Not a simple single issue or solution. Severe flooding in Thailand is caused by a combination of natural, environmental, and human factors:
1. Monsoon Rains: Thailand experiences heavy rainfall during the monsoon season, typically between May and October. This prolonged rainfall can lead to river overflow, flash floods, and the saturation of soil, which contributes to flooding.
2. Tropical Storms and Typhoons: Occasionally, tropical storms or typhoons pass through Thailand or nearby regions, intensifying rainfall. These storms can bring sudden, intense rainfall, which overwhelms rivers and drainage systems.
3. Geography and River Systems: Thailand’s geography, with low-lying areas and a network of rivers such as the Chao Phraya, Mekong, and Mun rivers, makes it vulnerable to flooding. These rivers can easily overflow during heavy rainfall, inundating surrounding areas.
4. Deforestation and Land Use Changes: Deforestation and land clearing for agriculture, urbanization, and industrial activities reduce the land’s natural water absorption capacity. The removal of trees and vegetation increases surface runoff, leading to faster accumulation of water in rivers and floodplains.
5. Urbanization and Poor Drainage Systems: Rapid urban development, especially in cities like Bangkok, has reduced green spaces and disrupted natural water flow. Increased impermeable surfaces (like concrete) prevent water from seeping into the ground, and aging or inadequate drainage systems struggle to cope with the large volumes of water.
6. Climate Change: Climate change has intensified rainfall patterns, leading to more frequent and severe rainfall events. Rising sea levels also contribute to coastal flooding, especially in low-lying coastal areas and regions around river deltas.
7. Dam Mismanagement and Water Release: Thailand has several dams to control water supply and prevent drought, but during heavy rainfall, the controlled release of water from dams can lead to downstream flooding. Mismanagement or uncoordinated water release, especially during peak rainy seasons, can exacerbate flood risks.
8. Subsidence: Ground subsidence, particularly in Bangkok, where over-extraction of groundwater has caused the ground to sink, worsens flooding. Subsidence makes it difficult for water to drain and increases the impact of rising sea levels and coastal flooding.
Each of these factors can act alone or in combination, often resulting in prolonged, severe flooding that affects homes, infrastructure, and agriculture, especially in central and northeastern Thailand.