FEEDBACK-CONTROL OF BASIN-IRRIGATION SYSTEM

A number of methods developed for feedback control of surface-irrigation systems are reviewed. In particular, the results of the application of estimation/optimization feedback control on a basin-irrigation system are reported. It is shown that the feedback control system did consistently better than the farm irrigators in terms of net infiltrated depth and application efficiency. In some cases, the potential application efficiencies predicted from theory are shown to be not attainable. Infiltration and roughness parameters show considerable variation from irrigation to irrigation and from basin to basin. While basin-to-basin variation in infiltration shows a well-defined pattern, the other variations appear random and are not correlated with conditions at the time of irrigation. The implications of these results for feedback control of surface irrigation are discussed.