Use of Climate Information in Water Allocation: A Case of Study in a Semiarid Region

The value of climate information has been explored by various scholars and in various sectors, but its operational use, particularly in water resources management, in countries like Brazil remains limited. This article describes climate and inflow forecast systems used in the process of water allocation in the state of Ceara (Brazil) and evaluates their performance at three key reservoirs in the state for forecasts issued in January for the period from January to May when most of the annual rainfall and inflows occur. To illustrate the value of forecasting in the water-allocation process, a simple experiment based on the use of a decision support system (DSS) is carried out. The use of the DSS SIGA with inflows estimated from observations and forecasts demonstrated the value of forecasts in the process of water allocation, as the forecasts allowed for better identification of end-of-the-year reservoir volumes. The use of the forecast system successfully described the variability of the percentage of demands met and the demands identified using estimated inflows, in particular for the Banabuiu and Castanhao Reservoirs. Overall, the results of this study highlight the importance of climatic-hydrological forecasting in the process of water allocation.