Question 1

What are the differences in appearance between a debris flow and a mudflow deposit?

Accepted Answer

A debris flow has coarse boulders concen

Question 2

How would a hydrograph for a drainage basin change if major urban growth were to occur upstream?

Accepted Answer

A)  The hydrograph would be higher and narrower. 
B)  The hydrograph would be both higher and last longer. 
C)  The hydrograph would be lower but last longer. 
D)  The hydrograph changes only with wildfire, logging, or overgrazing, not urban growth. 
E)  The hydrograph becomes skewed, rising more slowly but dropping very quickly. 
A)  The hydrograph would be higher and narrower. 
B)  The hydrograph would be both higher and last longer. 
C)  The hydrograph would be lower but last longer. 
D)  The hydrograph changes only with wildfire, logging, or overgrazing, not urban growth. 
E)  The hydrograph becomes skewed, rising more slowly but dropping very quickly.

Question 3

Which of the following CANNOT be used to determine the depth of a debris flow in a canyon it moved through?

Accepted Answer

A)  bark battered off the upstream sides of trees up to that height 
B)  sand embedded in bark up to that height 
C)  rocks lodged in tree branches up to that height 
D)  the maximum height of sand eroded from the valley sides 
E)  the highest rocks on natural levees deposited by the flow 
A)  bark battered off the upstream sides of trees up to that height 
B)  sand embedded in bark up to that height 
C)  rocks lodged in tree branches up to that height 
D)  the maximum height of sand eroded from the valley sides 
E)  the highest rocks on natural levees deposited by the flow

Question 4

Which is likely to flow farther down to the flatter,wider part of a valley: a debris flow or a mudflow? Why?

Accepted Answer

A mudflow,because the tiny por

Question 5

Why are the deposits of streams graded with the largest boulders or pebbles at the bottom?

Accepted Answer

A)  The largest boulders are always at the bottom; they never move. 
B)  The largest boulders eroded from the stream bank immediately roll to the bottom and stay there. 
C)  Jostling of boulders, pebbles, and sand in turbulent water moves the boulders to the bottom. 
D)  As the water slows after a flood, the largest boulders drop out first. 
E)  Tributaries add additional sediment to the stream. 
A)  The largest boulders are always at the bottom; they never move. 
B)  The largest boulders eroded from the stream bank immediately roll to the bottom and stay there. 
C)  Jostling of boulders, pebbles, and sand in turbulent water moves the boulders to the bottom. 
D)  As the water slows after a flood, the largest boulders drop out first. 
E)  Tributaries add additional sediment to the stream.

Question 6

Why does stream level rise within a few hours of a heavy rain,even though you see no water running off the slopes?

Accepted Answer

Water seeping into the ground

Question 7

What are natural levees? Where do they form? Why do they form there?

Accepted Answer

They are subdued ridges of sed

Question 8

How would you calculate the discharge (or flow rate)of a stream?

Accepted Answer

Q = VA [Discharge (Q)= velocit

Question 9

Which of the following areas is LEAST likely to have a flash flood?

Accepted Answer

A)  western Washington state 
B)  southern Arizona 
C)  eastern Nevada 
D)  southern Texas 
E)  central South Dakota 
A)  western Washington state 
B)  southern Arizona 
C)  eastern Nevada 
D)  southern Texas 
E)  central South Dakota

Question 10

All of the following diminish the reliability of recurrence intervals EXCEPT:

Accepted Answer

A)  using data from a short time interval. 
B)  separating different meteorological conditions. 
C)  population growth and urbanization. 
D)  modifying the stream by channelization. 
E)  deforestation within the watershed. 
A)  using data from a short time interval. 
B)  separating different meteorological conditions. 
C)  population growth and urbanization. 
D)  modifying the stream by channelization. 
E)  deforestation within the watershed.

Question 11

What changes upstream from a site would likely lead to higher-level floods with the same rainfall pattern? What changes would occur for this stream's hydrograph?

Accepted Answer

Increased urbanization,channelization,bu

Question 12

A floodplain with a record since 1930 had its largest historic flood in 1999,and there is a slightly larger flood 12 years later in 2011.What,if any,change is there in the recurrence interval for the 1999 flood? Be numerically specific.

Accepted Answer

Recurrence interval for 1999 f

Question 13

Why are alluvial fans so broad,even though they form at the lower end of a narrow mountain canyon?

Accepted Answer

The stream in the narrow canyo

Question 14

What is the best long-term solution to avoiding a debris flow?

Accepted Answer

Do not live (or buil

Question 15

Why do braided streams form in a dry climate instead of meandering streams?

Accepted Answer

A)  The stream flows on a broad, flat surface, so it spreads out and braids. 
B)  The stream has too little water to carry the total sediment supplied. 
C)  The stream channel is so shallow that the stream flows easily over its banks. 
D)  Water soaks down to the water table, so it doesn't ever flow downslope. 
E)  There are so many channels that they can't help but cross one another to form a braided pattern. 
A)  The stream flows on a broad, flat surface, so it spreads out and braids. 
B)  The stream has too little water to carry the total sediment supplied. 
C)  The stream channel is so shallow that the stream flows easily over its banks. 
D)  Water soaks down to the water table, so it doesn't ever flow downslope. 
E)  There are so many channels that they can't help but cross one another to form a braided pattern.

What are the differences in appearance between a debris flow and a mudflow deposit?

How would a hydrograph for a drainage basin change if major urban growth were to occur upstream?

Which of the following CANNOT be used to determine the depth of a debris flow in a canyon it moved through?

Which is likely to flow farther down to the flatter,wider part of a valley: a debris flow or a mudflow? Why?

Why are the deposits of streams graded with the largest boulders or pebbles at the bottom?

Why does stream level rise within a few hours of a heavy rain,even though you see no water running off the slopes?

What are natural levees? Where do they form? Why do they form there?

How would you calculate the discharge (or flow rate)of a stream?

Which of the following areas is LEAST likely to have a flash flood?

All of the following diminish the reliability of recurrence intervals EXCEPT:

What changes upstream from a site would likely lead to higher-level floods with the same rainfall pattern? What changes would occur for this stream's hydrograph?

A floodplain with a record since 1930 had its largest historic flood in 1999,and there is a slightly larger flood 12 years later in 2011.What,if any,change is there in the recurrence interval for the 1999 flood? Be numerically specific.

Why are alluvial fans so broad,even though they form at the lower end of a narrow mountain canyon?

What is the best long-term solution to avoiding a debris flow?

Why do braided streams form in a dry climate instead of meandering streams?

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Exam 12: Streams And Flood Processes

What are the differences in appearance between a debris flow and a mudflow deposit?

How would a hydrograph for a drainage basin change if major urban growth were to occur upstream?

Which of the following CANNOT be used to determine the depth of a debris flow in a canyon it moved through?

Which is likely to flow farther down to the flatter,wider part of a valley: a debris flow or a mudflow? Why?

Why are the deposits of streams graded with the largest boulders or pebbles at the bottom?

Why does stream level rise within a few hours of a heavy rain,even though you see no water running off the slopes?

What are natural levees? Where do they form? Why do they form there?

How would you calculate the discharge (or flow rate)of a stream?

Which of the following areas is LEAST likely to have a flash flood?

All of the following diminish the reliability of recurrence intervals EXCEPT:

What changes upstream from a site would likely lead to higher-level floods with the same rainfall pattern? What changes would occur for this stream's hydrograph?

A floodplain with a record since 1930 had its largest historic flood in 1999,and there is a slightly larger flood 12 years later in 2011.What,if any,change is there in the recurrence interval for the 1999 flood? Be numerically specific.

Why are alluvial fans so broad,even though they form at the lower end of a narrow mountain canyon?

What is the best long-term solution to avoiding a debris flow?

Why do braided streams form in a dry climate instead of meandering streams?

Natural Hazards and Disasters

Plate Tectonics and Physical Hazards

Earthquakes and Their Causes

Earthquake Prediction and Mitigation

Tsunami

Volcanoes: Tectonic Environments and Eruptions

Volcanoes: Hazards and Mitigation

Landslides and Other Downslope Movements

Sinkholes, Land Subsidence, and Swelling Soils

Weather, Thunderstorms, And Tornadoes

Climate Change

Floods And Human Interactions

Waves,Beaches,And Coastal Erosion

Hurricanes and Nor’easters

Wildfires

Impact of Asteroids and Comets

The Future: Where Do We Go From Here?

Filters