Sediment Deposition in the Gezira Irrigation Scheme

PhD research project by Ishraga S. Osman

Improving the efficiency of irrigation via sediment management is needed for adequate water supply and food production. The Gezira Irrigation Scheme, which represents a sink of eroded sediment from upstream of the Blue Nile, has been chosen to study the impact of the improvement of land use management upstream of the Blue Nile on the downstream. The scheme has an area of 880,000 ha and is irrigated from the Blue Nile River. The scheme is facing severe sediment accumulation in its irrigation canals which represents a challenge to those responsible for the operation and maintenance of these canals. The sediment accumulation of canals reduces the canal conveyance capacity, causes irrigation difficulties and reduces the productivity of the scheme. Each year, large investments are required to maintain and to rehabilitate the canal system to keep them in an acceptable condition. This problem is not only seriously affecting the performance of the irrigation canals, but also jeopardizing their sustainability as well as affecting the production.

The aim of this research is to find a solution to reduce the impact of sediment accumulation in the irrigation canals by improving the operation and maintenance procedure. This will be achieved through better understanding of sediment processes in the irrigation canals. A link between the irrigation system operation and the resulting system performance will be established in terms of sediment transport in order to develop a rational plan for implementing needed changes. Sediment, hydraulic and operation data will be collected. Different operation scenarios will be conducted by applying SETRIC model to find a suitable strategy to reduce the sediment accumulation in irrigation canals.