Abstract
Substantial fluctuations in precipitation and runoff have occurred over the Nile Basin in recent decades. Ten-year mean flows of the Blue Nile (Khartoum gauge) during the 20th century have ranged from 42.2 to 56.7 km3 and for the White Nile (Malakal gauge) from 25.5 to 36.9 km3. These fluctuations have been responsible for changes in decade-mean Main Nile discharge of up to ± 20% which have had important consequences for water resource management in both Egypt and Sudan.
This paper provides a review of the Nile Basin hydrology incorporating, for the first time, analyses of the relationships between precipitation and runoff fluctuations in the instrumental period for each of the eight major sub-basins within the Nile Basin. These sub-basins possess very different physical, climatic and hydrological characteristics. Over 90% of the Main Nile discharge originates from only four of the sub-basins; Lake Victoria, Blue Nile, Atbara, and the Sobat. Interbasin correlations of 40 y (1945-84) precipitation and runoff annual time series identify two broadly homogeneous regions; the Ethiopian highlands (Blue Nile and Atbara) and the Lake Victoria and Equatorial Lakes (White Nile). These regions posses contrasting precipitation regimes whose interannual variations are uncorrelated in time and which are therefore associated with different atmospheric circulation anomalies. The observed relationships between catchment precipitation and runoff, however, are not straightforward and the sensitivity of runoff to precipitation fluctuations varies from basin to basin. Some of the water resource management implications of these fluctuations for Egypt are discussed. With water demand in Egypt alone set to increase 17% by the year 2000, it is critical that the role of future climate change in Nile water management is thoroughly assessed based on a correct modelling of the diverse hydrological characteristics of the various Nile sub-basins.
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References
Abu-Zeid, M. and Abdel-Dayem, S.: 1992, ‘Egypt Programmes and Policy Options for Facing the Low Nile Flows’, in Abu-Zeid, M. A. and Biswas, A. K. (eds.),Climatic Fluctuations and Water Management, Butterworths and Heineman, Oxford, pp. 48–58.
Abu-Zeid, M. and Hefny, K.: 1992, ‘Water-Resources Assessment and Management in Egypt during Conditions of Stress’,WMO Bull. 41 (1, 35–46.
Allan, J. A.: 1990, ‘Review of Evolving Water Demands and National Development Options’, in Howell, P. P. and Allan, J. A. (eds.),The Nile, Resource Evaluation, Resource Management, Hydropolitics and Legal Issues, SOAS-RGS, London, pp. 181–192.
Balek, J.: 1990, ‘Assessment of Historical Changes in Aquatic Environments under Climatic Impacts’,Water Resourc. Developm. 6(3, 178–186.
Bhatt, U. S.: 1989, ‘Circulation Regimes of Rainfall Anomalies in the African-South Asian Monsoon Belt’,J. Clim. 2, 1133–1144.
Chesworth, P.: 1990, ‘History of Water Use in Sudan and Egypt’, in Howell, P. P. and Allan, J. A. (eds.),The Nile, Resource Evaluation, Resource Management, Hydropolitics and Legal Issues, SOAS-RGS, London, pp. 40–58.
Collins, R. O.: 1990, ‘Historical View of the Development of Nile Water’, in Howell, P. P. and Allan, J. A. (eds.),The Nile, Resource Evaluation, Resource Management, Hydropolitics and Legal Issues, SOAS-RGS, London, pp. 153–180.
Currie, R. G.: 1987, ‘On Bistable Phasing of 18.6-Year Induced Drought and Flood in the Nile Records since AD 650’,Int. J. Climatol. 7, 373–389.
Datta, R. R.: 1981, ‘Certain Aspects of Monsoonal Precipitation Dynamics over Lake Victoria’, in Lighthill, Sir James and Pearce, R. P. (eds.),Monsoon Dynamics, pp. 333–349.
Demissie, M.: 1990, ‘Analysis of Drought in Ethiopia Based on Nile River Flow Records’, inThe State-of-The-Art of Hydrology and Hydrogeology in the Arid and Semi-Arid Areas of Africa, Proceedings of the Sahel Forum, IWRA, Illinois, pp. 159–168.
Dugdale, G., Hardy, S., and Milford, J. R.: 1991, ‘Daily Catchment Rainfall Estimated from Meteosat’,Hydrol. Process. 5, 261–270.
Eischeid, J. K., Diaz, H. F., Bradley, R. S., and Jones, P. D.: 1991,A Comprehensive Precipitation Data Set for Global Land Areas, U.S. Department of Energy, TR051, Washington.
Eklundh, L. and Pilesjo, P.: 1990, ‘Regionalization and Spatial Estimation of Ethiopian Mean Annual Rainfall’,Int. J. Climatol. 10, 473–494.
El-Tahir, E. A. B.: 1989, ‘A Feedback Mechanism in Annual Rainfall, Central Sudan’,J. Hydrol. 110, 323–334.
Evans, T.: 1990, ‘History of Nile Flows’, in Howell, P. P. and Allan, J. A. (eds.),The Nile, Resource Evaluation, Resource Management, Hydropolitics and Legal Issues, SOAS-RGS, London, pp. 5–39.
Farmer, G.: 1981,Regionalisation and Study of an Alleged Change in the Regional Climatology of East Africa, Unpublished Ph.D. Thesis, University of Sheffield, U.K.
Flohn, H. and Burkhardt, T. H.: 1985, ‘Nile Runoff at Aswan and Lake Victoria: A Case of Discontinuous Climate Time Series’,Zeitschr. Gletscherkde. Glaziolgeol. 21, 125–130.
Flohn, H.: 1987a, ‘Rainfall Teleconnections in Northern and Northeastern Africa’,Theor. Appl. Climatol. 38, 191–197.
Flohn, H.: 1987b, ‘East African Rains of 1961/62 and the Abrupt Change of the White Nile Discharge’,Palaeoecol. Africa 18, 3–18.
Folland, C., Owen, J., Ward, M. N., and Colman, A.: 1991, ‘Prediction of Seasonal Rainfall in the Sahel Region Using Empirical and Dynamic Methods’,J. Forecast. 10, 21–56.
Hassan, F. A.: 1981, ‘Historical Nile Floods and their Implications for Climatic Change’,Science 212, 1142–45.
Hellden, U. and Eklundh, L.: 1988,National Drought Impact Monitoring - A NOAA NDVI and Precipitation Data Study of Ethiopia, Lund Studies in Geography No. 15, Lund University Press.
Howell, P. P. and Allan, J. A.: 1990,The Nile, Resource Evaluation, Resource Management, Hydropolitics and Legal Issues, SOAS-RGS, London.
Howell, P. P., Lock, M., and Cobb, S.: 1988,The Jonglei Canal: Impact and Opportunity, Cambridge University Press, Cambridge.
Hulme, M.: 1990, ‘The Changing Rainfall Resources of Sudan’,Trans. Inst. Brit. Geogs. 15, 21–34.
Hulme, M.: 1992, ‘Rainfall Changes in Africa: 1931–60 to 1961–90’,Int. J. Climatol. 12, 685–699.
Hurst, H. E. and Philips, P.: 1933,The Nile Basin, Volume IV, Ten-day Mean and Monthly Mean Discharges of the Nile and Its Tributaries, Ministry of Public Works, Physical Department, Cairo.
Hurst, H. E.: 1938,The Nile Basin, Volume V, The Hydrology of the Lake Plateau and the Bahr el Jebel, Ministry of Public Works, Physical Department, Cairo.
Hurst, H. E.: 1950,The Nile Basin, Volume VIII, The Hydrology of the Sobat and White Nile and the Topography of the Blue Nile and Atbara, Ministry of Public Works, Physical Department, Cairo.
Hurst, H. E.: 1951, ‘Long-term Storage Capacity of Reservoirs’,Trans. ASCE 116, 770–799.
Hurst, H. E., Black, R. P., and Simaika, Y. M.: 1965,Long Term Storage, Constable, London.
Hydromet: 1981,Hydrometeorological Survey of the Catchments of Lake Victoria, Kyoga and Mobutu Sese Seko: Project Findings and Recommendations, UNDP/WMO, Geneva.
Institute of Hydrology: 1984,A Review of the Hydrology of Lake Victoria, ODA, London and IH, Wallingford.
Janowiak, J. E.: 1988, ‘An Investigation of Interannual Rainfall Variability in Africa’,J. Clim. 1, 240–255.
Karl, T. R. and Riebsame, W. E.: 1989, ‘The Impacts of Decadal Fluctuations in Mean Precipitation and Temperature on Runoff: A Sensitivity Study over the United States’,Clim. Change 15, 423–447.
Kite, G. W.: 1981, ‘Recent Changes in Level of Lake Victoria’,Hydrol. Sci. Bull. 26, 233–243.
Kite, G. W.: 1982, ‘Analysis of Lake Victoria Levels’,Hydrol. Sci. Bull. 27, 99–110.
Lamb, H. H.: 1966, ‘Climate in the 1960s’,Geog. J. 132, 183–212.
Lovett, R. and Wood, C. A.: 1974, ‘Rainfall Reliability in Ethiopia’,Weather 31, 417–424.
Morth, H. T.: 1967, ‘Investigations into the Meteorological Aspects of the Variations in the Level of Lake Victoria’,East Agrian Met. Dept. Memoirs IV (2), 1–22.
Nemec, J. and Schaake, J.: 1982, ‘Sensitivity of Water Resource Systems to Climate Variation’,Hydrol. Sci. J. 27, 327–343.
Nicholson, S. E.: 1986, ‘The Spatial Coherence of African Rainfall Anomalies: Interhemispheric Teleconnections’,J. Clim. Appl. Meteorol. 25, 1365–1381.
Nicholson, S. E. and Entekhabi, D. I.: 1986, ‘The Quasi-Periodic Behaviour of Rainfall Variability in Africa and Its Relationship to the Southern Oscillation’,Archives Meteorol. Geophys. Bioclim. (A)34, 311–348.
Palmer, T. N.: 1986, ‘Influence of the Atlantic, Pacific and Indian Oceans on Sahel Rainfall’,Nature 322, 251–253.
Piper, B. S., Plinston, D. T., and Sutcliffe, J. V.: 1986, ‘The Water Balance of Lake Victoria’,Hydrol. Sci. J. 31, 25–37.
Popper, W.: 1951,The Cairo Nilometer, University of California Press, Berkeley and Los Angeles.
Riehl, H., El-Bakry, M., and Meitin, J.: 1979, ‘Nile River Discharge’,Mon. Wea. Rev. 107, 1546–1554.
Rodhe, H. and Virji, H.: 1976, ‘Trends and Periodicities in East African Rainfall Data’,Mon. Wea. Rev. 104, 307–315.
Salas, J. D. and Boes, D. C.: 1982, ‘Modelling of the Equatorial Lakes Outflows’, in Singh, V. P. (ed.),Statistical Analysis of Rainfall and Runoff, Water Resources Publications, Colorado.
Schaake, J. C.: 1990, ‘From Climate to Flow’, in Waggoner, P. E. (ed.),Climate Change and U.S. Water Resources, Wiley, New York, 177–206.
Schaake, J. C.: 1992, ‘Precipitation Analysis for Ethiopia’, Paper presented at the International Workshop on Analysis Methods of Precipitation on a Global Scale, Organised by the Global Precipitation Climatology Centre, September 14–17, 1992, Koblenz, Germany.
Shahin, M.: 1985,Hydrology of the Nile Basin, Elsevier, Amsterdam.
Sutcliffe, J. V. and Knott, D. G.: 1987, ‘Historical Variations in African Water Resources’, in Solomon, S. I., Beran, M., and Hogg, W. (eds.),The Influence of Climate Change and Climatic Variability on the Hydrologic Regime and Water Resources, IAHS Publication No. 168, Oxfordshire.
Sutcliffe, J. V. and Lazenby, J. B. C.: 1990, ‘Hydrological Data Requirements for Planning Nile Management’, in Howell, P. P. and Allan, J. A. (eds.),The Nile, Resource Evaluation, Resource Management, Hydropolitics and Legal Issues, SOAS-RGS, London, pp. 107–136.
Sutcliffe, J. V. and Parks, Y. P.: 1987, ‘Hydrological Modelling of the Sudd and Jonglei Canal’,Hydrol. Sci. J. 32, 143–159.
Todini, E. and O'Connell, P. E.: 1979,Hydrological Simulation of Lake Nasser, Volume 1 - Analysis and Results, IBM Italia Scientific Centres, Italy and Institute of Hydrology, Wallingford.
Vincent, C. E., Davies, T. D., and Beresford, A. R. C.: 1979, ‘Recent Changes in the Level of Lake Naivasha, Kenya, as an Indicator of Equatorial Westerlies over East Africa’,Clim. Change 2, 175–189.
Waterbury, J.: 1988, ‘Water Use and Demand in the Nile Basin’, in Howell, P. P., Lock, M., and Cobb, S. (eds.),The Jonglei Canal: Impact and Opportunity, Cambridge University Press, Cambridge, pp. 64–84.
Wigley, T. M. L. and Jones, P. D.: 1985, ‘Influences of Precipitation Changes and Direct CO2 Effects on Streamflow’,Nature 314, 149–152.
Williams, M. A. J. and Faure, H.: 1980,The Sahara and the Nile, A. A. Balkema, Rotterdam.
World Bank: 1989,Sub-Saharan Africa Hydrological Assessment Sudan, World Bank-UNDP, RAF/87/030.
Yevjevich, V. M.: 1963,Fluctuations of Wet and Dry Years: Part I - Research Data and Mathematical Models, Hydrology Paper I, Colorado State Univ., Fort Collins, 55 pp.
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Conway, D., Hulme, M. Recent fluctuations in precipitation and runoff over the Nile sub-basins and their impact on main Nile discharge. Climatic Change 25, 127–151 (1993). https://doi.org/10.1007/BF01661202
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DOI: https://doi.org/10.1007/BF01661202