Abstract:
Ethiopia depends on rain fed agriculture with limited use of irrigation for agricultural
production. Evaluation of land suitability and water resources availability is very important for
irrigation and planning water resources projects. Chemoga River has not been used for
irrigation purpose due to this fact agricultural production is very low in this area. This study is
initiated with the objective of evaluate the land resources potential of Chemoga watershed for
surface irrigation development by using Geographic Information System with multi criteria
dissection evaluation and analytical hierarchy process. Irrigation suitability of each land
parameters was classified based on the Food and Agricultural Organization guideline for land
evaluation in to highly suitable (S1), moderately suitable (S2), marginally suitable (S3) and
marginally not suitable (N) suitability classes independently. The factors that were considered
for evaluation of the land suitability for surface irrigation were slope, land use/cover, soil depth,
soil drainage, soil texture, road access and distance of the river. After evaluating the land
capability of surface irrigation, irrigation suitability map was developed. Analytical hierarchy
process method was utilized to identify the weight of each criterion from the pair wise
comparison matrix. The weighted sum overlay analysis was used to generate the suitability map
in a geographic information system environment and the map was classified in to four suitability
classes. Land suitability potential was evaluated by overlying the parameters indicate that 42.67
% of slope, 90.68 % of land use/ land cover, 69.08 % of soil depth, 60.98% of soil drainage,
68.02% of soil texture, 89.70% of river proximity and 87.4% of road proximity of the study area
were identified to be in the range of highly suitable to marginally suitable for surface irrigation.
By weighting analysis of all parameters 15.91% of the study area was found to be highly
suitable, 31.94% moderately suitable, 21.20% marginally suitable and 30.95% were not
suitable. By comparing the irrigation water demand and available dry months stream flow of the
river, irrigation water demand was greater than available stream flow of the dry months. The
overall result indicates that most of the Chemoga river watershed was (80093.09 ha) potentially
suitable for irrigation development from the total study area for potato, tomato, cabbage and
onion. To irrigate this land 118.76m3/s gross irrigation water is supplied to the field for these
crops resulted from CropWat software and to irrigate all the identified irrigable area, the
decision maker should take the mitigation measure by expand irrigation technology, construct
storage structures across a river, exploring water from ground has to be implemented in the sub
basin of river
