This document discusses modeling water allocation in the transboundary Umbeluzi River between Mozambique and Swaziland. It presents the research objectives of assessing requirements for integrated water resource management in transboundary systems using water allocation models. The main results section describes applying three water allocation models (WEAP21, WRYM, SBM) to estimate water demand and natural runoff in the Umbeluzi River basin by 2025. The models analyze the reliability of water supply for key users and find frequent shortages for some users, with deficits lasting up to 57 months. The conclusions state that intensive cooperation is needed for water sharing in drought-prone regions and that additional tools are needed to assess the severity