Résumé : In this paper, the flow of water in several elements of the water supply system of the city of Apamea (Syria) is simulated. The studied elements were used in the 6th century A.D. (Byzantine period). These simulations allow a modern point of view analysis of the water supply system, in terms of water flow rate, energy loss, decanter efficiency, ... This analysis provides a qualitative description of the water supply system of the city, supplementing the field observations.