In FRANCE, for about twenty years now, water control has been achieved in canals specially designed for optimum efficiency in water conveyance and distribution. The regulation techniques consist in particular in using downstream or upstream float gates and baffle distributors — often used in Morocco for example. Their use implies specially designed canals with adapted civil engineering works and dykes. The application of these regulation techniques on old canals with continuous flow very often implies heavy investment and is impossible on natural rivers. On the other hand, the development of micro-computers and data transmission networks, and the definition of mathematical methods dealing with control systems, have pointed the way to another approach to the problem set by improving the efficiency of the feeder canal control. Using these new techniques, the Compagnie d'Aménagement des Coteaux de Gascogne (CACG), in collaboration with a staff of researchers, has studied a new approach to water management, and since 1984 has produced a complete set of automatic control equipment allowing the irrigation of 4000 ha, with a system efficiency close to 0.9. This approach has been set up in particularly difficult conditions, the river being used to supply several irrigated perimeters. It could as easily be installed on a canal, where it is not economical to invest in the large hydraulic structures necessary for traditional control.; The economic stakes are important because it is a matter of improving the performance of existing structures with little specific investment (sensors, micro-computers, software) and with extensive improvement in the systems management.