This study examines climate change's impact on agricultural water scarcity in the McKenzie Creek watershed, which is part of the Great Lakes Basin and serves as a critical ecosystem service provider for various communities, including the Six Nations of the Grand River. The research employed the GSFLOW model to simulate watershed hydrology from 1961 to 2099, utilizing eleven General Climate Models under Representative Concentration Pathways (RCP) 4.5 and 8.5 scenarios. The methodology uses model outputs (streamflow, evapotranspiration, and soil moisture) and agricultural water use data to quantify blue (BWS) and green water scarcity (GWS) through a water footprint approach. Blue water refers to surface and groundwater resources, while green water denotes soil moisture that supports plant growth. Results indicated that under current water usage, BWS is categorized as "low." However, if water withdrawals reach the maximum permitted levels, BWS could escalate to "significant" or "severe" levels, indicating a potential future water crisis. Furthermore, the study projected an increase in annual average GWS throughout the 21st century, with the eastern portion of the watershed experiencing slightly higher GWS. Regional GWS variation could increase blue water withdrawals, potentially affecting downstream water availability and exacerbating tensions between Indigenous and non-Indigenous water users. The implications of this research are significant for water resource management and climate change adaptation, particularly for Six Nations as they develop a climate resiliency plan. The study underscores the importance of considering both BWS and GWS in assessing the effects of climate change on water resources within Great Lakes watersheds.