The system of total water use control index (TWUCI) has been established in China since 2011. However, current TWUCI is static all year round, making a poor adaptation to dynamic inflow and a deviation between water plans and actuals. To this end, an innovative methodology, namely “forecast-decision-implementation-renewal” (FDIR), is proposed to carry out the real-time determination of the TWUCI. Streamflow prediction is first used to determine adaptive TWUCI, and then the optimal water allocation model considering both the TWUCI and ecological demand is developed to make a decision-making of water supply system. The updated information at next stage will be fed back to the model, obtaining new water supply plan. By applying the method by scrolling over periods, real-time decisions for water transfer and water release could be derived. An application with the FDIR is successfully implemented in the Fuhe River Basin of eastern Jiangxi Province, China. The results show that the TWUCI in the remaining period increases/decreases when the inflow scenario becomes drier/wetter. With dynamic operating decisions, the water shortage ratio in the water-use area declines by 3.8%~25.3% when inflow scenario(IS) changes from wet to dry, while the actual water supply is reduced to the TWUCI when dry IS turns to wet. In this way, The FDIR provides a dynamic operating decision that guarantee the water consumption in the remaining period always within the TWUCI, and realizes flexible management for water use. It is expected to be useful for socio-water adaptation to future climate changes towards a sustainable regional development.