In the present study, a weekly operational planning model has been developed using a simulation technique for the Tambiraparani river system in Tamil Nadu, India. A planning model has been developed incorporating the important features of the existing operational policy. Paddy is the main crop cultivated in three seasons, although banana is cultivated to an appreciable extent, it has not been recognized in the existing operational policy. The major task of the water resources manager is to find the area under paddy during the third season namely, the Advance Kar season. The main objective of the present study is to simulate the temporal distribution of the available water in the Tambiraparani river system. Simulation is carried out for various possible extents of Advance Kar area and banana area for various initial storage conditions. It is found that the entire Tambiraparani river system could be managed without deficit by reducing the release of water by 10–25% during the non-stress crop periods and also by lagging the starting period of the season by one or two weeks. If this management is practiced during average inflow years, it is possible to maintain the same final storage as the initial storage during the start of the season. Thus the polices derived using the present study would be more useful to the system managers enabling them to authorize the area under paddy during the Advance Kar season and also to help them to maintain the required storage for the next season.