1. Chapter 18

2. 1. In which direction is the stream migrating?
toward the left
toward the right
The stream’s position is not migrating.

3. 2. Which type of stream is shown?
straight
braided
meandering

4. 3. Which type of stream is shown?
straight
braided
meandering

5. 4. Braided streams are more common in areas with:
steady discharge.
wide fluctuations in discharge.
very steep slopes.
None of the above.

6. radial dendritic trellis rectangular
5. Which drainage pattern is typical of streams that overlie horizontally bedded sedimentary rocks?
radial
dendritic
trellis
rectangular

7. 6. Rectangular drainage networks typically develop over bedrock that is:
mountainous.
jointed.
folded.
horizontal.

8. 7. The waterfall below is mainly the result of:
erosion.
deposition.
both erosion and deposition.

9. 8. Streams ___ sand grains at lower velocities and ___ them at higher velocities.
erode; deposit
deposit; erode
transport; deposit
erode; transport

10. 9. A delta forms when water flowing through a stream reaches a:
lake.
ocean.
mountain.
A and B.

11. 10. Given the same discharge, which stream will have the highest velocity?
narrow, deep
wide, shallow
rough channel
All will flow at the same velocity.

12. 11. The recurrence interval of floods of a certain discharge is dependent on:
climate of the region.
width of the floodplain.
size of the channel.
All of the above.

13. 12. What is the probability that a flood of 1500 m3/s will occur this year on this river?
90%
50%
20% 2%

14. 13. How much greater is the discharge of a 10-year flood than an annual flood on this river?
10x 5x
3.6x
1.5x

15. 14. True or False: A stream will erode or deposit sediment along its bed until it reaches a sustainable concave-upward profile.
True
False

16. 15. What would happen to a river’s long profile if a dam were built halfway along its length?
Nothing; the long profile would be unaffected.
A small concavity in the profile would coincide with the location of the dam.
A small convexity in the profile would coincide with the location of the dam.
The entire long profile would reverse its orientation.

17. 16. Which types of features can alter the local base level of a stream?
layer of resistant bedrock
movement of a fault block
creation of a dam
All of the above.

18. 17. True or False: The gradient of a stream typically increases as one proceeds from its headwaters toward its mouth.
True
False

19. 18. As river water moves from headwaters to base level within a fluvial system, its energy (~speed) ________ and the average sediment size it can carry __________.
decreases; increases
decreases; decreases
increases; increase
increases; decreases

20. 19. The perennial source of water in most fluvial systems is:
rainfall.
snow/ice melt.
groundwater.
hurricanes.

21. 20. What fluvial deposit is generated due to overflow of water from the stream channel to the floodplain?
an alluvial fan
point bar deposits
natural levees
deltas