Streams and Flooding

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43 cards   |   Total Attempts: 188
  

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What is the hydrologic cycle?
The hydrologic cycle is the cycle through which water in the hydrosphere moves.
What are the main reservoirs and the directions and relative magnitudes of the fluxes between these reservoirs?
Main reservoirs are oceans, clouds (atmosphere), glaciers, ground water and lakes and streams; greatest fluxes are from the ocean to the atmosphere
What is residence time?
Residence time
How is residence time calculated?
Residence time = size of reservoir / rate of influx- average time of water molecule to exist in the ocean and then go back into condensation is 34 years
What is the largest reservoir of water on Earth?
Largest reservoir of water on earth is oceans
What is the largest reservoir of unfrozen freshwater?
Largest of unfrozen freshwater is ground water
What is a stream?
A stream is flowing water in a channel
What is a drainage basin?
A drainage basin is the region in which surface water drains into a particular stream
What is discharge
A discharge is the amount (volume) of water flowing past a given point over a particular time interval
How is discharge calculated?
Cubic feet per second (CFS) Q=VA – q is discharge v is velocity a is area
What is alluvium?
Alluvium is general term for particulate stream sediment
What is the main factor in determining how much sediment a stream can carry?
The main factor in determining how much sediment a stream can carry is stream capacityThis depends on discharge and amount of sediment available
What are the three ways in which erosion occurs in streams?
Hydraulic Action: the friction of moving water loosens rock fragments and soil from the sides and base of the stream channelAbrasion: the grinding of sediment particles that wares them down and enlarges the stream channelDissolution: chemical attack on minerals in sediments and stream channel- places ions in solution
What is the gradient of a stream?
The gradient of a stream is the slope of a stream channel
How does it change over the length of a typical stream,
The gradient near the source It is usually a steeper slope and as the stream continues on it gets less steep and carries smaller sediment