The Solid Earth - Chapter 3: Stream Valleys Flashcards
Two general types of stream valleys
Narrow V-shaped
Wide valleys
Most valleys are much broader at the top than is the ___ of the channel at the bottom
width
If a stream is narrow and V shaped, the primary work of the stream has been _______ toward base level
downcutting
Two most prominent features of a narrow valley
rapids
waterfalls
_____ _____ create rapids by acting as a temporary base level upstream while allowing downcutting to continue downstream
Resistant beds
Places where the stream profile makes a vertical drop
Waterfall
RE Niagara Falls: as the water plunges over the lip of the falls, it erodes the less resistant ____
shale
The flat valley floor that is produced when the stream’s energy begins moving side to side
floodplain
When a river erodes laterally, creating a floodplain, it is called a(n) _____ floodplain
erosional
_____ floodplains are produced by deposition
Depositional
Streams that flow upon floodplains, whether erosional or depositional, move in sweeping bends called ____
meanders
Erosion is more effective on the ____ of a meander
downstream
When the river erodes to the next narrow neck of land, the shorter channel segment is called a ____
cutoff
The abandoned bend of a river after a cutoff is formed is called an _____ lake
oxbow
One method of flood control is to straighten the stream by creating artificial ____
cutoffs
