As spring approaches reservoir operators need to decide on a regulation plan that will maximize the power producers’ production potential. Typical factors that can influence this planning are available resources, energy demand (both current and future) and market prices. The HSFS is intended to assist operators by supplying information regarding water resources during the spring flood period. Seasonal forecasts are made at the beginning of each month starting in January through to May giving information on the timing of the onset and the volume of the spring flood. This information is considered together with other contextual information and the regulation plan made. The plan is reassessed each month following new updated forecasts from the HSFS and other contextual information.