Test Bank Streams And Flooding Exam Prep Ch8

Chapter 08 Test Bank: Streams and Flooding

Multiple Choice Questions

1. What best describes the basic role of streams in the Earth system?

A. drain water from the landscape and transport sediment

B. link the atmosphere to the oceans in the hydrologic cycle

C. provide water to the interior of continents

D. help remove carbon dioxide from the atmosphere

E. transport sediment and create valuable gold deposits

2. Which of the following terms is used to describe the volume of water flowing past a specific point in a stream over a given time period?

A. overland flow

B. discharge

C. square volume

D. specific capacity

E. flux

3. Which of the following is NOT part of the hydrologic cycle?

A. transpiration

B. overland flow

C. sequestration

D. infiltration

E. evaporation

4. What best explains why groundwater baseflow is important to maintaining a healthy stream ecosystem in humid climates?

A. provides dissolved ions necessary for plant growth

B. removes bacteria and viruses that are harmful to plants and animals

C. decreases stream erosion

D. reduces the intensity and duration of floods

E. provides streams with a steady flow of water during dry periods

5. Which of the following statements best describes losing streams?

A. common in humid regions where groundwater flows into streams.

B. common in arid regions where some of the stream water flows into the groundwater system.

C. common in humid regions where some of the stream water flows into the groundwater system.

D. common in arid regions where groundwater flows into streams.

6. What best describes a drainage basin?

A. a part of the landscape where water is rapidly drained away.

B. a circular depression in the topography where water accumulates.

C. a circular depression in the topography where sediment accumulates.

D. the land area that collects water for a given network of streams.

E. a part of the landscape that stays above freezing and water remains a liquid.

7. What best describes the headwaters of a drainage basin?

A. collection of streams that empty into a body of water.

B. those parts of a drainage basin where groundwater discharge into streams.

C. those parts of a drainage basin where water infiltrates into the groundwater system.

D. collection of small channels in the upper part of a basin that merge into larger streams.

E. those parts of a drainage basin that lie above base level.

8. Streams located near the mouth of a river are quite different compared to those near the headwaters. What best characterizes streams near the mouth?

A. low velocity, high discharge, and straight channels

B. low velocity, low discharge, and meandering channels

C. high velocity, low discharge, and straight channels

D. low velocity, high discharge, and meandering channels

E. high velocity, high discharge, and straight channels

9. What best explains why stream valleys become wider over time?

A. deposition of sediment creates a valley floor.

B. meandering streams undercut their banks and cause mass wasting.

C. streams get further above base level.

D. stream velocity becomes greater over time.

E. tectonic uplift causes valleys to widen naturally.

10. In addition to cutting laterally, streams can also cut downward in their channels to form deep valleys and canyons. What best explains how streams can cut downward through solid rock?

A. water flowing rapidly over the bedrock causes erosion.

B. physical weathering of bedrock by freeze and thaw action.

C. occurs in areas where streams encounter weaker layers of bedrock.

D. acidic water causing chemical weathering of the bedrock.

E. transported sediment causes abrasion of bedrock.

11. Why is hydraulic sorting of sediment important in environmental geology?

A. it produces elevated terraces that are less likely to be flooded

B. it causes streams to reach base level more rapidly

C. all of the answers listed here

D. it separates those streams that are flood prone from those that are not

E. it produces relatively pure deposits of sand and clay

12. Some rivers naturally carry more water than others. Which of the following best explains why the Amazon River in South America carries 12 times more water than the Mississippi?

A. all of the answers listed here

B. the Amazon has a much larger channel

C. there is much less human development along the Amazon

D. the Amazon’s drainage basin lies mostly within a tropical rainforest

E. the Amazon is a much longer river

13. How do hydrologists measure the severity of floods?

A. the amount of land area that is inundated along a floodplain

B. how fast the water rises in the channel

C. the amount of land area that collects water from a rain event

D. the height (stage) above which a stream overflows its banks

E. the number of people that are impacted along a floodplain

14. What best explains how hydrologists determine the frequency of flooding?

A. locate the 100-year floodplain on maps

B. predictions based on rainfall duration and intensity data

C. predictions based on rainfall volume and wind speed data

D. predictions based on topographic maps and precipitation data

E. calculate recurrence intervals from historical discharge records

15. Which of the following natural factors affect the degree or severity of flooding?

A. rainfall volume and infiltration capacity of the ground

B. size of raindrops and slope of the land

C. size of the raindrops and wind speed

D. rainfall volume and wind speed

E. slope of the land and wind speed

16. What best characterizes downstream flooding?

A. fast moving floodwaters that follow small tributaries

B. small volume flood that slowly rises and falls

C. floodwaters that rapidly rises and falls

D. slow moving floodwaters that follow small tributaries

E. large volume flood that slowly rises and falls

17. Which of the following statements is NOT true with respect to dams and reservoirs?

A. water released from reservoirs is cooler than a natural stream, which harms aquatic ecosystems.

B. sediment is trapped behind dams and slowly fills in reservoirs.

C. stream discharge becomes fairly uniform, which harms aquatic ecosystems.

D. reservoirs serve as an important source of fresh water.

E. dams are generally not effective at flood control and are mainly used to generate electricity.

18. Which of the following are effective ways of reducing the effects of flooding?

A. all of the answers listed here

B. channelization

C. wetlands restoration

D. artificial levees

E. erosion controls

19. Which of the following statements is NOT true regarding artificial levees?

A. used to help keep the channel straight so water flows faster

B. raises the height a stream must reach before overflowing its banks

C. creates the potential for catastrophic flood in areas downstream

D. makes flooding worse in areas upstream

E. can be made of concrete or earthen materials

20. Which of the following best explains why urbanization has led to larger and more frequent floods?

A. large areas of land are covered with impermeable surfaces

B. rainwater tends follow roadways and becomes more concentrated

C. heat island effect of cities produces more frequent rains

D. rainfall volume is naturally higher over areas where vegetation is more sparse

E. irrigation of yards and landscaping

21. What is an adverse consequence of engineering structures built to control flooding?

A. It allows the stream to be used as a source of water.

B. It allows the stream to be used as a source of food.

C. It allows the stream to be used for transportation.

D. It tends to encourage development in areas which had been avoided due to frequent flooding.

22. What is the term for the sinuous pathway through which a stream flows?

A. Floodplain

B. Channel

C. Wetland

D. Lake

23. The term "discharge" refers to

A. the volume of water flowing through the channel per unit time.

B. the speed of water flowing through a channel.

C. the weight of water flowing through a channel.

D. the amount of sediment carried by a stream channel.

24. What is meant by the "lag-time" on a stream hydrograph?

A. Time between rain events

B. Time between floods

C. Time between rain event and flood peak

D. Time between flood peak and the next rain event

25. What is meant by the term "baseflow?"

A. The level of flow during a flood

B. The level of flow on a floodplain

C. The level of flow when fed by groundwater alone

D. The speed of water flowing along the base of a channel

26. What is the term for a topographic high separating two drainage basins?

A. Headwaters

B. Mouth

C. Delta

D. Drainage divide

27. What is another term for "drainage basin?"

A. Base level

B. Watershed

C. Floodplain

D. Pothole

28. What is another term for "stream sediment"?

A. Cutbank

B. Alluvium

C. Colluvium

D. Levee

29. What is evidence for stream abrasion in solid rock?

A. A pothole

B. A point bar

C. A cutbank

D. A meander

30. What is the term for the lowest level to which a stream can erode?

A. Base flow

B. Mouth

C. Base level

D. Base discharge

31. What is the name for a deposit formed where a stream enters a lake or ocean?

A. Levee

B. Point bar

C. Delta

D. Alluvial fan

32. What is the term for the pair of ridges on the floodplain running parallel to the stream bank?

A. Point bar

B. Stream terrace

C. Backswamp

D. Levee

33. How is the percent probability calculated from the recurrence interval (RI)?

A. 10/RI

B. 1/RI

C. 10 x RI

D. 1 x RI

34. What is meant by the term "infiltration capacity"?

A. The rate of downward movement of water through the soil

B. The ability of the ground to absorb water

C. The amount of discharge caused by groundwater

D. The total amount of water a stream channel can hold during a flood

35. Which of the following tends to reduce the magnitude of flooding?

A. Increasing intensity and duration of rainfall

B. Increasing ground cover by impermeable materials

C. Increasing vegetation

D. Increasing drainage basin size

36. Which is another name for a flash flood?

A. Upstream flood

B. Downstream flood

C. Storm surge

D. Earthflow

37. Which of the following is true about flash floods?

A. Lag time is very long

B. Floodplain is very wide

C. Generally affects only large regions

D. Generally affects only localized areas

38. What usually causes a downstream flood?

A. Regional accumulations of water upstream

B. Localized accumulations of water upstream

C. Storm surge during high tide

D. Very rapid deltaic sedimentation

39. Which human activity does not increase the frequency and severity of flooding?

A. Destruction of wetlands

B. Construction of bridges and culverts

C. Paving surfaces with impermeable materials

D. Increasing lag time caused by sewers

40. All of the following are effective for reducing flood hazards except

A. construction of dams.

B. filling stream channels with excessive sediment.

C. construction of artificial levees.

D. channelization.