Taiwan’s flood period spans from May to the end of November each year. These seven months are Taiwan’s plum rains and typhoon seasons with the most rainfall. Plum rains mainly come from the cloud and rain system above the Yangtze River basin, while typhoons are mainly caused by the atmosphere depression of the Pacific Ocean. They both bring continuous torrential rains which can cause floods. To mitigate floods, in the past years the Water Resource Agency has executed flood-related projects on rivers for more than 2,000km, coastal protection measures for 500km, and local drainage improvement for more than 3000km.