Floods: Hazards of Surface and Groundwater Systems

There are many different types of floods, ranging from slowly rising regional floods to dramatic flash floods and coastal floods. Floods have become increasing hazardous over the last 200 years, as people have been moving onto floodplains and modifying rivers, streams, and entire river systems. Human modifications to rivers and floodplains have resulted in more frequent, stronger, and faster moving floods. Considered the most common natural hazard, floods affect more people and cause more damage than any other hazard including earthquakes, volcanic eruptions, landslides, and tsunamis.