Buffalo Bill Reservoir near Cody, Wyoming is managed by Reclamation for multiple purposes, including water supply, hydropower, recreation, environmental flows, and flood control. The reservoir's inflows are primarily supplied by seasonal snowmelt, and forecasting inflow volume and timing of peak inflow over the snowmelt period is important for operations. Reclamation, CADSWES, and NCAR teamed to perform a case study examining risk-informed decision making on Buffalo Bill Reservoir. The project team generated and analyzed the skill of reservoir inflow forecast ensembles, developed a framework for seasonal risk-informed decision making within RiverWare, and evaluated its effectiveness. In this presentation, we describe the approach for risk-informed decision making using RiverWare and describe several lessons learned about operations using inflow ensembles and risk-informed trade-offs.

We are updating the risk-informed decision-making methodology based on these lessons. This time, we are focusing on operations at Ruedi Reservoir in Colorado. We are simplifying the framework developed for Buffalo Bill to analyze trade-offs between water supply, flood control, and hydropower production, rather than each of the operational goals for each of the reservoir's authorized purposes. The method also incorporates the ability to make both seasonal and short-term decisions. We will also evaluate additional seasonal forecast sources, including National Weather Service ensembles and disaggregated statistical forecasts for risk-informed decision-making.