An Approach for Probabilistic Hydrological Drought Forecasting

This paper proposes an approach to monitor and forecast hydrological drought in a probabilistic manner. The proposed approach deals with the supply and demand variables and the role of carryover in a system to estimate the probability of drought severity at different hydroclimatlogical conditions as well as different storage volume levels. This approach might be of significance when the supply and demand variables of a water resources system change considerably by climate variation. Major probability values and their mutual use in the proposed drought forecasting method are discussed. The presented approach is applied for the hydrological drought forecasting of Zayandeh‐rud river basin in Iran. This probabilistic view of drought monitoring and forecasting is useful for risk‐based decisions in water resources planning and management. The proposed index could be used to overcome the lack thereof in the existing surface water supply index.