Ch. 1 Profile and Topography of Racing Beach
Benjamin Law
2013, Ch1, 1
Ch 1. Profile and Topography of Racing Beach
I took a look at the slope, width and surface coverage of Racing Beach. I measured the slope
of the beach and found that the beach was consistent with the previous years profiles. I also
measured out the surface coverage of different types of beach. I noted down sand (2cm or
smaller), cobble (2cm to 20cm) and rocks (20cm +). I found that the majority of the beach
was cobble, that the sand increased as you headed south, and that the rocks were all
clustered on the north end. I explored the idea of quantifying the surface coverage of the
beach, and I refined the methods that I used for this project.
Introduction
Of the many aspects of the shoreline, the surface of the beach is one that is subject to
many changes. Over time, the beach profile (slope of the beach) changes; these changes are
caused by the tides, wave intensity and weather of the area. Each of these different
components adds to the erosion and change of the beach. As the tides more in and out, the
water is constantly moving over the top of the beach, eroding the rocks. In addition, certain
aspects of the beach, such as protective structures and the width, can influence the erosion
rates. In general it's been found that as the width of the beach increases, the force of the
erosion decreases (Charles H. Carter, 1986). Another aspect that adds to erosion is the wave
intensity; as the wave intensity increases, the water hits the rocks with more force which makes
the force of erosion intensify. Another part of the beach that is subject to change is the surface
of the beach. The surface changes with more frequency and speed than the beach profile. Two
things that affect the surface of the beach are the tides and the weather. As the tides come in
and out it moves things around on the beach, changing the location of the berm and detritus
layers. During storms or high winds, the tides become more severe, changing the surface even
more. Because of these two features, the surface of the beach is constantly changing on a
season (and sometimes daily) basis.
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For the beach that CSW studies (racing beach), there are several different aspects that
are important to note. The beach has a jetty on the north side of it. From there, the beach gets
progressively shallower and sandier as you head towards the southern end. There is a
longshore current towards the north end. Since the beginning of CSW studies on this beach
there has been no significant change to the profile.
In order to better understand and study this beach it is important to continue the beach
profile study; even though there has been no change, if there is a change, the beach profile will
be a key tool in finding and understand this change. In addition, more studies will be added on
to document the surface of the beach and how it changes as you move down the beach, as well
as how it changes over time. This information will allow us to better understand the connection
between the weather, tides and beach of Racing Beach.
Materials
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2 Meter sticks
String
Level
GPS
Small ruler
Small shovel
Camera (with wide angle lens)
Method
Profile:
1. Using the GPS, find the locations of each profile
Profile C: To the left of the path at the northern end of the beach.
(19T 362019/4601878)
Profile B: To the left of the path across from the large house
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(19T 362031/4601836)
Profile A: Across from the middle of house #95
(19T 362048/4601770)
Profile A’: Half way between Whittemore and Dusty Miller Rd
(19T 362055/4601602)
New Profile A’’: Between 1st and 2nd stair
(19T 362063/4601442)
2. Starting at the top of the beach, measure the vertical drop every 1 meter on the way to
the low tide.
3. Use two meter sticks separated by 1 meter of string (make sure that the 0 mark side is
touching the ground).
a. To take the vertical drop, tie the string to the 50 cm mark on the landward meter
stick; then, using the level, move the string up and down the shoreward meter
stick until it is level.
b. The vertical drop for that 1 meter segment will be given by the number the string
lines up with (on the shoreward meter stick) minus 50 cm.
Topography:
1. Using the GPS coordinates (above) find the profile spots
2. Split the area between C and B profile into 2x2 meter quadrats
3. Use a long string with 2 meter segments marked into it to quickly measure out the
quadrats. Mark the corners of the quadrats with flags.
4. Mark down a rough estimate of the sand, cobble, boulder, and large boulder percent
coverage using the international scale system (PDF)
5. Take a photo of the quadrat with the flags in sight
6. Use photoshop to better estimate the percent coverage of the different types of surface
7. Mark out quadrats (2 quadrats deep) on both sides of each of the other profiles
8. Take measurements and photographs of each of these quadrats
Cobble Study:
1. Using the quadrats from the topography study, take a scoop of rocks off the top of the
quadrat in the middle.
2. Take the length of the rock (the longest side being the length)
2013, Ch1, 4
Figure 1, 2013 Profiles
14m
13m
12m
11m
10m
9m
8m
7m
6m
5m
4m
3m
2m
1m
0m
0
-20
-40
Total Drop (cm)
-60
-80
C
B
-100
A
A'
-120
A''
-140
-160
-180
-200
Meters from Top of Beach
Figure 1, Comparison between the different profile locations in 2013. This shows that no one side of the beach has a
significantly different slope. It also shows that profiles B and C are longer than the others.
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Figure 2, A'' Comparison
16m
15m
14m
13m
12m
11m
10m
9m
8m
7m
6m
5m
4m
3m
2m
0m
1m
0
Total Drop (cm)
-50
-100
2010
2011
2012
-150
2013
-200
-250
Meters from Top of Beach
Figure 3, A' Comparison
16m
15m
14m
13m
12m
11m
10m
9m
8m
7m
6m
5m
4m
3m
2m
1m
0m
0
Total Drop (cm)
-50
-100
2010
2011
2012
-150
2013
-200
-250
Meters from Top of Beach
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Figure 4, A Comparison
21m
20m
19m
18m
17m
16m
15m
14m
13m
12m
11m
10m
9m
8m
7m
6m
5m
4m
3m
2m
1m
0m
0
-50
Total Drop (cm)
-100
2010
2011
-150
2012
2013
-200
-250
-300
Meters from Top of Beach
Figure 5, B Comparison
50
24m
23m
22m
21m
20m
19m
18m
17m
16m
15m
14m
13m
12m
11m
9m
10m
8m
7m
6m
5m
4m
3m
2m
1m
0m
0
Total Drop (cm)
-50
2010
2011
-100
2012
2013
-150
-200
-250
Meters from Top of Beach
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Figure 6, C Comparison
22m
21m
20m
19m
18m
17m
16m
15m
14m
13m
12m
11m
9m
10m
8m
7m
6m
5m
4m
3m
2m
1m
0m
0
Total Drop (cm)
-50
-100
2010
2011
2012
-150
2013
-200
-250
Meters from Top of Beach
Figure 2, Figure 3, Figure 4, Figure 5, Figure 6, compares the different profiles to the previous year’s findings. The
slopes are all consistent, but this year’s profile is shallower than the previous years.
Figure 7, C-B Percent Coverage
100%
90%
80%
Percent Coverage
70%
60%
Sand Percent
50%
Cobble Percent
40%
Rock Percent
30%
20%
10%
0%
1
2
3
4
5
Quadrats Away From Road
6
7
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Figure 7, this is the percent coverage of sand, cobble and rock between the profiles of B and C. There is a clear trend
that the amount of cobble lessens as you approach the water. The sand coverage is low overall, although it is
slightly higher in the middle of the beach. The amount of rocks greatly increases as you approach the water.
j
Figure 8, A Percent Coverage
100%
90%
80%
Percent Coverage
70%
60%
Sand Percent
50%
Cobble Percent
40%
Rock Percent
30%
20%
10%
0%
4
3
2
Quadrats Away from Road
1
Figure 8, this is the percent coverage around the A profile. The majority of this area is made up of cobble, and
towards the end of the beach it becomes sand .
Figure 9, A' Percent Coverage
Percent Coverage
120%
100%
80%
60%
Sand Percent
40%
Cobble Percent
Rock Percent
20%
0%
1
2
3
Quadrats Away from Road
4
Figure 9, this is the percent coverage around the A' part of the beach. The majority of this part of the beach is made
up of cobble, although as you approach the shore it becomes mostly sand.
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Figure 10, A'' Percent Coverage
100%
90%
Percent Coverage
80%
70%
60%
50%
Sand Percent
40%
Cobble Percent
30%
Rock Percent
20%
10%
0%
1
2
3
Quadrats Away from Road
4
Figure 10, this is the percent coverage around the A'' part of the beach. This part of the beach is almost entirely
made up of sand.
Figure 11, Percent Coverage
100%
90%
80%
Percent Coverage
70%
60%
Sand Percent
50%
Cobble Percent
40%
Rock Percent
30%
20%
10%
0%
C-B Profile
A Profile
A' Profile
A'' Profile
Profile
Figure 11, this is the total percent coverage for the different profiles. The amount of sand on the beach increases as
you head southwards. The large rocks are only found between C and B.
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Figure 12, Average Rock Size
6
Rock Length (cm)
5
4
3
A Profile
A' Profile
2
1
0
1
2
3
4
Quadrats Away From Road
Figure 12, this shows the average rock size as for specific quadrats as you head towards the water. On the whole it
looks like it is getting slightly smaller.
Conclusion
My first project, the beach profile, found that the beach slope has not changed
significantly from the previous yours, but it also became apparent that the beach was shallower
than the last several years. Although the beach has been wider in the past couple of years, the
profile studies of 2008 and 2009 indicate that the beach has been this shallow before. Since the
beach has been recorded to be this shallow before, the shallowness of the beach this year was
probably caused by the fact that the beach was in neap tides, rather than spring tides. Neap
tides happen around twice a month (caused by the cycles of the moon), and during neap tides
the difference between the high and low tides is the shallowest (causing a shallower beach
during low tide).
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The topography part of my experiment showed that the coverage of sand grew
progressively larger as you headed from the north end to the south end of the beach. The
cobble coverage is large in the areas of C, B, A, and A' profiles, with the highest coverage in the
A and A' areas. The rocks were found to be only in the C-B area. The reason the rocks are found
in the C-B area is that when the jetty was created rocks were placed into the C-B area and were
large enough to withstand the tides. The amount of sand increases as the beach heads south is
because the beach becomes shallower which increases the erosion.
Another aspect of the topography experiment that was interesting to note, was that a
clear pattern emerged in the C-B area. In the uppermost part of the beach, the majority of the
area is cobble, as you head west (towards the water) the amount of sand increases, and the
amount of larger rock increases. As you continue, the sand goes away, and the area is almost
entirely larger rocks. These trends are caused by the erosion rates and the tides; as the tides
come in, they push the smaller and more moveable rocks towards the top of the beach creating
the berm of the beach. The rocks on the lower end of the beach are large enough to withstand
the tides. The sand fills in the spots of the beach with relatively low wave actions.
For the rest of the beach, where the majority of the beach was cobble, I found that as
the cobble grew closer to the shore, the average size of the cobble became smaller.
In order to better measure the surface area of the beach, there are several improvements that
could be made to the way I conducted my topography experiment. First off, this project should
preferably be a 2 person project, because it is quite a bit easier to lay out the 2x2 meter
quadrats with 2 people. Second, instead of flags, something like beanbags should be used to
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mark out the quadrats; I found that flags have a hard time sticking into the rocky beach at the
right spot, and often they would have to be put in crocked, which would disrupt what the
quadrat size appeared to be. Finally, using a long string with 2 meter distances marked out
makes it easier to mark out quadrats in lines (rather than using 2 meter sticks to find the spot).
Since the surface of the beach changes with such speed, it is important to continue this study so
that we will be able to understand and see how the beach changes through the seasons.
Additionally, by understanding how the surface of the beach changes, we will gain a new
understanding of the connection the beach has to the tides and weather of the area.
Bibliography
Bertness, Mark. 2002. Ecology of the Atlantic Seashore
CSW Profile Studies
Charles H. Carter, Charles B. Monroe and Donald E. Guy Jr., 2008,Lake Erie Shore Erosion: The
Effect of Beach Width and Shore Protection Structures
2007, SO 14688-1,
http://www.jiban.or.jp/file/organi/bu/kijyunbu/isokentou/vote/SR_ISO_146881_JP_comment.pdf
Australia Government Bureau of Meteorology, National Tides Tables 2008.
http://www.bom.gov.au/oceanography/tides/met_effects.shtml
2013, Ch1, 13