Surface Irrigation Potential Assessment Using GIS and HBV Model: A Case Study at Fetam Watershed, Upper Blue Nile, Ethiopia

Abstract Small-scale rainfed small-holder farming accounts for about 85% of Ethiopia's food supply. As a result, the increase in crop production does not correspond to the increase in the country's population. As a result, in order to alleviate this problem, irrigation must be used to supplement rainfall farming. It is critical to do this assessment of potential water resources and suitable terrain for irrigation in every section of the country. As a result, this study began to assess the Fetam watershed's irrigate and land resource potential for irrigation development. Irrigation suitability problems like as slope, soil type, land usage land cover, and distances as a water source are used in justification to designate potentially irrigable earth. Data from several government agencies was obtained and utilized, including hydrological, meteorological, Digital elevation model, soil drainage, soil depth, soil texture, and agro-climatic map data. In addition, satellite pictures were utilized in this study. Irrigation appropriateness was assessed using a geographic information system with multi-criteria decision evaluations, and the HBV and CROPWAT 8 models were utilized to determine the likelihood of water resources and irrigation water requirements. The coefficient of determination (R 2 ), Nash Sutcliffe models efficiency (NSE), and Percent Biases (PBIAS) of the performance evaluation statistics were 0.54, 0.51, + 15 and 0.69, 0.67, -15, respectively, indicating that the HBV model performance is satisfactory. In general, there are 12583.47 ha of appropriate lands used for irrigation inside research areas.