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103 Cards in this Set

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Including offshore outer continental shelf production, where does Louisiana rank in the production of natural gas compared to the other 49 states in our country?
2nd
What is associated w/ changes in LA’s sea level during the Ice Ages?
Terraces
What formed as a distributary of the Mississippi River?
The Atchafalaya River
Shallow/wide streams:
Braided streams
A delta that is not strongly influence by waves or tides:
River-dominated delta (Mississippi River Delta)
Drainage pattern that develops when relatively flat-lying material erodes uniformally:
Dendritic
What often forms in areas w/ a lot of flash flooding?
Braided streams
What are the 5 main depositional features of meandering streams?
1) point bar/cut bank
2) oxbow lake
3) floodplain
4) natural levee
5) terrace
Where do streams usually have deposition?
On the shallow side (inside)
The “swirling” process which drills out circular holes in the bottom and sides of streams:
Abrasion
What types of streams migrate over time?
Meandering streams
What percentage of Louisiana's population (approximately 4 million people) live in coastal parishes?
Just over 50%
What 4 characteristics will produce the slowest stream velocity?
Gentle gradient; shallow, wide channel; rough bottom
What marks the floodplain where it used to flow when it was at a higher elevation?
Terrace
Drainage pattern that forms where there are mountain ridges separated by valleys:
Trellis
What prevents a river’s ability to flood and spread sediment out into the ocean?
Artificial levees
All material that is deposited by a stream:
Alluvium
During periods low water (i.e. little or no rainfall), streams will undergo a large amount of ____.
Deposition
The sand and gravel fractions of a stream’s load:
Bedload
What resource does the Western U.S. obtain from braided stream deposits and alluvial fans?
Groundwater
What 2 river/stream features are commonly found in LA?
Meandering streams and deltas
Narrow/ deep streams:
Meandering streams
Channels with the fastest velocity are usually ____.
Semicircular
What are the 4 types of drainage patterns?
1) Dendritic
2) Radial
3) Rectangular
4) Trellis
How much of the United States’ wetland loss occurs in LA?
80%
How does roughness affect a stream’s velocity?
Any obstructions (i.e. “roughness”) in a stream will slow down the stream’s velocity.
A fan-shaped deposit of alluvium that forms when mountain streams empty onto valley floors:
Alluvial fans
Explain the structure of the Mississippi River and the Red River before the 15th century:
The Red River and Mississippi River were separate rivers, and were positioned parallel to each other.
Streams with very high amounts of bed load tend to:
Become braided
What erosional process is not usually seen in LA and why?
Abrasion – not usually seen in LA b/c it requires a lot of sand and gravel, and LA’s water is mostly muddy.
Why hasn’t the Mississippi River changed its course through avulsion in a long time?
Because of artificial levees
If a stream channel is 20 feet wide, 10 feet deep, and flowing at a velocity of 10 feet/sec, what is its discharge? Hint: Area = width x depth.
2000 cubic feet/sec
The portion of a stream’s load that cannot be seen in the water:
Dissolved load
What process creates point bars?
Deposition
What percentage of the Earth’s water consists of rivers, streams, creeks, bayous, lakes, groundwater, etc.?
Only 1%
What did Capt. Henry M. Shreve, do to the Mississippi River?
The entrance to the Atchafalaya River was blocked by a log jam, so Capt. Shreve dug a canal through the Turnbull's Bend and shortened the river’s travel time.
The slope of a stream bed:
Gradient
What type of bed load is most commonly seen in LA?
Suspended load
Curves and bends in a stream channel:
Meanders
Why are stream channels steeper on one side than on the other?
They are asymmetrical
What is one way to measure the discharge in large bodies of water?
Find out the elevation of the water surface
Transportation of sand downstream through a series of hopping, skipping, and leaping motions:
Saltation
What erosional process requires the most energy?
Scouring
Small stream that flows into a large stream:
Tributary
As a stream increases its channel length by developing a mature meander pattern, it also:
Decreases its discharge
How much of the U.S. wetlands are in LA?
40%
What erosional process produces potholes?
Abrasion
Where are point bars deposited?
On the INSIDE of the meander bend
All material transported by a stream:
Load
Where are rectangular drainage patterns found?
On fractured rock
What 2 factors control a stream’s functions?
1) velocity
2) discharge
An area that is covered by water in a flood:
Floodplain
Channels with the slowest velocity usually have what characteristics?
1) wide/shallow
2) narrow/deep
Where do streams usually have erosion?
On the steep side (outside)
How can you measure a stream’s velocity?
Measure velocity w/ a current meter
What are the 2 types of erosion?
1) Scouring
2) Abrasion
Outside part of meandering stream that is created by erosion of the channel wall:
Cut bank
What forms when a river empties into a standing body of water?
Delta
What are the 3 main functions of streams/rivers?
1) Erosion( removes material)
2) Transportation (transports material)
3) Deposition (deposits the transported material)
What generally decreases downstream along the length of a stream?
Gradient
What formed Louisiana?
Deltas
How much of the Earth’s water is in the oceans?
97%
Particles that roll and slide along the bottom of streams:
Bed load
Streams with very high amounts of bed load tend to:
Become braided
How many different periods of avulsion has the Mississippi River Delta undergone in its lifetime?
7
How do you calculate stream/river discharge?
Q = A x V
Discharge = cross-sectional area x velocity
The cycling of water from the atmosphere, to the Earth, and back to the atmosphere:
The hydrologic cycle
Where does the Western U.S. acquire a large amount of its groundwater?
From braided stream deposits and alluvial fans
Transport of gravel through a series of rolling, sliding motions:
Traction
What process primarily occurs during floods?
Erosion
As a stream increases its channel length by developing a mature meander pattern, it also:
Decreases its discharge
How does gradient affect a stream’s velocity?
The steeper the slope of the stream, the faster the velocity.
Bed load that gives water its taste:
Suspended load
Including offshore outer continental shelf production, where does Louisiana rank in crude oil production compared to the other 49 states in our country?
1st
What are the terraces in Louisiana associated with?
Changes in the sea level during the Pleistocene epoch (Ice Age)
Slightly elevated land surfaces on either side of a river channel that form from the accumulation of sediment deposits:
Natural levee
Drainage pattern that forms on cone-shaped mountains (volcanoes):
Radial
The speed at which the water in a stream/river is moving:
Velocity
All land area drained by a stream and its tributaries:
Drainage basin
Streams that flow as single, sinuous, S-shaped channels:
Meandering streams
An abandoned meander that has been cut off from the river:
Oxbow (if it is dry)

Oxbow lake (if it is filled w/ water)
Where does 2% of the Earth’s water reside?
In icecaps and glaciers
What is transported either along or close to the streambed?
Bedload
What causes a stream to deposit its load, and what type of load is deposited first, and which is last?
The stream’s velocity slows down and causes a decrease in flow energy, depositing the bed load first and the suspended load last.
Narrow/deep streams:
Meandering streams
Where are cut banks located?
On the OUTSIDE of the meander bend
Where do braided streams usually form?
In areas w/ a lot of flash flooding
What is the impact of Louisiana’s loss of wetlands?
1) Oil and gas industries (coastline is moving northward and exceeding 3 mile limit)
2) Seafood industries
3) Coastal wetlands are Louisiana’s first line of defense against hurricanes
Process in which running water picks up loose material from the bottom of a streambed; requires the most energy:
Scouring
Ancient or abandoned floodplains:
Terrace
What happens as more water comes in contact w/ the bottom and sides of the stream’s channel?
The slower it makes the stream’s velocity
What 3 things control a stream’s velocity?
1) GRADIENT (slope) of stream bed
2) SHAPE of channel
3) ROUGHNESS in bottom of stream
The volume of water flowing past a point in a given period of time:
Discharge
Drainage pattern that contains right-angled bends:
Rectangular
What is causing the coastal wetlands of LA to erode at such an extreme rate?
Avulsion
When does erosion usually occur?
During periods of high velocity and discharge; primarily during floods
What process creates cut banks?
Erosion
What 2 factors cause the meandering motion of streams?
1) Corkscrew motion of channel
2) Asymmetry of channel
What forms when mountain streams empty onto valley floors?
Alluvial fans
Shallow/wide streams:
Braided streams
What causes rivers to change coarse?
Avulsion
What type of drainage pattern is commonly found in LA?
Dendritic
In 2004, the commercial fish harvest in Louisiana exceeded 1 billion pounds with a dockside value of $274 million. What percentage of the commercial fish harvest does this represent for the lower 48 states in our country?
26%