Abstract:
Poor irrigation conveyance infrastructure is the major challenges of Omo Kuraz II sugarcane
irrigation scheme. This study assesses the performance left bank main canals of the Kuraz
Sugarcane Irrigation, focusing on conveyance efficiency, water delivery capacity, effectiveness
of infrastructure, and water surface elevation ratios. Soil texture was evaluated through
hydrometer test analysis in laboratory where field capacity and permanent wilting point were
estimated using pressure plate apparatus. Crop water requirement and irrigation duty were
estimated through CropWat model by using soil and climate data as input. Climate data was
collected from Kuraz automatic climate station. Canal discharge was measured using floating
techniques and actual canal cross section such as depth and width were measured using tap
meter. The maximum discharge at two cross drainage structure was estimated using
Hydrological HEC-HMS model. The functional and non-functional infrastructure in the
scheme were counting through field survey. The results reveled that the representative soil
texture was clay and the mean value of soil dry bulk density, field capacity, permeant wilting
point of soil were 1.36g/cm³, 40.2% and 26.4%, respectively. The total crop water and
irrigation requirement for sugarcane were 1761.9mm and 950.1mm respectively. The irrigation
duty of the sugarcane was varied from 0.12 l/s/ha (April) to 0.44 l/s/ha (August). The
conveyance efficiency of main canal was varied from 48.7% to 95.1% with average value of
74.7%. The conveyances efficiencies secondary canal 1, secondary canal 2 and secondary
canal 3 were 77.8%, 84.4%, and at 83%, respectively. The irrigation water delivery capacity
of the left bank main canal was 30.3%. The effectiveness of the infrastructures was 87.5%
(secondary Canal 5), 78.6%, (secondary Canal 6), 96.3% (secondary canal 10), and 38.7%
(main canal). Additionally, the study reveals a progressive reduction in water surface elevation
ratio (WSER) with increasing canal length with mean value of 63.8%. The maximum discharge
of catchment at outlets of cross drainage 13 and 14 were 46.1m3/s and 73.4m3/s, respectively.
Generally, Kuraz sugarcane irrigation scheme found under poor performance status that shows
urging silt removal, and infrastructure maintenance are needed to enhance scheme status
