in the south and December and January in the north.

Koppen Geiger Climate ZonesAverage Annual PrecipitationAverage Temperature

Average monthly precipitation for the Democratic Republic of the Congo showing minimum and maximum (light blue), 25th and 75th percentile (blue), and median (dark blue) rainfall Average monthly temperature for the Democratic Republic of the Congo 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)

More information on average rainfall and temperature for each of the climate zones in Democratic Republic of the Congo can be seen at the Democratic Republic of the Congo 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 resource page.

Surface water

The Congo River is the largest river basin in Africa, and the second largest in the world after the Amazon, and drains all surface water in the country. It has a number of large tributary rivers, many of which have been dammed for hydroelectric power production.

Major surface water features of the Democratic Republic of the Congo. 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 resource [page

Soil

Soil Map of the Democratic Republic of the Congo, 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 the Democratic Republic of the Congo, from the European Space Agency GlobCover 2.3, 2009. For more information on the map see the land cover resource page

Water statistics

2000 2005 2011 2014 2015
Rural population with access to safe drinking water (%) 31.2
Urban population with access to safe drinking water (%) 81.1
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) 11,648
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 0.0533
Renewable groundwater resources (Million cubic metres/year) No data No data No data No data No data
Groundwater produced internally (Million cubic metres/year) 421,000
Fresh groundwater withdrawal (primary and secondary) (Million cubic metres/year) No data No data No data No data No data
Groundwater: entering the country (total) (Million cubic metres/year)
Groundwater: leaving the country to other countries (total) (Million cubic metres/year)
Industrial water withdrawal (all water sources) (Million cubic metres/year) 146.8
Municipal water withdrawal (all water sources) (Million cubic metres/year) 464.9
Agricultural water withdrawal (all water sources) (Million cubic metres/year) 71.9
Irrigation water withdrawal (all water sources)1 (Million cubic metres/year) 71.9
Irrigation water requirement (all water sources)1 (Million cubic metres/year) 19.6
Area of permanent crops (ha) 900,000
Cultivated land (arable and permanent crops) (ha) 8,000,000
Total area of country cultivated (%) 3.412
Area equipped for irrigation by groundwater (ha) No data No data No data No data No data
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 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

This section provides a geological map and a summary of the geology of the Democratic Republic of the Congo at a national scale (see the Geology resources page for more details).

More detailed geological information can be found in other maps and reports (see the list in the References section, below), including:

  • A UN report (1989) with information current at the end of the 1980s.
  • A lithological map of the DRC, developed by the World Soil Information (ISRIC) as part of developing a Soil and Terrain Database (SOTER) for Central Africa. The lithological classes in SOTER are based on a geological map of the Congo at 1 : 2 million scale compiled by the Musée Royal d'Afrique Centrale (MRAC) (Lepersonne 1974). The SOTER database also includes data on landforms and hydrographic networks. The lithological classes are described in van Engelen et al. 2006. The lithological map is available as a GIS shapefile.
  • The 1974 geological map of the DRC (Lepersonne 1974) was recently updated (2015) by the Musée Royal d'Afrique Centrale (MRAC) in Belgium, on behalf of the DRC Ministry of Mines, as part of the World Bank-funded PROMINES project (Fernandez-Alonso 2015). This map is not publicly available. It shows no changes in lithological contours from older geological maps. It did redefine the chronostratigraphical and lithostratigraphical divisions at Supergroup and Complex level, and reallocate the geological units represented according to the new definitions.


Geology of the Democratic Republic of the Congo at 1:5 million scale. Developed from map published originally by UNESCO (Furon and Lombard 1964), digitised by and made available by the USGS (Persits et al. 2002). For more information on the map development and datasets see the geology resource page


Summary

The youngest sediments in the DR Congo are various sequences of largely unconsolidated Tertiary to Quaternary sediments, which cover much of the country. They include river valley alluvium, lateritic gravels and lacustrine deposits. There are also small areas of Quaternary volcanic rocks in the far east, associated with the East African Rift.

Below these in many areas are a series of unmetamorphosed and largely undeformed sedimentary rocks, ranging in age from Palaeozoic (largely Upper Carboniferous) to Cretaceous.

The oldest rocks in the country are Precambrian in age, of various types including metamorphosed sedimentary and igneous rocks, all variously metamorphosed and deformed.


Geological Environments
Key Formations Period Lithology
Sedimentary, largely unconsolidated
Alluvium, lacustrine, aeolian, lateritic and other unconsolidated deposits Tertiary to Quaternary Fine to coarse sands and gravels; clays and sandy clays. In some areas, such as underlying the Batékés Plateau and southeast Kasaï, the sediments consist mainly of semi-continuous sandy loam and soft sandstone (Partow 2011).
Sedimentary, consolidated
Soft sandstones and argillaceous rocks Cretaceous
Well-consolidated sandstones and argillaceous rocks Upper Carboniferous to Jurassic Karoo-type sandstones and in some cases calcareous rocks.
Precambrian
Metasedimentary rocks Precambrian Metamorphosed quartzites, schists, limestones, dolomitic limestones and dolomites. The calcareous rocks are often karstic.
Crystalline granitic and metamorphic rocks Precambrian Crystalline granitic and metamorphic basement rocks, part of the African Craton

Hydrogeology

This section provides a summary of the hydrogeology of the main aquifers in the Democratic Republic of the Congo. More information is available in the report United Nations (1989) (see References section, below). 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.

So far there has been no systematic hydrogeological exploration across the DRC. The only available hydrogeological data are those produced by REGIDESO (Regie de Distribution d'Eau de la Republique Democratique du Congo - the national company of water supply and sanitation), NGOs and mining companies, specific to particular regions of the country. SNEL (1957) presented a country-scale general hydrogeological overview, and a hydrogeological map available to view (as a scanned image) from the BGR WHYMAP website. Though the report is very rich and descriptive, it does not present data on aquifer characterisation.


The hydrogeology map 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).

The DRC is also covered by the SADC hydrogeological map and atlas (2010), available through the SADC Groundwater Information Portal.

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


Unconsolidated or Consolidated Sedimentary - Intergranular Flow

Named Aquifers General Description
Alluvial sands and gravels; lateritic gravels; aeolian sands; other sand and gravel deposits Boreholes in unconsolidated sands and gravels, between 5 and 15 m thick, have recorded specific yield values of 1.5 to 10 m³/hour/m of drawdown; transmissivity 0.1.65 x 10-3 (United Nations 1989).

In the Cuvette Centrale and Oubangui areas, coarse alluvial sediments up to 120 m thick occur, with recharge from direct rainfall infiltration and indirectly from river infiltration. Areas which are known to have particularly good potential include Libenge and the alluvial plain between the N’Djili River and Ngaliema Bay in Kinshasa (Partow 2011).

The Tertiary-Quaternary aquifer underlying the Batékés Plateau and southeast Kasaï, consisting mainly of semi-continuous sandy loam and soft sandstone, is up to 100 m thick. It has relatively low productivity, although it sustains many streams by baseflow. Recharge is largely from direct rainfall infiltration (Partow 2011).



Sedimentary - Intergranular & Fracture Flow

Named Aquifers General Description
Cretaceous and Mesozoic-Palaeozoic sandstones A borehole in soft Cretaceous sandstones, which have layers of argillaceous material, was recorded at 160 m deep, with a specific yield value of 4 m³/hour/m of drawdown; transmissivity value of 130 m²/day, and a storage coefficient of 6.5 x 10-4 (United Nations 1989).

Mesozoic Karoo-type sandstone and calcareous aquifers, which occur in large parts of the Cuvette Centrale, including around Gemena, Kisingani and northern Kasaï, receive rapid recharge. They have low to moderate productivity. In certain areas, fracturing has led to the development of karstic systems, which have higher productivity (Partow 2011).

Groundwater is likely to be low in dissolved solids and minerals (Partow 2011).

Sedimentary - Fracture Flow

Named Aquifers General Description
Metamorphosed limestones and dolomitic limestones, including the Lubumbashi dolomites; quartzites and other non-calcareous rocks Karstic metamorphosed limestones and dolomitic limestones can form highly productive aquifers, dominated by rapid karstic flow, such as the Lubumbashi dolomites in southern Katanga (Partow 2011). Boreholes up to 150 m deep are recorded, with specific yield values of 3 to 11 m³/hour/m of drawdown; a transmissivity value of 130 m²/day, and a storage coefficient of 0.3 x 10-5 (United Nations 1989).

Non-karstic Precambrian metasedimentary rocks typically form low productivity aquifers, possibly locally moderately productive where there is extensive fracturing.

Karstic and carbonate aquifers have alkaline groundwater. Where there are sulphide minerals in the rock, as in some schists, or in gypsum, as found at Katanga, groundwater can be highly mineralised (Partow 2011).

Basement

Named Aquifers General Description
Precambrian Basement Crystalline basement rocks. Forms local aquifers in weathered and/or fractured zones, usually low producivity but occasionally moderate. The aquifer properties are controlled by the depth of weathering (regolith) and the degree of fracturing of unweathered bedrock. Fractured bedrock alone can sometimes supply relatively good yields, but has low storage and cannot sustain these yields in the long term. Weathered regolith provides additional storage.

Groundwater typically has low levels of mineralisation and a below-neutral pH (Partow 2011).

Groundwater Status

Most of the information in this section is taken from Partow (2011), who provides a detailed overview of water issues in the country (see Reference section, below).

Information on the extent and quality of groundwater resources and springs in the Democratic Republic of the Congo is scarce, and where available is often outdated and of limited geographic coverage (Partow 2011).

However, the available information points to pressures on groundwater resources in some areas. Increasing water demand, combined in some cases with drought-prone areas, has led to seasonal water shortages in some areas (Partow 2011).

Groundwater use and management

Most of the information in this section is taken from Partow (2011), who provides a detailed overview of water issues in the country (see Reference section, below).

Groundwater use

Despite the abundance of surface waters, and the fact that up to date and accurate information on water use in the country is not available (Partow 2011), the vast majority (around 90%) of the population is thought to be dependent on groundwater for drinking water, mainly from springs (Partow 2011). These are mainly simple capped spring heads, and are used both in rural villages and in the rapidly growing peri-urban areas. Large-scale water production from springs through distribution networks is also an important water source for many cities, including Mbuji-Mayi, Lubumbashi, Kisingani, Bunia, Beni, Gemena and Lisala (Partow 2011).

Groundwater is also abstracted from hand dug wells, using hand pumps or mechanical pumps. Groundwater from wells is estimated to account for approximately 10 percent of the country's drinking water supply (Partow 2011).

There are only an estimated 1,000 deep-drilled boreholes in the country, most of which were drilled between the 1960s and 1980s, especially during the International Decade for Water Supply and Sanitation. They abstract from various aquifers, with yields ranging from 15 to 300 m³/h (United Nations 1989) (although mostly from 15 to 80 m³/h - Partow, 2011). Since the 1990s, limited borehole drilling has been carried out, though in the past several years it has been rapidly developing with international assistance. REGIDESO reported that a few new water supply boreholes were drilled between 2010 and 2017.

The number of groundwater sources by province in 2010 was reported by REGIDESO as follows:

Provinciale Number of boreholes and wells Number of springs
Katanga 16 19
Kasai Occidental 8 5
Nord Kivu 6
Sud Kivu 5
Prov. Orientale 6 4
Bandundu 18 3
Maniema 3
Bas-Congo 17 2
Equateur 14 2
Kasai Orientale 17 2
Kinshasa 13 1
Maniema 1
Total Country 109 54

Groundwater monitoring

There is no inventory of springs at national and provincial levels (Partow 2011). However, there are some data on groundwater sources for localised regions, held by several NGOs and mining companies, including in Katanga, South Kivu, North Kivu, Kasai and Oriental Provinces.

Groundwater legislation and management

Nile IWRM-Net (2007), Chishugi and Xu (2010) and Partow (2011) (see reference list below) provide a detailed discussion of the water sector in the DRC, including responsible bodies and legislation and how these are changing.

Water sector governance is structurally weak, characterised by a multiplicity of laws and institutions with often overlapping and conflicting mandates. The DRC lacks a clear water policy, a framework water law and a dedicated water ministry to guide and lead sustainable development of the sector. With the government reform initiative that begun in 2006 with the support of development partners, particularly the German Technical Cooperation’s (GTZ) water reform project (RESE), this situation may change.

Management of water resources is the governmental responsibility of the Ministry of the Environment, Nature Conservation and Forestry (MECNE), as provided by Ordinance No. 75-231 of 22 July 1975 (ADF 2007). At least six institutions/authorities are involved:

- Ministry of Environment, Nature Conservation, Water and Forest – MECNE (Directorate of Water Resources)
- Ministry of Energy – MINE (National Commission of Energy – NCE)
- The national company of water supply and sanitation – REGIDESO
- Ministry of Rural Development – MDR (The national Service of Rural Hydraulics - SNHR);
- Ministry of Planning - MINIPLAN (Congo National Action Committee for Water Supply and Sanitation – CNAEA)
- Ministry of Health - MSE (The rural health zone - ZSR)
- Ministry of public works and Infrastructure – MTPI (The service of drainage : Office de Voirie et Drainage – OVD)


Transboundary aquifers

The Democratic Republic of the Congo shares a number of aquifers with neighbouring countries. These include (Altchenko and Vilholth 2013):

- the Kalahari/Katanga basin, shared with Zambia;

- the Congo/Zambezi basin, shared with Angola;

- the Tanganyika aquifer, shared with Tanzania, Rwanda and Burundi;

- the Precambrian dolomitic aquifer, shared with Angola;

- a coastal sedimentary aquifer shared with Angola;

- the Cuvette Centale aquifer, shared with the Congo;

- the Mgahinga aquifer, shared with Rwanda and Uganda; and

- the Western Rift Valley Sediment aquifer, shared with Uganda.


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


References

The following provide more information on the geology and hydrogeology of the Democratic Republic of the Congo.

Many of these, and others, can be accessed through the Africa Groundwater Literature Archive

Online resources

SADC Groundwater Information Portal

General information on surface water and groundwater resources in SADC


Documents

Altchenko Y and Vilholth KG. 2013. Transboundary aquifer mapping and management in Africa: a harmonised approach. Hydrogeology Journal Vol.21, Issue 7, pp. 1497-1517.

Ndembo J. 2009. Apport des outils Hydrogéochimiques et Isotopiques à la gestion de l’Aquifère du Mont AMBA (République Démocratique du Congo). Thèse, Université d’Avignon et des Pays de Vaucluse. pp. 203.

SNEL MJ. 1957. Contribution à l’étude hydrogéologique du Congo Belge. Service Geologique, Bull. No. 7. Fasc. 2. Juillet 1957

United Nations. 1989. Groundwater in Eastern, Central and Southern Africa: Zaire. United Nations Department of Technical Cooperation for Development, Natural Resources/Water Series No.19, ST/TCD/6.

UNEP. 2011. Water Issues in the Democratic Republic of the Congo: Challenges and Opportunities. UNEP Technical Report

UNEP. 2011. Problematique de l’Eau en Republique Democratique du Congo: Defis et Opportunites. UNEP Rapport Technique


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