Lab 06_ FLUVIAL PROCESSES AND LANDSCAPESLAB 06 FLUVIAL PR.docx

Lab 06_ FLUVIAL PROCESSES
AND
L
AND
SCAPES
LAB 06: FLUVIAL PROCESSES
AND
L
AND
SCAPES
Note:
Please refer to
the
GETTING STARTEDmodule to learn how to maneuver
through,
and
how to answer
the
lab
question
s, in
the
Google Earth (
) component.
KEY TERMS
You should know
and
underst
and
the
following
terms
:

Alluvial fan
Drainage divide
Oxbow Lake
Basin
Drainage pattern
Sinuosity
Braided streams
Entrenched me
and
er
Stream discharge
Cutbanks
Hydrograph
Stream order
Delta
Me
and
ering river
Water
shed
Drainage density
Me
and
er scar
LAB LEARNING OBJECTIVES
After successfully completing this module, you should be able
to do
the
following
tasks:
·
Describe

the
concepts of sub-basins
and
water
sheds
·
Identify different human
water
uses of a river
·
Construct a stream order
for
a river system
·
Compute drainage density of a given basin
·
Identify drainage patterns of river networks
·
Explain how braided rivers
and
me
and
ering rivers are
for
med
·
Identify
the
physical features common to a me

and
ering river system
·
Describe
the
physical conditions necessary to
for
m alluvial fans
INTRODUCTION
This module examines fluvial processes
and
l
and
scapes.
Topic
s include
water
sheds, drainage patterns
and
densities, stream order, me
and
ering
and
braided streams,
and
alluvial fans. While
the
se

topic
s may appear to be disparate, you will learn how
the
y are inherently related.
The
modules start with four opening
topic
s, or vignettes,
which
are found in
the
accompanying Google Earth file.
The
se vignettes introduce basic concepts of fluvial processes
and
l
and
scapes. Some of
the
vignettes have animations, videos, or short articles that will
provide ano
the
r perspective or visual explanation
for
the
topic
at h
and
. After
read
ing
the
vignette
and

associated links, answer
the
following
question
s. Please note that some links might take a while to download
based on your Internet speed.
Expand
the
INTRODUCTION
folder
and
the
n
select
Topic
1:
Introduction
Read
Topic
1:
Introduction
Question
1:
Which
of
the

following
is a
reason
for
the
location
select
ed
for
the
first
English
settlement
in
the
New
World
,
Jamestown
,
VA?
A.
Prime
agricultural

l
and
B.
On
the
advice
from
the
Native
Americans
C.
Deep
water
port
D.
The
l
and
was
al
read
y
cleared
Read

Topic
2: Rivers of Life
Question
2:
If our ability to predict floods has improved significantly, why
does economic loss continue to rise? (Check all that apply).
A.
Increased urbanization
B.
Increased population
C.
Increased development along coasts
D.
Increased real estate values
Read
Topic
3: Rivers of
Was
te
Question
3:
What are potential outcomes or conditions resulting
from
too much nitrogen running off
from
agricultural
fields? (Check all that apply).
A.
Eutrophication of

water
bodies
B.
Decrease in crop production
C.
Contamination of ground
water
D.
Health issues in infants
Read
Topic
4: Erosion
Question
4:
List three ways in
which
humans contribute to stream bank erosion.
A.
Vegetation removal
B.
Increase in impervious surfaces
C.
Wave
from
boats
D.
Wind action on exposed banks
Read

Topic
5: Trans
port
ation
and
Deposition
Question
5:
What impacts do dams have on
the
trans
port
ation of sediment? Check all that apply.
A.
Decrease in sediment trans
port
ation upstream
from
dam
B.
Increase in sediment trans
port
ation downstream
from
dam
C.
Decrease in sediment trans
port
ation downstream
from
dam
D.

Increase in sediment trans
port
ation upstream
from
dam
Collapse
and
uncheck
the
INTRODUCTION
folder
For
the
remaining
port
ions of this module, you will identify
and
explain
the
geographic distribution, patterns,
and
processes associated with fluvial environments. In doing so,
you will recognize
and
appreciate
the
impact of rivers.
GLOBAL PERSPECTIVE
Expand

the
GLOBAL PERSPECTIVE
folder
and
the
n
expand
the
World
Rivers
folder
. Double‑click
and
select
any continent or
world
region. To display river in
for
mation (name
and
approximate length) click any river in
the
Google Earth 3-D pane.
Collapse
the
World

Rivers
folder
.
Major Cities on Rivers
Expand
Major Cities on Rivers
.
For
each
question
below, type
the
latitude
and
longitude coordinates into
the
Search
field
and
the
n press
Enter
. When you arrive at your destination, find
the
in
for
mation that you will use to fill in
the
blanks below:
Question

6:
33 18 59 N, 44 23 33 E
City:
A.
Atlanta
B.
Baghdad
C.
Cairo
D.
Dusseldorf
River:
A.
Mississippi
B.
Euphrates
C.
Tigris
D.
Nile
Question
7:
30 03 29 N, 31 14 05 E
City :
A.
Paris
B.

Moscow
C.
Cairo
D.
Shanghai
River:
A.
Ohio
B.
Jordan
C.
Zambesi
D.
Nile
Question
8:
48 51 26 N, 2 21 04 E
City:
A.
London
B.
Madrid
C.
Paris
D.

Buenos Aires
River:
A.
Rio de la Plata
B.
Seine
C.
Thames
D.
Volga
Question
9:
Montreal, Canada.
Latitude: A. 45° 30’S B. 73° 33’N C
.
45° 30’N D. 73° 33’S
Longitude: A. 45° 30’E B. 73° 33’N C. 45° 30’S D. 73° 33’W
River:
A.
Montreal
B.
St. Lawrence
C.
Hudson
D.
Ottawa

Collapse
and
uncheck
the
GLOBAL PERSPECTIVE
folder
WATER
SHEDS
AND
DRAINAGE DENSITY
Expand
the
WATER
SHEDS
AND
DRAINAGE DENSITY
folder
.
A drainage basin is an area of l
and
in
which
a stream receives
water
, predominately by surface runoff, through flow,

and
ground
water
flow. Drainage basins are topographically divided
from
each o
the
r by
the
highest points of elevation, so that all
water
from
the
ridges
and
hills flow into a given drainage basin
and
the
reby into a given stream. This topographic delineation is
commonly referred to as a
water
shed (
the
drainage divide between two drainage areas), although many in
the
United States use
the
term
water
shed interchangeably with drainage basin or catchment.
A large drainage basin can contain several smaller drainage
basins or sub-basins.
The

nested nature of
the
se sub-basins is determined by topography as well as where
the
water
flows out of
the
drainage area, known as
the
outflow point.
In Figure 1, dash-lines
A
,
B
,
and
C
demarcate
the
water
sheds of
the
tributary streams, while dash-line
D
delineates
the
water
shed of a larger drainage basin
for
the
larger streams,

which
includes
the
smaller tributaries
and
the
ir sub-basins.
Figure 1.
Water
shed map (Source:
Maidstone Lake USGS 7.5 minute map
).
Underst
and
ing
water
sheds are im
port
ant because stream flow
and
water
quality are influenced by
the
nature of
and
changes in
the
drainage basin. We can determine what is happening in our
river basins by examining
the
water
flow

and
water
quality
from
a river’s outflow point. Changes to
water
flow or
water
quality in rivers could be due to ei
the
r natural events (such as lightning induced
for
est fires increasing soil erosion) or human modifications (such
as
agricultural
practices increasing pollution).
Double-click
and
select
Columbia River
Water
shed
.
The
Columbia River
water
shed encompasses 258,000 square miles (approximately
the
size of France), with 220,000 square miles in
the
U.S.
and

38,000 square miles in Canada.
The
length of
the
river is approximately 1243 miles, making it
the
15th longest river in
the
United States.
Uncheck
Columbia River
Water
shed
.
Check
the
Columbia River Sub-basin US only
folder
. Click on each sub-basin in
the
Google Earth map pane to identify its name.
Question
10:
How many Columbia River sub-basins in
the
United States are displayed on
the
map?
A.
7
B.

8
C.
9
D.
10
Uncheck
Columbia River Sub-basin US only
.
Expand
the
Columbia River
Water
shed - Fly Over
folder
.
The
Google Earth flying simulation of
the
Columbia River shows how
the
basin is a multi-use
water
shed. Do
the
following
steps to reduce confusion
for

the
duration of
the
simulation:
1.
Uncheck all
the
check boxes in
the
Google Earth’s
Places
and
Layers
panes.
2.
Check only
the
Enable this check box
for
the
tour
check box to display
the
text in
the
simulation.
3.
Double-click

here to view
the
tour (Running Time: 2:06)
.
When
the
simulation stops, close
the
simulation control panel:
Question
11:
What
water
uses did you see as you traveled upstream on
the
Columbia River? (Check all that apply).
A.
Agriculture
B.
Flood control
C.
Power generation
D.
Recreation
E.
Ranching
Uncheck
Columbia River
Water

shed - Fly Over
.
Expand
the
Stream Order
folder
.
Stream Order
Figure 2. Stream order (16.9 Arbogast 2
nd
. Ed.).
Stream order
is a measure of
the
size of a stream based on a hierarchy of tributaries. Using
the
Strahler stream order method,
the
smallest tributaries are assigned
the
value of 1. When two streams with different order numbers
join,
the
resulting stream is assigned
the
value of
the
higher order numbered stream.
In Figure 2, two streams with an order number of 1 join to
for
m a stream with an order number of 2. However, when one
stream with an order number of 1 joins a stream with an order

number of 2,
the
stream remains a 2. Large river systems typically have a higher
stream order.
The
Mississippi River
for
example has a stream order of 10.
The
Strahler stream order number
for
a given stream is dependent on
the
scale as
which
one views a stream network. A stream with an order number of
3 on a 1:24,000 map,
for
example, might have an order number of 1 on a 1:1,000,000
scale map, as fewer rivers are displayed on a smaller scale map.
D
ouble-click
and
select
the
Willamette River
folder
.
In this particular map,
the
Willamette River has a Strahler stream order of 5. Though not
all streams are labeled with

the
ir order, you should be able to determine how
the
stream ordering system works. You might have to zoom in to
see
the
labels clearly.
Double-click
and
select
the
Snake River
folder
.
For
Question
s 12 to 15, identify
the
stream order number
for
rivers A, B, C,
and
D:
Question
12:
River A:
A.
1
B.

2
C.
3
D.
4
Question
13:
River B:
A.
1
B.
2
C.
3
D.
4
Question
14:
River C:
A.
1
B.
2
C.

3
D.
4
Question
15:
River D:
A.
1
B.
2
C.
3
D.
4
Uncheck
the
Stream Order
folder
.
Stream Density
Double-click
and

select
the
Stream Density
folder
.
Figure 3. Drainage basins (16.8 Arbogast 2
nd
. Ed.).
Notice
the
two sub-basins that are highlighted.
The
smaller one is
the
Willamette River
water
shed
and
the
larger one is
the
Snake River
water
shed.
The
drainage density of a basin measures how well a
water
shed is drained
and
depends largely on
the

underlying bedrock
and
topography of
the
basin. Basins with high relief
and
exposed bedrock tend to have a higher drainage density.
Use
the
following
for
mula to calculate
the
stream density of each sub-basin (show your work):
In o
the
r words,
the
[drainage density] equals
the
[total length of all streams] divided by
the
[area of
the
drainage basin]
Double-click
and
select
Snake All Streams

.
Double-click
and
select
Willamette All Streams
.
Willamette River
water
shed:
The
area of
the
Willamette River sub-basin is 11,500 square miles.
The
total length of all streams in
the
Willamette River sub-basin is 12,800 miles.
Question
16:
What is
the
stream density of
the
Willamette River sub-basin?
A.
12800 / 11500 = 1.11
B.
11500 / 12800 = 0.90
C.
12800 / 11500 = 1.43

D.
11500 / 12800 = 0.95
Snake River
water
shed:
The
area of
the
Snake River sub-basin is 108,000 square miles.
The
total length of all streams in
the
Snake River sub-basin is 138,000 miles.
Question
17:
What is
the
stream density of
the
Snake River sub-basin?
A.
108000 / 138000 = 0.78
B.
138000 / 108000 = 1.28
C.
108000 / 138000 = 0.83
D.
138000 / 108000 = 1.48
C

ollapse
and
uncheck
WATER
SHEDS
AND
DRAINAGE DENSITY
folder
.
DRAINAGE PATTERNS
Expand
the
DRAINAGE PATTERNS
folder
.
Figure 4. Drainage patterns (16.7 Arbogast 2
nd
Ed.).
The
drainage patterns
of a stream system (a network of streams
and
tributaries) depend largely on
the
topography on
the
l
and

as well as
the
structure of
the
underlying bedrock. Areas subject to faulting often produce
rectangular drainage patterns, while areas with folded
topography (mountains) often have trellis drainage patterns.
Volcanoes typically
for
m radial drainage patterns. Dendritic drainage patterns are
common in areas with non-porous, impermeable bedrock.
Double-click
and
select
Drainage pattern 1
.
Question
18:
Identify Drainage pattern 1:
A.
Radial
B.
Trellis
C.
Rectangular
D.
Dendritic
Now that you have identified Drainage pattern 1, double-click
and

select
drainage patterns 2 to 5 to identify
the
m.
Question
19:
A.
Radial
B.
Trellis
C.
Rectangular
D.
Dendritic
Question
20:
A.
Radial
B.
Trellis
C.
Rectangular
D.
Dendritic
Question

21:
A.
Radial
B.
Trellis
C.
Rectangular
D.
Dendritic
Question
22:
A.
Radial
B.
Trellis
C.
Rectangular
D.
Dendritic
Collapse
and
uncheck
the

DRAINAGE PATTERNS
folder
BRAIDED STREAMS
Double-click
and
select
the
BRAIDED STREAMS
folder
.
Fast moving streams originating
from
mountainous glacial areas or regions with an abundance of
erodible sediment, often trans
port
great quantities of coarse material such as s
and
and
gravel within
the
channel. As
the
stream velocity decreases (topography becomes less steep)
however,
the
discharge is insufficient
and
the

stream can no longer carry
the
sediment load. In essence,
the
deposited bed load
for
ms bars (or
eyots
) within
the
stream channel,
for
cing stream channel to diverge
and
converge among
the
deposits.
The
se constantly shifting channels within
the
larger river channel are what give
the
stream its braided appearance.
The
Delta River is an example of a braided stream near
the
town of Delta Junction, Alaska. Notice
the
network of broad yet shallow stream channels that diverge
and
converge, separated by bars of deposited bed load.
Question
23:
Based on
the

location
and
the
deposition type, explain why this stream
for
ms a braided pattern.
A.
The
steep slope of
the
river means that
water
flows faster
and
can easily carve out a series of channels
for
ming a braided stream
B.
The
slow flowing river means that not much sediment can be
carried by
the
water
and
hence,
the
load is deposited
for
C.

The
channels are stationary
and
it is
the
river that moves, thus creating a braided appearance.
D.
The
steep topography means
the
river is stationary
and
it is
the
channels that are constantly shifting,
for
Question
24:
Where does
the
sediment (deposition material) come
from
?
A.
The
sediment is actually in place
and
is not trans
port
ed. It is merely disturbed by
the

river,
which
for
ms bars of deposited bed load
B.
The
sediment
was
actually deposited upstream by me
and
ering rivers
and
over time headward erosion by
the
river created
the
braided stream
C.
The
sediment is
from
glacial erosion that is carried downstream by streams
from
the
melting glacier
D.
The
sediment is finely sorted
from
upstream wea
the

ring
and
erosion of loess deposits
Uncheck
BRAIDED STREAMS
ME
AND
ERING STREAMS
AND
FLOODPLAINS
Expand
the
ME
AND
ERING STREAMS
AND
FLOODPLAINS
folder
.
In contrast to braided streams, me
and
ering streams are
for
med in l
and
scapes with little relief, are generally slower moving,
and
carry finer sediments. In addition,
water
flow within me

and
ering stream typically is constrained to a single channel. As
the
ir name suggests, me
and
ering streams are identifiable by
the
ir
sinuosity
, or
the
bends
and
turns of
the
stream channel across a floodplain.
The
me
and
er of
the
channel occurs with
the
scouring of
the
channel on
the
outside of
the
bend (where flow is faster)
and
deposition on
the
inside of
the
bend (where flow is slower). This constant erosion or removal

of sediment
from
cutbanks
and
deposition of sediment
from
point bars produces
the
movement of
the
me
and
er across
the
l
and
scape, with past me
and
ers evident
from
oxbow lakes
and
me
and
er scars.
Click
Stream Process Animation
and
view
the
animation.

Erosion
and
deposition occurs primarily during periods of flooding. Many
rivers are prone to flooding, with some large flooding events
changing
the
course of
the
stream channel (by bypassing
the
me
and
er altoge
the
r
and
producing a straight reach). While natural or artificial levees
might prevent a stream
from
flooding, large flood events compromise levees, with
water
and
its suspended sediment spilling over
the
levees
and
depositing onto
the
surrounding floodplain.
Double-click
and
select

Mississippi River - Identify Features
.
Using
the
following
list of me
and
ering stream features, answer
Question
s 25 to 29 that apply to
the
Mississippi River map image in Google Earth.
A.
Oxbow Lake
B.
Point bar
C.
Me
and
er scar
D.
Outside of me
and
er
E.
Isl

and
F.
Inside of me
and
er
G.
Deep
channel (thalweg)
H.
Shallow channel
I.
Floodplain
J.
Low ground
K.
Cut bank
Question
25:
Stream Feature A:
A.
Oxbow lake
B.
Point bar
C.
Me

and
er scar
D.
Outside of me
and
er
E.
Isl
and
F.
Inside of me
and
er
G.
Deep
channel (thalweg)
H.
Shallow channel
I.
Floodplain
J.
Low ground
K.
Cut bank
Question
26:
Stream Feature

B
:
A.
Oxbow lake
B.
Point bar
C.
Me
and
er scar
D.
Outside of me
and
er
E.
Isl
and
F.
Inside of me
and
er
G.
Deep
channel (thalweg)
H.
Shallow channel
I.

Floodplain
J.
Low ground
K.
Cut bank
Question
27:
Stream Feature
C
:
A.
Oxbow lake
B.
Point bar
C.
Me
and
er scar
D.
Outside of me
and
er
E.
Isl
and
F.
Inside of me

and
er
G.
Deep
channel (thalweg)
H.
Shallow channel
I.
Floodplain
J.
Low ground
K.
Cut bank
Question
28:
Stream Feature D:
A.
Oxbow lake
B.
Point bar
C.
Me
and
er scar
D.
Outside of me

and
er
E.
Isl
and
F.
Inside of me
and
er
G.
Deep
channel (thalweg)
H.
Shallow channel
I.
Floodplain
J.
Low ground
K.
Cut bank
Question
29:
Stream Feature E:
A.
Oxbow lake
B.

Point bar
C.
Me
and
er scar
D.
Outside of me
and
er
E.
Isl
and
F.
Inside of me
and
er
G.
Deep
channel (thalweg)
H.
Shallow channel
I.
Floodplain
J.
Low ground
K.
Cut bank

Question
30:
Identify
the
dominant l
and
uses surrounding
the
river.
A.
Agriculture
B.
Mining
C.
For
estry
D.
Urban
E.
Fishing
Double-click
and
select
Mississippi River - Measure Distance
.
Do

the
following
steps to examine river sinuosity.
1
Verify that
Mississippi River
-
Measure Distance
is
the
only item checked in
the
Places
pane.
2
Go to
the
Google Earth icon bar
and
click
the
Show Ruler
tool .
Note:
Verify that
the
simulation control panel is closed:
3
Figure 2. Stream distance (image
from
Google Earth).

In
the
Ruler window, click
the
Path
tab
and
select
Miles
for
the
units.
4
Draw a straight line between
the
two points; that is, click point
and
the
n click point to determine
the
distance. This is
the
downvalley length.
5
Click
Clear
on
the

Ruler window to stop.
Question
31:
What is
the
length, in miles, of
the
channel?
A.
29
B.
16
C.
38
D.
47
Measure
the
distance of
the
channel (
the
me
and
er):
1
In
the
Ruler window, click
the

Path
tab
and
set
the
units to
Miles
.
2
Click point
and
click you as trace
the
path of
the
river until you get to point . This is
the
channel length. Figure 7 shows an example of how your path
might appear.
Question
32:
What is
the
length, in miles, of
the
channel?
A.
29
B.
16
C.
38

D.
47
The
sinuosity index (SI), also known as
the
me
and
er ratio, calculates how much
the
stream channel deviates
from
the
shortest path. Straight rivers have a SI close to 1, but this
number increases
the
more a river me
and
ers.
Question
33:
Use
the
following
for
mula to calculate
the
SI
for
this reach of
the

Mississippi River:
In o
the
r words,
the
[sinuosity index] equals
the
[channel length] divided by
the
[downvalley length].
A.
16 / 37 = 0.42
B.
47 / 29 = 1.62
C.
38 / 16 = 2.38
D.
38 / 29 = 1.31
Close
the
ruler tool. Uncheck
Mississippi River - Measure Distance
.
Double-click
and

select
San Juan River - Compare Features
.
The
San Juan River is ano
the
r me
and
ering stream, yet we do not see
the
classic oxbow lakes
and
me
and
ering scars we saw with
the
Mississippi River.
Question
34:
Compute
the
SI of
the
San Juan River
from
point A to point B.
A.
20 / 4 = 5.0
B.
6 / 10 = 0.60
C.
6 / 2 = 3.0

D.
8.5 / 3 = 2.83
Question
35:
Which
river (Mississippi River or San Juan River) has a higher SI?
A.
Mississippi River
B.
San Juan River
C.
The
y have
the
same
D.
Unable to discern
Use
the
following
navigation steps to examine
the
terrain:
Press
and
hold
the

Shift key (PC
and
Mac).
Use
the
scroll wheel on
the
mouse to see
the
l
and
scape in 3D. You can also use
the
Ctrl (Comm
and
key
for
Mac) or Shift keys in combination with
the
arrow keys to pivot
and
rotate
the
image.
Question
36:
Explain why
the
re are no classic oxbow lakes or me
and
er scars.
A.
The
y have been filled in by sediments
from

the
river
B.
The
surrounding material is too soft to allow
for
the
ir creation
C.
The
surrounding material is too hard to allow
for
the
ir creation
D.
The
river is downcutting faster than it can change course
Collapse
and
uncheck
ME
AND
ERING STREAMS
AND
FLOODPLAINS
ALLUVIAL FANS
Expand

the
ALLUVIAL FANS
folder
. Double-click
and
select
Alluvial Fan
.
Alluvial fans are comprised of
water
-trans
port
ed material or alluvium. Most alluvial fans consist primarily of
coarse grained material. In Death Valley, Cali
for
nia, notice
the
series of alluvial fans.
Do
the
following
steps to get a better view of
the
l
and
scape
and
to explore

the
topography:
1
Check
the
Nova Canyon 7.5 minute map
check box
and
compare
the
contour lines on
the
alluvial fan to those contour lines on
the
nor
the
ast
port
ion of
the
map. This make take a few minutes, depending on your Internet
connection speed.
2
Zoom in to
the
Death Valley region.
3
To see
the
l
and

scape in 3D:
PC:
Press
and
hold
the
Shift key
and
use
the
scroll button on
the
mouse. You can also use
the
Ctrl or Shift keys in combination with
the
arrow keys to pivot
and
rotate
the
image.
Mac:
Press Shift in combination with
the
up
and
down arrows. You can also use
the
mouse scroll wheel to zoom.
Question
37:
What geographic
and
topographic l
and

features are necessary to create alluvial fans?
Hint:
Where are
the
fans located physically as well as what features are required to
develop
the
m?
A.
Humid, flat l
and
scapes
B.
Arid, steep l
and
scapes
C.
Humid, steep l
and
scapes
D.
Arid, flat l
and
scapes

Lab 06_ FLUVIAL PROCESSES AND LANDSCAPESLAB 06 FLUVIAL PR.docx

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Lab 06_ FLUVIAL PROCESSES AND LANDSCAPESLAB 06 FLUVIAL PR.docx