Lab 13 - Topo Maps and Landforms v2023
docx
keyboard_arrow_up
School
Orange Coast College *
*We aren’t endorsed by this school
Course
A110
Subject
Geology
Date
Jan 9, 2024
Type
docx
Pages
7
Uploaded by SuperInternetBear20
GEOLOGY LAB
Name: _______________________________________
Topographic Maps
Activity 1: Drawing Contour Lines
Follow these Rules for Drawing Contour Lines:
●
Contour lines connect points with the
same
elevation.
●
When drawing contour lines, connect the data points with
one
, smooth line avoiding sharp
angles.
●
Contour lines never cross, branch off, or touch each other (there are exceptions).
●
When contour lines cross streams they point towards the higher elevation.
●
If a contour line is close to the perimeter of the map & does not form an enclosed circle,
continue it to the edge of the map.
●
Use a
pencil
to draw the contour lines and if you make a mistake,
erase
completely. You could
also complete the map digitally.
Helpful tips:
●
Before you start drawing contours lines, note the location of the highest elevation, the lowest
elevation, any water bodies, and the contour interval.
●
It is usually easier to start with the contour line that has the lowest elevation.
●
Only work on one contour line at a time!
1. With a pencil, draw in contour lines on the map (previous page) using a 10-foot contour interval.
2. Answer the following questions using the contour map you have completed:
a.
In what map direction does the stream flow?
b.
How were you able to determine this?
c.
What is the distance from the highest point on the map (X) to B?
Activity 2: Reading Topographic Maps
For the first example, examine the map of a portion of Yosemite National Park on the following page.
1. What is the contour interval of this map? (Show your work.)
2. Locate Yosemite Creek on the map. In which map direction does Yosemite Creek flow?
3. How were you able to determine the streamflow direction?
4. In general, how is the topography of the northern portion of the map area different from the southern
portion of the map area?
5. If you wanted to take an easy hike, would you select the Upper Yosemite Falls Trail or the Valley Loop
Trail? Why would you make this choice?
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
Activity 3: Interpreting Topographic Maps
Answer the following questions using the topographic maps provided. You may access Google Earth if
needed to view these landforms in “three” dimensions.
MAP A: MAMMOTH MTN. QUADRANGLE
1. What is the contour interval on this map?
2. What is the latitude of the northeastern corner of this map?
3. Locate White Wing Mountain
What is the elevation at its peak?
Which slope is steeper: the NW slope or SE slope? How can you tell?
4. Locate Crater Flat (E side of map).
What is the significance of the contours with hachure marks on them?
What is the elevation at the center of this feature?
5. In what compass direction is the Middle Fork of the San Joaquin River flowing? How can you tell?
6. What is the approximate elevation of Deadman Pass?
MAP B: SADDLE MOUNTAIN QUADRANGLE
7. What is the map scale?
8. What is the contour interval?
9. In what compass direction is the South Fork of the American River flowing?
10. Draw a simple sketch showing the shape of the stream valley of the American River in cross-section:
11. What is the approximate elevation where the Randolph Canyon tributary empties into the American
River?
12. What is the approximate elevation at the American River where the parcels #13, 14, 23, and 24 (red
outlined “boxes”) all meet?
13. What is the distance along the American River between the two points described in questions #11
and #12? (Measure the length of the river, not the direct distance – use a paper strip or string as a guide)
14. Calculate the stream gradient between these two points in
feet/mile
(show your work):
15. Convert the value you calculated in #14 to
meters/kilometer
(show your work):
MAP C: HARRISBURG QUADRANGLE
16. What is the type of drainage system in this map? What does this type of drainage pattern indicate
about the bedrock geology or topography of this area?
a.
Radial
b. Rectangular
c. Trellis
d. Dendritic
17. Examine the map pattern of the Conodoguinet Creek tributary (SW portion of map area). Is this
stream pattern
consistent with vertical or lateral erosion of the stream channel?
18. Examine the valley shape of the Conodoguinet Creek (examine contour patterns). Is this
valley shape
consistent with vertical or lateral erosion of the stream channel?
19. Briefly explain how your answers to #17 and #18 can be reconciled.
MAP D: MT. TOM QUADRANGLE
20. Draw a cross-section view of the Owens River valley as it passes through the Volcanic Tableland:
21. Calculate the average slope gradient between Rock Creek (E side of map area) and Wells Meadow
(show your work):
22. Calculate the average slope gradient between Wells Meadow and the mine prospect due east of
Round Valley Peak (show your work):
23. What is the water source for Wells Meadow?
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
24. Why are some of the contour lines near Mt. Humphreys and Four Gables blue?
25. Examine the valley of Pine Creek near the settlement of Scheelite. Draw a cross-section view of the
shape of the valley here:
26. Compare the shape of Pine Creek’s valley to the shape of the Owens River valley you drew in
question #20. What caused the different shape of Pine Creek’s valley? (HINT: check your answer to #24)
MAP E: NEEDLES QUADRANGLE
27. What type of landform is Threemile Lake?
28. Determine the width of the floodplain of the Colorado River. Show your work:
29. Sketch a profile (cross-section) view of the shape of the Colorado River valley near Needles, CA: