Flood
Overview
A flood (홍수, flood) generally refers to a natural phenomenon where the water level of a river, lake, or stream rises significantly above normal, submerging surrounding land. It is caused by various factors such as heavy rainfall, typhoons, storm surges, dam failures, and snowmelt, and is considered one of the most frequent and destructive natural disasters worldwide. Floods not only cause casualties and property damage but also have extensive social and economic impacts, including inundation of farmland, destruction of infrastructure, and spread of waterborne diseases.
Main Content
Causes of Floods
Floods are broadly divided into natural and anthropogenic factors.
- Natural factors: Typical examples include the rainy season (jangma), heavy rainfall, typhoons, storm surges (tsunamis), and rapid melting of snow and glaciers due to sudden temperature rises. In particular, climate change is altering precipitation patterns, increasing the frequency and intensity of localized heavy rainfall.
- Anthropogenic factors: Indiscriminate deforestation, river channelization, expansion of impermeable surfaces (urbanization), exceeding the design capacity of dams and levees, and insufficient drainage capacity increase flood risk. Additionally, sea level rise due to climate change exacerbates coastal flood risks.
Types of Floods
1. Fluvial Flood: Occurs when rainfall exceeds a river's capacity, causing overflow. This is the most common type.
2. Flash Flood: A sudden flood caused by localized heavy rainfall over a short period. The response time is very short, leading to high casualties.
3. Coastal Flood: Inundation of low-lying coastal areas due to sea level rise from typhoons, storm surges, or high tides.
4. Urban Flood: Flooding caused by rainwater not infiltrating into the ground due to impermeable paved surfaces in cities, leading to instantaneous runoff. Insufficient drainage capacity is a major cause.
5. Dam/Levee Failure Flood: An anthropogenic flood caused by the sudden release of large amounts of water due to structural defects or poor management.
Impacts of Floods
- Casualties: Deaths and injuries from drowning, electrocution, building collapse, and diseases.
- Property damage: Destruction and loss of homes, farmland, roads, bridges, and power and communication facilities.
- Environmental damage: Soil erosion, water pollution, ecosystem disruption, and spread of invasive species.
- Social and economic damage: Displacement of residents, disruption of economic activities, insurance losses, increased recovery costs, and threats to food security.
Flood Prevention and Preparedness
- Structural measures: Construction of dams, levees, and floodwalls; river dredging; creation of retention basins; and installation of drainage pumping stations.
- Non-structural measures: Establishment of flood forecasting and warning systems, land-use regulations (restricting development in floodplains), flood insurance, public education and evacuation drills, and early warning systems.
- Nature-based Solutions: Restoration of wetlands, forest protection, introduction of permeable pavements, and green infrastructure (rain gardens, green roofs).
Flood Response and Recovery
- Response: Monitoring weather forecasts, activating emergency response headquarters, issuing evacuation orders, conducting emergency rescues, and operating temporary shelters.
- Recovery: Damage assessment, support for displaced persons, infrastructure restoration, psychological support, and formulation of measures to prevent recurrence.
Recent Trends
As of 2024–2025, flood patterns are rapidly changing globally due to climate change. In 2024, record-breaking floods occurred in southern Brazil, Afghanistan, East Africa, Germany, and Spain. Notably, Storm Boris, which struck Central Europe (Poland, Czech Republic, Austria, Romania) in September 2024, caused the worst flooding since 1997. In early 2025, strong atmospheric river events triggered floods and landslides in California, USA, while urban flooding from heavy monsoon rains has repeatedly caused damage in East Asia (South Korea, Japan, China).
In terms of recent technological trends, improvements in the accuracy of flood prediction models using AI and satellite data, virtual simulations using Digital Twin technology, rapid damage assessment using drones, and real-time warning systems based on mobile apps are gaining attention. Internationally, climate adaptation policies based on the Sendai Framework for Disaster Risk Reduction and the Paris Agreement are being strengthened, and countries are expanding the creation of flood risk maps, floodplain management, and the adoption of nature-based solutions.
Related Topics
- [[Climate change]]
- [[Natural disaster]]
- [[Typhoon]]
- [[Dam]]
- [[Urban planning]]
---
AI-generated document · Improved together by the community