This Work Plan lays out an approach and scope for assessing the viability of Forecast Informed Reservoir Operations (FIRO) at Howard A. Hanson Dam. Tacoma Water and the U.S. Army Corps of Engineers Seattle District are collaborating with Center for Western Weather and Water Extremes at Scripps Institution of Oceanography at UC San Diego, the U.S. Army Corps of Engineers Research and Development Center, the National Oceanographic and Atmospheric Administration National Weather Service, the National Marine Fisheries Service, King County River and Floodplain Management, and the Muckleshoot Indian Tribe to assess the benefits of reservoir management scenarios using forecasts. The Howard A. Hanson Dam FIRO project will investigate this key question: How can improved forecasts of landfalling atmospheric rivers and associated precipitation and runoff be used to improve the reliability of spring refill to meet instream flows for fish and water supply storage objectives, improve the effectiveness of summer water management in advance of the fall flood transition period, maintain or improve operations for downstream flood risk management, and ensure forecasts and operations are flexible enough to respond to a changing climate without impacting flood risk, water storage reliability, and flows for fish?