Chapter 17

Which of the following conditions could lead to the formation of a waterfall? Choose one or more: A. faulting and displacement producing an escarpment B. glacial erosion deepening a trunk valley, forming a hanging valley C. water flowing over steps or large clasts on the streambed D. stream crossing a resistant ledge of rock

A. faulting and displacement producing an escarpment B. glacial erosion deepening a trunk valley, forming a hanging valley D. stream crossing a resistant ledge of rock

What factors cause the discharge of a stream to change? Choose one or more: A. human activity like using streams for irrigation of crops B. the size of the watershed C. the temperature of the stream water D. the amount of rain or snow falling in the watershed

A. human activity like using streams for irrigation of crops B. the size of the watershed D. the amount of rain or snow falling in the watershed

People build structures to try and prevent flooding. What structure is shown in the diagram below? Choose one: A. levee B. gate C. floodway D. dam

A. levee

As a stream downcuts through alluvium, as shown in the diagram below, a new lower floodplain develops. The remnants of the original alluvial plain remain as a pair of __________ Choose one: A. terraces B. waterfalls C. alluvial fans D. valleys

A. terraces

How do deltas develop? Choose one: A. when sediment-laden stream water enters standing water, like an ocean B. when an area of a stream becomes influenced by tides C. when stream velocity increases the competence of streams D. when a small tributary enters the trunk stream

A. when sediment-laden stream water enters standing water, like an ocean

Does the land surface outside of the watershed slope toward or away from the drainage divide?

Away

What is the difference between permanent streams and ephemeral streams?

Permanent streams- flow all year long Ephemeral streams- flow for only part of the year

What is the difference between a slow-onset flood and a flash flood? Match the descriptions with their term.

Slow-onset floods: flooding takes days to develop and lasts for days or weeks Flash floods: floodwaters rise so fast that It may be difficult to escape their path

A stream will deposit sediment when __________

its flow velocity decreases

How do you know the structure in the diagram from Part 1 is failing? Choose one or more: A. The sediment is slumping. B. Puddles are forming at the base. C. Sand volcanoes are forming. D. The upper portion has collapsed into the river.

A. The sediment is slumping. B. Puddles are forming at the base. C. Sand volcanoes are forming.

What is the difference between a stream's competence and capacity? Match the terms with their correct definitions.

Competence-refers to the maximum particle size a stream can carry Capacity-refers to the total quantity of sediment a stream can carry

What weather conditions can lead to flooding? Choose one or more: A. abrupt, heavy rains B. wind blowing at a high velocity over a river channel C. a long period of continuous rain D. a hot spell that rapidly melts snow

A. abrupt, heavy rains C. a long period of continuous rain D. a hot spell that rapidly melts snow

Define the discharge of a stream. Choose one: A. the amount of rainfall that enters a stream from a drainage basin B. the velocity of water flowing at the mouth of a stream C. the volume of water passing through a point on a stream per unit time D. the mass of water flowing through the entire stream at any given time

C. the volume of water passing through a point on a stream per unit time

The size of the clasts that settle at a particular locality depends on how slow the flow has become. Therefore, (1)_________ sediment tends to settle out upstream, where water flows faster, whereas (2)__________ grains settle out downstream, where water flows more slowly, and the (3)_____________ sediment settles out when the stream flows into a standing body of water.

1. coarser 2. finer 3. finest

What is the annual probability of a 50-year flood?

2%

The diagram below shows the drainage basins of two streams. Label the drainage divide.

A. Drainage divide

Label the location on this stream diagram where water is flowing fastest.

A. Fastest flow

Label the components of the stream on the diagram below.

A. Headwaters B. Mouth C. Tributary

Label the sources of water that can enter a stream.

A. Puddles, swamps, lakes B. Groundwater C. Melting ice or snow D. Precipitation

If a flood with a recurrence interval of 50 years occurred 5 years ago, does that mean there wouldn't be another one of the same size or larger for the next 45 years? Choose one: A. Yes; the recurrence interval determines how far apart in time these flooding events will occur. B. No; even though the average recurrence is 50 years, there is still a chance of a flood of that size occurring each year.

B. No; even though the average recurrence is 50 years, there is still a chance of a flood of that size occurring each year.

How does urbanization affect flooding? Choose one or more: A. More rainwater is able to infiltrate (seep into the ground). B. The peak discharge becomes higher. C. It decreases the lag time between rainfall and peak discharge. D. The amount of runoff increases.

B. The peak discharge becomes higher. C. It decreases the lag time between rainfall and peak discharge. D. The amount of runoff increases.

Downcutting in a stream __________ a channel, and headward erosion __________ a channel. Choose one: A. widens; shortens B. deepens; lengthens C. deepens; shortens D. widens; lengthens

B. deepens; lengthens

Why is the average velocity of a stream difficult to determine? Choose one: A. Not all of the water in the stream is at the same temperature. B. The amount of water flowing in a stream varies. C. Instruments used to measure water velocity in streams are often inaccurate. D. Not all the water in a stream moves at the same velocity past a given point.

C. Instruments used to measure water velocity in streams are often inaccurate.

Which of the following describes a braided stream? Choose one: A. a stream with a single channel that winds its way across the landscape B. a stream with no sediment being transported C. a stream that is divided into numerous stands weaving back and forth D. a stream that has a series of waterfalls and rapids

C. a stream that is divided into numerous stands weaving back and forth

A drainage divide __________. Choose one: A. separates drainage that flows into one ocean from drainage that flows into another B. is an obstacle in a stream that causes it to diverge C. is a relatively high ridge that separates two drainage basins D. separates the left side of a stream from the right side of a stream

C. is a relatively high ridge that separates two drainage basins

Stream sediment is deposited in a variety of settings. Which setting best describes the photo below? A. gravel in the bed of a mountain stream B. turbulent water carrying large sediment particles C. mud deposited along a gentle, slow-moving stream D. a muddy river entering a larger body of water

C. mud deposited along a gentle, slow-moving stream

What causes a braided stream to form? Choose one: A. An intense amount of runoff enters a stream during a storm. B. A stream channel dries up, leaving behind a channel of sediment. C. An extremely low gradient causes the channel to cut horizontally into the landscape. D. Abundant coarse sediment chokes the channel and prevents the formation of steep banks.

D. Abundant coarse sediment chokes the channel and prevents the formation of steep banks.

Match the three types of sediment loads with their descriptions.

Dissolved load-ions from weathered rocks and minerals Suspended load-tiny solid grains moving along with the water Bed load-large grains that bounce or roll along the stream bottom

Which type of stream is shown in the photo below?

Ephemeral

Which type of delta is shown in the photo below?

bird's-foot delta