A Hydroclimatic Forecast System to Support Decision-Making and Improve Water Security in an Agricultural Frontier of the Brazilian Cerrado

Water stress and conflict can emerge in regions with high water demand, making effective water resource management crucial for regional water security. This case study presents a comprehensive analysis of the hydroclimate behavior in Western Bahia, Brazil, and describes the development, evaluation, and operationalization of a hydroclimatic forecast system that forecasts minimum annual discharges, water stress levels, and rainy season onset, aiming to support decision-making, improve the regional governance of water resources, and improve water security. Western Bahia has experienced water stress in recent years, leading to a reduction in the amount of water in highly stressed regions like the Grande basin. The water scarcity issue may extend to other basins, as evidenced by lower streamflow values observed in the Corrente basin. To address this challenge, hydroclimatic forecasts were developed. The minimum discharge forecasts delivered a relative mean absolute error of 16.5%-27.8% on average for the study region. When combined with water stress forecasts, both provided valuable information for decision-making. Our rainy season onset forecasts had a mean absolute error of 15-20 days for two months' lead time and captured the region's west-east gradient of rainy season behavior. These combined hydroclimatic forecasts have the potential to enhance water security and support decision-making in Western Bahia.