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Water Resources in Sudan

River Nile, Sudan
Photo 1: River Nile, Sudan ( Source: David Stanley, Flicker).

The most abundant water resource is rainfall. It is estimated that the total precipitation is around 1,250 billion cubic metres (BCM).[1] Rainfall varies in amount and frequency (number of individual showers), with amounts generally decreasing from north to south. Sudan’s estimated annual rainfall since the secession of South has decreased from 1,060BCM to about 442BCM.[2] The rainy season runs from June to September with a peak in August.
Harnessing rainwater and floods is not widely practiced and water harvesting is poorly developed. Although the practice is old, it is only carried out on a small scale. Rainwater is used to cultivate around 35 million feddans[3] of sorghum and millet subsistence and semi-mechanized rain-fed agriculture. Most of the rainwater evaporates, although some recharges groundwater or run-off in seasonal streams.

At the watershed level, Sudan comprises seven main basins as shown in Figure 1.

  • Nile
  • Northern Interior
  • Lake Chad
  • North-east Coast
  • Lake Turkana
  • Baraka
  • Gash

Figure 1: Areas of Sudan’s basins (%)

Surface Waters

Sudan has around one million hectares of surface water, the most important of which is a 2,000km-long stretch of the Nile and tributaries. Wetlands cover 10% of the country,[4] whereas forests cover 4%.[5] There are many seasonal water courses (khors) that run during the short rainy season. Their discharge volumes, flow durations and water quality have never been gauged. The total annual discharge of the relatively perennial rivers, outside the Nile basin, is 7.0BCM. The most important of these are the Gash, Baraka and Khor Arbaat rivers in the east, Wadi Azoom and Galol as well as many others in Darfur, and Khor Abu Habil, which drains the Nuba Mountains of Southern Kordofan.

Wetlands
There are 30 distinct types of wetlands in Sudan.[6] Three have been designated as Ramsar sites (wetlands of international importance).[7] One of them is the mayas (oxbow lakes) in Dinder National Park (Map 1).[8]

River Nile water resources in Sudan
Map 1: Mayaas in Dinder National Park[9]

Sudan’s wetlands include:

  • Freshwater lakes. Examples are Er Rahad, Kundi, Keilak and Abyad in western Sudan. They are rich in biodiversity, especially water fowl and micro-invertebrates.[10]
  • Seasonal lakes. These are found in different regions and include Butu Rayia, Um Badir, al-Fula, Ras Amir, Um Baggara, Kibbew, Undur and Nzeli.[11]
  • Crater lakes. Two volcanic lakes are found in Jebel Marra (Dariba) and the Meidoub Hills (Malha). Both are saline.
  • Mountain streams include Wadi Shalengo, which drains a catchment area of approximately 8,450km² on the western flank of the Nuba Mountains, and extends south-south-west through a sandstone ridge to discharge into a delta region of approximately 2,200km² around Niama. The southern edge of this delta is drained by the Regaba al-Zarga channel complex, which joins the Bahr al-Ghazal about 150 kilometres downstream of the town of Abyei. Arbaat is the only perennial stream that drains the Red Sea Hills.

Hot springs. Akasha hot springs, at the tail of Lake Nubia, are the most accessible. Others are found in Quella (Jebel Marra), al-Harra (Wadi Azum) and in the Meidoub Hills

Groundwater

Groundwater is more readily available than other water resources during the long dry season. At least 80% of the population depends almost entirely on groundwater.[12] Away from the Nile basin and other non-Nilotic river wells, groundwater is the only source of water. Available groundwater is 900BCM, with an annual recharge of 1,563BCM.[13]

The Nubian Sandstone Aquifer System is shared by Sudan, Egypt and Libya. It is recharged from the Nile in Sudan (Map 2). With an area of almost 29% of Sudan, the system is the country’s most important aquifer. All the major aquifers and their annual recharge and abstractions are shown in Table 3.

Table 2: Annual recharge and annual abstraction from major aquifers in Sudan

AquiferStorage (km3)Annual recharge (km3)Annual abstraction (km3)
Nubian sandstone5030.3810.086
Um Ruwaba220.5820.04
Gezira380.1000.005
Alluvial deposits10.5000.096
Total5641.5630.227
water resources in Sudan River Nile Basin
Map 2 :Groundwater resources in Sudan and South Sudan.[14]

Nonconventional Water Resources

Prior to the introduction of UNICEF’s small bore hand pumps, villagers in western Sudan used to store water in the hollowed trunks of giant baobab trees (Adansonia digitata). In many other parts of the country, water is collected and stored in haffirs , a crude form of water harvesting for domestic, pastoralist and animal use in Darfur and Kordofan. There are thousands of haffirs of various storage capacities, some reaching thousands of cubic metres.

Total Water Availability

Sudan’s share of the water from the Nile is 20.5BCM measured at Sennar (Table 4). The non-Nilotic river provides 7BCM, with an additional 4BCM from groundwater. The Food and Agriculture Organization of the United Nations (FAO)[15] estimates the annual water withdrawal per capita to be 1,020m3.

Table 4: Summary of the available water in Sudan[16]

Water resourcesQuantity (BCM)Constraints
Sudan present share from the Nile water agreement (at central Sudan)20.5Seasonality, limited storage facilities, expected to be shared with riparian’s.
Water from wadis5.0 -7.0High variability in amounts, short duration flows, difficult to monitor or harvest, some shared with neighbors.
Renewable groundwater4.0Deep water, high cost of abstraction, remote areas, lack of infrastructure.
Present total30.0
Expected from reclamation of swamps6.0High capital investment social and environment problems expected.
Total36

[1] Makawy, A.Y.I., 2013. Transboundary Water in Sudan Post the Separation of South Sudan. Faculty of Engineering, University of Khartoum.
[2] Ibid.
[3] One feddan is 1.04 acres or 0.43 hectares.
[4] Moghraby, A.I. el-, 2011. ‘Water Security After the 9th of January Referendum.’ A presentation to the Sudanese Environmental Forum.
[5] FNC, 2014. Forest National Corporation Report 9.
[6] UNEP, 2015. Towards a Wetlands Inventory for the Sudan. Unpublished UNEP report.
[7] Available at www.ramsar.org/wetland/sudan, accessed [19/8/2017].
[8] Van Hoven, W.K.; Tayeb, G.; Kwotel, F.T.; Ding, K.A.; Moghraby, A.I. el-, 1998. Management Plan for the Dinder National Park. UNDP Project SUD /98/G41.
[9]Abdel Hameed, S.M.; Awad, N.M.; Ammna, A.H.; Abdel Rahim, O; Moghraby, A.I. el-, 1997. ‘Water Management in the Dinder National Park, Sudan.’ Agriculture and Forest Meteorology Journal, 84:89-96.
[10] Green, J.; Moghraby, A.I. el-; Ali, O.M, 1984. ‘A Faunistic Reconnaissance of Lakes Kundi and Keilak, Western Sudan.’ Limnology and Marine Biology of the Sudan. Dumont, H.; Moghraby, A.I. el-; Dussougi, L.A. (eds). Springer.
[11] Moghraby, A. I. el-, 2011. ‘Water Security After the 9th of January Referendum.’ A presentation to the Sudanese Environmental Forum.
[12] UNEP, 2015. Towards a Wetlands Inventory for the Sudan. Unpublished UNEP report.
[13] Anonymous, 2004. IGAD-HYCOS Project Document, WHTCOS No. 1.
[14] Abdo, G.; Salih, A., 2012. ‘Challenges Facing Groundwater Management in Sudan.’ Paper presented at the Annual Conference of Postgraduate Studies and Scientific Research, 17-20 February 2012, Khartoum, Sudan. Available at http://khartoumspace.uofk.edu/bitstream/handle/123456789/9745/Challenges_Facing_Groundwater_Management_in_Sudan.pdf?sequence=1, accessed [19/8/2017].
[15] FAO, 2008. Recent Developments in Agricultural Research in the Sudan (SRO/SUD/623/mul).
[16] Elamin, A.W.M., 2013, Water Resources in Sudan, https://www.researchgate.net/publication/275016737_Water_Resources_in_Sudan, accessed [19/8/2017].