Question 1

What are common levee failures? What makes levees more susceptible to these types of failures?

Accepted Answer

Common levee failures are caused by bank erosion from river currents or waves,slumps into the channel,or seepage.Water seeping rapidly enough through parts of a levee erodes sediment at the side of the levee,which may then progress until the levee is in danger of failure.Cloudy water seeping out can indicate that soil is being washed out of the levee through a process called piping.Levees can be more susceptible to these types of failures because of their composition from local material.The floodplain materials on which levees are built are often composed of old permeable sand and gravel channels surrounded by less permeable muds.The floodplain muds beyond the current channel are sediments that were left behind by the river where it spilled over a natural levee to flow on the floodplain.

Question 2

Which of the following statements is NOT true about the effects of mining sand or gravel from a streambed or banks?

Accepted Answer

A)  There aren't any negative effects; the stream merely brings in more sand and gravel. 
B)  Removal of sediment makes the stream erode its channel deeper. 
C)  Increased erosion by the stream can affect roads and bridges. 
D)  Deepening the channel lowers the water table and affects agriculture. 
E)  Deepening the channel can affect water supplies. 
A)  There aren't any negative effects; the stream merely brings in more sand and gravel. 
B)  Removal of sediment makes the stream erode its channel deeper. 
C)  Increased erosion by the stream can affect roads and bridges. 
D)  Deepening the channel lowers the water table and affects agriculture. 
E)  Deepening the channel can affect water supplies. A

Question 3

A study of more than 8000 U.S.dams by the Army Corps of Engineers indicated that what proportion of the dams were unsafe?

Accepted Answer

A)  1/10 
B)  1/5 
C)  ¼ 
D)  ⅓ 
E)  ½ 
A)  1/10 
B)  1/5 
C)  ¼ 
D)  ⅓ 
E)  ½ D

Question 4

What process does NOT lead to the failure of a river levee?

Accepted Answer

A)  water overtopping the levee 
B)  erosion of the levee by the river currents 
C)  slumping of banks of the levee into the river 
D)  sandbagging the levee to raise its height 
E)  piping or seepage through the levee 
A)  water overtopping the levee 
B)  erosion of the levee by the river currents 
C)  slumping of banks of the levee into the river 
D)  sandbagging the levee to raise its height 
E)  piping or seepage through the levee

Question 5

Roughly what depth of flowing stream is dangerous to drive through?

Accepted Answer

A)  10 cm (4 inches) 
B)  30 cm (1 foot) 
C)  60 cm (2 feet), since water would then be over the axles 
D)  120 cm (4 feet), since water would then be window-height 
E)  180 cm (6 feet), since water would then be above the roof of the car 
A)  10 cm (4 inches) 
B)  30 cm (1 foot) 
C)  60 cm (2 feet), since water would then be over the axles 
D)  120 cm (4 feet), since water would then be window-height 
E)  180 cm (6 feet), since water would then be above the roof of the car

Question 6

Why does the channel bed of a river confined between levees gradually build higher with time?

Accepted Answer

Sediment carried from upstream or eroded

Question 7

Which effect do levees NOT have on a stream?

Accepted Answer

A)  They raise the flood level. 
B)  They increase the water velocity next to the levee. 
C)  They raise water level just downstream. 
D)  They raise the water level upstream. 
E)  Over time, they deepen the stream channel bottom. 
A)  They raise the flood level. 
B)  They increase the water velocity next to the levee. 
C)  They raise water level just downstream. 
D)  They raise the water level upstream. 
E)  Over time, they deepen the stream channel bottom.

Question 8

Define and explain the process of streambed mining.What are the consequences of streambed mining?

Accepted Answer

Today,large amounts of sand and gravel a

Question 9

What is avulsion?

Accepted Answer

A)  A flooding stream permanently leaves its old channel to form a new floodplain channel. 
B)  A stream tends to avoid moving in a straight line: it tends to meander. 
C)  Streams often drop most of their sediment load quickly as the water velocity drops after a flood peak. 
D)  Streams tend to maintain a nearly constant meander radius for a given discharge. 
E)  Streams tend to be locked into their meandering channels, avoiding changing channels during a flood. 
A)  A flooding stream permanently leaves its old channel to form a new floodplain channel. 
B)  A stream tends to avoid moving in a straight line: it tends to meander. 
C)  Streams often drop most of their sediment load quickly as the water velocity drops after a flood peak. 
D)  Streams tend to maintain a nearly constant meander radius for a given discharge. 
E)  Streams tend to be locked into their meandering channels, avoiding changing channels during a flood.

Question 10

Which of the following is NOT a feature of a modern debris flow trapping structure?

Accepted Answer

A)  spillway 
B)  water overflow pipes 
C)  permeable dams 
D)  cross-linked steel pipes 
E)  sand and mud from the floodplain 
A)  spillway 
B)  water overflow pipes 
C)  permeable dams 
D)  cross-linked steel pipes 
E)  sand and mud from the floodplain

Question 11

What human action does NOT negatively impact stream processes and cause excessive erosion?

Accepted Answer

A)  logging 
B)  overgrazing 
C)  planting trees 
D)  deforestation 
E)  fire 
A)  logging 
B)  overgrazing 
C)  planting trees 
D)  deforestation 
E)  fire

Question 12

If you find a sand boil on a floodplain,what does that indicate?

Accepted Answer

Sand boils form when sand is carried to

Question 13

What is a debris flow? What areas are most affected by debris flows? What is the best solution to minimize the impact caused by these dangerous flows?

Accepted Answer

Debris flows are among the most dangerou

Question 14

As dictated by current restrictions,what is the maximum amount the level of a 100-year flood can be encroached (raised)as a result of building?

Accepted Answer

A)  3 feet 
B)  6 inches 
C)  0.3 meters 
D)  1 meter 
E)  18 inches 
A)  3 feet 
B)  6 inches 
C)  0.3 meters 
D)  1 meter 
E)  18 inches

Question 15

What are the four main reasons cited for building large dams on rivers?

Accepted Answer

Flood control,hydroe

Question 16

Which of the following is NOT a common reason cited for building large dams on rivers?

Accepted Answer

A)  flood control 
B)  hydroelectric power 
C)  water supply (or irrigation) 
D)  raise groundwater levels upstream 
E)  recreation 
A)  flood control 
B)  hydroelectric power 
C)  water supply (or irrigation) 
D)  raise groundwater levels upstream 
E)  recreation

Question 17

What is urbanization and how does it contribute to flooding?

Accepted Answer

Urbanization involves transforming natur

Question 18

Why is it almost impossible to keep water from seeping under a levee and out onto a floodplain?

Accepted Answer

A)  Bigger rocks are typically placed at the bottom of levees, and they are most permeable. 
B)  Levees are built on floodplains marked everywhere by old permeable stream channels. 
C)  People building levees often forget to line the stream channel with plastic. 
D)  Piping (large tubes) are built near the top of the levee to prevent overtopping. 
E)  Metallic walls that are placed into the ground rust and fail after two or three years. 
A)  Bigger rocks are typically placed at the bottom of levees, and they are most permeable. 
B)  Levees are built on floodplains marked everywhere by old permeable stream channels. 
C)  People building levees often forget to line the stream channel with plastic. 
D)  Piping (large tubes) are built near the top of the levee to prevent overtopping. 
E)  Metallic walls that are placed into the ground rust and fail after two or three years.

Question 19

Which of the following is NOT a good use for floodplains?

Accepted Answer

A)  agriculture 
B)  parks 
C)  playing fields 
D)  golf courses 
E)  shopping centers 
A)  agriculture 
B)  parks 
C)  playing fields 
D)  golf courses 
E)  shopping centers

Question 20

What are the best detection devices to warn people of an already-moving debris flow?

Accepted Answer

A)  a tripwire 
B)  natural sounds created by the flow 
C)  an acoustic flow monitor 
D)  a visual film monitor 
E)  a natural barrier 
A)  a tripwire 
B)  natural sounds created by the flow 
C)  an acoustic flow monitor 
D)  a visual film monitor 
E)  a natural barrier

What are common levee failures? What makes levees more susceptible to these types of failures?

Which of the following statements is NOT true about the effects of mining sand or gravel from a streambed or banks?

A study of more than 8000 U.S.dams by the Army Corps of Engineers indicated that what proportion of the dams were unsafe?

What process does NOT lead to the failure of a river levee?

Roughly what depth of flowing stream is dangerous to drive through?

Why does the channel bed of a river confined between levees gradually build higher with time?

Which effect do levees NOT have on a stream?

Define and explain the process of streambed mining.What are the consequences of streambed mining?

What is avulsion?

Which of the following is NOT a feature of a modern debris flow trapping structure?

What human action does NOT negatively impact stream processes and cause excessive erosion?

If you find a sand boil on a floodplain,what does that indicate?

What is a debris flow? What areas are most affected by debris flows? What is the best solution to minimize the impact caused by these dangerous flows?

As dictated by current restrictions,what is the maximum amount the level of a 100-year flood can be encroached (raised)as a result of building?

What are the four main reasons cited for building large dams on rivers?

Which of the following is NOT a common reason cited for building large dams on rivers?

What is urbanization and how does it contribute to flooding?

Why is it almost impossible to keep water from seeping under a levee and out onto a floodplain?

Which of the following is NOT a good use for floodplains?

What are the best detection devices to warn people of an already-moving debris flow?

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

Streams And Flood Processes

Waves,Beaches,And Coastal Erosion

Hurricanes and Nor’easters

Wildfires

Impact of Asteroids and Comets

The Future: Where Do We Go From Here?

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Exam 13: Floods And Human Interactions

What are common levee failures? What makes levees more susceptible to these types of failures?

Which of the following statements is NOT true about the effects of mining sand or gravel from a streambed or banks?

A study of more than 8000 U.S.dams by the Army Corps of Engineers indicated that what proportion of the dams were unsafe?

What process does NOT lead to the failure of a river levee?

Roughly what depth of flowing stream is dangerous to drive through?

Why does the channel bed of a river confined between levees gradually build higher with time?

Which effect do levees NOT have on a stream?

Define and explain the process of streambed mining.What are the consequences of streambed mining?

What is avulsion?

Which of the following is NOT a feature of a modern debris flow trapping structure?

What human action does NOT negatively impact stream processes and cause excessive erosion?

If you find a sand boil on a floodplain,what does that indicate?

What is a debris flow? What areas are most affected by debris flows? What is the best solution to minimize the impact caused by these dangerous flows?

As dictated by current restrictions,what is the maximum amount the level of a 100-year flood can be encroached (raised)as a result of building?

What are the four main reasons cited for building large dams on rivers?

Which of the following is NOT a common reason cited for building large dams on rivers?

What is urbanization and how does it contribute to flooding?

Why is it almost impossible to keep water from seeping under a levee and out onto a floodplain?

Which of the following is NOT a good use for floodplains?

What are the best detection devices to warn people of an already-moving debris flow?

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

Streams And Flood Processes

Waves,Beaches,And Coastal Erosion

Hurricanes and Nor’easters

Wildfires

Impact of Asteroids and Comets

The Future: Where Do We Go From Here?

Filters