Rivers and Flooding 3 Flashcards
When do braided streams occur?
when the sediment load is high
What does the formation of natural levees cause?
Causes the channel of the river to rise higher than the surrounding plain
What are floodplains?(in reference to activity and change)
floodplains are extremely active and dynamic, constantly changing and under immense anthropic pressure
What about the subsurface of a floodplain makes it complex over time?
numerous migrations of the channel over time
Delta
low, nearly flat area of land formed near the mouth of a stream where it enters a lake or the ocean; commonly triangular or fan-shaped and crossed by branching distributary channels
Alluvial Plain
is a largely flat landform created by the deposition of sediment over a long period of time by one or more rivers coming from highland regions, from which alluvial soil forms
What is a flood?
a flood is an overflow of water that submerges land which is usually dry
What causes floods?
- heavy rain
- floods
- flash floods
- fires
- Dams
- New development
- Change in land management
- Ice jams
- Hurricanes and Tropical Storms
- Storm Surges
- Snow Melt
- Spring thaw
- Climatic Cycles(La Nina…)
- Levees
What tool is used to measure water and record data?
USGS Gaging Stations
Riffle
shallow water, fast current, turbulent surface, gravel, rubble, or boulder bottoms
-In big rivers they are called rapids
Run
deeper than a riffle, with moderate to fast current; surface not as turbulent; bottom materials range from small gravel to rubble
Pool
deep, slow-moving water with a flat surface
What does the shape of the channel influence?
-the velocity of the water
Meanders
- parts
- and do they change over time?
-are dynamic
Parts
-point bar
-cut bank
Yazoo Tributary
-tributaries that run parallel to the main river
