Hydrogeology of Burundi: Difference between revisions

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||The productivity of fractured basement rocks depends on the localised nature and extent of fracturing, and the presence and thickness of a weathered zone. In the eastern and western provinces groundwater is found largely in fractured granite, gneiss and permeable quartzite. A north-south trending belt of semi-permeable metamorphic basement rocks, including schist and quartzite, extends along the border of the western province.  
||The productivity of fractured basement rocks depends on the localised nature and extent of fracturing, and the presence and thickness of a weathered zone. Due to tectonic activity, the basement can be well fractured, with boreholes appropriately sited in fault zones indicating transmissivities of 100 - 1000 m2/day. A thick weathered zone, which can be up to 100 m over granite and schist basement rocks, can also provide significant storage. Fracturing can, however, compartmentalise an aquifer which can affect the long-term sustainable yield of a borehole. This is the case, for example, in Gitega in Central Burundi.
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Revision as of 16:06, 15 January 2019

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


This page has limited information and needs to be updated. If you have more information on the hydrogeology of Burundi, please get in touch!


One of the smallest and most densely populated countries in Africa, Burundi was an independent kingdom for over 200 years until the early 20th century. It was colonised first by Germany, and after the First World War by Belgium, and governed together with present day Rwanda as Ruanda-Urundi until independence in 1962. Initially, independent Burundi was a monarchy, but after a period of civil and military unrest the monarchy was abolished and a one-party republic established in 1966. Burundi has continued to experience multiple periods of unrest, often involving ethnic violence between Hutu and Tutsi, including two periods in which genocide was identified, first in the 1970s and again in the 1990s. Since the 1990s Burundi has had a multi-party state, but has continued to experience periods of political and military unrest, such as disrupted presidential elections and a coup attempt in 2015. After the International Criminal Court (ICC) began to investigate potential human rights crimes by the country, Burundi left the ICC in 2017.

Decades of civil and military unrest has left the national infrastructure in very poor state, including water and sanitation services. Burundi has a largely rural population largely employed in subsistence agriculture, but high population density and lack of land access mean many farmers can’t support themselves. Pressure to increase agricultural land has resulted in widespread deforestation. Export earnings are also largely dominated by agriculture (mainly coffee and tea), but account for only a small proportion of GDP. External aid accounts for over 40% of the national income. Burundi has resources of a number of metal minerals, but a relatively small mining industry, of which gold provides the biggest export income. Most of the country’s electricity is produced by hydroelectric power stations.

With relatively high rainfall, Burundi has relatively abundant water resources, but because rainfall and surface water are unevenly distributed both spatially and seasonally, and because water supply infrastructure is poor, there is significant pressure on water resources. Most rural communities rely on groundwater, including numerous natural springs.


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 B É and Bellwood-Howard, I. 2018. Africa Groundwater Atlas: Hydrogeology of Burundi. British Geological Survey. Accessed [date you accessed the information]. https://earthwise.bgs.ac.uk/index.php/Hydrogeology_of_Burundi

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 Terms of use for more information.

Geographical setting

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

General

Capital city Bujumbura
Region Eastern/Central Africa
Border countries Rwanda, Tanzania, the Democratic Republic of the Congo
Total surface area* 27,830 km2 (2,783,000 ha)
Total population (2015)* 11,179,000
Rural population (2015)* 9,875,000 (88%)
Urban population (2015)* 1,304,000 (12%)
UN Human Development Index (HDI) [highest = 1] (2014)* 0.3999

* Source: FAO Aquastat

Climate

Koppen Geiger Climate ZonesAverage Annual PrecipitationAverage Temperature

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

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

Burundi has relatively abundant surface water resources, because of high rainfall and storage in marshes and lakes. A dense hydrographic network means that it has a high hydroelectric potential. Among the internal rivers are the: Kaburantwa, Kagunuzi, Mpanda, Murembwe, Mugere, Mubarazi, Muhira, Mutsindosi, and Ruvubu rivers. There are also large areas of marshes, and the major lakes Cohoha and Rweru (African Development Fund 2005).


Major surface water features of Burundi. Map developed from World Wildlife Fund HydroSHEDS; Digital Chart of the World drainage; and FAO Inland Water Bodies. For more information on the datasets used to develop the map see the surface water resource [age

Soil

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


Water statistics

1998 2000 2005 2014 2015
Rural population with access to safe drinking water (%) 73.8
Urban population with access to safe drinking water (%) 91.1
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) 899.9
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 2.297
Total renewable groundwater (Million cubic metres/year) 7,470
Exploitable: Regular renewable groundwater (Million cubic metres/year) No data No data No data No data No data
Groundwater produced internally (Million cubic metres/year) 7,470
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) 15
Municipal water withdrawal (all water sources) (Million cubic metres/year) 43.1
Agricultural water withdrawal (all water sources) (Million cubic metres/year) 222
Irrigation water withdrawal (all water sources)1 (Million cubic metres/year) 200
Irrigation water requirement (all water sources)1 (Million cubic metres/year) 28.4
Area of permanent crops (ha) 350,000
Cultivated land (arable and permanent crops) (ha) 1,550,000
Total area of country cultivated (%) 55.7
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

The geology map shows a simplified version of the geology at a national scale. More information is available in the report UN (1988) and in reports from the work carried out by BGR and BRGM, which includes a map of groundwater potential of Burundi (see References section, below).



Geology of Burundi at 1:5 million scale. Developed from USGS map (Persits et al., 2002). For For more information on how the map was developed see the geology resource page)

Summary

The geology of Burundi is dominated by Precambrian basement rocks. In the west, these mainly comprise metasedimentary rocks intruded by granites, while in eastern and central parts, the geology is dominated by quartzite, schist and gneiss.

Geological environments
Key formations Period Lithology
Unconsolidated
Alluvium and lake sediments Cenozoic Unconsolidated sediments primarily infilling the tectonic valley of the Western Rift; also alluvial sediments along rivers and lakes which form smaller outcrops that are too small to be shown on this map.
Volcanic rocks
Cenozoic Basaltic rocks outcrop in the extreme north-west of Burundi (not mapped at this scale).
Precambrian
Archean complex Palaeoproterozoic Predominantly gneiss, intercalated with amphibolite and quartzite.
Burudian Mesoproterozoic Metasedimentary rocks, largely quartzite with lesser amounts of intercalated schist.
Malagarasian Metasedimentary rocks, largely schist and quartzite, which outcrops in the south-east and overlies the Burundian.

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 is available in the report UN (1988) and in reports from the work carried out by BGR and BRGM, which includes a map of the groundwater potential of Burundi (see References section, below).


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

Unconsolidated

Aquifer Productivity Named Aquifers and General Description Water quantity issues Water quality issues Recharge
Variable Productivity Unconsolidated sedimentary deposits largely consist of alluvial sands, silts, gravels and clays, forming narrow aquifers along river valleys and terrace deposits along Lake Tanganyika. Aquifer properties are variable, depending largely on lithology, but where the alluvium is dominated by coarser grained deposits, storage capacity and transmissivity may be high. Recharge is generally high due to close connection with rivers and wetlands.

Volcanic

Aquifer Productivity Named Aquifers and General Description Water quantity issues Water quality issues Recharge
Moderate Productivity Little is known about groundwater in the volcanic rocks, which are largely basaltic lava flows.

Fractured Basement

Aquifer Productivity Named Aquifers and General Description Water quantity issues Water quality issues Recharge
Variable Productivity The productivity of fractured basement rocks depends on the localised nature and extent of fracturing, and the presence and thickness of a weathered zone. Due to tectonic activity, the basement can be well fractured, with boreholes appropriately sited in fault zones indicating transmissivities of 100 - 1000 m2/day. A thick weathered zone, which can be up to 100 m over granite and schist basement rocks, can also provide significant storage. Fracturing can, however, compartmentalise an aquifer which can affect the long-term sustainable yield of a borehole. This is the case, for example, in Gitega in Central Burundi.

Groundwater use and management

Groundwater use

Records in 2005 showed that at one point there were at least 35,000 developed natural springs in Burundi tapping groundwater for water supply, and 811 groundwater-based drinking water systems (likely to be drilled or dug wells equipped with hand pumps), but that most of these were non-functional (African Development Bank 2005). Lack of infrastructure development means there has been relatively little borehole drilling for water supply. In rural areas it is likely that people make use of groundwater from hand dug wells, possibly on a seasonal basis, as well as the numerous natural springs.


Groundwater management

Years of political instability have contributed to Burundi's water sector being in very poor state.

Several government bodies share responsibility for water resources and supplies. This can cause poor coordination of planning and water resource development, with competition in the allocation of water between sectors. The institutions involved include (USAID 2010):

- The Directorate General for Water and Energy of the Ministry of Water, Energy and Mines, which leads overall water policy formulation
- The Directorate of Water Resources (DRH), which develops and maintains the national water master plan
- The Directorate General of Rural Water and Electricity(DGHER), which oversees rural drinking water and sanitation
- The Water and Electric Authority ((REGIDESO), which is responsible for urban service provision
- Communal Water Authorities, which are responsible for rural service provision and linked to District Users committees (African Development Fund 2005).

General improvement of water supplies in Burundi is a policy and development priority, and the urgency of this task means that there is a broad focus on all aspects of water resources and supply. Policies are focussed on implementing the principles of community based management and integrated water resource management (IWRM).

There is an attempt by government and some donors to encourage the development of the small amount of private sector involvement in the water sector. In 2005, the African Development Fund estimated there were 30 private consultancy firms in Burundi active in water services, such as borehole drilling.

A database which in 2009 had limited information about groundwater sources. A GTZ-supported project included work to develop a central database at the national water authority.


Transboundary aquifers

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

References

References with more information on the geology and hydrogeology of Burundi can be accessed through the Africa Groundwater Literature Archive.

HAHNE, K. (2014): Lineament mapping for the localisation of high groundwater potential using remote sensing - Technical Report No. 4, prepared by IGEBU & BGR: 52 p., 53 fig., 2 tab.; Hannover. (PDF, 9 MB)

HECKMANN, M., VASSOLO, S. & TIBERGHIEN, C. (2016): Groundwater Vulnerability Map (COP) for the Nyanzari catchment, Gitega, Burundi. – Technical Report No. 7, prepared by IGEBU & BGR: 96 p., 33 fig., 14 tab.; Hannover. (PDF, 6 MB)

PFUNT, H., TIBERGHIEN, C. & VASSOLO, S. (2016): Numerical Groundwater Model for the Nyanzare well field at the town of Gitega, Burundi. – Technical Report No. 8, prepared by IGEBU & BGR: 46 p., 18 fig., 4 tab.; Hannover. (PDF, 2 MB)

Alexis Gutierrez, Jean-Marie Barrat. Groundwater resources of Burundi. New elements and decision making tools. 35th International Geological Congress : IGC 2016, Aug 2016, Cape Town, South Africa

African Development Fund. 2005. Burundi: The rural water infrastructure rehabilitation and extension project. Appraisal report. Infrastructure Departmetn Central and West Regions, Ocin, September 2005.

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

USAID. 2010. Burundi Water and Sanitation Profile. March 2010.

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