THE IMPACT OF SEDIMENT TRANSPORT ON IRRIGATION CANAL AND ITS EFFECT ON APPLICATION UNIFORMITY OF SPRINKLER IRRIGATION SYSTEM ON EAST BANK CANAL, FINCHAA SUGAR ESTATE, ETHIOPIA

Abstract

Sprinkler irrigation technology helps in more efficient use of water by eliminating field water conveyance channels, thereby reducing water loss. The amount of sediment transport and the impact on irrigation uniformity is important for better management of an irrigation system. This study was focused on the impact of sediment transport in the canal and its effect on application uniformity of sprinkler system on east bank canal Finchaa Sugar Estate. Its objective was to determine the effect of sediment on the canal and application uniformity distribution of sprinkler irrigation system at Finchaa, East Bank Sugar Estate .Currently serious irrigation problems were observed at Finchaa East bank sugar estate which raised from poor irrigation water quality containing sediment entered from upstream of the river which affects both canal structure and application uniformity of the system canal conveyance efficiency leading to inadequacy and inequity in water distribution to crops. This poor distribution could be due to the reason that the sprinkler nozzles were worn out and increase in diameter because of the action of wear and tear by the sediments.In order to analyze the effect of the problem different techniques have been taken in to account, it includes: Suspended sediment samples were collected from weir, inlet to end of canal at an average of eight kilometers along the canal using US D-74 suspended sediment sampler. The samples were analyzed in laboratory for sediment concentration, sediment rate discharge and particle size distribution along the canal and its effect on application uniformity of water distribution. The CUC and DU results for the new nozzle were above the minimum recommended values of 85% and 80% respectively at all test pressures. The specific discharge measurement showed that, both the upstream and downstream old nozzles were applying excess irrigation water causing loss of water, energy and yield in extreme cases may result in groundwater rise. But sediment deposition in irrigation canals results in rising canal bed levels, reduced canal capacities, and problems in supplying the required amounts of water to some or all parts of the irrigated area. Sediment deposition in irrigation canals results in rising canal bed levels, reduced canal capacities, and problems in supplying the required amounts of water to some or all parts of the irrigated area and there was a high over flowing of water occurring in the conveyance system at the end of the canal due to the accumulation of sediment in the canal