Sedimentation Problems In The Blue Nile Reservoirs And Gezira Scheme

Younis A. Gismalla

Younis A. Gismalla the Hydraulics Research Station

Abstract

The development in Sudan is basically dependent on the Blue Nile water. The high sediment load brought by the river during its flood has major influences on the design and operation of the reservoirs built across the river and the schemes irrigated from it. Sediment deposited in reservoirs reduces the useful life of the reservoirs as well as diminishes the benefits from the dam (irrigation and power genera(ion). Large operational costs are incurred every year in dredging the sediment from reservoirs and canal sediment clearance. The sediment monitoring programme launched in 1988 in Gezira Scheme and the Blue Nile, has revealed very important results and answered many vital questions regarding sedimentation in Gezira Scheme. On average 8.5 million tons of sediment enters Gezira scheme every year. More than 97% of this sediment is very fine; therefore, standard methods of sediment exclusion at the intakes will not offer a solution. More than 70% of the sediment can be excluded if the canals gates are closed during the period 20^th July to 31st August.

This paper reviews the sedimentation problem in the Blue Nile and Gezira Scheme and its management options based on the outcomes of the monitoring programme.

References

 Ahmed A. A. , (2003). Towards improvement of irrigation system management. AMCAW Conference, Addis Ababa, Ethiopia.
 Brune, G.N. (1953). Trap efficiency of reservoirs. Transaction of the American Geophysics Union, Vol. 34.
 Churchill, M.A. (1948). Discussion of analysis and use of reservoir data. By C. Gottschalk in the proceedings of the Federal Interagency Sedimentation Conference, Denver, Clorado, January 1948, pp. 139.
 Fadul E.M. (2001). Development of alluvial canals design procedures. HRS report.
 Gismalla Y. A. (2006). Sedimentation in Small Dams of Western Sudan. Proceedings of the International Sediment Initiative Conference (ISIC), pp 259-628, 12-15 November 2006, Khartoum, Sudan.
 Gismalla Y. A. , Fadul E M. (2006). Design and remodelling of stable canals in Sudan. Proceedings of the International Sediment Initiative Conference (ISIC), pp371-384, 12-15 November 2006, Khartoum, Sudan.

 Gismalla Y A. (2009). The Sediment Monotoring Programme, Annual report for the year 2008. The Hydraulics Research Station. Wad Medani, Sudan.
 Hamad O.E. (1993). Optimal operation of a reservoir system during a dry season. Ph.D. Thesis. University of 'Newcastle Upon Tyne. Newcastle, UK.
 Hamid S H. (2001). Sedimentation in Sudanese irrigation systems. Proceedings of the Sediment Transport & Watershed Management Workshop, pp. 87-97, 21 November 2001, Khartoum, Sudan.
 HR Wallingford, "Research for Rehabilitation: Siltation monitoring study", Final report, EX 2394 and EX 2244 October 1990,
 Hussein A.S and Yousif D.M. (1994). Prediction of settling basins performance for very fine sediment. Proceedings of the International conference on Efficient Utilization and Management of Water Resources in Africa. Part One, pp. 75-85, 1-4 February 1994. Khartoum, Sudan.
 Hussein et al, (2005), "Reservoir sedimentation", Nile Basin Capacity Building Network, NBCBN, Khartoum, Sudan
 Hussein A.S. (2006). Reservoir sedimentation, Roseires reservoir as a case Study. A keynote speech in the International Sediment Initiative Conference (ISIC), 12-15 November 2006, Khartoum, Sudan.
 Hussein A s Ahmed, A.A. and Ahmed S. E. (1986). Sedimentation problems in the Gezira Scheme. Proceedings of the international conference on Water Resources Needs and Planning in Drought-prone Areas, pp. 947-955, 12-16 December 1986, Khartoum, Sudan.
 Matthews, I.S.G. (1952). Investigation of Stable Channels in the Gezira Canalisation Scheme. SID, Tech. Note No 3/52.
 Mohamed T.A., Ahmed S.E. and Hamad OF (2001). Sediment transport management practices in reservoirs, irrigation canals and pumps} schemes inlets. Proceedings of the Sediment Transport & Watershed Management Workshop, pp. 75-85, 21 November 2001, Khartoum, Sudan.
 Nestor J. V. (1998). Sediment transport in irrigation canals. Balkema, Rotterdam 1998. pp 13
 ENTRO (2007). Eastern Nile Watershed Management Project. Cooperative Regional Assessment (CRA) for Watershed Management. Distributive Analysis. Easter Nile Technical Regional Office (ENTRO). Addis Ababa, Ethiopia 2007.