lab_3_ex_6__1_.docx
docx
keyboard_arrow_up
School
Grand Rapids Community College *
*We aren’t endorsed by this school
Course
106
Subject
Geography
Date
Feb 20, 2024
Type
docx
Pages
8
Uploaded by MasterWaterJay42
This study so
E
ur
x
ce
6
w
–
as
S
d
t
o
r
w
ea
n
m
loa
s
de
a
d
nd
by
F
1
l
0
o
0
o
0
d
00
in
87
g
9925770 from CourseHero.com on 02-01-
https://www.coursehero.com/file/64438449/lab-3-ex-6-1docx/
1
Exercise
6
Streams and Flooding
In this lab you will:
James S. Reichard
Georgia Southern University
Student Name
Section
learn to identify drainage divides and floodplains on a map in order to access the potential for flooding at a given location. You will also examine the historical discharge record of a stream and learn how to calculate the recurrence interval of flood events.
Background Reading and Needed Supplies
Prior to doing this exercise you should read Chapter 6 in the textbook.
With respect to supplies, you will need a calculator, ruler, and colored pencil.
This study so
E
ur
x
ce
6
w
–
as
S
d
t
o
r
w
ea
n
m
loa
s
de
a
d
nd
by
F
1
l
0
o
0
o
0
d
00
in
87
g
9925770 from CourseHero.com on 02-01-
https://www.coursehero.com/file/64438449/lab-3-ex-6-1docx/
54
Part II
–
Floodplains
Recall from the textbook that a floodplain (Figure 6.3) is the relatively flat area that lies
adjacent to a stream or river. During high discharge events, a stream will overflow its banks and
inundate its floodplain. Also recall that in downstream areas where the gradient decreases and the channel approaches base level, rivers tend to meander more and produce wider floodplains.
Floods here are referred to as downstream floods
. In contrast to flash floods, downstream floods occur slowly and involve greater volumes of water. Of course the level to which any floodplain becomes inundated will depend on the amount of discharge.
Figure 6.3
To minimize the risk of flooding, a building should be located as far above the elevation of the channel as is practical. Since placing a building on an active floodplain virtually guarantees damage from a flood, it is important to recognize the uppermost edge of a floodplain. As can be
seen in Figure 6.3, the floodplain's edge is marked by an abrupt increase in slope. On a topographic map, this abrupt slope increase occurs where the contour lines become closely spaced. For example, the purple lines on the topographic map in Figure 6.4 coincide with the upper edge of the floodplain where the slope abruptly increases. Note that due to erosion, this change in slope is oftentimes more gradual and, therefore, not as obvious on a map.
4) Using a purple-colored pencil or marker, carefully trace the edge of the floodplain along the north-south flowing stream on the eastern side of the map in Figure 6.4. Note that part of the
floodplain has already been mapped for you.
5) Are there any buildings or roads within the floodplain? Explain why.
There are no buildings or roads within the floodplain because the probability of having property or
vehicle damage is evitable in high risk flood zones especially on the valley floor. A floodplain
represents the base level of all water flow. So, because of the greater amount of water volume in
that flat surface, any building or road in its path will unundate the area. This could leave buildings
or roads underwater for a long period of time.
6) In Figure 6.4, part of the drainage divide on the south side of the tributary named Big Branch
has already been mapped for you. Continue tracing this drainage divide (in red) until you come to the southern most edge of the map.
This study so
E
ur
x
ce
6
w
-
a
S
s t
d
r
o
e
w
a
n
m
loa
s
de
a
d
n
b
d
y
F
1
l
0
o
0
o
00
d
0
i
8
n
7
g
9925770
from CourseHero.com on 02-01-
https://www.coursehero.com/file/64438449/lab-3-ex-6-1docx/
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
https://www.coursehero.com/file/64438449/lab-3-ex-6-1docx/
7) The drainage divide you mapped in Figure 6.4 follows the high ground that is left behind when streams naturally etch, or cut, into the landscape. Describe the general relationship between drainage divides and human uses of the landscape that you see on the map (e.g.,
buildings and roads).
The connection between drainage divides and the human use of the landscape is because of the elevation of drainage divides. These drainage divides represent high points of the ground that if humans were to survive a flood. They would have a greater chance if they were able to reach higher grounds. Building and roads are ideal along the divide because during extensive rainfall the
water is forced to flow down into one of its tributaries. This reduces the rate of flood fatalities due to a vehicle floating or building being flooded with water. There are also floodplain zone regulations that prohibit commercial, industrial, and residential buildings from being developed in that are
8) The western extension of the drainage divide you just mapped is shown in Figure 6.5. Using
a red pencil or marker, trace the other drainage divides that lead into the city of Glenville.
9) Notice how many of the divides that you mapped merge in the direction of Glenville.
a) In terms of landscape usage and flood hazard, explain why the city was originally built in
an area where drainage divides converge.
The city was original built in an area where drainage divides converge because there drainage
divides were the best option to protect communities from flood hazards.
b) The landscape throughout this part of Georgia's coastal plain is very similar to that of the
Glenville area. In terms of drainage divides, where do you suspect most towns and cities
are located on the coastal plain? Why?
I suspect most towns and cities are located on the coastal plain because of the abundant natural
resources that people had access to such as an unlimited water supply.
10) Find the circle labeled "Sewage Disposal" located to the southeast of Glenville. With respect to the topography, give two reasons why the city's sewage treatment plant was located here.
The city’s sewage treatment plant was located here because the sewage plant is able to drain
water from its city streets. So, that the streets will not become overflooded and pose a threat to
buildings and roads. Also, sewage plants are way to remove pollutants. So, the water that’s been
cleaned can be reusable and renewable for human consumption and for agricultural uses.
This study so
E
ur
x
ce
6
w
–
as
S
d
t
o
r
w
ea
n
m
loa
s
de
a
d
nd
by
F
1
l
0
o
0
o
0
d
00
in
87
g
9925770 from CourseHero.com on 02-01-2024 15:41:07 GMT -06:00
https://www.coursehero.com/file/64438449/lab-3-ex-6-1docx/
d Flooding
source was downloaded by
Figure 6.5
(
USGS Glenville, G
'
A, Quadrangle)
}, -
(9,
-
-
II
=.:
I
..
I
.
•
:
..
·
.
178 .<
;(
s-
f
'
.
"
','
"
),\
1,1,11
Ex 6 - Streams an
This study
100000879925770 from CourseHero.com on 02-01-2024 15:41:07 GMT -06:00
https://www.coursehero.com/file/64438449/lab-3-ex-6-1docx/
11) The topographic maps in Figure 6.6 show some of the many housing developments that
have been constructed in Stone Mountain, Georgia, which is a suburb of Atlanta.
a) Using a purple pencil or marker, continue tracing the edge of the floodplain in both maps.
b) Circle those homes that are at a high risk of flooding with a black pencil or marker.
c) List 3 reasons why a developer would build homes in an area with such a high potential for
flooding.
1.
The low probability of a major hurricane making landfall near U.S. coastal areas.
2.
The availability of flood insurance has mitigated the financial risks.
3.
The pro-development policies at the state and local level protecting developers.
12) Suppose you are in the market to buy a new home. Based on what you learned in this exercise, describe how you might avoid purchasing a home in an area with a high risk of
flooding.
I personally would not purchase a home in a flood zone area or near rivers, oceans, lakes or streams. I would avoid any area with stream.
This study so
E
ur
x
ce
6
w
–
as
S
d
t
o
r
w
ea
n
m
loa
s
de
a
d
nd
by
F
1
l
0
o
0
o
0
d
00
in
87
g
9925770 from CourseHero.com on 02-01-2024 15:41:07 GMT -06:00
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help
59
Figure 6.6 (USGS Stone Mountain, GA, Quadrangle, 1973 photo-revised edition)
A)
B)
Ex 6 – Streams and Flooding
This study source was downloaded by 100000879925770 from CourseHero.com on 02-01-2024 15:41:07 GMT -06:00
This study source was downloaded by 100000879925770 from CourseHero.com on 02-01-2024 15:41:07 GMT -06:00
https://www.coursehero.com/file/64438449/lab-3-ex-6-1docx/