The International Boundary and Water Commission (IBWC) is a binational agency that oversees boundary and water treaties between the United States and Mexico, including the 1944 Water Treaty that governs how the flows in the Rio Grande from Ft. Quitman, Texas to the Gulf of Mexico are to be shared between the countries. In October of 2020, the IBWC established a work group that consisted of technical members from IBWC, Comisión Nacional del Agua (CONAGUA), U.S. Department of Interior (DOI), and the Texas Commission on Environmental Quality (TCEQ). This international team was tasked with developing a binational model of the Rio Grande basin to analyze the impact of proposed water management scenarios in comparison to policies that are currently in effect. Of particular interest are the impacts on water deliveries under the 1944 Water Treaty and the impacts on how water is distributed to users throughout the system. To accomplish this task, the team has adapted TCEQ allocation policies into a RiverWare model developed by CONAGUA and is actively developing policy rules to simulate different management scenarios. The team has also developed performance indicators to assess impacts of interest, and these data will help the two countries negotiate a new Treaty Minute to increase reliability and predictability of Rio Grande water deliveries.