Linking Hydrological Uncertainty with Equitable Allocation for Water Resources Decision-Making

Water resources allocation decisions have always been subject to uncertainty, but it has rarely been explicitly included. Greater competition for scarce resources and future uncertainties in supply suggest that risk estimates are required for different management decisions. Models are often used to generate information that can be used in decision making and a water allocation model is presented that is linked to an existing hydrological model that generates uncertainty ensembles and a model that generates environmental water requirements. The allocations are based on socio-economic values that quantify the impact of deficits in normal supply during dry periods when available water is reduced. It is designed to be flexible in terms of how allocations are made during deficit periods and provides outputs that account for the uncertainties in the input hydrological data. Two examples are provided to illustrate the application of the model and it is concluded that the outputs should be useful when combined with emerging approaches to uncertain decision-making and the identification of risk. The model is part of a broader project that aims to improve the way that uncertainty is dealt with in water resources decision-making.