eWater Source is Australia's first river basin-scale water modelling system aimed at improving integrated water resources management (IWRM) by integrating various existing models and allowing users to track water ownership, trade, and manage diverse demands. It is a flexible platform that facilitates decision-making regarding water sharing for ecological and human use by providing a comprehensive approach that incorporates policy, management, and scientific input. Developed with funding from government and research bodies, eWater Source aims to enhance collaboration among stakeholders and contribute to a sustainable water management framework.