Geoscience Reference
In-Depth Information
CHECK YOUR UNDERSTANDING
1.
Describe the concept of runoff.
has been stable for a long period of time with a consis-
tent climate? Why?
8.
Name and describe three landforms associated with a
stream that is striving to reach a graded condition.
9.
Name and describe three landforms associated with a
graded stream.
10.
How can deposition and erosion both occur along a
stream meander?
2.
Define the concept of
drainage basin
and describe one
of the major watersheds in North America. What are the
boundaries of this drainage basin, and what are some of
the major tributaries?
3.
Imagine that two drainage basins are found in a humid
environment. One of the watersheds has high drainage
density, whereas the other one does not. Assuming that
each drainage basin lies within a region of similar relief,
what environmental variable most likely accounts for the
difference in drainage density? Why?
11.
Imagine that you encountered a stream with well-
developed meanders that are deeply entrenched.
Describe two reasons why this landscape would
evolve.
4.
What is the minimum number of tributaries that a fourth-
order stream has? How many stream confluences are
there in this watershed?
12.
Why is a terrace an abandoned floodplain? Describe
the two ways that terraces form.
13.
Describe the formation of river deltas.
14.
Why is peak discharge greater in streams contained
within urban areas than those in the surrounding
countryside?
15.
Describe how a dam provides flood control for a city
that lies downstream of the structure.
5.
Name four primary hydraulic variables. Provide an
example of how one variable influences another.
6.
Compare and contrast the concept of
base flow
and
base level
.
7.
Which landscape is more likely to contain graded
streams: one that has recently been uplifted or one that
ANSWERS TO VISUAL CONCEPT CHECKS
VISUAL CONCEPT CHECK 16.1
The correct answer is
. The Danube is a high-order stream. You can tell that the Danube is a high-
order stream because it is large, with high discharge. This appearance results from the numerous
lower-order tributaries that feed into the river.
a
VISUAL CONCEPT CHECK 16.2
The correct answer is
. The stream is not graded. Remember that graded streams have shallow
slopes that allow a stream to migrate horizontally. This stream has a very steep slope, which means
that most of its energy will be used to erode vertically.
d
VISUAL CONCEPT CHECK 16.3
The whitish plumes of sediment in the Indian Ocean from the Godarvi and Krishna rivers are present
because the ocean is relatively still compared to the flowing streams. As a result, stream velocity slows
where they flow into the ocean, causing sediment to be deposited. The whitish plumes are fine-grained
sediments such as silts and clays that are floating in suspension.
