Hydrogeology of Nigeria

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


Professor Moshood N. Tijani, Department of Geology, University of Ibadan, Nigeria

Emily Crane, Kirsty Upton, Brighid Ó Dochartaigh, British Geological Survey, UK

Geographical Setting

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


Estimated Population in 2013* 173615345
Rural Population (% of total)* 53.91%
Total Surface Area* 910770 sq km
Agricultural Land (% of total area)* 79.1%
Capital City Abuja
Region Western Africa
Border Countries Benin, Chad, Cameroon, Niger
Annual Freshwater Withdrawal (2013)* 13110 Million cubic metres
Annual Freshwater Withdrawal for Agriculture* 53.75%
Annual Freshwater Withdrawal for Domestic Use* 31.27%
Annual Freshwater Withdrawal for Industry* 14.99%
Rural Population with Access to Improved Water Source* 49.1%
Urban Population with Access to Improved Water Source* 78.8%

* Source: World Bank


Nigeria's climate is highly variable, from tropical in the south to semi-arid in the north.

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

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

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

Surface water

The main rivers in Nigeria are the Niger and the Benue, which converge and flow together into the Niger Delta, one of the world's largest river deltas.

There are both national and regional bodies responsible for river flow gauging and data storage. The Nigeria Hydrological Services Agency (NIHSA) is responsible for assessment of surface water resources through collection of data such as river stage, discharge, water quality and sediment transport. NIHSA maintain a nation-wide network of hydrological stations.

The Niger Basin Authority (NBA) is also involved in river flow gauging of the River Niger at 18 stations in Niger, and store the data at their headquarters in Niamey, Niger Republic. The Lake Chad Basin Commission gauges river flow at 2 stations on the Komadugu–Yobe River in the Chad Basin Catchment. The Power Holding Company of Nigeria (PHCN) also maintains river flow gauging stations along the River Niger at Kainji and Jebba; they hold these data for use in operating their hydropower systems.

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


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

Land cover

Nigeria has highly variable land cover, including tropical rainforest, Sahel savanna, mountain plateaus and coastal plains.
Land Cover Map of Nigeria (For the key to the map and more information on the datasets used see the land cover resources section)


The following section provides a summary of the geology of Nigeria. More detailed information can be found in the key references listed below: many of these are available through the Africa Groundwater Literature Archive.

The geology map below was created for this Atlas. It shows a simplified version of the geology of Nigeria at a national scale. The map is available to download as a shapefile (.shp) for use in GIS packages.

Nigeria Geology2.png
Geological Environments
Key Formations Period Lithology Structure
Alluvium Quaternary Deposits vary in thickness and lithology, with sands, gravels, silt and clay all present in varying proportions. These occur along the main river valleys and are thickest (15 - 30 m thick) in valleys associated with the rivers Niger and Benue (Adelana et al. 2008).
Igneous – volcanic
Basalts, pyroclasts Tertiary - Quaternary Basalts, pyroclasts
Chad Basin - Sedimentary
Chad, Kerri-Kerri and Gombe formations Cretaceous - Quaternary The dominant lithologies in the Chad Basin, in the northeast of Nigeria, are sandstone, siltstone and shale.

The Quaternary age Chad Formation is up to 840 m thick and consists of poorly sorted fine to coarse-grained sand, with sandy clay, clay and diatomite (Adelana et al. 2008).

The Tertiary age Kerri-Kerri Formation consists of lacustrine or fluvio-lacustrine loosely cemented cross-bedded coarse- to fine-grained sandstones, with locally occurring claystones, siltstones, ironstones, lignites and conglomerates. It rests unconformably on the Gombe Sandstone Formation, and thickens towards the centre of the Chad Basin, where it is overlain by the Chad Formation (Adelana et al. 2008).

The Cretaceous age Gombe Sandstone Formation consists of estuarine and deltaic sediments, deposited on marine shales with sandstone/shale intercalations. The lower deposits of siltstone, mudstone and ironstone are overlain by well-bedded sandstones and siltstones. The upper part of the formation contains coals and cross-bedded sandstones (Adelana et al. 2008).

Niger Delta Basin - Sedimentary
Unconsolidated: Deltaic Formation Tertiary - Quaternary Tertiary to Quaternary unconsolidated sediments at the top of the Niger Delta Basin sequence comprise coarse to medium grained unconsolidated sands and gravels with thin peats, silts, clays and shales (Adelana et al. 2008).
Benin, Agbada and Akata formations Tertiary There are three main deeper sedimentary formations in the Niger Delta Basin. The oldest is the Akata Formation, and is predominantly shaly, with sandstone lenses in the upper parts. The Agbada Formation is predominantly sandy in its upper part, with shale and sandstone beds in roughly equal proportion in its lower part. It may be over 3000 m thick in places, and contains petroleum. The youngest is the Benin Formation, which comprises predominantly (over 90%) sand and gravelly sandstone with shale and clay intercalations. The Niger Delta sedimentary rocks are over 10 km thick in total.
Sokoto Basin - Sedimentary (Iullemeden)
Sokoto Group (Gwandu, Kalambaina and Dange formations) Tertiary Nigeria's Sokoto Basin represents the southeastern part of the Iullemmeden basin, which stretches across parts of Mali, Niger, Benin and into northwest Nigeria. The Tertiary rocks of the Sokoto Basin are mostly interbedded sandstones, clay and some limestone (Pavelic et al. 2012).

The Gwandu Formation (of Eocene-Miocene age) crops out in the west of the Sokoto Basin and comprises interbedded semi-consolidated sand and clay. It unconformably overlies the Kalambaina Formation in the north and centre of the basin (Adelana et al. 2008). The Kalambaina Formation consists of clayey limestone with modular crystalline limestone, and is underlain by the Dange Formation, a marine clay shale. The Kalambaina and Dange Formations are collectively known as the Sokoto Group and are of Paleocene age (Adelana et al. 2008).

The total thickness of the Sokoto Basin is over 1250 m
Rima Group (Wurno, Dukamaje and Taloka formations), Illo/Gundumi Formation Late Jurassic - Cretaceous The uppermost Rima Group comprises a series of marine fine-grained sand and friable sandstone, mudstones, and some marly limestone and shale (Adelana et al. 2008). The group is divided into three formations north of the River Sokoto, which from younger to older are Wurno, Dukamaje and Taloka formations. The lower formations are similarly marine sandstones, clays and limestones (Adelana et al. 2008). The total thickness of the Sokoto Basin is over 1250 m
Nupe Basin - Sedimentary
Nupe, Patti and Lokoja sandstones Cretaceous The Nupe Basin is alternatively known as the Bida or Niger Basin. The basin contains largely continental sandstones, siltstones, claystones and conglomerates (Adelana et al. 2008).
Upper Benue Basin - Sedimentary
Bima Sandstone Tertiary The Upper Benue Basin consists of a thick succession of continental sandstones overlain by marine and estuarine shales and limestones. The basal formation is the Bima Sandstone (Adelana et al. 2008).
Bima, Yolde, Pindija and Kerri-Kerri formations Cretaceous Marine arkosic, gravelly, poorly sorted cross-bedded sandstones and sandy limestones (Adelana et al. 2008). The sedimentary rocks lie unconformably on the Precambrian Basement Complex
Lower Benue Basin - Sedimentary
Ezeaku, Makurdi, Keana, Awe and Asu River formations Cretaceous The Lower Benue Basin consists of shales, silts and silty shales with subordinate sandstones and limestones, intruded by dolerite dykes (Adelana et al. 2008). The sedimentary rocks lie unconformably on the Precambrian Basement Complex
Igneous – younger granites
Younger granites Jurassic An-orogenic volcanic and hypabyssal rocks emplaced within the Precambrian Basement Complex. Arcuate to circular intrusions forming ring-like complexes.
Precambrian Basement Complex
Migmatite-Gneiss Complex (quartzites, amphibolites, marble) Liberian (ca 2800 Ma) to Pan African (ca 600 Ma) These rocks are found in the north-central area of Nigeria, including the Jos Plateau, and in the southwest of Nigeria. They comprise gneisses, migmatites, granites, schists, phyllites and quartzites (Adelana et al. 2008). Metamorphism is in the amphibolites facies range.
Schist belt Precambrian Schist belts, comprising phyllites, schists, quartzites and banded iron formations, found in northwestern Nigeria. Folds
Older Granites Upper Proterozoic Intruded into the migmatite-gneiss complex and the schist belts.


Nigeria Hydrogeology2.png

Dominantly Unconsolidated

Named Aquifers General Description Water quantity issues Water quality issues Recharge
Alluvium Alluvial aquifers occur along major river valleys, and are thickest (15 - 30 m thick) along the rivers Niger and Benue. Largely unconfined, with shallow water tables. None Recharge from direct rainfall and infiltration from rivers
Niger Delta Basin: Deltaic Formation, Benin Formation The unconsolidated aquifers of the Niger Delta Basin are extensive and high yielding. The upper Deltaic Formation is unconsolidated and largely unconfined with shallow water table (0-10 m below ground level) (Offodile 2002).

The older Benin Formation is partly consolidated. It is largely unconfined, but locally confined by lower permeability beds. Water table is typically between 3 and 15 m below ground level (Offodile 2002), but can be as much as 55 m deep.

The aquifers can provide yields from 3 to 60 l/s. Borehole depths range from 10 to 800 m.

None Salinity problems arising from sea water intrusion; iron problems; pollution problems. Recharge is mostly from direct rainfall.

Igneous - Volcanic

Named Aquifers General Description Water quantity issues Water quality issues Recharge
Volcanic rocks, including basalts Igneous volcanic aquifers provide low to moderate yields, usually below 3 l/s. These aquifers are typically unconfined, with typical variations in water table depth of less than 5 m. Aquifer thickness varies substantially, and borehole depths of 15 to 50 m are common. None Water quality is generally good. Direct rainfall recharge.

Chad Basin - Sedimentary - Intergranular

Named Aquifers General Description Water quantity issues Water quality issues Recharge
Chad, Kerri-Kerri and Gombe formations The Chad Formation can be unconfined or confined depending on local conditions. Deeper sandstone layers are often confined and can be artesian. Yields of between 2.5 and 30 l/s are quoted. The water table depth is often between 10 and 15 m (Offodile 2002).

The Gombe Sandstone has relatively low permeability, usually providing yields of about 1 to 5 l/s.

Relatively little is known about the Kerri-Kerri Formation at depth.

None Water quality is generally good. Recharge is mainly by infiltration from rainfall.

Sokoto Basin - Sedimentary - Intergranular

Named Aquifers General Description Water quantity issues Water quality issues Recharge
Sokoto Group (Gwandu and Kalambaina formations); Rima Group (Wurno, Dukamage and Taloka formations); Ilo/Gundimi Formation The lower sands of the Gwandu Formation are often confined; upper layers are unconfined. Water table can vary from 20 to 100 m depth. Storage is typically high. The Kalambaina Formation is locally permeable with perched aquifers in sandier layers (Offodile 2002).

The sand layers of the Wurno Formation are moderately yielding, with a restricted recharge area. The Taloka Formation provides variable yields. It is sometimes confined by clay layers (Offodile 2002).

The gritty, conglomeratic and gravel layers of the Ilo/Gundumi Formation act as aquifers, often confined by clayey layers at depth, when artesian conditions can occur. Shallower aquifer layers are usually unconfined. Typical yields are 2 to 8 l/s. Variable transmissivity values have been quoted, from less than 10 to nearly 1000 m²/day (Offodile 2002).

Nupe Basin - Sedimentary - Intergranular

Named Aquifers General Description Water quantity issues Water quality issues Recharge
Nupe Sandstone, Patti & Lokoja Sandstone The Nupe Sandstone is slightly cemented, but the dominantly fine grained sandstones and interbedded clays, mudstones nad siltstones through much of the sequence reduce groundwater potential. Overall, borehole yields are poor and highly variable, but where sandstones dominate, borehole yields of ~2 to 4 l/s are seen, and coarser conglomerate beds at the base of the sequence may support higher yields (Offodile 2002). The Patti and Lokoja sandstones are thought to have similar hydrogeological characteristics to the Nupe Sandstone. Recharge is directly from rainfall and, where there are overlying alluvial deposits, through these

Upper Benue Basin - Sedimentary - Intergranular

Named Aquifers General Description Water quantity issues Water quality issues Recharge
Bima Sandstone, Yolde Sandstone These formations have relatively low permeability and usually provide poor to moderate yields of about 1 to 5 l/s. They vary substantially in thickness. The water table depth is usually between 60 and 165 m. Boreholes range in depth from 30 to 300 m. None Water quality is generally good. Recharge is mainly by infiltration from rainfall.

Lower Benue Basin - Sedimentary - Intergranular & Fracture

Named Aquifers General Description Water quantity issues Water quality issues Recharge
Makurdi, Keana, Ezeaku, Awe and Asu River Group formations These formations tend to be indurated and dominated by fracture flow (although the Makurdi Sandstone is less so). Typical yields are around 2 to 8 l/s, but wide variations are seen, depending on the degree of fracturing and deep weathering. The aquifers therefore tend to be localised, and vary greatly in thickness. They are usually unconfined with the water table at about 10 - 40 m depth. Boreholes are typically 40 - 150 m deep. None Water can be highly mineralised. Direct rainfall recharge.


Named Aquifers General Description Water quantity issues Water quality issues Recharge
Basement aquifers Basement rocks can form local aquifers if the degree of weathering and/or fracturing is sufficient. Crystalline and coarse-grain rocks, such as gneiss and migmatite, become sandy on weathering, thus preferentially forming aquifers. Argillaceous meta-sedimentary rocks tend to be become clayey with low permeability when weathered, forming aquitards. Overall, basement aquifers tend not to be high yielding. They typically vary in thickness from 10 to 25 m, with water table depth varying from about 5 to 15 m. Boreholes tend to be drilled to depths between 10 and 70 m, depending on local conditions. None Water quality is generally good. Direct rainfall recharge.

Groundwater Status

Groundwater recharge

The total renewable groundwater resources potential in Nigeria is estimated at 155.8 billion cubic metres per year (BCM/year), derived from estimated total annual groundwater recharge (JICA 2014). This estimated groundwater recharge at a regional level:

Region Estimated Groundwater Recharge (BCM/year)
Niger North (Northwest Nigeria) 5.0
Niger Central (West-central Nigeria) 20.5
Upper Benue (East-central Nigeria) 19.3
Lower Benue (East Nigeria) 18.6
Niger South (South-central Nigeria) 31.9
Western Littoral (Southwest Nigeria) 23.4
Eastern Littoral (Southeast Nigeria) 32.8
Chad Basin (North-east Nigeria) 4.3
Total 155.8

Groundwater-surface water interaction

There is interaction between the River Niger and sedimentary aquifers in the Sokoto Basin.

Groundwater use and management

Groundwater use

Groundwater is used in Nigeria for domestic, agricultural and industrial purposes. The cities of Calabar (coastal southeastern Nigeria) and Port Harcourt (capital of Rivers State, south Nigeria) are totally dependent on groundwater.

JICA (2014) recorded a total of 64,494 boreholes in Nigeria, extracting an estimated total of 6,340,000 m³/day. The groundwater access points identified were:

  • Boreholes with motorised pump :19,758
  • Boreholes with hand pump :44,736
  • Shallow hand-dug wells :13,108

A 1996 survey by the Federal Ministry of Water Resources (FMWR) found only 63% of Nigerian boreholes were actually in working order, with many out of action due to pump failure (JICA 2014).

Groundwater management

Groundwater management institutions

There are many bodies with responsibility for groundwater management in Nigeria. They include the government agencies:

  1. Nigeria Hydrological Services Agency (NIHSA) whose mandate is water resources (groundwater and surface water) assessment of the country; its quantity, quality, availability and distribution in time and space
  2. Nigeria Integrated Water Resources Management Commission (NIWRMC) that is responsible for regulation of water use and allocation
  3. The state Ministries of Water Resources and their Rural Water Supply and Sanitation Agencies (RUWATSSAN), responsible for provision of water to their various States
  4. All the River Basin Development Authorities, which are also parastatals of the Federal Ministry of Water Resources involved in the provision of water supply to rural environments within their catchments.

Legal framework for groundwater management

Legislation has been developed but is awaiting enactment.

Groundwater for the future

Groundwater could contribute to increasing future water demand by upgrading existing borehole infrastructure, switching from hand pumps to motorised pumps (JICA 2014).

During their project to update Nigeria's Water Resources Masterplan, JICA (2014) identified issues that were affecting both yield and quality of groundwater in Nigeria:

  • overabstraction leading to water level decline and boreholes drying up
  • contamination of groundwater resulting from sea water intrusion and infiltration of domestic and industrial contaminants.

Modelling by JICA (2014) suggested that climate change would lead to an overall decline in groundwater recharge in Nigeria, with the impact most likely greatest in the North Niger and Chad basins. This modelling suggested declining groundwater levels would occur, leading to previously productive boreholes becoming dry. The study suggested the following measures to increase resilience to climate change in Nigeria's groundwater supply:

  • drill future boreholes 20 m deeper
  • position pumps at greater depth (20 m deeper than present)

Transboundary aquifers

Nigeria has a number of transboundary aquifers:

  1. The Iullemeden, Taoudeni/Tanezrout Aquifer Systems (ITAS) shared by Algeria, Benin, Burkina Faso, Mali, Mauritania, Niger and Nigeria.
  2. The Chad Basin Aquifer shared by Cameroon, Central African Republic, Chad, Niger and Nigeria.
  3. The Keta Basin Aquifers shared by Ghana, Togo, Benin and Nigeria.
  4. The Benue Trough shared by Cameroon and Nigeria
  5. The Rio Del Rey Basin shared by Cameroon and Nigeria along the coast.

A mechanism for the management of the Iullemeden aquifer is in development, as Nigeria has just ratified an Agreement. The Lake Chad Basin Commission manages issues on the Chad Basin. Groundwater management activities on other Basins are yet to commence.

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

Groundwater monitoring

There is a national groundwater level monitoring programme with 43 monitoring points, 32 of which are equipped with data loggers. The frequency of monitoring at sites with data loggers is daily, and sometimes twice daily.

The Nigeria Hydrological Services Agency (NIHSA), an agency of the Federal Ministry of Water Resources (FMWR), carries out the monitoring of groundwater level, and the data are stored at their headquarters in Abuja.

The NIHSA is also responsible for water quality monitoring, but as yet a full programme is not in place due to lack of equipment.


Many of the references below, and others relating to the hydrogeology of Nigeria, can be seen in the African Groundwater Literature Archive.

Key Geology References

Adelana SMA, Olasehinde PI, Bale RB, Vrbka P, Edet AE and Goni IB. 2008. An overview of the geology and hydrogeology of Nigeria. In: Adelana, S.M.A. and MacDonald, A.M. Applied Groundwater Studies in Africa. IAH Selected Papers in Hydrogeology Volume 13. Taylor & Francis, London, UK.

Mpamba NH. 2006. Comparative Analytical Model for Groundwater Monitoring in the Urban and Rural areas of Zambia – Groundwater Resources Data and Information . The University of Zambia, Lusaka, Zambia.

Nwajide CS. 2013. Geology of Nigeria’s sedimentary basins. CSS Bookshops Ltd

Rahaman MA and Malomo S. 1983. Sedimentary and crystalline rocks of Nigeria In: Ola, S. A. Ed. Tropical soils of Nigeria in Engineering Practice. Rotterdam. Balkema.

Kogbe CA. 1976. Microbiostratigraphy of lower Tertiary sediments from the southeastern flank of the Iullemeden basin, N.W. Nigeria. In: Kogbe C. A. (Ed.). 1976. Geology of Nigeria. Elizabethan Publishing Company, Lagos, Nigeria.

Obaje NG. 2009. Geology and mineral resources of Nigeria. Springer.

Key Hydrogeology References

JICA. 2014. The project for review and update of Nigeria national water resources master plan; Vol.2. Japan International Cooperation Agency : Yachiyo Engineering Co., Ltd. : CTI Engineering International Co., Ltd. : Sanyu Consultants Inc. [JICA report PDF]

Kogbe C. A. (Ed.). 1976. Geology of Nigeria. Elizabethan Publishing Company, Lagos, Nigeria.

Offodile ME. 2002. Groundwater study and development in Nigeria. Mecon Services Ltd, Jos, Nigeria.

Pavelic P, Giordano M, Keraita B, Ramesh V and Rao T. (Eds.). 2012. Groundwater availability and use in Sub-Saharan Africa: A review of 15 countries. Colombo, Sri Lanka: International Water Management Institute (IWMI). 274 p. doi: 10.5337/2012.213 [Pavelic et al., 2012, PDF]

Wardrop Engineering Consultants. 1985. Bauchi State hydrogeology, Hydrogeology Map 1:500000. In : Bauchi State Agricultural Development Programme. Borehole project final report. Wardrop Engineering Consultants, 1985.

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