Assignment 4 W24 - Landforms
pdf
keyboard_arrow_up
School
Queens University *
*We aren’t endorsed by this school
Course
102
Subject
Geography
Date
Apr 3, 2024
Type
Pages
7
Uploaded by CorporalWorld7224
GPHY102 Page 1 GEOGRAPHY 102, Winter 2024 Assignment #4 Fluvial, Aeolian and Coastal Landforms GENERAL INSTRUCTIONS Complete the following exercises. For this assignment, you will need to access to a computer with internet capability. Answer each of the questions individually, in order, in a neat typewritten report. Answers should be succinct sentences, direct and to the point. Using 12-point font and one-inch margins, the total length of your written submission should be approximately three to four double-
spaced pages as a PDF
. Please organize your report with the question numbers but WITHOUT the question/instruction text included in this document. Marks will be deducted for including the instructions in your submission. Due Date: Friday 5 April 2024 at 11:59 p.m. EST (submit to onQ) Late Penalty: 10% per day penalty will apply without a valid excuse approved prior to the deadline. Email submissions are not acceptable. ATTENDANCE
Each assignment will have a graded attendance component. Full marks can be received for attending the introductory class for each assignment. Attendance will be taken by the TA at the beginning of each tutorial class. If the introductory class is missed, partial marks can be earned for attending the subsequent working classes prior to the assignment due date. ****************************************************************************** Introduction
Geomorphology is concerned with the processes and landforms at the surface of the Earth. In this assignment, you will work with topographic maps and satellite imagery to interpret fluvial and aeolian landforms. In addition to interpreting the landforms, you will be deducing processes, as well as interrelationships between landforms using superposition and elevation. In addition to the material in this assignment, you will need to access either Google Maps (or similar like Bing), Google Earth Pro (which you should already have), or a website such as onlinetopomaps.net to obtain aerial images of the areas in the assignment. All locations given in the assignment are based on Google search terms. Some questions reference maps that are included at the end of the assignment instructions along with their sources.
GPHY102 Page 2 EXERCISE 1: Map Features
In this section, you will investigate and map features related to fluvial, aeolian, and coastal processes. For an aerial view, search for Athabasca Sand Dunes Provincial Park in Google Maps. Select satellite mode to view the image and reposition it as necessary. You can also go to onlinetopomaps.net and choose ArcGIS (Satellite) from the drop-down list in the top left corner of the map (see Map 1a just for reference). Zooming out will give you a better perspective of this area. Note the prominent delta built into Lake Athabasca by the William River
. A copy of the river delta area topographic map is presented below. To obtain elevations from onlinetopomaps.net
, use the feature ‘My TOPO’ from the same drop
-down list. You’ll need to zoom in for elevations to be visible. This area is dominated by coastal processes on Lake Athabasca, river processes within the William River, and aeolian processes in the surrounding area. The latter are evident by the extensive dune complexes and sheets of aeolian material in the area. Remember that vegetation stabilizes aeolian deposits, hence active areas are likely to be minimally vegetated. Prior to answering the questions below, you should take some time to explore the entire area of Athabasca Sand Dunes Provincial Park and familiarize yourself with the landscape and the location of any notable features. 1.
Consider first the prominent beach ridges on the William River delta. What do they indicate about change in the water level of Lake Athabasca? (1 mark)
2.
Based on the topographic map, estimate the elevation change in lake level. What evidence do you use to constrain this change? On Map 1b, mark with neat, clear letter L and an arrow to a point, the location that constrains the lower elevation, and a U for the upper elevation. This can be done by saving the image and editing it with typed or drawn features. (4 marks)
3.
What evidence is there that the direction of flow on the William River delta has changed? There are 2-3 significant elements you should be able to see. Consider both the channels on the delta, any eroded beaches, and presence of sediment deposits in the coastal lake. (3 marks)
4.
On Map 1b, the area with beach ridges on the delta is mapped as wetland (indicated by the letter ‘w’ surrounded by dashed lines
). Why would this be the case? Consider where these features are located and how they differ. (2 marks)
5.
To the west of the William River, the boundary that defines the northwestern edge of a large aeolian deposit is sharp (beige colour). Using the topographic map, what elevation does that boundary appear to be at? (1 mark)
6.
How would you characterize the boundary between the William River and the aeolian deposits located to the north and west of the river? Why do you think the boundary is like this? (3 marks)
7.
Given this boundary, and the dune shape, what compass direction (orientation) does the wind come from in this area and why? (3 marks)
GPHY102 Page 3 8.
Based on your understanding of aeolian transport, explain why the slope on the southwest bank differs from the opposite bank in profile AB on Map 1c. Next, draw the path AB in Google Earth and include the elevation profile as a screenshot (hint: look for the William River delta flowing into Lake Athabasca to orient yourself). (2 marks + 2 marks)
9.
What impact does the aeolian sediment have on the channel morphology of the William River? (2 marks)
10.
What evidence is there that the William River has responded to lake level changes? Consider lake level change to be a form of base level change, so what would you expect with a lowering base level? (2 marks)
EXERCISE 2: Meandering Rivers For this section, refer to Maps 2a and 2b that show a reach of the North Saskatchewan River southwest of Edmonton. For an aerial view, go online and type Keephills AB into the location search. The river is located just south of this location. Meandering rivers take on many forms and are generally have more limited sediment supply. They move laterally through progressive erosion on the outside of bends, where the thalweg approaches the bank, matched by deposition on the inside of bends in what are termed point bars
. Erosion is destructive, so it is not associated with sediment deposits, but may be characterized by curved steep banks. This relatively slow river evolution is usually visible from aerial photographs and by landform patterns. Over time, the river may extensively re-work floodplain deposits through erosion and deposition. 11.
Zoom into the river just south of Keephills online. Compare the pattern of channels in the North Saskatchewan River to the William River in the previous section. Consider the number of channels and their apparent stability (what clues do you use?). (3 marks)
12.
Looking at the imagery, what texture do you see in the fields surrounding the river? What do you think might have caused this texture? (3 marks)
13.
Look at the topography and elevations in Map 2a and 2b. What features do you see in the topography in the river valley? (2 marks)
14.
The contour interval in Map 2a and 2b is 50 feet (approximately 15 m). Compare the distance between the 2200’ and 2250’ contours along the river. Identify any locations where they are widely separated. First, what does this separation indicate (consider slope and position relative to the elevation of the river)? At these locations, what landforms do the fields show? Given this combination of landform and elevation evidence, would you consider this as part of the contemporary floodplain? If not, what landform does this represent? (4 marks)
15.
Looking at the topography surrounding the river around the perimeter of Map 2a/2b, and considering your conclusions in question 14, what do you think has happened to the river over the long term in terms of base level change? Would you consider this aggradation or degradation? (4 marks)
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
GPHY102 Page 4 Total Marks for Assignment 4 = [12.5% of final grade] Map 1a:
Satellite image of the William River Delta and Athabasca Sand Dunes, Alberta. Source: http://onlinetopomaps.net/
GPHY102 Page 5 Map 1b:
Topographic map of the William River Delta. Lake Athabasca is to the north. Contour lines shown in light grey. Source: 1:50,000 topographic map sheet at http://onlinetopomaps.net/
GPHY102 Page 6 Map 1c: Source: http://atlas.nrcan.gc.ca/site/english/maps/topo/index.html
. © Department of Natural Resources Canada. All rights reserved.
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
GPHY102 Page 7 Map 2a:
North Saskatchewan River, near Keephills, AB (southwest of Edmonton) Map 2b:
Topographic map of North Saskatchewan River, near Keephills AB (SW of Edmonton) Source: http://onlinetopomaps.net/