Abstract. In drought years, it is important to have an estimate or prediction of the probability that a water shortage risk will occur to enable risk mitigation. This study developed an improved logistic probability prediction model for water shortage risk in situations when there is insufficient data. First, information flow was applied to select water shortage risk factors. Then, the logistic regression model was used to describe the relation between water shortage risk and its factors, and an alternative method of parameter estimation (maximum entropy estimation) was proposed in situations where insufficient data was available. Water shortage risk probabilities in Beijing were predicted under different inflow scenarios by using the model. There were two main findings of the study. (1) The water shortage risk probability was predicted to be very high in 2020, although this was not the case in some high inflow conditions. (2) After using the transferred and reclaimed water, the water shortage risk probability declined under all inflow conditions (59.1% on average), but the water shortage risk probability was still high in some low inflow conditions.