Lab #1
docx
keyboard_arrow_up
School
University of Toronto, Scarborough *
*We aren’t endorsed by this school
Course
EESB02
Subject
Geography
Date
Dec 6, 2023
Type
docx
Pages
7
Uploaded by sindhuhu
Principles of Geomorphology – Lab #1
Basin Morphometry – Highland Creek Catchment
Part 1
1.1)
The stream orders, number of streams in each order and average stream lengths of each
are displayed in the table below:
Stream Order
# of Streams
Avg. Stream Lengths (obtained from topographic maps)
1
21
102.6/21 = 4.88/2.5 = 1.954 km =
1954.29 m
2
6
54.8/6 = 9.13/2.5 = 3.653 km =
3653.33 m
3
2
22/2 = 11/2.5 = 4.400 km =
4400 m
4
1
15.6/1 = 15.6/2.5 = 6.240 km =
6240 m
1.2)
(A)
The graph of stream order vs. number of streams obtained from the printed maps
of the Highland Creek catchment is displayed below:
0.5
1
1.5
2
2.5
3
3.5
4
4.5
1
10
100
f(x) = 51.44 exp( − 1.02 x )
R² = 0.98
Stream Order vs. Number of Streams
2020
Stream Order
Number of Streams
(
B)
The graph of stream order vs. the average stream length (in metres) obtained from the
printed maps of the Highland Creek catchment is displayed below:
0.5
1
1.5
2
2.5
3
3.5
4
4.5
100
1000
10000
f(x) = 1495.34 exp( 0.37 x )
R² = 0.95
Stream Order vs. Average Stream Length
2020
Stream Order
Avg. Stream Length (m)
1.3)
The relationship between the stream order vs. the number of streams seems to have a
strong negative relationship as observed visually as well as through the correlation
coefficient (R
2
= 0.9847). Whereas, the relationship between the stream order vs. average
stream length is observed to have a strong positive correlation (R
2
= 0.95).
2.1)
The bifurcation ratio
(ratio of the number of streams in one order to that in the next
higher order):
B
R1
= N
0
/ N
0 + 1
B
R1
= 21
/ 6
B
R1
= 3.5
B
R2
= N
0
/ N
0 + 1
B
R2
= 6/2
B
R2
= 3
B
R3
= N
0
/ N
0 + 1
B
R3
= 2/1
B
R3
= 2
2.2)
Drainage Density
(ratio of the total length of streams over the total drainage area of the
basin) is as following.
The total drainage
area
of the basin calculated in lab 1 was 118.5 km
2
.
D = ∑L / A
D = (stream order 1 + stream order 2 + stream order 3 + stream order 4) / total area
D = (41.04 km + 21.92 km + 8.80 km + 6.24 km) / 118.5 km
2
D = 78km / 118.5 km
2
D = 0.66/km
2.3)
Length Ratio
(ratio of the average length of streams of a given order to the average
length of the next lower order):
L
R1
= Average length stream
order 2 /Average length
stream order 1
= 3.653 km / 1.954 km
= 1.87
L
R2
= Average length stream
order 3 /Average length
stream order 2
= 4.4 km / 3.65 km
= 1.20
L
R3
= Average length
stream order 4 /Average
length stream order 3
= 6.24 km / 4.4 km
= 1.42
2.4)
Relief Ratio
(ratio between basin total relief and basin length):
Max elevation
(from GIS):
206.434
Min elevation
(from GIS): 71.502
Length
of the entire Highland Creek: 38 inches (measured from the printed maps using a
ruler)
Conversion:
38 inches *
1
cm
0.393701
inches
*
20000
cm
1
cm
*
1
m
100
cm
=
19303.99 m
R
H
= H/L
0
(H= Max-min elevations)
R
H
= (206.4 – 71.5)/
19303.99
R
H
= 0.007
2.5)
Basin form
Length obtained: 19303.99 m = 19.30 km
Width: 21 inches *
1
cm
0.393701
inches
*
20000
cm
1
cm
*
1
m
100
cm
=
10667.99
m
= 10.67 km
B
f
= A/L
basin
2
(Basin length = (Length + Width)/2)
B
f
= 118.5 km
2
/ {(19.30km + 10.67km)/ 2}
B
f
= 118.5 km
2
/ 14.985 km
B
f
= 7.91/km
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
2.6)
Stream Frequency
(measured through dividing the total # of streams of all orders by the
area of the basin)
F
s
= ∑ N
streams
/ A
F
s
= (21 + 6 + 2 + 1)/ total area
F
s
= 30/118.5 km
2
F
s
= 0.25/km
2
3)
The graph of stream order vs. stream number of 2020 values for the Highland Creek,
superimposed with the 1954 and 1971 values is displayed below:
0
1
2
3
4
5
6
7
8
9
1
10
100
1000
10000
Stream Order vs. Stream numbers
(1954 & 1971 & 2020)
1954
1971
2020
Stream Order
Stream number
The graph of stream order vs. average stream lengths of 2020 values for the Highland Creek,
superimposed with the 1954 and 1971 values is displayed below:
0
1
2
3
4
5
6
7
8
9
1
10
100
1000
10000
100000
Stream Order vs. Average Stream Lengths
(1954 vs. 1971 vs. 2020)
1954
1971
2020
Stream Order
Avg. Stream Lengths (m)
(A)
There are plenty of observable and significant differences in both of the graphs when the
years 1954, 1971, and 2020 data are compared. The first graph of stream order vs. the
number of streams shows clearly that as the years have passed by since 1954, the number
of streams in each order have undoubtedly decreased. The number of streams in order 1
declined from 6205 down to 21 in just about 66 years. Even within 17 years, from 1954
to 1971, the number of streams drastically dwindled with only 2406 remaining, down
from 6205. Similarly, the average lengths of the streams also had perceptible differences
when compared. The average stream lengths of all orders increased substantially in 2020
compared to the lengths in 1954 and 1971. The highest increase was amongst the lengths
of order 1.
(B)
Although 66 years might appear like a long period of time with lots of room for change, it
is regardless an abrupt decline in the number of streams. There are a number of factors
that could’ve affected the number of streams over time. The first and biggest factor being
land adaptation by humans because of the increase in population for obvious reasons and
other factors could be things like climate change, shifts in precipitation patterns, etc. The
upsurge in the average stream lengths is sort of a by-product from the decline in the
number of streams. The average lengths of each order (especially order 1) was very small
in 1954 as well as 1971 because of the huge number of streams at the time. As the
number of streams decreased, the length of the streams stayed fairly the same/long
overtime therefore causing the average length to increase.
Part 2 – GIS component
For this part of the assignment, all the values used were obtained from the GIS software.
Stream Order
# of Streams
Avg. Stream Lengths
1
21
1498.27 m = 1.50 km
2
6
3787.09 m = 3.79 km
3
2
4981.00 m = 4.98 km
4
1
7027.90 m = 7.03 km
A.
Length ratio:
L
R1
=
Average length stream
order 2/Average length
stream order 1
= 3787.09 / 1498.27
L
R1
= 2.53
L
R2
=
Average length stream
order 3/Average length
stream order 2
= 4981.01 / 3787.09
L
R2
= 1.32
L
R3
=
Average length stream
order 4/Average length
stream order 3
= 7027.90 / 4981.01
L
R3
= 1.41
B.
Relief ratio
R
H
= H/L
0
(H= Max-min elevations)
R
H
= (206.4 – 71.5)/16258.0608
R
H
= 0.008
C.
Drainage density
D = ∑L / A
D = (stream order 1 + stream order 2 + stream order 3 + stream order 4) /
D = (31463.74 + 22722.56 + 9962.017 + 7027.901) / 114422628.6869
D = 71.18 km / 114.42 km
2
D = 0.62/km
D.
If we were to compare and contrast the GIS data with the non-GIS method used to extract
information about the catchment of Highland Creek, we would notice that the non-GIS
method was not accurate but incredibly close to being accurate. This is obviously because
when collecting the data using the printed maps with instruments, there is always error
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
involved (either human error or instrumental error).
0.5
1
1.5
2
2.5
3
3.5
4
4.5
100
1000
10000
1498.27
3787.09
4981
7027.9
1954.29
3653.33
4400
6240
Stream order vs. Average lengths
GIS & non-GIS method
GIS method
non-GIS method
Stream order
Average lengths (m)
Looking at this graph of GIS average lengths of streams vs. the non-GIS average lengths
of streams on a semi-logarithmic scale, its easier to visualize that the numbers from non-
GIS method were very close to the GIS method. You can also tell the difference from the
values of length ratio, relief ratio and drainage density, that were calculated for both, that
non-GIS method was slightly inaccurate.
References
United Nations, Department of Economic and Social Affairs, Population Division (2019).
World Population Prospects 2019, custom data acquired via website.
https://population.un.org/wpp/DataQuery/
Toronto, Canada Population 1950-2020. (n.d.). Retrieved from
https://www.macrotrends.net/cities/20402/toronto/population
The Impacts of Climate Change on Rivers. (n.d.). Retrieved from
https://www.americanrivers.org/threats-solutions/clean-water/impacts-rivers/#