Reservoir operators rely on hydrologic forecasts to guide decision-making, such as how much water to store or release. These decisions are especially important in California, where reservoir releases must balance environmental needs with agricultural and urban water demands. This project evaluates the accuracy of different seasonal hydrologic forecast products and how they influence reservoir operations when used in the CalSim3 model, a planning tool jointly developed by the USBR and the California Department of Water Resources. Although all forecasts aim to predict reservoir inflows, they are developed using different methods, which can lead to different estimates of future water availability. To better understand these differences, this study compares multiple hydrologic forecast products and evaluates how they affect model outcomes, providing insight into how
This project is a part of the Multidisciplinary Water Training and Operations Program.
Image credit: Reservoir illustration generated using OpenAI ChatGPT (2026).