The Abbay River BasinAbbay River Basin is the main basin, with 176,000 km2 in the Blue Nile River. It originates from four main tributaries in the highlands around Lake TanaLake Tana and drains to the border of SudanSudan through the Grand Renaissance Dam, GERDGrand Ethiopian Reminiscence Dam (GERD). The Abbay River BasinAbbay River Basin has 13 main tributaries and runs about 900 km of river courses from Lake TanaLake Tana to leave EthiopiaEthiopia. This part of the book tries to address the natural resources and irrigation potentialIrrigation potential as compared to the overall country’s potential in the first two parts. The third and last part tried to share a case study in the upstream Lake Tana basinLake Tana basin. This part covers irrigationIrrigation water loss and productivity in a small irrigationIrrigation system under a mixed crop-livestock farming system, as well as water availability and stress at the watershed level. There is huge water loss from traditional irrigationIrrigation water management. However, a very small amount of the water loss through leakage and canal overflow produced grass around the canal banks and drainage basins. This could benefit feed for cattle during the dry season, when feed supply is a big problem. Productivity of irrigationIrrigation water (kg m−3) was seen with an improved measuring approach that can consider both straw and grain since straw production is also equally important for the mixed farming system. Together with low land productivityLand productivity (kg ha−1) due to shortage and misuse of irrigationIrrigation water, there are rooms to increase irrigationIrrigation water productivityWater productivity. The water availability and stress under watershed level have been assessed with different land usesLand use, watershed treatments, and irrigationIrrigation water abstraction.