Human activities and climate factors both affect the availability of water resources and thernsustainability of water management and that in turn affect agricultural water managementrnespecially in already dry regions, water has become scarcer with increasing requirements fromrngrowing population, economic development. Although progress has been made inrnunderstanding variability of runoff, the impacts of climate variability and human activities onrnagricultural water management (actual evapotranspiration) and (discharge accumulated in thernriver network) remain less well understood. rnSouth omo Gibe basin which is one of the sub basin in Ethiopia has suitable land water resourcernfor agriculture for both farm and livestock and currently huge investment are found on irrigationrnproject, and from these the dominant is state owned irrigation like kuraz sugar developmentrnirrigation project in the sub basin which planned to irrigate sugarcane on 175,000 hectare ofrnland. According to works design and supervision enterprise that prepare design document of thernproject the water requirement of the plant is modeled with cropwat considering onlyrnatmospheric water demand and put the yield in figure in its report. rnHowever now a time In south Omo Gibe sun basin a frequent happening of high and lowrnrainfall, less work on soil conservation practice and deforestation are observed as causes ofrnchanging of climate and land degradation that make the need for improved and resilientrnagricultural water management to have greater yield of the crop with environmentalrnsustainability and so efforts towards improved and resilient agricultural water management isrnmust. rnTherefore, the main objective of the research presented here is to study the effect of climaternchange specifically drought and land degradation on water demand and crop yield in the area ofrnstudy and compare the existing crop oriented model used for the design of crop waterrnrequirement of the crop in the project area with agro hydrological model for better irrigationrnmanagement under climate change and land transformation. To achieve this purpose, anrnavailable code that takes into account the interaction between soil, water, atmosphere and plantsrnSWAP model is used after assessing the challenges in the sub basin and identifying adaptationrnstrategy for improved agricultural water management and compared with Cropwat model.rnconsequently, it is tried to analyze the impact of future climate changes and land transformationrnwater demand for irrigation and relative crop yield in the Kuraz irrigation project area. rnFrom the result of the performance of the two model SWAP model result of actual rnevapotranspiration and irrigation water requirement is greater than the designed crop water rnrequirement of cropwat model output which can be calibrated with yield of sugarcane. And therncomparison of the two models shows that SWAP model outputindicate the actualrnevapotranpiration and irrigation water requirement is greater than the CROPWAT model output f the designed irrigation water requirement that can make conform with yield reduction ofrnsugarcane the in project area as a calibration method due to shortage of data. rnEven though the reduction of sugarcane is happen due to technical inefficiency as I can get thernresult of research paper on irrigation management practices in kuraz irrigation project, climaternchange and land degradation plays large effect in this technical inefficiency of irrigation waterrnmanagement more than different tillage practices. in this research due to shortage of data tornmeasure soil moisture and ground water data in the project area I used the yield reduction datarnfrom analysis of technical efficiency sugarcane production. rnFrom this result neglecting other factors that decrease the yield of sugarcane and considering therneffect of climate change and land degradation only, it shows the need of irrigation water will bernhigh to maintain good yield of sugarcane in the future. Today, the sugar corporation suppliesrn300 mrn3rn/sec which is the minimum release discharge from Gibe III hydropower project. This rnmeans that the corporation should focus on works that increase the amount of water forrnirrigation in the future. rnConsequently, taking into account all the simplification and the uncertainties in the model, it isrnsafer for the corporation to increase the water supply capability in the future, particularly usingrna better approach of soil and water management integrated with sub basin scale soil and waterrnconservation practices should be followed, in order to cope the increasing water demand in thernfuture.