Illustration of the Relationship between Alarm Stage and River Cross-section
Definition of the Third Degree Alarm Stage of the Flood Forecast System (using Danshuei River as an example)
3rd Stage Warning Water Level
When the river stage will probably pass the threshold of the high shore within two hours, notify county and city governments to close water gates, spill gates and pumping stations,
2nd Stage Warning Water Level
When the river stage will probably pass the top threshold of the dike within five hours, evacuate residents in the depression areas. Every flood-control unit mobilizes the staff preparing disaster rescue equipment and material and staying on strict alerts. Restrain bridges, seal off culverts and launch flood-control measures.
1st Stage Warning Water Level
When the river stage has reached the project flood stage, or will probably pass the top threshold of the dike within two hours, decide the time to evacuate residents in the depression areas and begin evacuate residents in the possible flood zone, with facility hazard mitigation and disaster rescue, for emergency evacuation measures.