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Investigative Geography
- Unit GG3a from Legacy
Specification DATE: May 2005 |
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An
investigation into stream channel characteristics |
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A group of students wanted
to study various characteristics of a local stream. They decided to
measure a number of channel variables over a distance of 10km
downstream. Their fieldwork was carried out during two consecutive days
in October following a period of rain. |
WJEC exam 2005 |
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The map below shows the
location of the stream and contours showing the relief. |
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| 1a) |
Give a possible title, in
the form of a question for this study. (2 lines) |
(2) |
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| b) |
Suggest two major
potential problems associated with stream channel fieldwork. (4 lines) |
(2) |
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| 2. |
The table below sets out
data collected at 15 sites along the stream from Point A to
Point B. |
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| Site Number |
Distance downstream (km) from
A |
Height above sea level (m) |
Mean velocity (m/sec) |
Stream width (m) |
Mean depth (m) |
Mean discharge(cumecs) |
Median bedload size (cms) |
| 1 |
0.0 |
106 |
0.32 |
0.66 |
0.13 |
0.03 |
8.9 |
| 2 |
0.8 |
82 |
0.29 |
0.61 |
0.17 |
0.03 |
9.1 |
| 3 |
1.6 |
66 |
0.38 |
0.84 |
0.23 |
0.07 |
8.4 |
| 4 |
2.5 |
54 |
0.42 |
0.97 |
0.19 |
0.08 |
8.0 |
| 5 |
3.7 |
43 |
0.63 |
1.01 |
0.29 |
0.18 |
7.3 |
| 6 |
4.8 |
38 |
0.58 |
1.38 |
0.37 |
0.29 |
7.6 |
| 7 |
5.5 |
36 |
0.91 |
2.42 |
0.42 |
0.92 |
7.1 |
| 8 |
5.9 |
35 |
1.07 |
3.09 |
0.49 |
1.62 |
6.2 |
| 9 |
6.7 |
33 |
0.94 |
2.88 |
0.55 |
1.49 |
5.7 |
| 10 |
7.3 |
31 |
1.32 |
3.41 |
0.63 |
2.84 |
5.4 |
| 11 |
7.7 |
30 |
1.48 |
3.82 |
0.78 |
4.41 |
4.9 |
| 12 |
8.1 |
29 |
1.50 |
4.14 |
0.72 |
4.47 |
4.5 |
| 13 |
8.6 |
28 |
1.49 |
4.97 |
0.84 |
6.22 |
4.3 |
| 14 |
9.3 |
27 |
1.66 |
5.21 |
1.04 |
8.99 |
3.8 |
| 15 |
10.0 |
26 |
1.78 |
4.73 |
0.89 |
7.49 |
4.0 |
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| a) |
Using the appropriate data
from the table above, and within a copy or print out of the frame below
[or by excel on a graph plotter], construct a long profile of the stream
channel from Point A to Point B.
Label the vertical and horizontal axes. |
(3) |
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| b) |
Describe the shape of the
long profile you have constructed. (2 lines) |
(2) |
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| 3. a) |
Explain why a mean value was
calculated for the velocity at each site (4 lines) |
(2) |
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| b) |
The bed load has been
calculated as a median value. How is a median value calculated? (2
lines) Research: Look up
measures of central tendency |
(1) |
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| c) |
Suggest two ways to
find out if there was a relationship between any pair of variables in
the table of data. (4 lines) |
(2) |
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| d) |
State which channel variable
in the table shows a negative relationship with distance from the
source. (1 line) |
(1) |
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| e) |
Using all the information
given in this investigation, suggest reasons why any conclusions might
be of limited value. (8 lines) |
(4) |
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Extension
work: |
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| 5. |
Use two ways to show that
there is a relationship between distance downstream and median bedload
size. Measure the strength of this relationship. |
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| 6. |
Does the discharge help to
account for this relationship? |
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| 7. |
During this fieldwork along
the 10km of stream channel the students became aware that pollution
appeared to be a problem along certain stretches of the stream due to
human influences of agricultural land-use, and urban and industrial
development. |
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Explain how the students
could have organised and carried out their data collection in order to
successfully study the pollution along this stream. (15 lines) |
(6) |
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Research reading:
http://www.nku.edu/~scienceed/Brian%20Schefold.pdf |
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http://www.mulberrycentre.com/downloads/Biology%20fieldwork%20summaries%202.pdf
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http://www.hokoon.edu.hk/download/geography/CE_Stream/CE_Stream_e.pdf
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http://chamisa.freeshell.org/pollution.htm |
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