Thai Flood 2011: Rapid Assessment for Resilient Recovery and Reconstruction Planning



1.1 Introduction

Thailand is no stranger to natural disasters. The country has a long history of drought and flood cycles in seasonal variance. Flooding occurs every year in the Chao Phraya River Basin. Tropical storm cycles come from the east through Laos and Vietnam and touchdown in the northern parts of the country where water collects and flows downstream into the basin. With a changing climate and increasing variance and severity of weather, events similar to this flood may no longer be only 50 years in frequency.

Thailand has dealt with catastrophic floods in the past. In 1942, the flood level in Ayuthaya reached 5.51 m and inundated Bangkok for two months; 1983 brought a cyclone that inundated the country for five months, causing THB 6.6 billion in damage; and unprecedented rainfall in 1995 inundated the largest recorded area of 5,400 m3. Though the 2011 flood area was smaller than the area affected in 1995, the impact it had on life and the cost of damage – more than 100 times the 1983 damage costs – was unprecedented. These factors contributed to the 2011 floods registering on the magnitude of roughly a once in every 50 or 100 years event.