Water Erosion and Depositional Features

Topic 6 Water Erosion & Depositional Features

Name ______Period _____

Answer Questions #1-4 using the description and diagram below: A mixture of colloids, clay, silt, sand, pebbles, and cobbles is put into stream I at point A. The water velocity at point A is 400 cm/sec. A similar mixture of particles is put into stream II at point A. The water velocity in stream II at point A is 80 cm/sec.

_____1. Which statement best describes what happens when the particles are placed in the stream? A. Stream I will move all particles that are added at point A. B. Stream II will move all particles that are added at point A. C. Stream I cannot move sand. D. Stream II cannot move sand.

____ 2. Which statement is the most accurate description of conditions in both streams? A. The greatest deposition occurs at point B. B. Particles are carried in suspension and by bouncing along the bottom. C. The particles will have a greater velocity than the water in the stream. D. As the stream velocity decreases deposition occurs.

____ 3. If a sudden rainstorm occurs at both streams above point A, the erosion rate will A. increase for stream I, but not for stream II B. increase for stream II, but not for stream I C. increase for both streams D. not change for either stream

____ 4. What will most likely occur when the transported sediment reaches lake II? A. Clay particles will settle first. B. The largest particles will be carried farthest into the lake. C. The sediment will become more angular because of abrasion. D. The particles will be deposited in sorted layers.

5. How does velocity of the water affect the sediment size it can carry? ______6. What is meant when it is said that sediment is carried in suspension? ______

7. How fast would a stream have to travel to move each of the particles sizes below? A. 0.0003 cm size particle = ______cm/sec B. 0.03 cm size particle =______cm/sec C. 3.0 cm size particle =______cm/sec D. 30.0 cm size particle =______cm/sec

8. Name a type of sediment that can be carried in solution and then deposited by precipitation or evaporation. (hint there are mines for these minerals across NYS.)

Answer: ______

____ 9. Which graph best represents the relationship between a stream's velocity and the size of the largest particles it can carry downstream?

A B C D

____ 10. If sediment has been transported by a stream, due to abrasion, the sediment appearance will become

A. rough and jagged B. rounded and rough C. jagged and rounded D. rounded and smooth

The diagram below shows points A, B, C, and D on a meandering stream.

____ 11. At which letter point on the diagram does the greatest stream erosion occur?

12. Why is a meandering river like the Rio Grande and unsatisfactory boundary between the United States and Mexico? ______Answer Questions 13-16 using the description and diagram below: The map shows a stream flowing into a lake. Letters A through F represent locations in the stream and lake.

____ 13. Which diagram best represents the change in the stream’s elevation from location A to E?

A B C D

____ 14. Which diagram best represents the cross section of the stream at location C? [Note that letters N and S represent the north and south sides of the stream.]

A B C D

____ 15. Where would the greatest amount of sediments most likely be deposited by this stream?

A. E B. B C. F D. D

____ 16. Which size of sediment would probably be deposited farthest out in the lake?

A. sand B. silt C. clay D. pebbles The map below shows a meandering river. A–A’ is the location of a cross section. The arrows show the direction of the river flow. Bend

____ 17. Which cross section best represents the shape of the river bottom at A–A’?

A B C D

18. Sketch the following graphs: e z i Fla S De tne nsi ss ty

Settling Time Settling Time Settling Time

19. Draw a picture of sediment that has been vertically sorted. Such as a landslide into still water. Cliff

20. Draw a picture of sediment that has been horizontaly sorted. Such as sediment deposited in a river delta. Stream Lake

Lake Bottom 21. Sketch the following graphs: f e o

p e o l m S u l o V r e t a W

Stream Velocity Stream Velocity

22. Over a 4 day period in June of 1972, Hurricane Agnes dropped 35 cm of rain on the Allegany and Susquehanna River Watersheds. This included the Allegany-Limestone Area. Record flooding occurred 36 to 48 hours after the heaviest rain. Why didn’t the flooding occur during the rain?

______