Floods in changing streams

摘要

Flood damage continues to rise in many parts of the world, even when measured in constant monetary units. The rise in flood damage is caused in some instances by the human settlement of flood plains, which augments the stock of property and exposed population within flood-prone areas. In other instances, flood damage increases in response to the cumulative effects of watershed impacts on the streamflow response to precipitation. In addition, the large uncertainty which surrounds the estimates of rare flood events, especially in ungauged streams, frequently leads to the under-estimation of flood risk. This article examines key factors that effect time-changing flood damage, and presents a case study that illustrates human-induced contributions to flood damage.