mona vale road west upgrade - review of environmental

34 Landscape Character, V isual Impact Assessment & Urban Design Study November 2016

VIEWPOINT 1

Description of the setting Properties along Kanangra Avenue looking from within their properties towards the proposal.

Element visible of the project At most minor glimpses of the roadway.

Category of viewer Residents

Nature of impact Adverse

Visual sensitivity High

Magnitude of impact Negligible

Overall rating of visual impact Negligible

Comment / mitigation measuresMost properties would not be impacted due to the screening effect of existing vegetation. No notable impact and no mitigation measures recommended.

Figure 5.2 View from Kanangra Avenue looking east towards Mona Vale Road.

Figure 5.3 Viewpoint location.

Approximate extent of widening Approximate extent of widening beyond green median

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MONA VALE RD - PROPOSED ROAD UPGRADE BETWEEN McCARRS CREEK RD AND POWDER WORKS RD

VIEWPOINT 2

Description of the setting Properties along Kanangra Avenue looking from within their properties towards the proposal.

Element visible of the project At most minor glimpses of the roadway.

Category of viewer Road user


Visual sensitivity Moderate due to the high visual quality of the setting

Magnitude of impactModerate, the wider road will diminish the visual presence of the bushland. More extensive seaviews would likely occur as a result of the wider road corridor.

Overall rating of visual impact Moderate

Comment / mitigation measuresLimit overall corridor width by avoiding a central median. Retain bushland setting as close to the road corridor as practical.

Figure 5.4 View from Mona Vale Road looking east, east of Terrey Hills.


Extent of cutting

Extent of cutting

Shared user path


Figure 5.6 View from Kanangra Avenue looking towards Mona Vale Road, within the Bloodwood Scribbly Gum Woodland


VIEWPOINT 3

Description of the setting Bushland setting wedged between the existing Mona Vale Road and Wirreandra Road

Element visible of the project Road would be partially visible in the mid-distance

Category of viewer Wirreandra Road users


Visual sensitivity Moderate, due to the strong visual presence of the bushland setting

Magnitude of impact Moderate


Comment / mitigation measures

The proposal would be more visible when seen in a perpendicular angle to Wirreandra Road. Hence, the impact is at most moderate. It is important to review batters from the new road alignment and consider the retention of mature trees in key areas to mitigate visual impacts. This would be further explored and refined during detail design.

Extent of batter

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VIEWPOINT 4

Description of the setting Residential property with a horse stud. Rural properties within a bushland setting.

Element visible of the project Glimpses to the new extension of Powder Works Road might be attainable.



Visual sensitivity High due to the residential land use.

Magnitude of impact Negligible, extensive vegetation would limit any views towards the proposal.


Comment / mitigation measures No mitigation measures identified.

Figure 5.8 View from the property at the corner of Harvey Road and Bungendore Street.

Figure 5.9 Viewpoint location. Note: photograph is not representative of viewpoint.


VIEWPOINT 5

Description of the setting Residence surrounded by bushland within mid-slopes.

Element visible of the project Limited views of the proposed extension of Powder Works Road along one side of the property.



Visual sensitivity High due to the residential land use and serene setting.

Magnitude of impactLow, existing planting within the garden perimeter would provide effective screening. A new fauna underpass which would be screened by vegetation, is proposed between Bungendore Street and Addison Road.



Limited exposure of the proposal through the introduction of a new local road. The magnitude of impact is considered limited with traffic being the most visually exposed element. Any opportunities to provide verge planting to increase the screening effect should be reviewed.

Figure 5.10 Large estate with manicured gardens situated along Addison Road.


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VIEWPOINT 6

Description of the settingStands of Monterey Pines provides somewhat a forest like setting. Adjacent residential properties have manicured gardens with a grassed understorey.

Element visible of the project New local road (extension of Harvey Road) would impact existing sheds in the mid-ground.

Category of viewer Residents / staff members of the Baha’i Temple complex


Visual sensitivity High due to the residential land use, heritage value, including pine trees and Baha’i Temple complex significance.

Magnitude of impactHigh, the proposal would require the removal of some vegetation including Monterey Pines. New local traffic would adversely impact on the visually serenity of the area.

Overall rating of visual impact High

Comment / mitigation measuresAdditional screen planting within the complex grounds would assist in mitigating the proposal. The introduction of retaining walls would limit the project footprint and limit impacts to existing vegetation within private properties.

Figure 5.12 View of the grounds within the Baha’i Temple complex adjacent to a large villa.


Road is in a cutting

Retaining walls flank the road


VIEWPOINT 7

Description of the setting Farm like setting with stands of trees and grassed understorey.

Element visible of the project Local road would be visible in the foreground and from various properties.

Category of viewer Road users and property owners which include commercial and residential land use.


Visual sensitivityModerate, due to the inter-mix of commercial and residential properties. For road users, a moderate rating is assessed due to the high visual quality of the setting.

Magnitude of impactHigh, the introduction of a multi-lane local road would contribute in create a urban rather than rural character. The deviation of Baha’i Temple Way further reinforces the visual dominance of the street network within the setting.

Overall rating of visual impact Moderate to high


The proposal would transform the area into a more urban environment. Appropriate landscape design measures would assist in visually settling the new roadworks. It should be noted, that this area has been targeted by the NSW Government for development. Hence, this area would undergo a major visual transformation.

Figure 5.14 View from the intersection of Powder Works Road and Mona Vale Road looking along the alignment.


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VIEWPOINT 8

Description of the setting Rural to semi-rural setting with paddocks for horses, grassed open areas and stands of trees.

Element visible of the project Minor glimpses to the new extension of Powder Works Road might be attainable.

Category of viewer Students, staff and visitors


Visual sensitivity Moderate due to the nature of the land use as an educational facility with outdoor grounds..

Magnitude of impactNegligible, the extensive buffer zone with effective vegetative screening would limit the visual exposure of the proposal.


Comment / mitigation measures No mitigation measures identified.

Figure 5.16 View from the school grounds looking towards the proposed extension of Powder Works Road.



VIEWPOINT 9

Description of the setting Park like setting with established gardens and a strong bushland backdrop.

Element visible of the project Mona Vale Road in the background.

Category of viewer Temple visitors and staff


Visual sensitivityHigh, due to the high visual quality of the setting, the cultural significance of the complex in combination with the use of the grounds.

Magnitude of impactNegligible, the widened road would barely be visible. Some bushland on the far side of the road would be impacted, yet the bushland backdrop would be retained.


Comment / mitigation measuresThe visual impact is considered negligible. Efforts should be undertaken, particularly during construction to minimise the loss of vegetation along the eastern verge.

Figure 5.18 View from the Baha’i Temple looking towards Mona Vale Road.


Approximate extent of road widening beyond

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VIEWPOINT 10

Description of the setting Large block with an established garden and prominent villa in bushland setting.

Element visible of the project Road widening would be fully visible.

Category of viewer Road user


Visual sensitivity Moderate, due to the scenic quality of the road corridor.

Magnitude of impactModerate, the wider road would create a more open character and slightly diminish the presence of the bushland. Some tree clearing and a new rock cutting would somewhat change the existing setting.


Comment / mitigation measuresClearing of existing vegetation should be minimised. Develop strategic landscape design measures that allow potential retention of significant trees where practical.

Figure 5.20 View along Mona Vale Road, west of Addison Road.


Extent of cutting

Traffic barrier

Shared user path

Approximate extent of road widening beyond


Table 5.1 Visual impact summary table

SUMMARY OF VISUAL IMPACTS

The adjacent table 5.1, summarises the visual impacts of the various assessed viewpoints that the project would likely have.

The impacts are predominantly either negligible or moderate. One viewpoint has been identified with a moderate to high visual impact, and another one with a high visual impact, as a result of the extension of Powder Works Road.

It should be noted however, that with the Government’s land development release area in Ingleside, a significant visual transformation of the setting is expected, that would limit the overall visual intervention of the proposal, in comparison with the likely future character of the area.

From those viewpoints identified with a moderate visual impact, two are within the road corridor. This is due to the high visual quality of the setting that the road crosses, resulting in a higher visual sensitivity.

v i e w p o i n t s e n s i t i v i t y m a g n i t u d e i m p a c t

1 High Negligible Negligible

2 Moderate Moderate Moderate

3 Moderate Moderate Moderate


5 High Low Moderate

6 High High High

7 Moderate High Moderate-high

8 Moderate Negligible Negligible


1 0 Moderate Moderate Moderate

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6 . 0 P R O P O S E D U R BA N D E S I G N S T R AT E GY

This chapter outlines the urban design vision for the corridor, a corridor strategy, and a set of urban design objectives and principles to guide design development of the project.Mona Vale Road is a vital east-west arterial road in the Northern Beaches region of Sydney. It serves as a freight, light vehicle and cycling route and caters in places for localised pedestrian movements. The road links Pittwater Road at Mona Vale to the Pacific Highway at Pymble. The Mona Vale Road East and West upgrades are the remaining sections of the road yet to be duplicated to provide two traffic lanes in each direction. Given the close proximity of the two sections, and the similarities in physical context, the urban design vision articulated here applies to both east and west upgrade projects.

6 . 1 U R BA N D ES I G N CO R R I D O R V I S I O N

The road journey offers a variety of experiences, designed in response to the adjacent built and landscape context. This responsiveness to context provides a degree of legibility along the road for local people as well as wider regional users. These landscape experiences include traversing the ridgeline between the Garigal and Ku-ring-gai Chase National Parks, distant views to the Pacific Ocean and Sydney’s northern beaches, the immediacy of the bushland adjacent to the road, large outcrops of Hawkesbury sandstone, both shallow and deep sandstone cuttings and views of the escarpment to the west. Travelling east, as the road leaves the national parks, a prominent landmark, the Baha’i Temple, comes into view before it opens up to reveal views of the residential areas of Ingleside.

6 . 2 U R BA N D ES I G N S T R AT E GY

The urban design strategy for the road corridor recognises the existing landscape character and seeks to integrate the widened road sensitively into its particular landscape setting. The design aims to reinforce and reveal the attributes of the Hawkesbury sandstone landscape while introducing new structures and elements where needed. Broadly speaking, the urban design approach is to maintain a level of consistency with existing duplicated stretches of Mona Vale Road and in particular to adopt a common suite of landscape elements for both the Mona Vale Road East and West Upgrades. Key ocean and coastal views, as well as district views, would be maintained. Disturbance to the natural and built environment is planned to be minimised through careful

consideration of the most appropriate alignment while the suite of proposed architectural elements would contribute to the route’s distinctiveness and legibility. See Figure 5.2.1 Urban Design Strategy

URBAN DESIGN OBJECTIVES AND PRINCIPLES

Objective 1: To fit sensitively with the landform and bushland setting that gives the corridor its identity.

Ensure that the urban, landscape and engineering design are well integrated and that the road sits comfortably along the ridgeline landscape.

The principles to achieve this are:

• Respond to existing landform and rock outcrops in the horizontal and vertical alignment of the road and road related structures

• Maintain a consistency with adjacent, already widened sections of Mona Vale Road

• Minimise as far as possible the use of retaining walls whilst also mitigating the extent of batters and loss of vegetation

• Carefully consider the form, colour and texture of retaining walls in relation to the predominantly bushland setting in which they are proposed

• Ensure a quality outcome in any cuttings where weak clay seams or rock floaters are encountered

• Avoid the use of shotcrete and consider the use of salvaged blocks in areas of weakness

• Carefully consider the design of termination of cuttings so that they appear as natural as possible (new and extended cuttings through areas of sandstone rock should be carried out using methods that guarantee successful salvage of sandstone block and facing material of suitable size, shape and good condition for use where required in cuttings and/or embankments.

Objective 2: To protect and incorporate natural patterns and ecology into the design.


• Consider the road alignment and footprint so as to minimise damage to the natural ecology including endangered vegetation and fauna habitat along the route

• Ensure protection of areas of endangered vegetation, specifically, the roadside occurrence of Microtis angusii (Angus’ Onion Orchid)

• Explore the potential for safe fauna connectivity across the corridor by means of culverts and fauna over-bridges in appropriate locations; ensure that design of fauna crossings minimises their visibility at road level and that approaches facilitate use by the identified species

• Design should aim to create optimal conditions for revegetation in all disturbed areas; in such areas use plants of local provenance from the appropriate ecological vegetation classes

• Ensure that fauna fencing is set back from the road edge and that it does not unnecessarily intrude on views; carefully consider terminations of fauna fencing in the design.

Objective 3: To incorporate the heritage and cultural attri-butes of the corridor.


• Consider carefully the alignment of the corridor in relation to the significant rock outcrop and the identified rock engravings along the ridgeline

• Minimise the road footprint and promote a considered design response to the Baha’i Temple precinct

• To otherwise respond sensitively to the heritage, cultural and natural sites and elements that occur adjacent to the road corridor

• To provide a considered design response for roadside retaining walls and other structures and associated landscaping/screening where the alignment is close to rural/residential properties.


SCREENING VEGETATION

NATIVE BUSHLAND EDGE

STREET TREE PLANTING

FUTURE RESIDENTIAL AREAS

CULTURAL LAND MARK

POSSIBLE HORSE TRAILS

RECREATIONAL CYCLE ROUTE (ON ROAD)

TRAILS

FAUNA OVERPASS

FAUNA UNDERPASS

MULTI-USE PATH ALIGNMENT

POTENTIAL MONA VALE ENTRY AVENUE PLANTING

DISTRICT VIEWS

OCEAN AND COASTAL VIEWSRETAINED AND ENHANCED

FUTURE NEIGHBOURHOOD CENTRE

INGLESIDE DRAFT CONCEPT PLAN:

EXISTING SCHOOLS

SIGNIFICANT SANDSTONE CUTTINGS

SIGNIFICANT RETAINING WALLS0 4000m

NARRABEEN CREEK

MULLET CREEK

FERN CREEK

DEEP CREEK

WIRREANDA CREEK

MCCARRS C

REEK

SMITH CREEK

BOORALIE ROAD

KIMBRIKI ROAD

DAOR I KI RBMI K

TUMB

URRA

STR

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ADDI

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ROAD

MONA

VAL

E RO

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POWDER WORKS RD

LANE COVE ROAD

CHILT

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MANOR ROAD

SOPHIE AVENUE

HARVEY ROAD EXTENSION

INGLESIDE ROAD

BOUN

DARY

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DAYD

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ST

POND

EROS

A PA

RADE

WAL

LABY

CIR

CUIT

FOLEY ST

MONA VALE ROAD

WARATAH ROAD

INGLESIDE ROAD

LAUREL ROAD WEST

SAMUEL STREET

EMMA STREET

MONA VALE ROAD

WIR

REAN

DA R

OAD

WarriewoodEscarpmentMcC

ARRS

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K ROAD MONA VALE ROAD

INGLESIDE

MONA VALE

WARRIEWOOD

JUBILEE AVE

MACPHERSON ROAD

KING

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VINEYARD STREET

JEANETTE AVENUE

WALLANA CRESENT

MAXWELL STR

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WARATHA STREET

BORONIA ROAD

WAL

TER

ROAD

WATTLE ROAD

Katandra BushlandSanctuary Reserve

Ingleside Park

Mona Vale

Baha’i Temple

Cemetery

GarigalNational Park

TERREY HILLS

INGLESIDE

KU-RING-GAI CHASE

REVEGETATION TO BUSHLAND ADJACENT TO RETAINING WALLS

REMOVAL OF ROAD PAVEMENTS AND SITE REVEGETATION SUBJECT TO NEGOTIATIONS WITH NATIONAL PARKS AND WILDLIFE SERVICE

FAUNA OVERPASS (LANDBRIDGE)

RE-SITED BUS STOPS KIMBRIKI ROAD

SHARED USE PATH ALONG WESTERN VERGE OF MONA

PROTECTED ROADSIDE AREA OF ANGUS ONION ORCHID

MONA VALE ALIGNMENT DEVIATES AROUND CULTURAL LANDMARK

TO WEST HEAD / CHURCH POINT

NEW BUS TURNAROUND

POTENTIAL SHARED USE PATH CONNECTION

RELOCATED BUS STOP TO POWDER WORKS ROAD

BRIDGE OVER TUMBURRA STREET3 SPAN BRIDGE INCORPORATING FAUNA PASSAGES OPEN STRUCTURE -SAFE - CLEAR SIGHTLINES POTENTIAL HORSE TRAIL

TEXTURED RETAINING WALLS SYMPATHETIC TO THE SETTING

SANDSTONE CUTTINGS TO MIMIC EXISTING

POTENTIAL SHARED USE PATH ACCESS

PITTWATER RSL

NEW LOCAL SHARED USE PATH CONNECTIONS

MONA VALE ENTRY AVENUE

EMERGENCY ARRESTOR BED

EXISTING 4 LANE SECTION OF MONA VALE ROAD

FUTURE NEIGHBOURHOOD CENTRE WITH COMMUNITY CENTRE

TO DUFFYS FOREST

SIGNIFICANT OCEAN VIEW

TERREY HILLS PRIMARY SCHOOL

TO PYMBLE & PACIFIC HIGHWAY

VIEW TO BAHA’i TEMPLE

VIEWS OVER NATIONAL PARK

SOPHIE GALSTAUN SCHOOL

VIEWS OVER NATIONAL PARK

TO WARRIEWOOD

TO ELANORA HEIGHTS & WARRIEWOODTO ELANORA HEIGHTS

& WARRIEWOOD

TO BAYVIEW TO BAYVIEW

BAHA’i TEMPLE RETAIN AND ENHANCE LANDSCAPE SETTING

POTENTIAL FAUNA CROSSING

HIGHLY TEXTURED RETAINING WALLS WITH ADDITIONAL SCREENING VEGETATION

Figure 6.1 Urban Design Strategy Plan

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Objective 4: To achieve improved accessibility and con-nectivity across and along the corridor


• Design for safe and convenient connections to and across the road alignment to adjacent streets and areas

• Consider walking, cycling and public transport modes as part of the project scope and design

• Ensure that bus stops proposed at Tumburra Road are well connected to the local path network, are conveniently located for users and allow for continuing traffic flow

• Optimise the multi-use path route to create a stimulating experience for users and design to minimise gradients and coordinate with local road connections; consider shade provision and visual interest as well as sight lines in planting design.

Objective 5: To achieve a legible experience in movement

Ensure a stimulating travel experience that highlights the features of the existing landscape.


• Maintain and enhance existing views to the Pacific Ocean and ensure new views are exploited to improve the road user experience

• To maintain localised views across the National Parks from the alignment and distant and localised views to landmarks such as the Baha’i Temple.

• Consider the distinctive precincts that make up the corridor in the design strategy, not least the National Parks on either side of the corridor

• Emphasise the strategic points along the route so as to heighten the travel experience.

Objective 6: To design a simple, unified and maintainable suite of road and roadside elements


• Use standard road elements such as safety barriers, pedestrian fencing and signage in a neat, uncluttered and well articulated manner

• Ensure that road furniture does not detract from, or impede, existing or new views along the corridor

• Avoid noise walls as far as possible but where they are required fully integrate walls into the project design and ensure consistency with other built form elements.

SURVEILLANCE AND SAFETY

The design development phase of the project should consider Safety in Design and Crime Prevention Through Environmental Design (CPTED) in accordance with the guidelines as set out in the following document:

‘Crime prevention and the assessment of development applications: Guidelines under section 79C of the Environmental Planning and Assessment Act (1979)’, NSW Department of Urban Affairs and Planning (2001).


7 . 0 U R BA N C O N C E P T D E S I G N

12 3

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7 . 1 CO N C E PT D ES I G N O V E R V I E W

The concept design applies the urban and landscape design objectives and principles articulated in Chapter 6.0 Proposed Urban Design Strategy. These objectives and principles will be considered through all phases of the proposal.

The Mona Vale Road West urban design concept is comprised of a series of plans that illustrate the entire corridor of the proposed upgrade and selected cross-sections at particular locations to demonstrate the application of these principles. The cross-sections across the alignment are generally shown in places where considerable change is likely or significant new elements would be added.

Figure 6.1 Concept Key Plan below shows the relative position of each concept plan in the wider context.

7 . 2 CO N C E PT D ES I G N P L A N S

The following plans and sections illustrate the proposed urban and landscape concept design for the Mona Vale Road West upgrade.

Figure 7.2 Concept key plan

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CONCEPT DESIGN OVERVIEW

The landscape design input concept has been based on the application of safety, security and aesthetic principles to create a sustainable, ecological, low maintenance design which fits within the broader landscape setting- of the National Parks and surrounding rural landscapes.

OVERVIEW OF VEGETATION TYPES

The native vegetation communities as further described in section 6.4, across the project site cover a diverse range of woodlands and forests, including the endangered Duffys Forest Ecological Community.

To the east of this section, there are more heath landscapes alongside the eucalypt woodland assemblage generally found in the north east of Sydney. It is widely distributed above the northern beaches where a massive ramp of Hawkesbury Sandstone, known as the Hornsby Plateau, rises northwards until the Hawkesbury River. These sandstones are characterised by a series of rugged sandstone slopes and rocky benches which support only a skeletal and impoverished, sometimes poorly drained, sandy soil.

Some tree canopies include stunted, sometimes mallee like, Red Bloodwood (Corymbia gummifera) and Scribbly Gums (Eucalyptus haemastoma/Eucalyptus racemosa), with the Mallee Yellow-top Ash (Eucalyptus luehmanniana) occurring on very rocky, thin soils associated with sandstone benching.

Certain areas have been cleared for development at different periods and a mix of native and exotic plant species are found in these zones. Although much of the site is relatively weed free, due largely to its ridge top position at the top of the catchment, exotic weed species are present along certain sections of the alignment and should be cleared and replaced with appropriate native plants.

RE- VEGETATION DESIGN STRATEGIES

Refer to the integrated Urban Design Plans that illustrate the main re vegetation strategies. Key strategies include:

• minimal interference into the natural bushland setting- as explained in section 1.1, for Natural re vegetation, narrow strips of mulch only where planting is not proposed, and no planting in areas of rock.

• expose the local geology of the area.• accept than any new areas of planting will require maintenance and access,

along with OHS issues. Thus measures to limit these areas must be applied in this setting, provided there are not soil erosion issues

• utilise indigenous plants from the local vegetation communities as the re-vegetation palette. These species are compatible with the soil landscapes, the arid site conditions and will perform better than other native plants.

• avoid use of hybrid species in areas adjacent national parks and natural areas.• retain views through to the “borrowed landscape” of the National Park and

reserves , especially where only narrow areas for re vegetation are created. This will ensure there is minimal interference with the landscape setting, despite widening of the road corridor.

• avoid “hedging” the corridor with dense shrubbery and artificial grasses. and introducing foreign tree species to the natural bushland setting.

• minimise construction work zones through bushland areas to maintain as much of the established environment as possible.

• utilise species that are self-seeding ( ie. not hybrids) and also use Acacias another species as nursery crops to ensure plant succession and growth.

• maximise use of mass planting beds, not seeding as hydro seeding or direct seeding with native shrubs and native grasses is not successful. Most re vegetation areas are shown as mass planting beds, supplemented with areas of interplanting amongst existing vegetation and compost blankets used on the high rock batters that are difficult to maintain. Mass planting areas, rather than seeding will ensure the permanent plants are more suited to the area. Issue with seeding is that the native shrubs that succeed are limited and normally higher and would create more monoculture effect in a diverse landscape. Also the seeding would require more maintenance, and OHS issues.

• introduce “natural regeneration procedures” for the linear areas of rock base in

front of new rock cuttings. The intent is not to bring in topsoil, but to provide sufficient cultivation and mulch layer to allow for natural germination from remnant soil seed banks or seeds that naturally disperse from nearby sites. These areas are generally level, and have minimal chance of soil erosion. According to the ‘National Restoration Standards - Australia’, “plant species may recover through re sprouting or germination from remnant soil seed banks or seeds that naturally disperse from nearby sites”.

• ensure any cover crop is sterile. And will not re-seed into the bushland areas. • maintain a high diversity of plant mix to reflect the local provenance and to be

able to respond to wide climatic changes.• use plant mixes that are hardy, that require minimal water, and be

predominantly self-sustaining in the long term.

CUTS AND FILLS;

To minimise visual impacts in the natural landscape setting the following strategies have been adopted

• vary the landscape treatment and allow for views through to adjacent bushland areas; this creates bands of low shrubs and native grasses in between high shrub and mixed planting areas.

• for large fills, vary the planting design to ensure for most areas there is a more open feel to the mixed canopy planting against the road pavement/multi use path, through using lower shrub understorey beneath the tree canopy. This will maximise spatial flows to the landscape beyond., and to the denser plantings on the bottom of batters, including denser and higher shrub plantings. This approach also provides good visual mitigation for adjacent viewers.

• for large rock cuts, provide planting in mass planting beds for a three metre width against the access bench, to ensure safe, OHS practice during construction. These areas will utilise organic fibre matting in lieu of mulch, to avoid maintenance problems and to ensure plant success. where necessary, jute mesh may be used to provide additional batter stabilisation.

• Utilise compost blanket for the longer sections of batter, beyond this three metre zone. These areas are difficult to maintain and pose OHS risk both during the construction and maintenance periods.


Key urban concept design elements include:

• re vegetation with low native shrubs and grasses to disturbed roadside areas• provision of mixed canopy plantings on southern verge, with areas of lower

plantings of low indigenous shrubs, native grasses to maintain views to coastline

• dense screening to the retaining wall

7.2.1 CONCEPT PLAN 1

Refer to figures 7.3 and 7.4 .

This section starts just east of McCarrs Creek Road at Chainage 0 to Chainage 640 to the east, with the Ku-ring-gai Chase National Park to the north of the corridor.

The beginning of the upgrade occurs adjacent to Kanangara Road in Terrey Hills, and the multi-use path begins on the northern side within the existing road footprint.

The widening occurs through bushland on the southern side of the alignment where initially a cutting is required to widen the road footprint. The land on the southern side then falls away, necessitating a fill retaining wall beginning at chainage 520 and then a further cutting occurs at chainage 630. A cutting and retaining batter are also required on the northern side at chainage 700. The road edge here is also bushland.

Figure 7.3 Section @ Ch 580

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Avoid impacts to endangeredspecies that lie close to the corridor

Avoid impacts to hollow bearingtrees that lie close to the corridor

3.0m wide shared use pathto tie into Kangara Road

CH 580

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Existing left in/left outproperty access to remain

Left in/left out providedto existing substation

Provide left in/left out to existing fire trail

JOINS CONCEPT PLAN 021

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LEGEND

Batter Native mixed canopy planting- Bloodwood, Scribbly Gum Woodland (BSGW)- Duffy Forest Ecological Community (DFEC)- Yellow Top Ash Mallee (YTAM)- Peppermint Angophora Forest (PAF)

Native shrub planting

Native low shrubs, native grasses & ground covers

Compost blanket to steepinaccessible areas

Spot planting Eucalypts -25L size

Vegetated swale

Feature concrete retaining wall

Shared use path, 3.0 m wide

Hydroseeding dryland grass

Earthworks

Planting & Grassing

Interplanting with nativeshrubs and grasses

Water Sensitive Urban Design

Retaining Walls

Pavements & Elements

Rock cutting

Native grasses & ground covers

Mass Planting Beds

Mix A

Mix B Native shrubs & grasses mixon fauna overpass Pedestrian path

WEST Sheet 11:2.000 @A3

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Figure 7.4 Concept Plan 1 / Scale 1:2000

0 100m



• Maintain and enhance easterly views to the coastline and Pacific Ocean, and northern views into the Ku-ring gai Chase National Park

• integration with a landbridge/fauna overpass at chainage 1140-1240• integration of fauna fencing• a retaining wall is introduced on the southern verge from 780 to 940, to meet

Kimbriki Road area• small rock cuttings occur between chainage 680 ( south verge) to 860 (north

verge)


Refer to figure 7.5.

This section begins at chainage 640 and runs east to just past the fauna overpass.

The escarpment falls away sharply to the south and a small residential pocket occurs on the eastern side of Kimbriki Road. Immediately after the Kimbriki Road intersection Dense, rocky bushland characterises the terrain on both sides of the alignment.

The fauna overpass structure is proposed before the road swings further north around the significant rock outcrop.

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mixed canopy of varying shrub densities and plantings of low shrubs and native grasses to maintain views to adjacent borrowed landscapes


Refer to figures 7.6 and 7.7.

From Chainage 1220 to Chainage 1820.


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mixed canopy of varying shrub densities and plantings of low shrubs and native grasses to maintain views to adjacent borrowed landscape to Garigal National Park


Refer to figures 7.8 and 7.9

From Chainage 1820 to Chainage 2520.


• integration of the alignment of fauna fencing to minimise its visual impact on Mona Vale Road and from residential areas

• extension of the multi-use path• introduction of a retaining wall from chainage 2470 to the east

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Refer to figures 7.10 and 7.11.

From Chainage 2560 to Chainage 3260On the northern verge, the retaining wall continues to contain the extended east bound carriageway. The road aligns with existing footprint on the southern verge, only until chainage 2520 , from where the rock cutting in to existing rock extends to around chainage 2720. From here the road widens on the southern verge, and requires a retaining wall to contain the higher levels., till reaching chainage 2940. A smaller retaining walls begins at chainage 3020 and ends at 3200.


The multi-use path winds through the bushland toward the Baha’i Temple on the northern side of the alignment from chainage 2800, to follow an existing track and create an improved user experience. To the north on the curve of the Baha’i Temple site, the road meets the existing four lane, dual carriageway section.


• various retaining walls and rock cuttings to contain the widened alignment.• diversion of the multi-use path through bushland adjacent the Baha’i temple

site, to follow an exisitng track and to create an improved use experiecne• revegetation with Peppermint Angophora Foest speceis till past Addison Road,

then Duffys Forest Ecological Community speceis in the vicinity of the Baha’i Temple site

• a fauna underpass in vicinity of chainage 2600

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7.2.6 CONCEPT PLAN 6/7

Refer to figure 7.13. Including Harvey Road extension, and link to PowderWorks Road.


• minor landscape treatment works, including native grassing and tree planting• introduction of retaining walls along Harvey Road extension• provision of a fauna underpass between Addison Road and Bungendore Street

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Figure 7.13 Concept Plans 6/7

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7 . 3 D ES I G N C R I T E R I A F O R S T R U CT U R ES A N D CO M P O N E N T S

DESIGN CRITERIA FOR RETAINING WALLS AT MONA VALE ROAD

Retaining walls are expected in the following 7 locations: • From approximately 285 metres east of Kanangara Road, on the southern

side of the west bound carriageway (approximately 110 metres long with a maximum height of 5.1 metres)

• From the Kimbriki Road intersection running westwards on the southern side of the west bound carriageway (approximately 150 metres long with a maximum height of 6 metres)

• From the Kimbriki Road intersection running eastwards on the southern side of the west bound carriageway (approximately 60 metres long and a maximum height of 2.8 metres)

• Approximately 260 metres west of Kimbriki Road intersection running eastwards on the northern side of the east bound carriageway (approximately 270 metres long and a maximum height of 11.6 metres)

• At the intersection of Tumburra Street – (approximately 80 metres long and a maximum height of 4.8 metres)

• On the northern side of the east bound carriageway approximately 190 metres east of Tumbarra Street (approximately 140 metres long and a maximum height of 8.0 metres)

• On the southern side of the west bound carriageway, 75 metres east of Addison Road, running eastwards (approximately 180 metres long and a maximum height of 7.9 metres)

• On the southern side of the west bound carriageway, 80 metres on from the preceding wall, running eastwards (approximately 160 metres long and a maximum height of 3.7 metres).

The retaining walls required are all in fill situations, most face bushland and are not visible from the highway. The conceptual approach for the concrete facing panels is to reference the sandstone cuttings that are a strong feature of this section of Mona Vale Road. The panels form a two metre by two metre staggered grid and the pattern helps to disguise the joints between panels to create a more homogeneous surface.

The design employs a three panel module system mounted in a predetermined compositional pattern to achieve a rich random texture. The third panel module is based on the first module, except it is turned by 90 degrees counterclockwise.The pattern of the panels is designed as an abstract illusion to reflect the marks in sandstone cuttings – the vertical marks created by the splitting or cutting of the rock face and the horizontal seams that occur naturally in the sandstone. This subtle surface pattern and texture is intended to mediate the perceived scale of the retaining walls and assist in helping these structures recede as background elements in the bushland context.

The following design criteria apply: • Reinforced soil wall with concrete facing panels to be designed with explicit

reference to sandstone cuttings - this is to be achieved with an abstract concept

• Precast concrete facing panels with a strong pattern and texture to discourage graffiti

• Use of warm dark oxide to visually recede these elements, blending the wall into its landscape context and preventing unnecessary glare from the northern sunlight

• Wall terminations that appear to disappear into the ground. Ensure the wall is designed to extend as far as is required to achieve this

• Fixings that are concealed and discreet• Provision of open, transparent fence to maintain openness and views for

shared use path users where retaining walls are located adjacent to the shared use path.

• Integration of the noise barrier with the retaining wall design to form one aesthetic composition where a noise wall is required and is less than 1200mm in height.

• Provision of planting in front of the noise wall to soften its appearance and to reduce the visual impact where possible

• Use of a consistent retaining wall design finish for both the east and west upgrades.

• Use of twin steel rail and post system traffic barriers to allow through views to the surrounding landscape and to reduce the height of the concrete portion of the structure in elevation.

Figure 7.14 Typical section - Barrier detail at retaining wall

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Figure 7.15 Concept for reinforced soil walls to reflect the sandstone geology and texture of the area.

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REFERENCE IMAGE: SANDSTONE CUTTING WITH VERTICAL SAW CUTS

REFERENCE IMAGE: SANDSTONE CUTTING WITH VERTICAL SAW CUTS


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Figure 7.16 Concept for reinforced soil walls to reflect the sandstone geology and texture of the area.

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DESIGN CRITERIA FOR CUTTINGS A number of large cuttings are required along the alignment and would form distinctive, visually prominent elements. The existing sandstone cuttings along the alignment help to define the character of the road. Due to the high quality of the sandstone the cuttings can be steep, thereby minimising the construction footprint required.

The following design criteria apply: • Tall near vertical cuttings are desirable where the rock strength allows • Avoid benching where possible to minimise the construction footprint • Avoid the use of shotcrete. If shotcrete is required a suitable minimisation

strategy should be developed by the design team• Cuttings should be designed to be as natural looking as possible• Feather the ends of the cuttings into the natural environment • Catch drains are to be hidden as far as possible • Solid sandstone blockwork or stone pitching should be considered for highly

visible areas where stabilisation is required.

NOTE: New and extended cuttings through areas of sandstone rock shall be carried out using methods that guarantee successful salvage of sandstone block and facing material of suitable size, even shape and good condition for use where required in cuttings and/or on embankments.

DESIGN CRITERIA FOR NOISE WALLS (IF REQUIRED) Noise barriers may be required on the Mona Vale Road (a detailed acoustic assessment is being proposed as part of the REF). The following design criteria would apply should noise walls be a necessary part of the Mona Vale Road upgrade design:

• Limit the number of noise barrier types to provide consistency and to simplify the look and identity of the road

• Noise barriers are to be streamlined in plan. All angles to be smoothed off to create soft sinuous curves

• Noise barriers are to run parallel to the road edge. If this is not possible a smooth exit and return curve is required

• Barrier heights to be rationalised to limit the number of height changes. A consistent top edge line is required

• Avoid stepping of the top edge wherever possible. Tilt panels so that they run parallel to the ground plane. Consider impacts of fixing details at the post.

• The appearance of both sides of the noise barrier should be considered depending on the specific location.

• Fixing systems and footings must be concealed• The use of a warm grey oxide should be applied to visually recede these

elements.• Provide an end treatment which is integral with the barrier design and

responsive to the context of the termination point• Maximise the opportunities for planting to screen walls and to help deter graffiti.

DESIGN CRITERIA FOR RETAINING WALLS AT HARVEY ROADRetaining walls would be required along Harvey Road extension, east of Addison Road. As this local road is set within a residential area, its treatment is proposed more in line with the surrounding land use.

The following design criteria apply: • Use of Besser type concrete blocks with a rough finish.

• Use a colour finish that complements the sandstone geology setting.

Figure 7.17 Example of a Besser block with a rough finish.

DESIGN CRITERIA FOR FAUNA UNDERPASSESTwo fauna underpasses are proposed, with one crossing Mona Vale Road, east of Tumburra Street and the other located across Harvey Road extension, between Addisson Road and Bungendore Street. These structures would provide for fauna permeability between the national park and fauna movement corridors north of Mona Vale Road. The underpasses would consist of a precast concrete culverts.

The following design criteria apply: • Locate fauna underpass where they are well hidden from local roads.• Make use of the topography to minimise any earthworks and limit the impact of

the works.


DESIGN CRITERIA FOR BRIDGES

Mona Vale Road BridgesThe Upgrade includes one bridge in the western section, a fauna overpass over the new Mona Vale Road alignment, 150 metres east of Kimbriki Road.

Figure 7.18 Fauna Overpass over Mona Vale Road - Cross section

Built Form

The following design criteria apply: • Avoid a central pier to maximise the visual permeability through the bridge.• Retain consistency with other built form elements through the use of precast

concrete panels for abutment walls. These panels should provide the same naturalistic pattern as used for the retaining walls along the whole project

• Use a warm grey oxide for concrete surface finishes to visually recede this elements

• Fauna fencing on the bridge shall be set back from the parapet edge a minimum of 1.5m. This would reduce the prominence of this element.

• Maintenance access is to be provided on either side of the bridge inboard of the parapets, accessed through a gate in the fauna fence. The maintenance access would be positioned lower to limit the overall height of the parapet.

Landscape Design

The indicative section below indicates a recommended construction technique that is sustainable, light weight, and relatively low maintenance. Rather than using normal soil or heavy growing media, we recommend a lighter weight, mostly recycled materials medium that has a much lower saturation rates.

Typical saturation weights , including the weight of the vegetation would be:• middle weight- 400mm depth- 200kg/m2- 250kg/m2;• heavy weight- 800mm- 1000mm depth - 500kg/m2

This would mean that the structural elements could possibly be reduced and a more elegant structure designed.

Planting for the surface would reflect the heath form vegetation of the Hornsby sandstone Heath Woodland, with maximum small trees/large shrubs of 4m-5m height and planted at least 10 metres from the parapet line.

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Figure 7.19 Fauna Overpass over Mona Vale Road - Montage


DESIGN CRITERIA FOR BUS STOPS There are four existing bus stops within the proposal corridor that require relocation, two on the westbound (south) side of the highway and two on the eastbound (north) side. The current stops do not have bus shelters and are not connected to any made paths. They sit in the gravel area of the road shoulders near the Kimbriki Road and Tumburra Street intersections.

At Kimbriki Road, the stops would be restored to similar positions adjacent to the carriageways following the widening, but upgraded to comply with the standards cited below.

These bus stops are to be incorporated into the alignment of the proposed shared use path and/or footpath network and would be serviced directly from the proposed bus bays. All bus stops are to have mobility-impaired access in accordance with the ‘Disability Discrimination Act’ (1992) and ‘Disability Standards for Public Transport’ (2002).

The following design criteria apply:

• Bus stops shall be designed in accordance with the ‘STA Bus Infrastructure Guide’ (2011) document

• Bus stops shall be arranged to ensure a minimum 2.5 metres clear width where possible for adjacent shared use paths to allow continuity and ensure clearance for cyclists and pedestrians to pass safely

The stops at Tumburra Street would be removed due to safety and accessibility issues. In this case, the intent is for the public to use the existing bus stops to the southeast of the intersection of Powder Works Road.

DESIGN CRITERIA FOR SHARED USE PATHS A multi-use path is proposed along Mona Vale Road from Kanangara Road on the eastbound (north) side of the alignment, adjacent to the road shoulder and continues along the northern edge till the Baha’i Temple where it veers off the main alignment and runs through the roadside bushland, roughly parallel with the road before terminating at Baha’i Temple Way.

The following design criteria apply: • A 3m wide shared use path would be provided for the length of the proposal

with the exception of the area near the Bahai Temple where it is proposed to retain and upgrade the existing 2.5m path to avoid impact on locations of Grevillea caleyia. The shared use path would then tie into the existing 1.2m path at the extent of works

• Where shared use paths and footpaths are located adjacent to retaining walls or steep embankments, a safety railing shall be provided

• Where a shared use path is less than 1.0 metre from the back of kerb incorporate the area between the shared use path and kerb into the shared use path rather than having a narrow planting strip

• Maximise shade planting to paths and extent of landscape buffers where possible.

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SCREENING RETAINING WALLSAreas beside retaining walls are planted with hardy, indigenous shrubs, trees, and native grasses to provide visual mitigation. These areas are quite narrow in many areas, in order to minimise impacts to adjacent bushland. Where space permits, it is intended that larger trees in particular would provide shadow play on vertical surfaces, foiling the visual bulk of walls.

SIZE OF PLANT STOCKTo ensure plants survive, and to ease the need for providing unnecessary watering , small size plants ( tubestock) will be used , and there will be minimal use of semi-advanced or advanced stock.

This approach is more sustainable and will provide longevity and plant succession, as well as providing more sustainable cultivation and topsoiling practices.

The largest tree stock proposed is 25 litre, given the site conditions.

7 . 4 R E - V E G E TAT I O N S T R AT E GY

The vegetation excerpt map ( refer figure 2.12) illustrates the vegetation patterning present in year 2000, and with the following key vegetation associations along the corridor are:

• Bloodwood-Scribbly Gum Woodland• Duffys Forest Ecological Community• Duffys Forest Translocation site• Yellow-top Ash Mallee• Peppermint –Angophora Forest

The majority of the corridor passes through dense bushland of the Garigal National Park and Ku-ring-gai Chase National Park. The varied plant associations reflect the soil landscapes previously described. The varied plant associations provide opportunity to reflect different tree and shrub species along the journey, thereby adding variety, interest and context to the corridor.

The Map excerpt identifies areas of Yellow-top ash Mallee, which seem to correlate with the Coastal Sandstone heath location of the other mapping.

Key vegetation species which will be used in re-vegetation strategies include:

DUFFYS FOREST ECOLOGICAL COMMUNITY

Open-forest of mixed and varying tree species composition.

Tree species(common) :• Angophora costata (Sydney Red Gum)

• Corymbia gummifera(Red Bloodwood

• Eucalyptus pilularis (Blackbutt)

• E. piperita (Sydney Peppermint)

• E.sparsifolia (Narrow-leaved Stringybark)

• Syncarpia glomulifera (Turpentine).

Less frequent, but prominent at some sites:• Eucalyptus agglomerata (Blue-leaved Stringybark)

• E. globoidea (White Stringybark)

• E. haemastoma (Broad-leaved Scribbly Gum)

• E. punctata (Grey Gum)

• E. resinifera (Red Mahogany)

Shrub species:• Banksia spinulosa,

• Bossiaea obcordata

• Ceratopetalum gummiferum

• Hakea sericea,

• Lasiopetalum ferrugineum

• Leptospermum trinervium

• Persoonia levis,

• Platylobium formosum

• Pultenaea tuberculata.

Native grass and Ground cover species:• Austrostipa pubescens

• Cyathochaeta diandra

• Entolasia stricta,

• Epacris pulchella,

• Imperata cylindrica,

• Micrantheum ericoides,

• Patersonia glabrata

• Pteridium esculentum

• Themeda australis

• Xanthorrhoea media

• Xanthosia tridentata.


PEPPERMINT-ANGOPHORA FOREST Open-forest.

Key tree species:• Eucalyptus piperita (Sydney Peppermint) • Angophora costata (Sydney Red Gum)

Other tree species may include: • Corymbia gummifera (Red Bloodwood)• Syncarpia glomulifera (Turpentine)• and, less frequently,-Eucalyptus punctata (Grey Gum) and E. resinifera (Red

Mahogany).

Low tree and shrub species:• Acacia suaveolens

• Allocasuarina littoralis,

• Banksia serrata

• Ceratopetalum gummiferum

• Dillwynia retorta

• Dodonaea triquetra

• Grevillea linearifolia


• Persoonia levis

• Platysace linearifolia

• Pultenaea flexilis.

Native grass and ground cover species:• Actinotus minor,

• Caustis flexuosa

• Dianella caerulea

• Entolasia stricta

• Lomandra longifolia

• Pteridium esculentum

• Stylidium productum

• Xanthosia pilosa and

• X.tridentata.

BLOODWOOD-SCRIBBLY GUM WOODLAND Woodland or open-forest, sometimes low woodland or low open-forest

Tree species:• Corymbia gummifera (Red Bloodwood)• Eucalyptus haemastoma (Broadleaved Scribbly Gum) are the dominant species

or co-dominant with one or more of:• Allocasuarina littoralis (Black She-oak)• Angophora costata

• Corymbia eximia (Yellow Bloodwood)• Eucalyptus oblonga (Sandstone Stringybark)• E. piperita (Sydney Peppermint)• E. sparsifolia (Narrow-leaved Stringybark).

Shrub species :• Acacia suaveolens

• Banksia serrata

• B. spinulosa

• Dillwynia retorta

• Grevillea buxifolia

• Lambertia formosa


• Petrophile pulchella

• Platysace linearifolia

• Pultenaea tuberculate

Native Grasses and Groundcovers:• Actinotus minor

• Caustis flexuosa

• Dampiera stricta,

• Entolasia stricta

• Lomandra glauca.

YELLOW-TOP ASH MALLEE (COASTAL SANDSTONE HEATH) Diverse, closed heath and low Eucalypt woodland assemblage.

Tree species:• Allocasuarina distyla (Scrub she-oak) • Corymbia gummifera (Red Bloodwood)- stunted form• Eucalyptus luehmanniana (Yellow-top ash)• Eucalyptus haemastoma/Eucalyptus racemosa (Scribbly gums)

Dominant Shrub species :• Acacia suaveolens

• Banksia ericifolia subsp. ericifolia (Heath-leaved Banksia)

The sclerophyllous shrub layer is very diverse with a range of other banksia species, tea-tree, wattles, hakeas, grevilleas and peas. There is variable cover of sedges and other monocots in the ground cover.

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The proposal is situated along a unique setting, dominated by bushland, a rugged topography and vistas towards the sea. These unique characteristics define the identity of the area and contribute to its visual sensitivity.

The rugged topography and dense bushland greatly contribute in limiting the visual exposure of the proposal to the surrounding areas. Although the extension of Harvey Road results in some landscape character and visual impacts, this component of the project is critical to improving safety and enhancing the overall future functioning of the area, whilst limiting impacts elsewhere in sensitive areas.

The landscape character and the visual impact assessment strongly correlate with each other, with the landscape character zone E, Semi-Rural Ingleside, to the east, likely experiencing the highest impact.

At the western end of the project, the visual and landscape character impacts are considered to be limited. The proposal would provide open views for motorists towards the bushland and beyond, thereby reinforcing the sense of place and uniqueness of the site, and providing a quality journey experience.

The majority of Mona Vale Road has been upgraded to either four lanes (two lanes in each direction) or six lanes (three lanes in each direction) and this section would complete the overall corridor upgrade. Hence it is a critical link that services the communities of Terrey Hills, Ingleside and Mona Vale and the adjoining suburbs of Eleanora Heights and Warriewood, resulting in a safer road with reduced traffic congestion. The project would also provide a safer route for recreational and commuter cyclists , improving the urban permeability and functioning of the wider area.

The concept design focuses on limiting visual and landscape character impacts in general, particularly along national parks and sensitive receivers such as residences and heritage properties. Key mitigation measures integrated into the project include:

• Re-configuration of local accesses to minimise project footprint and visual impacts in sensitive environs

• Situating the alignment so as to minimise impacts to aboriginal heritage items• Re-establishment of endemic plantings which reinforce the specific natural

Figure 8.1 Existing view of Mona Vale Road. The proposal aims to minimise impacts to the overall setting, whilst sensitively siting its alignment.

8 . 0 C O N C LU S I O N


vegetation communities of the area• Use of highly textured precast concrete panels, referencing the exposed

sandstone cuttings• Consideration of the future desired character of the area based on other

Government’s strategic planning initiatives• Minimisation of the project footprint, through the introduction of natural stone

retaining structures to minimise batter extents• Introduction of coloured oxide for specific built form components to visually

recede these elements.

The study proposes a site responsive design approach that looks at the range of conditions along the route and proposes the most appropriate treatments given the variable context. The resultant concept design is largely landscape driven and most of the mitigation measures adopted concentrate on the nature and extent of planting in any given location. The proposed retaining walls are explicitly inspired by the sandstone cuttings that are already a defining characteristic of the Mona Vale Road route. Similarly, any new or widened cuttings are planned to be relatively steep to heighten the immersive experience of the sandstone landscape.

mona vale road west upgrade - review of environmental

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