Chapter 6. The Work of Streams

Section 6.2

Bed Load

  Sediment that is carried by a stream along the bottomof its channel.

 Capacity

the total amount of sediment a stream is able    to transport.   

Alluvium  

The sorted material deposited by    a stream.                         

Delta

An accumulation of sediment formed where a stream enters     a lake or an ocean.

Natural Levee

An elevated landform that parallels a      stream and       acts to confine its water, except during floodstage.

Floodplain

The flat, low-lying portion of a    stream valley subject to periodic flooding.

Flood

Occurs when the discharge of a stream becomes   so great that it exceeds the      carrying capacity of its channel and overflows its banks.

Draining Basin

The land area that contributes water to a stream.  

Divide

An imaginary line that separates the drainage of      two streams; often found along a ridge.

Key Concepts

Q: How do Streams erode their channels and transport sediment?  Streams generally erode their channels lifting loose particles by abrasion,grinding, and by dissolving soluble material.

 

Q: How does stream deposition occur?Streams transport sediment in three ways.1. In solution (dissolved load)2. In suspension (suspension)3. Scooting or rolling along the bottom (bed load)

 

Q: What are the two types of stream valleys? Two types of stream valleys are Narrow Valleys and Wide Valleys.  

 

Q: What causes floods, and what are the major flood? Most floods are caused by rapid spring snow melt or storms that bring heavy rains over a large region.

 

Q: What is the relationship between a stream and a drainage basin? A drainage basin is the land area that contributes water to a stream.