The objective of this work was to analyze both the allocation of water among competing demands in a river basin and pricing policies for water. Based on a theoretical model that maximizes the net social benefits from the allocation of water over a finite period of time, it was used the dynamic systems approach to analyze various issues related to water resources management in a river basin, such as sustainability of water resources, and water pricing. The model was applied to the Araguari River Basin, located in the State of Minas Gerais.