Abstract:
Assessing availability of water source and land for irrigated agriculture is very important to
reach at a proper decision on the demand and supply of irrigation development. This study
was initiated with the objective of assessing surface runoff potential , land suitability
evaluation for irrigation and crop water demand of Hargeti river watershed for spate
irrigation development .The surface runoff potential was calculated by the soil Conservation
Service Curve Number ( SCS - CN) method.Crop water demand was estimated using
Hargreaves method. To identify potential irrigable land , irrigation suitability factors such as
soil type, slope, and land cover/use, were taken into account. The surface runoff potential
Hargeti sub catchment was assessed monthly based, the result shows there is high tempora l
variability of runoff observed. The irrigation suitability analysis o f these factors indicates that
54 % of soil is marginally suitable. whereas based on slope suitability 7 % and 31% of the
study area is in the range of highly to marginally suitable for surface irrigation system
respectively. In terms of land cover /use, 63 % and 35% of land cover/ use is in the range of
highly to marginally suitable. The overall analysis of these factors gave 29,200 ha of irrigable
land by surface irrigation system. Based on analysis of surface runoff potential and water
demand for selected crop, the potential irrigable land by spate irrigation is 3682 ha, thus the
potential can be enhanced through additional water harvesting activities.
