Landforms Ch. 5

Watersheds are defined by

drainage divides

T/F Deforestation in the headwater regions of a river can cause the river to flood more frequently in downstream areas.

True

T/F Erosion of the walls of a channel normally occurs on the outside curve of a meander.

True

T/F The Colorado River, which carved the Grand Canyon, no longer reaches the sea because of water extraction.

True

Which is typical of a rejuvenated system?

entrenched meanders, increased downcutting, and terraces only

Natural Levees are created during

floods

A squeeze-and-release action works to loosen and lift rocks in a stream channel. This is an example of

hydraulic action

A graph of stream discharge overtime for a specific location is a

hydrography

a drainage basin is defined by

its drainage divides

The ultimate base level is

Sea Level

Over the past 5000 years, the Mississippi River has produced how many distinct deltaic formations?

Seven

When a river reaches a base level, its forward velocity rapidly decelerates as it enters a larger body of standing water and __________ is formed.

a delta

The 100 year floodplain is

a level of flooding that occurs once every 100 years on average

A cutoff on a meandering stream results in the formation

an oxbow lake

The largest material that can be carried by a stream is carried

bed load

A landform created by erosion on the outside of a bend in a meandering stream channel is a

cutback

A landform created by deposition on the inside of a bend in a meandering stream channel is

point bar

T/F Rivers have played a relatively minor role in the geography of human history.

False

If you wanted to build a structure on a river bank-especially one that flows through unconsolidated sediments-you should build the structure __________ to maximize its lifetime.

above the point bar

particles that are dragged, pushed, or rolled along the bottom of a stream comprise the streams

bedload

The suspended load of a stream consists of particles that are

held aloft in the stream flow

streams flowing off a volcanic mountain typically display which type of drainage pattern

radial

Bed load is moved by

saltation and traction only

Stream transport involves all of the following except

sheet flow

Which of the following is true of New Orleans and the passage of Hurricane Katrina? a. Only one levee was breached. b. The flood protection features failed only after their design-failure limits were reached. c. Sections of New Orleans are below sea level. d. Six investigations found that the protection system was flawless.

c. Sections of New Orleans are below sea level.

T/F Rivers make excellent political boundaries given that they are obvious, clearly defined landform features.

False

T/F The Amazon River, the world's largest in stream discharge, has built an enormous arcuate delta into the Atlantic.

False

If the capacity of a stream is exceeded, __________ will occur.

aggradation

The construction of a dam across a river is likely to cause __________ upstream and __________ downstream.

aggradation; erosion

The downstream portion of a river

b. generally is of higher velocity, although it is masked by reduced turbulence.

the level below which a stream cannot erode its valley is

base level

4. Which of the following is incorrectly matched? a. rills - small-scale grooves in the land surface b. drainage divides - ridges that control the direction of drainage c. Allegheny and Missouri rivers - form the Monongahela at Pittsburgh d. Delaware River basin - comprised of parts of five states

c. Allegheny and Missouri rivers - form the Monongahela at Pittsburgh

Which of the following channel characteristics adjusts in response to changes in energy of flow and sediment load in the channel? a. channel slope b. channel width and depth c. both channel slope and channel width and depth d. None of these-river channel form is controlled exclusively by the type of rock or sediment through which the river flows

c. both channel slope and channel width and depth

Which of the following is incorrect regarding floodplains? a. They are formed by recurrent flooding in the area adjacent to the stream. b. Natural levees on either side of a stream are formed during times when the stream is at flood stage and overflows the bank. c. They are generally low-lying areas. d. They are characterized by rapids and low waterfalls.

d. They are characterized by rapids and low waterfalls.

1. Which of the following lists of processes are in the correct sequence as to their occurrence in nature? a. deposition, erosion, transport, weathering b. weathering, erosion, deposition, transport c. weathering, deposition, erosion, transport d. weathering, erosion, transport, deposition

d. weathering, erosion, transport, deposition

urban land cover

decrease infiltration, resulting in rapid flooding

The effect of urbanization on a typical stream hydrograph is to

decrease lag time between storm peak and peak stream discharge.

A drainage pattern that displays a branching pattern similar to the shape of a tree is a

dendritic drainage pattern

An interruption in a stream's graded profile of equilibrium is called a

nickpoint

Steep slopes and some relief generally produce which drainage pattern?

parallel