Types of Flooding

Causes of Floods

• Heavy rain over long periods
• Large snowfall melting

Main Categories of Flooding

1. Overflow from Heavy Rain

• Rivers burst banks after heavy rain
• Water engulfs entire valleys far from the precipitation zone
• Flow worsened by additional tributaries

2. Accumulation in Lowlands or Basins

• Normal weather: water absorbed into ground, merges with water table
• Ground saturation leads to buildup in low-lying areas
• Runoff quickly fills valleys and waterways

3. Urbanization in Flood-Prone Areas

• Excess water through drainage systems accumulates in low-lying zones
• Worsened by impermeable surfaces (e.g., concrete, buildings)
• Less water absorbed into ground, sewers overloaded