EAES 1207 Contaminated Sites Assignment - 23W KEY(1)
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Douglas College *
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1207
Subject
Geography
Date
Dec 6, 2023
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5
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For instructor use:
Name:
KEY
COMPLETE – INCOMPLETE – LATE
Student ID:
EAES 1207 – WINTER 2023
Lab 6: Topographic Maps & Contaminated Groundwater
OBJECTIVES
By the end of this lab, you should be able to:
1.
Use UTM coordinates to locate points on a topographic map
2.
Interpret elevation contour lines on a topographic map
3.
Interpret isoconcentration maps
SUPPLIES REQUIRED
Port Coquitlam topographic map, 1:50,000 scale (92G/7)
Pencil, white eraser and coloured pencils
30 cm length ruler
Carson map handout
FINDING LOCATIONS – THE UTM GRID
Question 1
Use the Port Coquitlam topographic map to answer the following questions:
What are the coordinates of:
The north end of Hoy Creek?
147E, 604N
The northernmost point of Lafarge Lake?
154E, 596N
The Mundy Park reservoir?
122E, 558N
What letter of the alphabet do you find at:
(037E, 591N)?
e (Westridg
e
)
(282E, 673N)?
K (LA
K
E)
(210E, 777N)?
i
(Penepla
i
n)
2
THE THIRD DIMENSION: ELEVATIONS
Question 2
Determine the elevation of the following features (provide a range for locations between contour lines)
Capitol Hill in Burnaby (011E, 594N)?
above 200 m and below 240 m; estimated approximately 210 m
Cypress Mountain (140E, 643N)?
between 800 and 840 m; est. approx. 830 m
Point (334E, 820N)?
between 400 and 440 m; estimated approx. 420 m
Question 3
Below is a snippet of the Mt. Seymour area of the map (near 030E, 700N). Using your knowledge about
interpreting the shape of the land from contour lines (this lab) and soil development along a slope (refer
back to Lab 3 in your manual if needed), clearly mark with an X a spot where you would expect to find a
well-developed soil. Explain why you chose this location.
Choose a spot with a gradual slope (widely-spaced contours), indicating a flatter surface. Many good
locations exist on on the west side of the diagram – one possibility has been marked. Wouldn’t want to be
too close to the river because the active floodplain would be an area that gets flooded regularly, impeding
soil development. There are some flatter areas around Dog Mountain and Dinkey Peak that could also be
reasonable locations to choose.
X
3
ACTIVITY: INTERPRETING ISOCONCENTRATION MAPS
The fictional town of Carson is located in the vicinity of a small abandoned gold mine. This gold mine
operated over a hundred years ago, and little evidence of it remains. However, historic gold mines are
associated with arsenic contamination due to acid mine drainage, and arsenic has recently been detected in
wells around Carson. Our task is to locate the site of the old mine and predict the path of arsenic
contamination from the mine using the provided handout (
note that this handout provides an
isoconcentration map layered over a topographic map of Carson
).
Question 4
Use the Carson map handout to complete the questions below:
Nine wells (labeled A to I) were tested for arsenic. Wells A-F and I are already on your Carson map.
Add Well G
(601E, 796N)
and Well H
(612E, 785N) to the map of Carson.
The arsenic concentration values measured at each well are provided in the table below. The detection limit,
or the lowest amount of a substance that could be reliably measured, is 1 ppb (parts per billion).
Write
in the measured arsenic concentration next to each well on the map :
Note that 10 ppb is the maximum
allowable concentration of arsenic in
Canadian drinking water.
Well #
Arsenic Concentration (ppb)
A
<1
B
<1
C
<1
D
26
E
<1
F
<1
G
15
H
6
I
5
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4
Based on the isoconcentration map of Carson (shown in coloured contours with a legend), where do you
think the old mine wastes were dumped? Explain your answer.
The old mine wastes were probably dumped in the Well D area. This is where the highest arsenic
concentration is found, and the arsenic appears to spread out from this location (concentrations get lower in
wells that are farther away).
Which way do you think groundwater is flowing? Indicate this on your map with a labeled arrow. Explain
your answer.
Tip: remember that
the coloured contours show arsenic concentration values, NOT surface
elevation
!
The groundwater appears to be flowing from the northwest to the southeast. If we look at the
isoconcentration contours, they are elongated in the southeast direction. The arsenic has spread farther to
the southeast than in any other direction.
5
Question 5
You have enough money left in your budget to drill two more wells (Well J and Well K). Where would you
drill these wells to improve the accuracy of your isoconcentration map?
Note: these will NOT be drinking water wells. They are research wells to help you learn more
about where the contamination originated and where it is going.
Clearly draw and label the wells on your map.
Provide the coordinates of each well:
Well J:
answers will vary
Well K:
answers will vary
Explain why you placed the wells where you did.
There are a number of good options. You would definitely want to put a well just north of Well D, as
we don’t have data in that direction and it’s possible that the mine wastes actually originate to the north
or northwest of Well D, rather than at Well D itself.
Question 6
Looking at the topography of the Carson map (the brown contour lines),
In which cardinal direction does each creek on your map flow? Be specific.
Curie Creek: southeast, Franklin Creek: east, Jemison Creek: northeast
Given that groundwater and surface water mix with each other, in which creek(s) do you expect
to find arsenic contamination? Briefly explain your reasoning.
Curie Creek is definitely expected to have some arsenic contamination, as parts of the creek fall within
the 5 and 10 ppb contours. Curie Creek feeds into Franklin Creek, so Franklin Creek is also likely to
have some arsenic contamination, albeit at lower levels, downstream of where the two creeks meet.
Jemison Creek may be clean, since it is relatively far from the plume and is not fed by Curie or Franklin
Creek (it feeds into Franklin Creek). The water in the streams comes from both groundwater and
rainwater, so the contaminant concentrations are likely to be lower than what we see in the groundwater.