Modelling interactions between climate, water, crops, and human decision-making requires coupling of biophysical and socioeconomic processes to model outcomes and explore potential futures. This study presents a novel coupled model of land-use change and ecohydrological processes in arid agricultural systems. The model links SWAT+, which simulates ecohydrological processes, including crop growth and irrigation water use, with CRAFTY, an agent-based framework that allocates land according to agent characteristics and resource conditions. Egypt is used as a case study where climate and socioeconomic stressors constrain agricultural production. The coupling captures how shifts in potential yields, driven by elevated CO$_2$ and warming, shape land-use change. Crop yields vary by crop and scenario, with the largest gains – and declines – under high-emission futures, while water use efficiency consistently improves, especially at higher CO$_2$ concentrations. Relying on open global datasets, the model provides a transferable approach for exploring climate adaptation in data-scarce, water-limited regions.