One of the methods for increasing productivity of water consumed in agriculture is by improved water supply management. This paper presents results from an optimization study of the Malampuzha irrigation project of the Bharathapuzha river basin of Kerala in India. The objective of this study is to determine whether significant improvements might be realized from optimization of operation of the reservoir system. To do this a mixed integer linear programming (MILP) model is developed and five different management strategies are tested. The result indicates that a management strategy with deficit irrigation by supplying less water in non-critical growth period and maximum water during stress sensitive periods is a best viable solution for better performance. A MILP model, rather than a linear programming (LP) model, is used to ensure that the reservoir does not spill before reaching its capacity.