Flooding
Flooding occurs as an overflow of water in a specific area, and it can happen for a variety of reasons, including: severe weather, tsunamis, and hurricanes. In this chapter, we are going to focus on flooding that occurs due to excessive run-off from rain or snowmelt, rather than those caused by earthquakes (tsunamis) or storm surges (hurricanes), in rivers. Rivers can be called by many names: streams, creeks, rivulet, tributaries, etc. Regardless of the name, they are one of the most important movers of water and sediment on the surface of Earth. Though they vary in size, streams can become overwhelmed by excess water and turn into dangerous, flows of water that can destroy any obstacle in its path. Historically, floods were also the most fatal disaster events, but deaths have been declining nationally due to steps taken to prepare for and recover from flooding. Globally there is still cause considerable loss of life in impoverished countries, and huge losses to infrastructure in more affluent societies.
Learning Objectives
After this chapter, you should be able to:
- Explain the hydrological cycle and its relevance to streams
- Describe a drainage basin and its importance in flooding events
- Describe the processes by which sediments are moved by streams and the flow velocities that are necessary to erode them from the stream bed and keep them suspended in the water
- Describe the annual flow characteristics of typical streams and the processes that lead to flooding
- Describe some of the important historical floods in the United States
- Determine the probability of a flood of a particular size based on the flood history of a stream
- Explain some of the steps that we can take to limit the damage from flooding
