Start-up strategy of contingency plan against blue-green algae crisis based on online method

It is a key problem to decide the time at which to active a contingency plan in the area of emergency management. Blue-green algae crisis represents a kind of emergency management problem whose growth rate or diffusion speed is unexpected. Based on online method and taking this crisis as the background, this work presented contingency plan start-up strategies for two cases where the loss is ceased immediately and where the loss gradually decreases to zero respectively. These strategies were proved to be optimal. An illustration about blue-green algae crisis in Taihu Lake was given as well. The conclusions provide guidance for decision makers to solve crucial emergencies.