Spatial and temporal rainfall variability and unsustainable land use practices have always been major bottlenecks for Ethiopian agriculture. Therefore, irrigation is vital to improve crop productivity and economic development in agricultural catchment. The objective of this study was to identify irrigation potential assessment in Chemoga catchment. The irrigation land suitability analysis factors indicate that (8.72%, 22.87%,21.37%, 47.04%) of slope is highly suitable to non-suitable respectively, (0.25%, 93.3%, 6.45%) of soil is in the range highly suitable to marginally suitable respectively, (88.26%, 11.52%, 0.22%) of land use is in the range highly suitable, marginally suitable, non-suitable respectively, (48.06%, 30.8%, 21.14%) of river proximity is in the range highly suitable to marginally suitable respectively and, (14%, 15.5%, 25.8%, 44.7%) of road proximity is in the range highly suitable to non- suitable respectively for irrigation system. The result of the weight overlay analysis revealed that 99.29% (356.29km2) of land in the watershed were in the range of highly suitable to marginally suitable class due to the combined effect of slope, soil, land use land cover, river and road proximity suitability and 0.71% (2.5km2) of the area were not suitable for irrigation. The calibration and validation results showed good match between observed and simulated stream flow with the 0.82 coefficient of determination (R2) , Nash-Sutcliffe efficiency (NSE) of 0.80 and with 11.38% relative Volume Error (RVE) for calibration, and R2 of 0.81, NSE of 0.83 and RVE of 3.027% validation period. The mean monthly surface water potential varied from 0.458m3/sec (sub watershed 1) to 22.22 m3/sec (sub-watershed 8). The irrigation water requirements of the dominant crops were found to be in the following order:-Cabbage (319.6mm), Wheat (287.5mm) and potato (269.9mm). To identify the soils suitability, only depth, texture and drainage class were considered, but chemical soil properties should be evaluated. Water storage structure is necessary because gross irrigation requirement was more than the watershed water supply.