Physical Geology Ch 14 - Streams & Floods

Backwash from the ocean

What is not a source of water in streams?
A. Runoff from surrounding lands
B. Direct rainfall
C. Backwash from the ocean
D. Groundwater discharge

228 m(^3)/s

What is the discharge of a stream with a cross sectional area of 12.0 m (^2) and an average velocity of 19.0 m/s?

1. Dissolved load
2. Suspended load
3. Bed load

Rank the 3 types of sediment load in a stream from smallest to largest
Suspended load
Bed load
Dissolved load

Capactiy

____________ is the amount of sediment that a stream can carry.

Competence

____________ refers to the largest particle size that a stream can carry.

Flooding

Which of the following is NOT a threat to the long-term sustainability of a river?
A. Pollution
B. Flooding
C. Excess water use
D. Urbanization

Canyon

Which of the following is an erosional stream landform?
A. Alluvial fan
B. Point bar
C. Canyon

All of the answers are correct

Which of the following is a depositional stream landform?
A. Alluvial fan
B. Natural levee
C. Point bar
D. All of the answers are correct

Base level

The lowest elevation to which a stream channel can erode is defined as its
A. Competence
B. Base level
C. Stream gradient
D. Longitudinal profile

Saltation

Which of the following is NOT a mechanism of erosion by running water?
A. Scouring
B. Abrasion
C. Breaking & lifting
D. Dissolution
E. Saltation

The volume of water passing a point on the stream bank in a given time.

Which of the following refers to stream discharge?
A. The volume of water passing a point on the stream bank in a given time.
B. The velocity of water passing a point on the stream bank in a given time.
C. The volume of sediment being transported by a stream in a given time.

500 m(^3)/s

If a stream channel has a cross-sectional area of 100m(^2) and the water flows an average of 5 m/s, what is the streams discharge?
A. 500 m/s
B. 500 m(^2)/s
C. 500 m(^3)/s

Runoff

All the water that falls on the landscape and eventually ends up in streams is called:
A. Sheetwash
B. Runoff
C. Watershed
D. Groundwater

Drainage network

An array of interconnected streams on the landscape is called...
A. Tributaries
B. Trunk streams
C. Drainage network

TRUE

Since it's unrealistic to build levees & reservoirs that could prevent all conceivable floods, it's sensible to allow some floodplains to revert to wetlands and to create floodways where flooding damage would be minimal.
TRUE or FALSE

FALSE

The capacity of a stream or river is the amount of water it carries (discharges).
TRUE or FALSE

TRUE

The jet stream was a key contributing factor to Mississippi Rive flooding in 1993 because it trapped warm, moist Gulf of Mexico air over the central United States.
TRUE or FALSE

TRUE

Plate tectonics events can produce mountains whose uplift can cause drainage reversal in existing river systems.
TRUE or FALSE

Amazon

The river with the greatest discharge in the world is the
A. Mississippi
B. Nile
C. Ob
D. Amazon

suspended load

Identify the FALSE statement. Streams cause erosion by
A. suspended load
B. scouring
C. breaking & lifting
D. abrasion

alluvial fans

Streams come down out of steep areas onto much flatter land, lose velocity, and drop material in wedge-shaped structures called
A. point banks
B. alluvial fans
C. levees
D. deltas

narrow, deep valleys

Fluvial landscapes that are early in their evolutionary progression have
A. broad floodplains
B. narrow, deep valleys
C. natural levees
D. oxbox lakes

6000 ft(^3)/s

The 100 feet wide and 10 feet deep river flows at an average velocity of 6 ft/s. Its discharge is:
A. 4,800 ft(^3)/s
B. 240 ft(^3)/s
C. 6000 ft(^3)/s
D. 660 ft(^3)/s

developed its shape b/c the ocean current there was stronger than the river current

Which statement is FALSE?
The Mississippi River Delta
A. consists of several distinct lobes
B. is the product of several avulsions
C. developed its shape b/c the ocean current there was stronger than the river current
D. is a bird's-foot delta
E. is the site of the city of New Orleans

make poor farmland...

Which of the following statements is FALSE? Deltas
A. may form where a stream empties into the quiet waters of a lake or the ocean
B. are likely to slowly sink and become swampland called a delta plain
C. make poor farmland b/c they flood regularly and flooding leaches out the minerals