LANDSCAPE FUNCTION ANALYSIS
MITCHELL
SU
STUDENT No. 660192 | NATURAL ENVIRONMENTS | SEMESTER 2/2013
1.0.0 INTRODUCTION 1.1.0 LOCATION PRESTON
FOOTSCRAY
Y CITYLINK TOLLWA
ESSENDON
BRUNSWICK
WARRANDYTE
BULLEEN
UNIVERSITY OF MELBOURNE
DONCASTER EASTERN
KEW CITY OF MELBOURNE MELBOURNE
TOORAK
CROYDON
FR E EWAY
BURWOOD
GLEN WAVERLY
NA O M
CLAYTON
FERNTREE GULLY NATIONAL PARK FERNTREE GULLY EASTLINK TOLLWAY
CAULFIELD
ROWVILLE
N
SH
2.5km
5km
7.5km
10km
E FR
0km
EW AY
Figure 1 - Location of Ferntree Gully National Park in Context of Metropolitan Melbourne (Apple 2013a).
The Lyrebird Walk and 1000 Steps Track is located within the Ferntree Gully National Park. The park is located within the suburb of Tremont and is approximately 33km south east of the Melbourne CBD. The area falls under the Yarra Ranges Council district and is managed by Parks Victoria. The UTM coordinates are E: 352095 N: 5805278.
ENVS10001 LANDSCAPE FUNCTION ANALYSIS 1
D ROA
1000 STE PS TRAC K
D
BELG VE RA
M
T. DAN DE N O
I
LIN
H IL L
N
RA
L
TR EE
AD RO
LYREBIRD WALK
ROA D
N
O ERW
FOR ES T
O
UND O
E
G UR TO
E
I
ST
BURWOO
0m
250m
500m
750m
Y WA IGH H D
RO AD
N
1000m
Figure 2 - Local Area of Ferntree Gully National Park (Apple 2013b).
1.2.0 POINTS OF OBSERVATION 5
ON E
TRE
4
EH
ILL
RO AD
6 3
1000 STEPS TRA CK
AD RO
WALK
ILL
2
CH UR CH
7
RD LYREBI
8
0m
200m
400m
600m
800m
MT. D
1
AN
DENONG TOURIST ROAD
N
Figure 3 - Points of Observation Within Ferntree Gully (Apple 2013c).
The following observation points along Lyrebird Walk and the 1000 Steps Track have been used as points of reference for this report. Data for each of these points have been collected from a previous site visit.
2 ENVS10001 LANDSCAPE FUNCTION ANALYSIS
OBSERVATION POINT 1 Eastings: 351976 Northings: 5805576 Elevation: 254m The area around Observation Point 1 display shallow soil on weathering rhyodacite. The color of the soil around this area in particular possesses a distinct iron oxide color that potentially indicate volcanic activity in the Ferntree Gully area. OBSERVATION POINT 2 Eastings: 351907 Northings: 5805940 Elevation: 324m Much like the Observation Point 1, Observation Point 2 possesses similar site attributes. However, a deeper soil profile allowed a more thorough investigation of the soil type and the local area’s geological history. OBSERVATION POINT 3 Eastings: 351987 Northings: 5806386 Elevation: 433m This observation point was noted to be the intersection with another walking track in the Ferntree Gully National Park. At this point, the effects of erosion became more obvious than at other points. OBSERVATION POINT 4 Eastings: 352075 Northings: 5806388 Elevation: 450m Observation Point 4 is known to be within close proximity to the head of the gully. The vegetation around this area was noted to have a slight variation from the rest of the walk. OBSERVATION POINT 5 Eastings: 352247 Northings: 5806613 Elevation: 485m This area is the junction with 1000 Steps Track and other walking tracks. At this intersection, a dam was sighted in the local vicinity which has sequential consequences on the flow of the creek further down the track. OBSERVATION POINT 6 Eastings: 352249 Northings: 5806501 Elevation: 467m The 1000 Steps Track largely follows the path of the gully around this observation point with each of them intersecting and interfering with each other. The effects of such interference has in some areas impeded the flow of the gully down the slope. OBSERVATION POINT 7 Eastings: 352169 Northings: 5806056 Elevation: 300m The gully levels off at the vicinity of this sight with alluvium deposits becoming visible. Influences due to alluvial erosion can be seen with the effects of meandering seen in the creek. OBSERVATION POINT 8 Eastings: 352089 Northings: 5805611 Elevation: 231m At this point, the west facing slope becomes visible from this area, impacting the aspect of vegetation growth in the mid to higher level canopies in particular.
ENVS10001 LANDSCAPE FUNCTION ANALYSIS 3
2.0.0 SITE ATTRIBUTES 2.1.0 GEOLOGY LEGEND RIVER/CREEK GEOGRAPHICAL BOUNDARY Dje - MT. EVELYN RHYODACITE Djf - FERNY CREEK RHYODACITE Djk - KALORAMA RHYODACITE Qa1 - UNNAMED COLLUVIUM Qc1- UNNAMED ALLUVIUM
Djf
N 0m
200m 400m 600m 800m
Figure 4 - Local Geology of Ferntree Gully (Geovic 2013).
The local geology of Lyrebird Walk and the 1000 Steps Track consists largely of Djf (Ferny Creek Rhyodacite) with deposits of Qa1 (Unnamed Colluvium) at the foot of the slope as shown in Figure 4. Ferny Creek Rhyodacite according to the VandenBerg, A.H.M. (1970), is an extrusive igneous rock formation that forms part of the Dandenong Ranges Volcanic Complex that was active thousands of years ago. Other key queues for an indication of past volcanic activity are the high relief slopes present in the area and absence of other rock types with the exception of areas directly adjacent to bodies of water. Given the location of the gully in the local vicinity of the walking tracks as well as the unnamed colluvium (Qa1) in Figure 4, observations at Observation Point 1 and Observation Point 8 suggests that sheet erosion on higher points of the slope has occurred, causing mass wasting in the form of Qa1. Other geological boundaries present in the figure were not considered due to their outlying position relative to the walking track. 2.2.0 LANDSCAPE TABLE 1 - SLOPE ELEVATION CHARACTERISTICS AT LYREBIRD WALK OBSERVATION POINT Angle (%)
1
2
3
19.44
17.63
15.84
4 ENVS10001 LANDSCAPE FUNCTION ANALYSIS
4 6.99
5 17.63
OBSERVATION POINT
1
2
3
4
5
Slope Classification
Moderately Inclined
Moderately Inclined
Moderately Inclined
Gently Inclined
Moderately Inclined
Morphological Type
Lower Slope
Mid Slope
Mid Slope
Mid Slope
Hillock
Relative Inclination
Minimal
Waxing
Waxing
Waining
Minimal
The landscape of Ferntree Gully along Lyrebird Walk follows a relatively shallow slope that remains consistent along all the observation points along the track with the exception of Observation Point 4. The sudden decrease in inclination is due to the area’s close proximity to the head of the gully present in Figure 4. TABLE 2 - SLOPE ELEVATION CHARACTERISTICS AT 1000 STEPS TRACK OBSERVATION POINT Angle (%)
5
6
7
8
17.63
21.26
8.75
15.84
Slope Classification
Moderately Inclined
Moderately Inclined
Gently Inclined
Moderately Inclined
Morphological Type
Hillock
Mid Slope
Mid Slope
Mid Slope
Relative Inclination
Minimal
Minimal
Maximal
Minimal
Along this portion of the site visit, the slope has no particular consistent gradient due to the various changes in landforms along the 1000 Steps Track. Observation Point 6 has a relatively steep gradient compared to the rest of the track and also is where the gully is most visible. Alluvial erosion has strongly influenced the landscape at this point but has been interrupted by the development of the walking track. At Observation Point 7, the gully levels off with alluvial deposits forming as a result of this change in inclination. At the final observation point, the characteristics of the slope become comparable to those of Observation Point 1 owing to their close proximity. The overall landscape has been heavily influenced by human impacts both recently as well as decades ago. According to the Parks Victoria (2000a), the local area experienced heavy logging in the 1850’s as a result of the establishment of a sawmill and continued so until the establishment of the national park in 1881, potentially providing enough time for negative feedback to create a noticeable effect on the cycle of succession in the local ecosystem. Evidence of this can be seen at Observation Point 7 wherein tree stumps with relatively clean breaks from the trunk are present.
ENVS10001 LANDSCAPE FUNCTION ANALYSIS 5
Figure 5 - Tree Stump at Observation Point 2 (Own Image).
Based on the size of other vegetation in the reserve, the diameter of these stumps suggest that many of trees cut down belong to those that grow to the tallest stratum. As a result, the tallest stratum at the present time is no longer the dominant stratum with the mid stratum - composed of much smaller and less established trees - being the dominant stratum. The overall effect of the reduction in the tallest stratum’s coverage density increases the total insolation received by lower levels of the ecosystem. A key indicator of increased insolation as an effect is the effect of aspect on vegetation growth on lower stratums.
Figure 6 - Example of Aspect at Observation Point 7 (Own Image).
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At Observation Point 7, increased insolation on lower stratums can be seen to have increased the rate of vegetation growth that would not have occurred otherwise without increased sunlight. At Figure 6, the moss and lichen would not have grown as abundantly on the right half of the tree trunk without it. On the other hand, the left side of the trunk shows little to no growth of such vegetation. It is expected that in order for the original state of equilibrium to return, ecological succession would need to cycle through the ecosystem on the scale of centuries if not a millennia. 2.3.0 SOILS
IV DR
E
K
T RAC 1000 STEPS
W A
LK
ILL CH UR
LYREBIRD
C
HYDROSOLS ORGANOSOLS KUROSOLS SODOSOLS
CH
FOREST R OAD
DORSET ROAD
FRANCIS
AD RO OD T WO EN DER SC UN RE
LEGEND
AV GR BEL LI N
ON G
AIL ER
0m
125m
250m
375m
RW OO D
HI
GH
MT DAN DE N
E BU
TOURIST ROAD
WA Y
N
500m
Figure 7 - Local Soil Profile of Ferntree Gully (ASRIS 2013). N.B. - Hatched Areas Indicate Urbanized Areas.
Within the local area of Lyrebird Walk as well as the 1000 Steps Track, the main soil type present are sodosols (Figure 7). These soils according to the Victorian Government’s Department of Environment and Primary Industries (2013), are noted for their poor drainage and unsuitability for agricultural purposes. Another aspect of sodosols that are a key aspect for the landscape of Lyrebird Walk and 1000 Steps Track are that these types of soils are particularly prone to alluvial erosion. As shown in Figure 8 below, the sodosols present in the Ferntree Gully area around Observation Point 2 have distinct red color in the B horizon that darkens as more organic material is intermixed with the soil in the topsoil. The exposed roots in the cut out of the soil serves an indicator for the soil’s characteristic susceptibility to erosion.
ENVS10001 LANDSCAPE FUNCTION ANALYSIS 7
Figure 8 - Soil profile at Observation Point 2 (Own Image).
In Figure 9, the soil along Observation Point 4, although still classified as a sodosol, is differing in color from the other observation points in that it lacks the distinctive red color in the B horizon. Furthermore, the topsoil and C horizon are much closer together, suggesting that the soil present in this area is more recent in age whereas other observation points had soil profiles that had a far longer time to develop.
Figure 9 - Soil profile at Observation Point 4 (Own Image 2013).
8 ENVS10001 LANDSCAPE FUNCTION ANALYSIS
2.4.0 HYDROLOGY AD RO OD T WO EN DER SC UN RE
IV DR
E
K
T RAC 1000 STEPS
W A
LK
ILL CH UR
LYREBIRD
C
CH
FOREST R OAD
DORSET ROAD
FRANCIS
5
AV GR BEL LI N
ON G
AIL ER
0m
125m
250m
375m
RW OO D
HI
GH
MT DAN DE N
E BU
TOURIST ROAD
WA Y
N
500m
Figure 10 - Local Water Catchment Are of Ferntree Gully (Indicated as Hatched Area) (Apple 2013 and Geovic 2013).
According to the Bureau of Meteorology (2013), Ferntree Gully is subject to variable rainfall averaging approximately 1,284mm annually. The consistently high levels of annual rainfall have a significant impact on the vegetation and natural processes around the Lyrebird Walk and 100 Steps Track area. Given the nature of sodosols and their susceptibility to erosion (Department of Environment and Primary Industries, 2013), consistent rain can have a larger impact on the growth of vegetation in the park through alluvial processes that erode rhyodacite and other soils higher up on the slope down to the foot of the gully . The local water catchment of the gully consists of the slopes surrounding the gully which surround it on three sides as seen in Figure 10. There are also two other channels that feed into the gully that follows the 1000 Steps Track and are spaced approximately between 200 to 450 meters apart. The streams were then further categorized into a tributary channel pattern as all the streams flow into a single integrated channel network due to them being all connected and possessing convergent channel network directionality as the angles of the streams were within 10 to 90 degrees of each other.
ENVS10001 LANDSCAPE FUNCTION ANALYSIS 9
Figure 11 - Stream Channel Erosion at Observation Point 6 (Own Image).
Erosional stream channel development present at Observation Point 6 appeared to be fixed and not migrating given the visibly large impact the stream channel has made into the the slope (Figure 11). The erosional process appears to have been occurring for decades now and appears to have impacted enough to expose C and even the D horizon of the soil profile. The deeply impacting effects of the steam can also be attributed to the presence of sodosols which are in particular more susceptible to erosion.
Figure 12 - Stream Channel Erosion at Observation Point 7 (Own Image 2013).
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As the stream progresses down further to the base of the slope, it appears that ground water and run off from rainfall accumulate, producing a stream flow with an increasingly higher volume and an increase in speed of the flow. This heavily amplifies the effect of erosion on the impacted area to a point where much like in Observation Point 7, the stream has completely eroded away the C horizon of the soil profile and even impacted the D horizon to some extent (Figure 12).
Figure 13 - Artificial Dam at Observation Point 5 (Own Image 2013).
An interesting aspect of human intervention to note at Observation Point 5 is the presence of a small dam at the junction between Lyrebird Walk and the 100 Steps Track (Figure 13). The location of the dam near the head of the gully has sequential consequences for the rest of the stream. It is assumed that the stream is not only fed by tributaries that converge into it, but also from wherever this damn is collecting water from. However, the presence of this dam is creating an impedance on the flow of the gully, reducing the total volume of water reaching the base of the slope, and hence lessening the effect of erosion further down stream. A consequence of this reduction in erosion can potentially reduce the volume of sediment deposited.
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3.0.0 REFERENCES Apple Maps 1.0, 2013c, “Map of Ferntree Gully National Park”, viewed 21.10.13, available through: http://www.apple.com/au/ios/maps/ Apple Maps 1.0, 2013a, “Map of Metropolitan Melbourne”, viewed 21.10.13, available through: http://www.apple.com/au/ios/maps/ Apple Maps 1.0, 2013a, “Map of Upper Ferntree Gully Local Area”, viewed 21.10.13, available through: http://www.apple.com/au/ios/maps/ ASRIS, 2013, “Lyrebird Walk Ferntree Gully ASC Soil Types”, map, viewed 22.08.13 <http://www.asris.csiro.au/mapping/viewer.htm> Bureau of Meteorology, 2013, “Climate Data Online”, viewed 26.08.13, <http:// www.bom.gov.au/climate/data/index.shtml> Department of Environment and Primary Industries (DPI), 2013, “GeoVic Map”, viewed 03.09.13 <http://mapshare2.dse.vic.gov.au/MapShare2EXT/imf.jsp?session=40205> Department of Environment and Primary Industries (DPI), 2013, “Sodosols”, viewed 21.10.13 <http://vro.dpi.vic.gov.au/dpi/vro/gbbregn.nsf/pages/soil_soil_gbb_sodosols> Parks Victoria, 2013a, “Ferntree Gully - Out of the Ashes”, viewed 21.10.13, <http:// parkweb.vic.gov.au/__data/assets/pdf_file/0017/315512/Heritage-story-Ferntree-Gully-Out-of-theashes.pdf> VandenBerg, A.H.M., 1970, “Ringwood, Victoria, geological 1 Mile Series Map”, Sheet No.849 Zone 7, 1st Edition, Geological Survey of Victoria.
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