watercourses contours (10m interval) watercourses section ... · populus x canadensis ‘serotina...

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Watercourses

Contours (10m interval)

Section 1

Major road

Braidwood township

Section 2

Mona C

reek

Gillamatong Creek

Mackeller Creek

Flood Creek

Kings Highway study sections

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Watercourses

Contours (10m interval)

Section 1

Major road

Braidwood township

Section 2

Mona C

reek

Gillamatong Creek

Mackeller Creek

Flood Creek

Kings Highway study sections

The Study Area

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Landscape Character Zones (LCZs)

Prominent Hills / Ridgelines

Major Hill Landmark

Watercourses

Broad valley defined by hills/ridgelines to east + west.

Broad valley of major creek flowing west defined by hills/ridgelines to south + north.

1

2

Landscape Character Zones

Narrow valley assoiciated with creek along northern edge of township.

Braidwood township.

Broad valley with network of creeks draining to west.

3

4

5

Mid + upper slopes along southern edge of broad valley.

Mount Gillamatong; major tree-covered hill forming regional landmark south-west of township.

6

7

Kings Highway study location

1.

2.

4.3.

5.

6.

7.

Landscape Character Zones

Zone of Visual Influence (ZVI) + Visual Envelope

•Zone of Visual Influence (ZVI) analysis is the process of determining the visibility of objects in the surrounding landscape using computer software and digital elevation datasets.

•ZVI illustrates potential visibility, and does not take into account trees, buildings, etc - the analysis is made on the basis of topography along.

•ZVI results indicate where an object definitely cannot be seen from, whereas actual visibility can only be determined via site survey.

•ZVI results are then used to determine the Visual Envelope. LEGEND

Visual Envelope

Watercourses


Major road

Community buildings / facilities

Residences

Miscellaneous viewpoints

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Visual Envelope

Watercourses


Major road


Residences


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Visual Envelope

Watercourses


Major road


Residences


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Trees situated on Section 1 of the Kings Highway

Major road

10km Zone of Visial Influence

Whole of tree visible

Top half of tree visible

Top of tree only visible

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Major road





Corkery Consulting • Landscape Architecture • Urban Design Kings Highway - Landscape Character + Visual Impact Assessment

19

4.3 VISUAL ENVELOPE MAP

The extent to which the roadside trees along the Kings Highway are visible from adjoining areas varies significantly along the Highway’s northern and eastern approaches to Braidwood. Views to the road are influenced by a combination of landform, vegetation, houses and other structures.

The ZVI analysis discussed in the previous section establishes the extent to which the roadside trees can be seen from adjoining areas, based on an analysis of topography alone.

The process of using the ZVI analysis to determine the Visual Envelope is illustrated below in Figure 3.3, while the extent of the Visual Envelope is illustrated in Figure 3.4.

FIGURE 4.4 - VISUAL ENVELOPE MAP + KEY VIEWPOINTSFIGURE 4.3 - PROCESS OF DETERMINING VISUAL ENVELOPE

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Major road





+

merge

X - discount areas of visibility beyond a reasonable distance from roadside trees

visual envelope at reasonable distance from roadside trees

ZVI section 1 of Kings Highway ZVI section 2 of Kings Highway

X

XX

X

X

X

combined ZVI

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Visual Envelope

Watercourses


Major road


Residences


0 1 2km

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Visual Envelope

Watercourses


Major road


Residences


0 1 2km

Visual Envelope Map

Aerial imagery sourced from Land and Property Management Authority, dated 2008.

WINTER

Lombardy Poplar

Golden Poplar

Pin Oak

--

--

--

SUMMER

Populus nigra var. italica

Populus x canadensis ‘Serotina Aurea’

Quercus palustris

Kings Highway Roadside Trees

VIEWS FRAMED BY LARGE VISTAS BETWEEN TREES

STRONG VERTICAL FORM OF POPLARS DEFINES EDGE OF VIEW ALONG HIGHWAY

VIEWS THROUGH LARGE SPACES BETWEEN TREES

LARGE VISTA BETWEEN TREES

HEIGHT TO ROAD CORRIDOR WIDTH RATIO APPROX 2:1

TYPE 1: Lombardy poplar (Populus nigra var. italica)

Characteristics

- Tall vertical form is a distinguishing feature that contrasts with the broad horizontality of the landscape

- Highly legible throughout the seasons; the dark grey upright skeletal branching is distinctive in winter and green foliage highly visible in summer

- The very high ratio of height to width is relatively rare and the main reason they are used to create roadside avenues

- Views out across the broader landscape from the Highway are framed by the vertical trees

- Compared to the Golden Poplar it has late autumn colour and leaf fall

- Tolerant of strong winds and drier poor soils

- Tendency to produce suckers

Lombardy Poplar (Populus nigra var. italica)

VIEWS BLOCKED BY LARGE TREE CANOPIES

FILTERED VIEWS THROUGH TREESHEIGHT TO ROAD CORRIDOR WIDTH RATIO APPROX 1:1

SMALL VISTA BETWEEN TREES

TYPE 2: Golden poplar (Populus x canadensis ‘Serotina Aurea’)

Characteristics

- Good proportion and consistent form is desirable characteristic for an avenue tree

- Broader canopy and lower height to width ratio than Lombardy Poplar

- Views between trees reduced as canopy grows wider, reducing space between trees

- Striking and distinct golden yellow autumn foliage

- Foliage colours appear early in autumn contrasting with the still evergreen Lombardy poplar

- Tolerant of strong winds and drier poor soils

Golden Poplar (Populus x canadensis ‘Serotina Aurea’)

VIEWS FILTERED/ BLOCKED BY LARGE TREE CANOPIES

MINIMAL FILTERED VIEWS THROUGH TREES

HEIGHT TO ROAD CORRIDOR WIDTH RATIO LESS THAN 1:1

MINIMAL / NO VISTA BETWEEN TREES

TYPE 3: Pin Oak (Quercus palustris)

Characteristics

- Distinctive drooping and ascending branching habit which becomes more rounded and broader in maturity

- Broad canopy; lower height to width ratio than Lombardy Poplars

- Views between trees reduced as canopy grows wider and space between trees is reduced

- Bronze red autumn colour

- Persistent leaf retention after autumn

- Roadside trees frequently require pruning of lower limbs as they tend to hang low

- Prefers moist fertile soil with unreliable performance in poor soils

Pin Oak (Quercus palustris)

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No avenue structure

Established avenue

Inconsistent avenue structure

FIGURE 4.8 - CURRENT VIEWS FROM THE KINGS HIGHWAY

Current Situations along the Kings Highway

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1

2

3

4

A

B

C

E

D

No avenue structure

Established avenue


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1

2

3

4

A

B

C

E

D

No avenue structure

Established avenue


no avenue structure.

Images sourced from Google Earth; dated January 2010.

inconsistent avenue structure.

established avenue - Golden Poplars.

B

A

C

D

Kings Highway - Section 1 [northern approach]

No avenue structure

Established avenue


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5

6

7

G

F

E


No avenue structure

Established avenue


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5

6

7

G

F

E

E

F

G

no avenue structure.

established avenue - Pin Oaks.


Kings Highway - Section 1 [northern approach]

No avenue structure

Established avenue


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8

9

10

H

I

J



H

I

Kings Highway - Section 2 [southern approach]

No avenue structure

Established avenue


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11

12

13

J

K

L

M

no avenue structure. inconsistent avenue structure.

J

K

L



No avenue structure

Established avenue


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14

15

M

N

O

established avenue - Lombardy Poplar


M

N

O



No avenue structure

Established avenue


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15

16

Q

P

inconsistent avenue structure.established avenue - Lombardy Poplar

P

Q



watercourses contours (10m interval) watercourses section ... · populus x canadensis ‘serotina...

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