This paper proposes a distributed control system under centralized intelligent supervision of wasted and level water in irrigation systems, which significantly facilitates decreases of water losses due to exploitation. A mathematical model of irrigation canals as automatic control objects is presented. An example of application in the Güira de Melena Irrigation System, in the Havana countryside, complements all the theoretical information offered. In this example, a general description of the irrigation system, of the simulation techniques, of the determination of the automatic control algorithms that facilitate an efficient water distribution, and of the fundamental characteristics of the communication and control equipment is given.