Abstract:
Evaluating the suitability of a landscape for irrigation in advance is critical for the sustainability
of an irrigation system. It needs supplementation from irrigated agriculture during dry season.
Assessment of land suitability for irrigation purpose is important to utilize scarce resources
efficiently and effectively for sustainable production of crops. There were only few studies on
assessment of irrigation potential in Ethiopia and none has been done in the study area.
Therefore, the aim of study was to assess the physical irrigation potential of Sibilu River
catchment, using Geographic Information System. The irrigation suitability factors such as slope
soil and land use land cover were weighted overlay in order to determine the most suitable land
by using pairwise analysis in order to determine the weight of each parameter. The collected
data were checked for inconsistency using double mass curve and the missing metrological data
were filled by normal ratio method. Irrigation suitability factors were classified based on the
Food and Agricultural Organization guideline for land evaluation in to highly suitable,
moderately suitable, marginally suitable and not suitable classes, where the final irrigable land
was identified by weighting the factors of suitability. The study used slope, soil and land use/
cover for irrigation suitability analysis with Geographic Information System based. The
irrigation suitability analysis of these factors indicated that 56.5% of slope,19.3% of soil and
89.82% of land use/cover area were in the range of highly suitable for surface irrigation system.
Over all the weighted overlay analysis of these factors gave potential irrigable land 57.53% of
the study area were found to be highly suitable whereas 0.42% not suitable for irrigation
developments. To grow on these identified irrigable areas, three crops such as cabbage, potato
and pepper were computed from climate input data using Food and Agricultural Organization
penman-monteith in CROPWAT 8.0 software and the command area was identified by
comparing the irrigation water demand and water potential of the water source in the study
area. In Conclusion, Sibilu River is highly suitable for surface irrigation in terms of suitability
factors. However, only 133 ha were irrigable and therefore the dry flows should be increased or
ground water should be constructed and water should be stored to meet irrigation potential.
