In 2011, Thailand experienced a massive flood. The Thai government reorganized the organizational structure of water resources management after this flood during 2011–12. The Yingluck administration planned both short-term flood mitigation projects and long-term flood prevention measures to be implemented by the new water resources management organization. However, later on, the structural reformation was criticized by the public, and the entire long-term measures planned in 2012 were scrapped by the Prayud administration after the Coup d’etat in May 2014. This study summarizes the incidents and the reformation process in a chronological order from 2011 to 2014.