Quiz # 1 Chapters 1 and 2 s1

Homework Questions for Lecture 11-12 ES 1000

Use these questions to test your knowledge of Lecture 11-12 on Streams and Groundwater

A. Short answer:

1. Hydraulic lifting occurs as a turbulent stream flows through fractures in ______.

2. Abrasion and hydraulic lifting are more ______in fast streams than in slow ones.

3. A graded stream responds instantaneously to any change in ______load or discharge in such a way as to establish a new graded state.

4. Every stream carries water from a watershed that is separated from other watersheds by a drainage ______.

5. In a curved section of a stream channel, the fastest water is near the ______of the curve.

6. In a straight section of a stream channel, the fastest water is in the ______of the channel just below the surface. B. Match the Terms.

1. abrasion_____ a. heavy sediment load

2. point bar deposit____ b. steep stream meets broad flat valley

3. saltation____ c. water table dropped.

4. floodplain ____ d. characteristic of karst

5. gradient ____ e. erosion and deposition equilibrium

6. alluvial fan _____ f. ability to carry sediment

7. braided stream _____ g. ability to move water between pores

8. capacity______h. volume space between grains

9. graded stream______i. meandering stream

10. base level_____ j. submerged during floods

11. Porosity _____ k. groundwater recharge

12. Permeability _____ l. bouncing

13. Disappearing stream ___ m. scrape stationary rocks

14. Collapse sinkhole _____ n. lowest possible erosion

15. Infiltration ______o. slope of streambeds

16. Competence ______p. largest particle carried C. True or False? Circle the correct answer.

1. A stream’s base level is the lowest level to which a stream can erode its channel. True or False?

2. A graded stream is one in which an equilibrium has been reached so that there is little net erosion or deposition. True or False? 3. After a stream bank collapses, partially blocking a channel with sediment, a stream’s velocity increases there. True or False?

4. During a flood, a stream’s power to erode its channel increases dramatically. The erosional power is proportional to the square of the velocity. True or False?

5. Stream piracy occurs when one stream captures the headwaters of another stream on the opposite side of a drainage divide. True or False?

6. The stream that erodes through its divide to capture the other slope drainage does so because of its steeper slope, greater discharge, and less resistant streambed rocks. True or False?

7. Braided streams are caused by an exceptionally high sediment load. True or False?

8. Streams develop meanders because something disturbs a straight channel. Uneven erosion starts when flow is deflected to one side. Erosion continues on the "outside" (cutbank) of curves, where water velocity is highest, while bar deposition occurs on the "inside" of curves, where water velocity is lowest. The result is greater channel curvature. True or False?

9. Alluvial fans are formed on low-land plains, while deltas are formed in a standing body of water. True or False?

10. Waterfalls tend to migrate upstream and become smaller as erosion wears away a resistant rock forming the local base level. True or False? 11. Streams disappearing into sinkholes identifies karst land. True or False?

12. Most caves are formed by subsurface dissolution of limestone. True or False?

13. Grading steep slopes (terracing them so that large areas are level) can enhance groundwater recharge because such a measure reduces the runoff from precipitation. True or False?

14. A perched water table is a water table found on top of a local impermeable layer lying above the zone of saturation. True or False?

15. A water table’s configuration (its underground depth) is usually random and unpredictable. True or False?

16. The greatest infiltration of surface waters would be on gentle slopes. True or False?

17. Porous, unconsolidated clays encourage infiltration better than fractured or jointed bedrock. True or False?

D. Multiple choice:

1) Which of the following statements about stream transport is TRUE? (a) A stream’s competence is a measure of the diameter of the largest particle that the stream can transport. (b)A stream’s competence is proportionate to the square of its velocity. (c) A stream’s capacity is a measure of the maximum quantity of sediment the stream can transport. (d)All of the above 2) Which of the following statements concerning a stream’s sediment load is NOT true? (a) The brown color in muddy rivers is caused by an unusually high dissolved load. (b)Large stones that cannot be carried within a stream’s suspended load can sometimes be transported by traction in the stream’s bed load. (c) Fine particles of clay are likely to be transported as part of the suspended load. (d)Both flat and low-density particles tend to remain within the suspended load.

3) Braided streams with large amounts of very coarse bed-load sediments deposit what bedform? (a) Point bars. (b)Mid-channel bars. (c) Levees.

4) Natural levees result when: (a) streams flood their banks and deposit sediment directly on top of the banks. (b)streams erode downward in their channel, leaving their banks higher relative to the surface of the stream. (c) hard, erosion-resistant rocks become part of a stream’s banks. (d)smaller streams flow parallel to a main stream and deposit material on the stream bank.

5) The highest point along a meandering stream would be: a) the channel bottom. b) the levees. c) the gravel bedload d) the point bar. 6) Which of the following conditions is most favorable for delta formation? (a) Where waves and currents immediately sweep away most of the river’s delivered sediments. (b)Where powerful storm waves carry all of the river’s delivered sediment. (c) Where a large sediment load is delivered to quiet coastal waters. (d)Where a small sediment load is delivered along the river’s short path to quiet coastal waters.

7) A large cone of depression is LEAST likely to develop when: (a) a large amount of water is removed from an aquifer. (b)there is little precipitation in an area. (c) the aquifer has minimum permeability. (d)recharge exceeds discharge.

8) Which of the following statements about water that contains dissolved calcium and bicarbonate ions is NOT true? (a) they cause the dissolution of limestone. (b)It is considered hard water and may leave calcium carbonate deposits in plumbing pipes. (c) It can be carried to the sea where marine organisms use it for building shells. (d)It may infiltrate through unconsolidated sediments and deposit calcite as a cementing agent.

9) Which of the following statements about limestone is NOT true? (a) The most soluble component of limestone is the mineral calcite. (b)Limestone dissolves most readily in pure water. (c) Calcium and bicarbonate ions are produced as a result of the dissolution of limestone by carbonic acid.

E. Mixed Format

1. Explain why stream water goes faster on the outside of a curve. 2. Explain why bed load is deposited on the inside of a curve 3. Explain why calcite is precipitated in caverns F. 1. Chi-Square. Continue Reading Lecture 13, up to slide 44. Measurements of surface water velocity are made in a curved section of a meandering stream. A length of rope 10 meters long is prepared and is used to mark known lengths of shore on both sides of the meander loop. Circular bits of paper from a three-hole punch are floated, one at a time, on the surface, and are timed along a marked length of shoreline, using a stopwatch. Two sets of data are collected: one for paper disks moving along 10 meters of outer curve (cutbank side), the other along 10 meters of inner curve (pointbar side). Every five trials are averaged, and the observations totaled for trials that average more or less than 2 meters per second. Velocity 0.1 - 2 m/sec 2.1 - 4 m/sec Column Totals Outside of 17 29 46 curve Inside of curve 31 19 50 Row Totals 48 48 Grand Total 96

Expected frequencies = (row total x column total) / grand total. These are below:

(48x46)/96 = (48x46)/96 = 23 23 (48x50)/96 = (48x50)/96 = The number of degrees of freedom n 25 25 is n = (# rows - 1) x (#columns - 1) = 1. However, no expected value is less than 10, so no Yates correction factor is needed. http://en.wikipedia.org/wiki/Yates%27_correction_for_continuity Questions: Consider the claim that water moves more quickly on the outside of the curve. a. State the null hypothesis and, for P = 0.05 b. Test it using Chi-square. A critical values table for X2 is in your Lecture 13.