Typhoon Morakot hit Taiwan during August 7-9, 2009. Its record-breaking rainfall caused catastrophic damage, making it the deadliest typhoon to visit Taiwan in the last 50 years. Conducting a three-months and 160-member-strong field investigation of the scale and causes of this disaster, this paper proposes strategies effective to improve flood prevention work in Taiwan. The severe flood disaster triggered by Typhoon Morakot’s excessive rainfall is attributable to four factors: (1) hydraulic system failures, (2) river flow retardation, (3) reservoir release, and (4) land subsidence. Based on these findings, this paper proposes comprehensive improvement strategies in hydraulic facility inspection, emergency response, river basin management, and climate change assessment to improve flood prevention work in Taiwan. This study combines governmental, academic, and public efforts in investigating effective post-disaster flood prevention strategies that we hope will prove to be a useful reference for other countries while facing such issues.