Although lot of work have been reported in forecast of inflows to reservoir, yet each basin
needs unique treatment to improve the forecast accuracy, and as such it is very difficult to generalize the
inflow modeling, particularly for monthly flow models. Further, for planning of water resources in a river
basin, long term flow forecasts are more important. In this work, an approach is suggested to improve the
forecasting of monthly inflows to the Manimuthar reservoir in the Tamarabarani river basin in Tamil Nadu,
India. The releases from Manimuthar reservoir act as a support to the Tamarabarani river system which plays
a vital role in agricultural production of the region. For the agricultural planning, it is desired to have monthly
prediction, and hence an attempt has been made herewith towards this.