Abstract:
Evaluating the performance of existing irrigation schemes helps to compare the potential of the
scheme with that of current service. Direct field data collection and secondary data were used
to address the objectives and answer the research questions. The main objective of the study
area was to evaluation the performance of Sile irrigation scheme and to know the problems and
suggest possible mitigation measures. It was important to study its performance level and
introduce the information to government and non-governmental organizations. This study was
done to identify and understand the current status of the performance of Sile irrigation scheme.
The scheme was evaluated using performance indicators such as conveyance efficiency (Ec),
relative water supply (RWS), and relative irrigation supply (RIS). It was also evaluated in terms
of water use indicators such as application efficiency (Ea), water storage efficiency (Es), deep
percolation (DP), and overall efficiency (Eov). For this study, three farm fields were selected
from the upper, middle, and lower streams of the irrigation scheme to account the performance.
Discharges were measured using a velocity stage probe and Parshall flume. The primary data,
like discharge measurements in the canals, measurement of applied water to the farm fields,
determination of soil moisture contents, soil physical properties, and secondary data, were
analyzed using CROPWAT, ARC GIS software, and Microsoft Excel. The results obtained for the
average conveyance efficiency of the main, secondary, and tertiary canals were 86.67%,
76.32%, and 54.8%, respectively, and the mean value of application efficiency was 60%. The
water conveyance efficiency of the canals and the water losses in water conveyance were
estimated by measuring irrigation water flow at different locations along the canals. The main
canal had high conveyance efficiency due to conceit structure, line canal. The secondary and
tertiary canals were poorly maintained, and some of the structures were not functional, which
caused water loss in the entire scheme. This result indicates that the values of most of the water
delivery and water use indicators were below the attainable values suggested by many
researchers. These values were due to illegal water abstraction, sedimentation of canals, and a
lack of maintenance. Therefore, regular maintenance and suitable management approaches are
required to improve the irrigation scheme's performance
