act ewa gl route env report

7/24/2019 Act Ewa Gl Route Env Report

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ENVIRONMENTAL

ASSESSMENT

PROPOSED 132Kv SUBTRANSMISSION LINEFROM WILLIAMSDALE TO THEODORE

SOUTHERN ELECTRICITY SUPPLY TO THE ACT

30 JUNE 2008


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30 June 2008 Proposed 132kV Subtransmission Line - Williamsdale to Theodore, ACT i

Project Team

Proponent

The General Manager NetworksActewAGLActewAGL House

221 London CircuitCanberra City ACT 2600

Consultant Team

Purdon AssociatesPlanning Assessment, Reporting3/9 McKay StreetTurner ACT 2612Ph: 02 6257 1511Fax: 02 6248 8347

Geoff Butler & AssociatesEcological Assessment38 Birchmans Grove,Wamboin, NSW 2620

Ph/Fax: 02 6236 9158

Vertego Environmental ConsultantsGPO Box 3268Canberra ACT 2601Ph: 02 62491560Fax: 02 62473227

Navin OfficerCultural Heritage Assessment4/71 Leichhardt Street

Kingston ACT 2604Ph: 02 6282 9415Fax: 02 6282 9416

Australian Bushfire Protection PlannersBushfire AssessmentRMB 3411 Dog Trap RoadSOMERSBY 2250 NSWPh: 02 43622112Fax: 02 43622204

LandData SurveyRoute Survey

3/151 Newcastle StreetFyshwick ACT 2609Ph: 02 6239 3088Fax: 02 6239 3089

Coffey GeotechnicsGeotechical Assessment16 Midura StFyshwick ACT 2609Ph: 02 6260 7288Fax: 02 6260 7211


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ENVIRONMENTAL ASSESSMENT EXECUTIVE SUMMARY


EXECUTIVE SUMMARY

General

In 2005 the ACT Government determined that a southern point of electricity supplyto the ACT be constructed. A subsequent study by ActewAGL and TransGrid in2006 identified a number of technical upgrades to the ACTs power supply thatwould be required in order to maintain sufficient supply.

An element in this series of infrastructure upgrades and new facilities is theconstruction by ActewAGL of a new 132kV dual circuit subtransmission line betweena proposed TransGrid substation south of Williamsdale and the existing networksouth of Theodore, a distance of approximately 15kms. This proposed developmentwill be an ActewAGL asset and is subject to this environmental assessment.

Separate but related assessments have been prepared by TransGrid for theproposed substation at Williamsdale and for the transmission line upgrade fromWilliamsdale to the Canberra substation at West Belconnen.

The main objectives of the Williamsdale to Theodore 132kV subtransmission lineproject are to:

provide a reliable and secure electricity supply to ACT customers includingCommonwealth Government agencies

provide sufficient capacity to meet current and predicted future demand

deliver an expanded network that balances efficient and effective security of

supply with community needs ensure the prudent expenditure of public funds

achieve a value-for-money investment

adopt a route for the new power line that minimises environmental impact anddisruption to existing rural lessees.

The proposed development comprises provision of a dual circuit 132kVsubtransmission line with the following design features:

single 29m length (24-25m above ground) concrete or steel poles set atapproximately 150m apart, and including twin pole structures at points along theroute where the line direction changes

each pole supporting six double circuit conductors (12 wires) and two earthwires

establishment of a 45m wide easement or corridor to accommodate thesubtransmission lines

installation of conductors with an aged finish to have a dull sheen

use of two temporary site compounds along the route during construction

construction / maintenance access.

The proposed subtransmission line route subject to evaluation in this report followsan initial route selection study undertaken by Purdon Associates for ActewAGL in2006.


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30 June 2008 Proposed 132kV Subtransmission Line - Williamsdale to Theodore, ACT ii

Tension Poles Suspension PoleNote: The above examples show 6 single conductors; the proposed development proposes double circuit

conductors

The route selection study identified and evaluated the most appropriate routeoption between the proposed Williamsdale substation and the existing ActewAGLnetwork. Three broad corridors were considered:

A straight line route from the Williamsdale Substation to Theodore traversedlarge areas of Native Reserve in the Act, as well as passing close to a number ofexisting rural dwellings. This route was not considered appropriate.

A route following the Monaro Highway road corridor was discounted for severalreasons including: visual impact as seen by travellers along this gateway into thenational capital; direct impact on a number of rural lessees; and impact on aheritage shearing shed

A route in NSW running parallel to the Monaro Highway was discounted becauseof the need to provide the ActewAGL asset inside the ACT.

The preferred corridor which is subject to the current proposal is a compromiseroute that avoids incursion into adjacent nature reserves, is visually unobtrusive asseen from the Monaro Highway, as well as maintaining network efficiency andminimising impact on rural leaseholders.

Schematic Diagram of ACT Network


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30 June 2008 Proposed 132kV Subtransmission Line - Williamsdale to Theodore, ACT iii

Route Description

The proposed route for the 132kV subtransmission line between the proposedWilliamsdale substation to the Theodore network is discussed in this report in termsof the following sectors:

Southern Sector - follows the existing TransGrid electricity towers from theproposed substation to the northern side of Angle Crossing Road, connecting tothe central sector

Central Sector- generally extends northward adjacent to the Rob Roy NatureReserve and west of Guises Creek

Northern Sector- commences near the rural dwelling on Block 1651 andextends north-west to connect with the existing ActewAGL network near theTheodore substation

Context of proposed subtransmission line Williamsdale to Theodore


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30 June 2008 Proposed 132kV Subtransmission Line - Williamsdale to Theodore, ACT iv

Aerial Photograph of the proposed route


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30 June 2008 Proposed 132kV Subtransmission Line - Williamsdale to Theodore, ACT v

Consultation

The route selection process and environmental assessment report preparation hasinvolved consultations with all affected rural lessees and relevant governmentagencies.

Feedback gained from the consultation has been considered by ActewAGL and theProject Team in the preparation of this report, and has resulted the furtherassessment of several route options.

Existing Conditions

The proposed subtransmission lines run in a north-south direction within mostlycleared agricultural land, in undulating topography, between the foothills of RobRoy Nature Reserve to the west and the Monaro Highway to the east.

A large part of the route is located within the Guises Creek catchment. All of theroute is located within the Murrumbidgee Catchment. The line route crossesseveral drainage lines and creeks including Guises Creek.

The region surrounding the study area comprises an undulating landscapeincorporating the slopes of the Rob Roy Range, the Murrumbidgee River valley andGuises Creek valley.

The land uses within the general locality include grazing, other agricultural uses andrural residential dwellings.

The route traverses seven (7) existing rural leases which have substantiallymodified vegetation and are used primarily for cattle and sheep grazing.

The northern and southern sectors of the route traverse identified areas of YellowBox Red gum woodland/grassland community. The central sector passes throughsubstantially modified native vegetation in the Guises Creek area.

A search of the ACT Aboriginal Sites Database and Heritage Register indicated that33 previously recorded Aboriginal sites may be affected by the construction of theWilliamsdale to Theodore Power line. These sites comprise 25 artefact scatters

(including a possible stone arrangement and a potential archaeological deposit) and8 isolated finds. There are no previously recorded European historic sites within theproposed route corridor.


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Impacts on the Environment

This environmental assessment has considered impacts of the proposed route onthe physical, human and natural environment.

The assessment of environmental impacts has shown that the proposeddevelopment will have some level of impact on the physical environment in allsectors, but will not create problems of a magnitude that could not be eitherovercome or mitigated in various ways.

The route would have some impact on native vegetation and habitat, particularly inforest areas, necessitating the removal of some trees of ecological and/or landscapevalue. The main influence of endangered fauna species on the route selectionrelates mostly to the likely loss of woodland habitat for the identified endangeredbirds that utilise woodland habitats. However, it is possible to undertake thedevelopment within the identified corridor in a manner that the transmission lines,poles and access tracks do not significantly impact on known important faunahabitat or the individual recordings of threatened species.

The proposed subtransmission route would be visible from a number of publicvantage points, the distance between the lines and the road, as well as siting of thepower lines, intervening topography and vegetation. The densely vegetatedbackground of the Rob Roy Range has high visual absorption capacity which willenable the poles to readily blend into the background.

The power lines will be seen from a number of rural properties along the route,although the minimum distance between dwellings and the subtransmission line isapproximately 500m.

Although a number of heritage resources have been identified within the generalarea of the route, none are of such significance or geographic extent to prohibit theproposed subtransmission line. Minor route deviations and/or mitigation would bepossible to address these issues at the detailed design and construction stage.

The electric and magnetic fields generated by the subtransmission lines are likely tohave negligible effect on the existing electric and magnetic field readings in andaround houses along the route due to the distance between the lines and thedwellings.


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30 June 2008 Proposed 132kV Subtransmission Line - Williamsdale to Theodore, ACT vii

Conclusions

The environmental assessment report has detailed a proposed development byActewAGL for the provision of a dual circuit 132kV subtransmission line betweenWilliamsdale and Theodore, and has identified potential impacts on the physical,human and natural environment.

The report represents information and assessment required as an input to overalldecision-making by ActewAGL and the Territory on the proposed subtransmissionlines.

During preparation of the environmental assessment, a number of route optionswithin the preferred corridor were examined by ActewAGL in response to issuesraised during stakeholder consultations. This input has been able to inform andmaterially influence the route refinement process, and the subsequent assessmentof the environmental impact of the route. The preferred route and technicalsolutions adopted by ActewAGL to minimise overall impact of the proposeddevelopment have been assessed in this report.

The report concludes that the proposed subtransmission lines would have a numberof potential benefits as follows:

increased reliability and security of electricity supply to existing and futurecustomers

cost effective development of all future components of the network.

some local employment generation

injection of capital works funding into the local economy.

The assessment made in this report shows that whilst the proposed developmentwill have varying impacts along the route on loss of vegetation, site access/egress,

and rural amenity. Proposed mitigation measures can be adopted by ActewAGL andimplemented at the development stage to minimise local environmental impact.

Specific mitigation measures have been identified and detailed in the report toaddress the following environmental matters:

Site contamination and waste management

Stormwater drainage and water quality

social impact

safety and security

air quality

property values

noise

visual impact

land use

stock management

bushfire risk

native vegetation and fauna

In summary, it is considered that the wider project objectives, preferred route andrecommended mitigation measures would outweigh the localised environmentalimpact on both the natural and human environment along the proposed route.

June 2008


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30 June 2008 Proposed 132kV Subtransmission Line - Williamsdale to Theodore, ACT ii

Table of Contents

CHAPTER 1

GENERAL INFORMATION ........................................................... 1

1.1

Introduction ................................................................................... 2

1.1.1 Background ............................................................................................ 21.1.2 Southern Supply to the ACT ...................................................................... 2

1.1.3

Name and Address of Proponent ................................................................ 31.1.4 Status of the Project ................................................................................ 3

1.1.5

Outline of Proposed Development ............................................................... 6

1.1.6

Environmental Assessment........................................................................ 8

1.1.7 Development Application .......................................................................... 8

1.2 Location of the Project .................................................................. 10 1.2.1 Location ................................................................................................ 101.2.2 Possible Future Extensions ....................................................................... 12

1.3

Description of the Project ............................................................. 12

1.3.1 Type of Development .............................................................................. 121.3.2 Purpose and Need ................................................................................... 151.3.3 Consultation .......................................................................................... 161.3.4 Relationship to Surrounding Development .................................................. 18

CHAPTER 2

EXISTING ENVIRONMENTAL CONDITIONS .............................. 192.1

Description of the Project Site ...................................................... 20

2.1.1

Topography & Drainage ........................................................................... 20

2.1.2

Geology ................................................................................................ 22

2.1.3 Flora ..................................................................................................... 242.1.4 Fauna ................................................................................................... 262.1.5 Heritage ................................................................................................ 272.1.6 Land Use ............................................................................................... 302.1.7 Landscape and Views .............................................................................. 31

2.2

Description of the Region Surrounding the Project Site ................ 31

2.3

Current Land Use Policy and Lease Conditions of the Site ............. 33

2.3.1 National Capital Plan ............................................................................... 332.3.2 EPBC Act 1999 ....................................................................................... 35

2.3.3

Territory Plan ......................................................................................... 352.3.4 Spatial Plan ........................................................................................... 36

2.3.5

Current Lease Conditions ......................................................................... 38

CHAPTER 3POTENTIAL IMPACT OF THE PROJECT ON THE ENVIRONMENT 403.1

Impact on the Physical Environment ............................................ 41

3.1.1 Geotechnical Impact ............................................................................... 413.1.2 Site Contamination ................................................................................. 423.1.3 Stormwater Drainage and Water Quality .................................................... 433.1.4 Traffic and Access ................................................................................... 45

3.2

Impact on the Human Environment .............................................. 45

3.2.1 Social Impact ......................................................................................... 453.2.2

Safety and Security Measures ................................................................... 46

3.2.3 Air Quality ............................................................................................. 46

3.2.4

Economic Impact .................................................................................... 473.2.5 Electromagnetic Fields ............................................................................. 48

3.2.6 Noise Assessment ................................................................................... 483.2.7 Visual Impact ......................................................................................... 493.2.8 Land Use ............................................................................................... 523.2.9

Cultural Heritage .................................................................................... 53

3.2.10 Bushfire Assessment .......................................................................... 53

3.3

Non-Human Biological Environment ............................................. 55

3.3.1

Impacts on Native Vegetation and Habitat .................................................. 55

CHAPTER 4

SUMMARY AND CONCLUSIONS ................................................ 58

4.1

Summary ...................................................................................... 59

4.1.1

Physical Environment .............................................................................. 59

4.1.2 Human Environment ............................................................................... 59

4.1.3

Natural Environment ............................................................................... 594.1.4 Summary of Mitigation Measures .............................................................. 59

4.1.5 Benefits ................................................................................................ 63

4.2

Conclusions .................................................................................. 64


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30 June 2008 Proposed 132kV Subtransmission Line - Williamsdale to Theodore, ACT iii

Figures

NOTE : F I GURES 13 23 ARE AT THE END OF THE REPORT

Figure 1: Schematic Arrangement of ACT Electricity Network ............................ 5

Figure 2: Metropolitan Context ..................................................................... 9

Figure 3: Location .................................................................................... 11

Figure 4: Surrounding Land Uses ................................................................ 18

Figure 5: Topography and Drainage ............................................................ 21

Figure 6: Vegetation ................................................................................. 25

Figure 7: Heritage Items ........................................................................... 29

Figure 8: Surrounding Region ..................................................................... 32

Figure 9: Extract from National Capital Plan ................................................. 34

Figure 10: Territory Plan ............................................................................ 37

Figure 11: Land Tenure .............................................................................. 39

Figure 12: Visual Assessment ...................................................................... 50

Figure 13: Route Sectors Southern, Central, Northern

Figure 14: Route Detail - Block 1653, Southern Sector

Figure 15: Route Detail Blocks 1470 & 1471, Southern Sector

Figure 16: Route Detail Blocks 1644 & 116, Central Sector

Figure 17: Route Detail Block 1623, Central Sector

Figure 18: Route Detail Block 1651, Central Sector

Figure 19: Route Detail Block 1533, Northern Sector

Figure 20: Route Detail Block 1635, Northern Sector

Figure 21: Vegetation Details Southern Sector

Figure 22: Vegetation Details Central Sector

Figure 23: Vegetation Details Northern Sector

Attachments

Attachment A:

EMF Profiles Study (ActewAGL)

Attachment B:

Ecological Assessment and Natural Resource Management (GeoffButler and Associates)

Attachment C: Cultural Heritage Assessment (Navin Officer)

Attachment D:

Bushfire Assessment (ABPP)

Attachment E: Geotechnical Assessment (Coffey Geosciences)

Any representation, statement, opinion or advice expressed or implied in this publication is made in goodfaith but on the basis that Purdon Associates, their agents and employees are not liable to any personfor any damage or loss whatsoever which has occurred or may occur, in relation to that person taking ornot taking (as the case may be) action, in respect of any representation, statement or advice referred toin this report.


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30 June 2008 Proposed 132kV Subtransmi ssion Line - Williamsdale to Theodore, ACT 1

Chapter 1

General Information

This Chapter provides details on the proponent, as well as the geographic locationand proposed type of development.


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1.1 Introduction

1.1.1 Background

The ACT currently receives the bulk of its electricity supply via the NSW electricitygrid through one substation operated by TransGrid and located at West Belconnennear Holt. The electricity supply is delivered to the ACT by TransGrid anddistributed by ActewAGL within Canberra.

The electricity supply system is broadly comprised of three functional tiers:

generation

bulk transmission and distribution

reticulation of electricity to customers.

Most of the electricity consumed in the ACT is generated at interstate powerstations and supplied to the electricity grid at high voltages. Transmission linescarry this bulk electricity to a high capacity (330kV) substation located at WestBelconnen. It is from this location that ActewAGL currently source 95% of theirpower. The electricity is taken at 132kV and 66kV from TransGrid and distributedby ActewAGL through subtransmission lines to a network of zone substationslocated throughout Canberra, where a further reduction of the voltage occursbefore reticulation through the distribution network to consumers.

In 2005 the ACT Government determined that a southern point of electricity supplyto the ACT be constructed and provided by TransGrid and ActewAGL in accordancewith electricity supply reliability criteria. Compliance with these criteria inestablishing a southern supply point would allow electrical supply to Canberra to bemaintained in the event of a special contingency that partially or fully removesTransGrids Canberra substation at West Belconnen from operation.

In response to the ACT Government's reliability criteria, ActewAGL and TransGridformed a Working Group to conduct a joint study of the medium to long termoptions of electricity supply to the ACT. The Working Group identified a number oftechnical upgrades to the ACT's power supply that would be required in order tomaintain sufficient supply and meet the criteria. The upgrade includes:

the construction of a 330/132kV substation at Williamsdale

the construction of a 132kV subtransmission line between the proposedWilliamsdale substation and the existing ActewAGL network.

the conversion of the Williamsdale to Canberra transmission line from a doublecircuit 132kV to single circuit 330kV.

1.1.2 Southern Supply to the ACT

The overall project is referred to as the Southern Supply to the ACT and involves

several component elements being separately supplied and maintained byTransGrid and ActewAGL.


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It represents a new large transmission network asset and a new large distributionasset that addresses the Network Service Criteria required by the Act Government.

However, the specific development that is the subject of this environmentassessment is the construction of a 132kV subtransmission line between

the proposed Williamsdale substation and the existing ActewAGL network.

The main purpose of the proposed subtransmission line is to provide a reliable andsecure supply to ACT customers, including Commonwealth Government agencies.

1.1.3 Name and Address of Proponent

General Manager NetworksActewAGLActewAGL House221 London CircuitCanberra City ACT 2600

GPO Box 366Canberra City ACT 2601

1.1.4 Status of the Project

ActewAGL owns the subtransmission and distribution networks within the ACT andis responsible for planning and developing those networks.

TransGrid and ActewAGL have responsibilities under the National Electricity Rules tocarry out joint planning to facilitate the optimal development of connectionsbetween the transmission and distribution networks within ActewAGLs networkarea.

Concurrent to the preparation of this environmental assessment, a separate reportis also being prepared by TransGrid for the proposed substation site atWilliamsdale. The proposed transmission lines that are the subject of this reportwill connect to this substation.

The ACT Government has recently prepared Network Service Criteria (contained inthe ACT Disallowable Instrument, Utilities Exemption 2006 No 1 under Utilities Act2000) applying to TransGrids network supplying the ACT. The criteria require(inter alia) TransGrid to provide by 2009 two or more geographically separate

electricity connection points (substations) at 132 kV and above to supply the ACT.

Essentially this requires establishment of a southern 330/132kV substation and132kV connections to the existing ActewAGL network by 2009 and provision of asecond 330kV supply to this new substation, independent of the Canberra330/132kV substation, by 2012.

TransGrid will provide a 330/132kV substation in the south-east area of the ACT,connecting into the existing Canberra to Cooma 132kV lines. A substation atWilliamsdale will also meet the reliability criteria recently established by the ACTGovernment to ensure diversity of supply to the ACT.

ActewAGL takes supply at 132kV from the Canberra 330/132kV substation (locatedon Parkwood Road West Belconnen, near Holt) and at 66kV from Queanbeyan


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132/66kV substation. The Canberra 330/132kV substation supplies Queanbeyansubstation and the Cooma/Bega area. (Figure 1 refers).

ActewAGL will provide the 132 kV connection from Williamsdale to the existing ACTsubtransmission network.

This environmental assessment follows initial line route selection studiesundertaken by Purdon Associates for ActewAGL in 2006, and further refinement ofthe route selection process after consultation with ACT Government Agencies andlocal lessees throughout the first half of 2007. The Route Selection and RouteRefinement tasks evaluated the various route options between the proposedWilliamsdale substation and the existing ActewAGL network.

The route selection report firstly identified and evaluated three broad corridors. Afurther potential corridor establishing a straight line route from theWilliamsdaleSubstation to Theodore was not considered appropriate as it traversed large areasof Native Reserve in the ACT, as well as passing close to a number of existing ruraldwellings.

The three corridors considered in the study comprised:

an eastern corridor in NSW dismissed by both TransGrid and ActewAGL onthe grounds that it did not meet functional and administrative requirements ofthe network and would pass through new urban settlement

a western corridor in the ACT through nature reserves dismissed by ACTParks Conservation & Lands (Environment & Recreation) on the grounds ofmajor environmental impact

a central corridor between the Monaro Highway and Rob Roy Nature Reserve

adopted as the preferred corridor, subject to more detailed assessment.

The preferred corridor was then further examined to identify a preferred routewithin it based on a range of route selection criteria including environmentalfeatures, network efficiency and impact on leaseholders.

The further three (3) route alignments within the preferred corridor that wereevaluated, included:

Monaro Highway

central valley

western edge.

T h e w e s t e r n e d g e o p t i o n i n t h e Ce n t r a l Co r r i d o r i s t h e p r e f e r r e d r o u t e a n d

t h e su b j e c t o f t h i s a s s es sm e n t .


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Figure 1: Schematic Arrangement of ACT Electricity Network

The overall network augmentation involves:

construction of a 132kV double circuit line to connect Williamsdale to theActewAGL 132kV network in the Theodore area

conversion of the existing transmission line between West Belconnen (CanberraSubstation) and Williamsdale, which presently operates as a double circuit132kV line, to operate at 330kV to supply Williamsdale (subject to separate PA)

establishment of a ring of 330kV lines surrounding the ACT and supplying anew 330/132kV substation in the Williamsdale area

construction of a two transformer 330/132kV substation at Williamsdale

provision of 330kV line switchbays at Canberra (West Belconnen) substation

reconnection of the two Cooma 132kV circuits to Williamsdale

upgrading of ActewAGLs existing Theodore Gilmore 132kV subtransmissionlines (second stage of the project)

construction of a single circuit 330kV line from Williamsdale to the Bungendorearea to complete the 330kV ring (possible future development subject toapproval by Australian Energy Regulator, not subject of this assessment)

augmentation of Williamsdale substation to provide an additional transformerand to connect the new 330kV line from the Bungendore area (possible futuredevelopment subject to approval by Australian Energy Regulator, not subject ofthis assessment)


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construction of a 330kV switching station in the Bungendore area (possiblefuture development subject to approval by Australian Energy Regulator, notsubject of this assessment)

The total project is referred to as the Southern Supply to the ACT. It involves anumber of component tasks performed by both TransGrid and ActewAGL,

depending on the responsibility of each agency.

While the overall project involves 2 proponents and 3 separate, but interrelatedprojects, it is the intention of both proponents (ActewAGL and TransGrid) toconcurrently submit their respective Development Applications to enable concurrentconsideration by ACTPLA and other ACT Government agencies.

1.1.5 Outline of Proposed Development

The scope of the proposed 132kV subtransmission line extension comprises theconstruction of a 15.9km section between the proposed TransGrid substation southof Williamsdale and the existing ActewAGL subtransmission network near theTheodore Zone Substation.

The proposed development consists of 132kV double circuit line on single concreteor steel poles with spans of approximately 150 along the route. A 45m wideeasement along this route is sought by ActewAGL to ensure ease of access forconstruction and maintenance as well as tree management and land use controlsunder and adjacent to the subtransmission lines. Normal farming activitiesincluding access to paddocks within the easement can continue unaffected by thesubtransmission lines.

ActewAGL considers that sufficient provisions are included in the existing Utilities

Act 2000and (Electricity) Public Safety Regulations to allow ActewAGL to operatethe lines without establishing a formal easement. However, the ActewAGL positionis that if the easement is established, a greater certainty and protection would beprovided to the leaseholders and to ActewAGL through the direct clarification ofrestrictions and mutual obligations. It is intended that ActewAGL would haveownership of all subtransmission line assets, but would not seek a lease orownership of the land under the subtransmission lines.

Elements of the proposed development for which this environmental assessmentreport is prepared comprise the following:

construction of a double circuit 132kV subtransmission line from Williamsdale to

existing ActewAGL network

establishment of a 45m wide easement to accommodate the twosubtransmission lines

approximately 90-100 suspension poles plus approximately 15 sets of twintension poles, all to be 24-25m high (above ground) and constructed ofconcrete or steel, and each pole supporting 12 conductors (wires) and twoearth wires

installation of conductors with an aged finish to have a dull sheen

use of two site compounds during construction

construction of access / maintenance trails.


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Tension Poles

Suspension PoleNote: The above examples show 6 single conductors; the proposed development proposes double circuitconductors


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1.1.6 Environmental Assessment

The specialist studies undertaken by members of the consultant team formattachments to this report. These studies encompassed the enlarged area(comprising a 100m corridor plus adjoining areas and investigating a range ofpotential route options), not just the immediate path of the preferred route of the

transmission line as detailed in this report.

Throughout this report the study area refers to the enlarged area and the site orsubject site refers to the actual route of the subtransmission line. In someinstances there are references to matters of significance in the study area but thesematters do not necessarily imply that the matter affects the line.

1.1.7 Development Appl ication

This environmental assessment report accompanies a Development Application for

the 132kV subtransmission line and forms part of a package of informationrelating to the overall proposals and contained in separate reports.

The package also includes:

Environmental Assessment for proposed TransGrid 330/132kV substation atWilliamsdale

Development Application for proposed substation

Environmental Assessment for upgrade of existing TransGrid 132kVtransmission lines to 330kV.

However each of these three items are the subject of independent assessmentreports and Development Applications.


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Figure 2: Metropolitan Context


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1.2 Location of the Project

1.2.1 Location

The study area is located in the south-eastern corner of the ACT and extends fromWilliamsdale near the NSW/ACT border to the existing ActewAGL network betweenthe Gilmore and Theodore substations (Figure 2 and Figure 3 refer). This areagenerally comprises a valley adjacent to the Monaro Highway and has anapproximate distance of 15.9km.

For the purposes of describing specific attributes of the route in this PA, the totalroute length has been divided into 3 sectors:

The s o u t h e r n s e ct i o n commences at the proposed TransGrid Williamsdalesubstation to be located within Block 1653 Tuggeranong (The Angle) andextends westward for 800m then north-west for 1.3km adjacent to and parallel

with the existing TransGrid transmission line and traversing Block 1471, AngleCrossing Road and Block 1653 Tuggeranong (Burraburoo). Within Block 1636the route extends generally north-east across open farmland for approximately2km. The route deviates near the northern boundary of Block 1636 forapproximately 500m to avoid, as far as practicable, areas of high value YellowBox Red Gum Grassy Woodland and to cross a valley without the need to entereither the Gigerline Nature Reserve or the Rob Roy Nature Reserve. The routethen traverse the southern section of Block 1644 Tuggeranong (Guises Flat)and extends northward across block 116 and again across block 1644 forapproximately 1.5km. The route at this point is adjacent to the easternboundary of Rob Roy Nature Reserve and, while the nature reserve boundarydoes not correspond with the cadastral or lease boundaries at this location, the

route remains within leased land.

The c e n t r a l s e c t i o n of the route extends in a generally north-east direction fora distance of approximately 2km from Block 1644 Tuggeranong (Guises Flat)across open farmland west of Guises Creek traversing 1623 (Sunny Lane).The route again deviates for 300m within Block 1623 to avoid an area of highvalue scribbly gums and an area of high value snow gums. The route thenextends generally northwards for approximately 3.5km into block 1651Tuggeranong (Rose Hill).

The n o r t h e r n s e c t io n of the route extends northward from the northern partof Block 1651 Tuggeranong across open farmland into Block 1633 (Bellview)for a distance of approximately 500m then the route traverses an area ofYellow Box Red Gum Grassy Woodland within Block 1633 for a distance ofapproximately 2km. The route then deviates to the north-west and traversesthe Rob Roy Nature Reserve to the west of Callaghans Hill for a distance ofapproximately 1.5km. The route then ends within Block 1684 Tuggeranongconnecting with the existing ActewAGL network near the Theodore ZoneSubstation, which is located within the Tuggeranong Hill Nature Reserve.


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Figure 3: Location

BELL VIEW

ROSE HILL

SUNNY LANE

GUISES FLAT

BURRABUROO

THE ANGLE

ROB ROYNATURE RESERVE

ROB ROYNATURE

RESERVE

EXISTING ACTEWAGL 132KvSUBTRANSMISSION LINES(THEODORE TO GILMORE

EXISTINGTRANSGRID

TRANSMISSIONLINES

PROPOSED TRANSGRIDSUBSTATION SITE

GIGERLINE

NATUREESERVE

SOUTHERNSECTOR

NORTHERNSECTOR

CENTRALSECTOR


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1.2.2 Possible Future Extensions

The overall subtransmission route represents the full scope of the proposed newsubtransmission lines.

There are no plans for further duplication of the proposed line within the study

area.

1.3 Description of the Project

1.3.1 Type of Development

ActewAGL intend to construct a 132kV subtransmission line having 440 MegaVoltAmps (MVA) continuous capacity from the proposed TransGrid substation atWilliamsdale to a connection with the existing 132kV Gilmore to Theodore

subtransmission lines.

The proposed transmission line will be constructed using concrete extruded poles of29m length (24-25m height above ground) or alternatively steel poles (rather thansteel towers) of the same height. The required easement width for the proposedtransmission line is 45m. Management and ownership of the new 132kVsubtransmission line will be ActewAGL's responsibility.

The existing 132kV Gilmore to Theodore subtransmission lines each have acontinuous capacity of 220MVA. It is proposed to upgrade this section of thenetwork to continuous capacity of 440MVA for each line but this work is not part of

this assessment report.

During construction, access along the transmission line will be required for heavyarticulated vehicles for the delivery of poles, other heavy vehicles for the boringand excavation of pole foundations, large cranes, and vehicles for the stringing anderection of the line conductors.

Access to the route will be provided by the installation of gates in fence lines alongthe route, some of which may need to be earthed, and the possible construction ofculverts in creek crossings where an alternative access is not available.

The constructed transmission line will need to allow for access by heavy vehiclesand 4WD vehicles at any point for the regular inspection and maintenance of thelines including vegetation management and after fault inspections. Low flyingaircraft may also be used to carry out inspection of the lines on an annual basis.

Access will also be required for line crews and elevating platform vehicles whenrepair of a line is necessary.

S u p p o r t S t r u c t u r e s ( P o le s )

The location and number of support structures required is a primary function of thefollowing variables which reflect industry and safety standards:

minimum ground clearance

easement width (which governs horizontal movement of conductors).


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The preliminary design provides for approximately 90-95 poles to be erected. Thiscomprises suspension poles and tension poles. Suspension poles support theweight of the conductors in straight sections of the alignment. Tensions poles arestronger, intended to support the full conductor tension in addition to the weight ofconductors and the effects of the wind. Tension poles would be required atapproximately 10 locations where the alignment changes direction, and each

tension pole supports 3 double conductors. The remainder of the poles would besuspension poles.

The average height of the poles would be approximately 24-25m above the groundwith an average span of 150m. However, the span length and the height of theconductors may vary due to site specific factors such as topography.

Co n d u c t o r s ( W i r e s)

Each pole would support three circuits, with each circuit comprising two sets ofpaired Uranus conductors. The conductors would be separated at approximately

50m intervals by aluminium alloy spacers to reduce the likelihood of shorting. Theconductors would be configured in a vertical arrangement. The vertical separationbetween the conductors would be approximately 2.5m.

The conductors would be aluminium with the overall diameter approximately27mm.

During manufacture, the conductors would be subjected to a sand-blastingtechnique known as shadow-lining to produce an aged finish with a very dullsheen. The conductors would be attached to the support poles by polymerinsulators.

Double earth wires would be provided at the top of each pole, approximately 2.5mabove the upper conductor. The overall diameter of each earth wire would beapproximately 18mm and is comprised of a fibre optic core surrounded byaluminium-alloy wire strands. The fibre optic core provides a high speed telemetriclink enabling the real-time monitoring of network integrity and the rapididentification of faults. The earth wire also protects the conductors in the event ofelectrical storms by earthing any lightning strike.

Minimum safety clearances to the ground, roads and other utilities are required byindustry standards and would be maintained at all times. The line will be designedto achieve a minimum ground clearance of 7m.


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Ac c e s s T r a i l s

For much of the proposed route, the subtransmission line will traverse open grazingland or be adjacent to existing transmission lines. In these locations access forconstruction and maintenance vehicles will be via existing tracks or across openfarmland. In the sections of the route where no tracks currently exist, it is

proposed to construct access trails. These trails will be similar in standard to firetrails and as such will be constructed in accordance with the ACT Code of ForestPractice, August 2005, which incorporates erosion and sediment control guidelinesand specifications in accordance with the TAMS Fire Access Standards/Guidelines.

Where construction or upgrading of existing tracks is required, they will have anominal width of 4 metres and a minimum pavement width of 3 metres. Generallythe track is to be designed with the crossfall into the slope to ensure that erosionand seepage across the track surface is reduced, reducing long term maintenancerequirements. The crossfall is to be a minimum of 3 per cent and a maximum of 10per cent.

Tracks will have at least a 0.5 per cent gradient to allow for surface drainage whilethe maximum gradient, for the safe use by heavy vehicles, is 20 per cent.Gradients between 10 and 20 percent will be subject to specific designconsideration as part of a Conservation & Environment Management Plan (CEMP)with regard to track surfacing and stormwater control, in order to reduce erosion,provide traction and stability for heavy vehicles, and reduce maintenance.

The surface of the trail will vary along the length of the transmission line route andbe influenced by soil type, gradient and stormwater flows. In most areas the trailswill have a crushed rock surface compacted to 95 per cent.

Short lengths of track such as across flat open grazing farmland may be treatedwith grass stabilisation methods with grass infill to provide a functional yet visuallyunobtrusive surface.

Erosion sediment control devices will be placed around the work areas to avoidsediment entering creeks. These devices will take the form of a silt fence with atemporary barrier of geotextile fabric (filter cloth) or hay bales (in areas outrsidehigh quality habitat areas), or a combination of both, used to intercept anysediment laden run-off.


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O p e r a t i o n M a i n t e n a n c e

ActewAGL inspects all transmission lines annually. These inspections involve adetailed examination of the condition of the line and associated assets, usually fromground level with the use of visual aids such as binoculars. In some casesinspections are carried out by aerial patrols. A 4WD vehicle would generally be

used to access each support structure for ground based inspections. In addition tothe ground inspection, all support structures are climbed every 6 years to confirmtheir structural integrity.

Maintenance work is generally only required if routine patrols reveal a potentialproblem or if a circuit sustains an electrical fault. Should ActewAGL need to returnto the site with heavy vehicles to undertake more extensive maintenance work,lessees would be notified in advance. Under emergency conditions it may not bepossible to give such notification, in which case ActewAGL would contact lessees atthe first available opportunity. Any disturbance to properties caused duringmaintenance would be repaired at the completion of work.

Co n s t r u c t i o n a n d W o r k f o r c e

The overall time frame for construction works is likely to be approximately sixmonths but activities would not be continuous on each property for all of thisperiod.

Construction work would include:

adjustments to fences and gates

access trails and clearing of some existing trees

drilling of pole footings and erection of poles

stringing and tensioning.

It is expected that the general hours of construction would be 7am to 6pm Mondayto Saturday.

1.3.2 Purpose and Need

The primary need for the development is to provide a 132kv line extension to thenew TransGrid substation for the ACT as a precaution against the failure ofTransGrids existing Canberra substation at West Belconnen. The ACT andCommonwealth Governments recognised that having one major substation and linefor Canberra made the city vulnerable to disruption of electricity services.

The proposed works (substation, transmission line upgrade and newsubtransmission lines) will allow a second supply to Canberra from the Williamsdalesubstation in the event of a loss of supply from the Canberra substation.

The National Electricity Rules requires that an augmentation or extension to the

transmission system should be identified by the Distribution Networks ServiceProviders (DNSP).


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In response to these actions by ActewAGL, TransGrid is required to undertake ananalysis of why the new large transmission network is a "reliability augmentation"and identify the actual or potential constraint or inability to meet networkperformance requirements.

The Rules define a reliability augmentation as:A transmission network

augmentation that is necessitated solely by inability to meet the minimum networkperformance requirements set out in schedule 5.1 or in relevant legislation,regulations or any statutory instrument of a participating jurisdiction.

For reliability augmentations, the option that passes the regulatory test is the onethat minimises the cost of meeting the minimum network performancerequirements set out in the Rules or via a jurisdictional requirement.

DNSPs are required to carry out an economic cost effectiveness analysis of options,to identify options that satisfy the regulatory test, to meet an identified necessityfor augmentation.

ActewAGL and TransGrid have jointly planned the 330kV and 132kV networkssupplying the Canberra area for many years. ActewAGL and TransGrid were alsorequired to consult with National Electricity Market participants in relation to theproposed solutions and preferred option.

TransGrid and ActewAGL have carried out joint annual planning reviews as requiredby the Rules and have identified that the new Network Service Criteria give rise to aneed for network augmentations and have carried out joint planning to determineoptions for these augmentations. The review of options and the National ElectricityMarket consultation process took place from September 2006 to January 2007. InJanuary 2007 ActewAGL and TransGrid completed the consultation process andfulfilled the National Electricity Market related requirements.

As a result of joint planning for this proposal it has been agreed that in meeting theabove requirements, TransGrid will construct substation works and augmentation ofexisting transmission lines, and that ActewAGL will construct any required 132kVsubtransmission line to its existing network.

1.3.3 Consultation

Ru r a l L e s s e e s

The proposed subtransmission line route traverses seven (7) rural leases (ReferTable 2.1) and one public road (Angle Crossing Road). The rural lessees whoseland will be crossed by the proposed subtransmission line have been consulted atvarious times throughout the study process, starting in May 2006 immediatelyfollowing the line route selection process and additionally in March 2007 and July2007 during the preparation of this report.

The consultation process included an information package with Frequently AskedQuestions for leaseholders. Individual interviews were held with the lessees ontheir land, and/or at ActewAGLs office in Tuggeranong, providing the opportunity

for lessees to show the consultant team and ActewAGL certain aspects of their landand to describe future plans which may be affected by the proposedsubtransmission line.


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G o v er n m e n t A g e n c i e s

As part of the route selection study process, two Agency workshops were held anda broad number of Government agencies were given the opportunity to providecomment on the proposed route. Agencies given a copy of the Line Route Selectionreport (that preceded the preparation of this PA) were:

National Capital Authority

ACTPLA DA assessment

ACTPLA Leasing Section

ACT Parks Conservation & Lands (Environment & Recreation)

ACT Heritage Unit

Roads ACT

Additional meetings were held with ACT Parks Conservation & Lands (Environment& Recreation) and the National Capital Authority to discuss specific aspects of the

route options.

O u t c o m e s o f C o n s u l t a t i o n

The initial route selection study was prepared exclusive of consultation withlandholders but was defined with the intention that the route could be realigned inresponse to issues raised. The reason the route was selected prior to consultationwas to provide stakeholders with some background information on which to basetheir comments.

The main issues raised by the rural lessees included:

the potential loss of "quiet enjoyment"

impact on land values associated with sale of the property

the effects of electric and magnetic fields (EMF)

adverse effects on views from rural dwellings

location of the lines restricting the location of future development including newdwellings

potential for soil erosion and weed infestation

security concerns about unauthorised access to their land

impact on existing fencing and gates

potential tree loss along the route

impact on access for bushfire management

the suitability of soils along the route for construction purposes.

The meetings with ACT the Research & Monitoring team within ACT ParksConservation & Lands (Environment & Recreation) revealed a previously unmappedendangered colony of snow gums surviving in atypical conditions.

The concerns of the stakeholders were used to help define the most suitable routewhich would achieve the goals of ActewAGL but cause minimal disturbance toenvironment and the lessees. A majority of lessees indicated support for theproject or a willingness to accept the subtransmission lines, however, at least one


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rural lessee remains strongly opposed to the passage of subtransmission linesthrough the property.

1.3.4 Relationship to Surrounding Development

The proposed transmission line links Williamsdale substation and existing ACTActewAGL electricity network. Major land uses adjacent to the subtransmission lineinclude:

rural uses including grazing

nature park and reserves

Monaro Highway

Angle Crossing Road

rural residential dwellings

Williamsdale Service Station.

Figure 4: Surrounding Land Uses

GIGERLINE

NATURE

RESERVE

MURRUMBIDGEE

CORRIDOR

NSW

ROB ROY

NATURE

RESERVE

NAMADGI

NATIONAL

PARK

WILLIAMSDALE

ANGLE

CROSING

ROYALLA

NOTE: GREEN SHADING DENOTES VEGETATION COVER

DARK GREEN SHOWS AREAS OF YELLOW BOX RED GUM GRASSY WOODLAND

ROB ROY

NATURE

RESERVE


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Chapter 2

Exis ting Envi ronmental

Condit ions

This Chapter provides details on the existing environmental conditions over the

length of the proposed route of the subtransmission lines.


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2.1 Descript ion of the Project Site

For the purposes of describing the environmental conditions and potential impacts,the proposed route has been divided into three sectors, as follows:

Southern Sector

Central Sector

Northern Sector

The Southern Sector commences at the site of the proposed TransGrid substationand extends generally in a westerly direction then northerly direction adjacent tothe existing TransGrid transmission lines, crossing Angle Crossing Road andextending to near the large dam on Block 1644 District of Tuggeranong.

The Central Sector generally extends northward adjacent to the Rob Roy Nature

Reserve and west of Guises Creek.

The Northern Sector commences near the rural dwelling on Block 1651 District ofTuggeranong and extends north-west to connect with the existing ActewAGLnetwork near the Theodore substation.

2.1.1 Topography & Drainage

S o u t h e r n S ec t o r

The general topographic profile undulates gently forming a series of open hillstraversed by a number of minor northeast-southwest and southeast-northwesttrending natural drainage lines. The slope of the topography was observed tosteepen significantly in the vicinity of several of the drainage lines.

This southern sector is characterised by side slopes of a significant knoll locatedimmediately north of the proposed TransGrid substation site. The slopes are mostlyin the order of 10% but in the west of the sector the slopes are up to 21%.

Ce n t r a l S e c t o r

The topography in the central part of the line route is generally identified as agently undulating valley floor traversed longitudinally by Guises Creek with anumber of small intermittent tributaries. The western edge of the line borders thebase of the Rob Roy Range where slopes are 0% - 21%.

The proposed route for the subtransmission line trends south to south-southwestand runs roughly parallel with Guises Creek along the lower slopes of the hills tothe west. The general topography along this segment of the proposed route slopesgently down towards the east-southeast. The proposed route traverses numerousminor and predominantly southeast-northwest trending natural drainage lines,which form a series of gently undulating east-southeast trending gullies and low

rounded spurs. The slope of the topography was observed to steepen in theimmediate vicinity of several of the more significant drainage lines.


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N o r t h e r n S e ct o r

The topography along this segment of the proposed route comprises moderate tosteep sided hills with a general slope down towards the east and northeast. Theproposed route traverses a number of southeast-northwest and northeast-southwest trending natural drainage lines. The slope of the topography was

observed to steepen significantly in the immediate vicinity of several of the moresignificant drainage lines.

Figure 5: Topography and Drainage


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2.1.2 Geology

S o u t h e r n S ec t o r

The amount and prominence of outcrop along this segment of the proposed route is

varied. The 1977 Geological Survey of NSW, Department of Mines, 1:100,000 scalegeological map covering the Williamsdale Region (Michelago, Geological SeriesSheet 8726, Edition 1) indicates that this sector of the proposed route is underlainby Late Silurian rhyolitic and rhyodacitic tuff, and minor siltstone, sandstone andlimestone of the Colinton Volcanics. The lithologies exposed in outcrop proximal toAngle Crossing Road appear to exhibit rhyodacitic to rhyolitic compositions, withquartz float evident in a number of places. Rock outcrops of rhyolitic compositionappear foliated and cut by a number of closely spaced (


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line route the geological map shows an inferred boundary between the rhyolitic andrhyodacitic tuff and a tuff comprised of quartz and pink feldspar, which is also partof the Colinton Volcanics. The inferred boundary between these lithological unitsappears to correspond with a marked steepening of the east facing slopes and theobserved tree line that runs parallel to Guises Creek. The geological map alsoshows occurrences of undifferentiated high-level gravels, sand, silt and tallus in the

vicinity of Guises Creek from about chainage CH 8400 to about CH 11600. Theexact extent and depth of these unconsolidated deposits is unknown.

It was not possible to gain access to this segment of the proposed route but thegeological map suggests that the subsurface profile will comprise rock types similarto those observed in outcrop proximal to Angle Crossing Road and described belowin Section 2.3. The lack of outcrop along the proposed route between chainages CH4600 and CH 11600 suggests a deeper soil profile, which may possibly beattributable to the close proximity of the proposed route to Guises Creek and thenumerous minor drainage gullies in the vicinity or to colluvial soils developed asslope wash off the hillsides.

A number of farm tracks visible to the west of Guises Creek and in the vicinity ofthe proposed route, will aid access to the site.

N o r t h e r n S e ct o r

The amount of outcrop along this segment of the proposed route decreasessouthwards, with extensive outcrop visible between chainages CH 0 and CH 2800and minor outcrop visible between chainages CH 2800 and CH 4600. The groundsurface along the proposed route for the subtransmission line appears in general tobe covered by low grasses and sparsely to densely distributed small to mediumsized trees. The density of the vegetation, in particular the trees, was observed to

increase in the vicinity of natural drainage lines.

The 1992, Bureau of Mineral Resources 1:100,000 scale geological map coveringthe Canberra Region (Canberra, Geological Series Sheet 8727, Edition 1) indicatesthat a northeast-southwest trending fault traverses the proposed route at aboutchainage CH 3800. The geological map indicates that the proposed route betweenchainages CH 0 and CH 3800 is underlain by Late Silurian rhyodacitic ignimbritesand minor volcaniclastic sediments and argillaceous sediments of the DeakinVolcanics. South of the fault between chainages CH 3800 and CH 4600 theproposed route is shown to be underlain by dacitic ignimbrite and minorvolcaniclastic sediments of the Colinton Volcanics.

The subsurface profile will comprise lithologies similar to those observed in outcropproximal to Angle Crossing Road. The soil profile appears to be shallow in thevicinity of rock outcrop and deeper weathering profiles should be anticipatedproximal to natural drainage lines.


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2.1.3 Flora

Geoff Butler and Associates together with Vertigo Environmental Consultants wereengaged to undertake an assessment of the ecology along the route. Thisassessment followed a desktop study which was undertaken at the route selectionstage. A copy of the Butler/Vertigo report is provided at Attachment B.

The Guises Creek valley is a contained valley comprising established grazing farmsadjacent to the forested hilly nature reserves. The area contains substantially orseverely modified native vegetation with some areas of moderately modifiedwoodland. North and south of the proposed route, this woodland comprises areasof endangered Yellow-Box Red Gum Grassy Woodland.

Yellow Box-Red Gum is an open woodland community in which either or both YellowBox (Eucalyptus melliodora) and Blakely's Red Gum (E. Blakelyi) are usuallypresent and commonly dominant or co-dominant. The trees form an open canopyabove a species rich understorey of native tussock grasses, herbs and scattered

shrubs and are utilised by a large number of animal species.

The ACT Lowland Woodland Conservation Strategy seeks to protect the naturalintegrity of the remaining lowland woodland ecosystems by maintain and improvingconnectivity to other native vegetation including woodland, avoiding furtherfragmentation and minimising harmful effects from adjacent land uses.

Most of the existing lowland woodland in the study area is identified as beingmoderately modified. This woodland 'category' comprises grassy woodland wheregrazing and other land uses have resulted in the loss of a significant component ofthe understorey and led to other changes in the composition of understorey native

species.

Small sections of the study area comprise a partially modified lowland woodlandwhich is considered to retain relatively unchanged remnants of the pre-Europeanecological community. These areas are considered to be of high natural integrity.

The Small Purple Pea (Swainsona recta) is another endangered species which hasalso been recorded within the general study area, primarily along the railway lineforming the ACT/NSW border.

ACT Parks Conservation & Lands (Environment & Recreation) has advised that a

significant remnant grove of Snow Gum Tableland Woodland has been identifiedalong Guises Creek, close to the large farm dam. This vegetation community hasnot been formally mapped by ACT Parks Conservation & Lands (Environment &Recreation) but has been broadly identified on Figure 22. Frost hollows in the studyarea were also identified as possible habitats on the Snow Gum TablelandWoodland. The Snow Gum Tableland Woodland is noted as being locallyendangered and possibly under greater threat of local extinction than otherwoodland communities.

The route selection study identified that any chosen route through this valley wouldfrom the loss of some tree cover and generate some ground disturbance resultingin the need for clearance to subtransmission lines and maintenance access.

The presence of threatened species and endangered ecological communities withinthe Guises Creek valley were key influences on route selection. It was not possible


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to identify any reasonable route that totally avoided the Yellow-Box Red GumWoodland community. However, the individual recordings of threatened species arein isolated localities and finalisation of a route and pole locations within theidentified easement that avoids these specimens is possible.

Figure 6: Vegetation


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2.1.4 Fauna

Geoff Butler and Associates together with Vertigo Environmental Consultants wereengaged to undertake an assessment of the ecology along the route. Thisassessment followed a desktop study which was undertaken at the route selectionstage. A copy of the Butler/Vertigo report is provided at Attachment B.

Ecological resource data provided by ACT Parks Conservation & Lands (Environment& Recreation) identified that the Pink Tailed Worm-Lizard (Aprasia parapulchella)has been recorded in the southwestern part of the study area, generally along theMurrumbidgee River corridor.

The Pink Tailed Worm-Lizard generally inhabits open woodland area withpredominantly native grasses such as Kangaroo Grass (Themeda triandra). It isfound beneath small, partially embedded rocks but spends considerable time inburrows. The main threat to this species is the removal of rocks and habitat andthe invasion of weeds.

The general study area has two threatened bird species recorded, the Brown TreeCreeper (Climacteris picumnus) and the Hooded Robin (Melanodryas cucullata).

In addition to the specific recordings of the above endangered species, Woodlandsprovide important habitat for other bird species declared as threatened under theNature Conservation Act 1980. ACT Parks Conservation & Lands (Environment &Recreation) have advised that any or all of the threatened or endangered birdspecies in the general southern ACT region may pass through the area. Theseinclude:

Swift Parrot (Lathamus dicolor)

Superb Parrot (Polytelis swainsonii)

Painted Honeyeater (Grantiella picta)

Regent Honeyeater (Xanthomyza Phrygia).

Woodland animals are an intrinsic part of the overall functioning of woodlandecosystems. They are essential for pollination and dispersal of many woodlandplants and are involved in nutrient recycling and maintenance of soil condition.Loss of species can alter ecosystem processes, which may adversely affect the

health of the ecosystem.

Although Guises Creek valley is not regarded as an area of high ecological value itcontains several important species and is used by others in transit.

Tuggeranong Hill is used as a "hill-topping" site for butterfly courtship displaybehaviour. This area is located between Conder and Theodore and, while outsidethe study area, it is immediately adjacent and connected to the area through theTuggeranong Hill Nature Reserve. There are seven butterfly species recorded here,including some species rarely seen in suburban settings. This area is also part ofthe nationally significant honeyeater migration route.

The main influence of endangered fauna species on the route selection relatesmostly to the likely loss of woodland habitat for the identified endangered birds thatutilise woodland habitats. It is possible to construct the lines within the identified


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easement to ensure that the transmission lines and poles do not significantlyimpact on known important fauna habitat or the individual recordings of threatenedspecies.

2.1.5 Heritage

A b o r i g i n a l H e r i t a g e

Navin Officer Archaeological Consultants were engaged to undertake a desktopassessment of the proposed subtransmission line route. The full report is providedat Attachment C.

A search of the ACT Aboriginal Sites Database and Heritage Register indicated that33 previously recorded Aboriginal sites may be affected by the construction of theWilliamsdale to Theodore Power line. They comprise 25 artefact scatters (includinga possible stone arrangement and a potential archaeological deposit) and 8 isolated

finds.

The following provides an inventory of previously recorded sites that may beaffected by construction activity and Figure 7 shows their location on topographicmaps of the area.

CR14-ACT 1:10 000 210480 570150 (GDA/MGA 692637.6059984) This site is anopen scatter of five stone artefacts.

CR15-ACT 1:10 000 210970 570270 (GDA/MGA 693130 6060093) This site is anopen scatter comprising quartz and silcrete flakes and chips.

TUG2 - Located in Block 1636 Tuggeranong, ACT 1:10 000 209736.571569(GDA/MGA 691920.8.6061416 Buffer Zone 25m) An open scatter of at least twoartefacts located on a low rise 200 m from an ephemeral creek.

TUG3 - Located in Block 1636 Tuggeranong, ACT 1:10 000 209757.571680(GDA/MGA 691944.6061527 Buffer Zone 25 m) An open scatter of at least fourartefacts located on a low rise 250 m from an ephemeral creek.

MRC62 -ACT 1:10 000 209950.9.572121 (GDA/MGA 692146.9.6061964 BufferZone 50m) Artefact scatter and possible stone arrangement located on the hilltop

west-southwest of Vallona Station. A scatter of quartz flakes occurs across the topof the hill. Four flakes had nice retouched margins. Also across the flattened top ofthe hill were scattered a large number of medium-sized stones. No overall patterncould be seen but the relationship of some of these stones is suggestive of a stonearrangement that has been all but destroyed. Six stones form part of one curve,and three and four stones, respectively, appear to form part of two parallel lines.

TUG6 - Located in Block 116 Tuggeranong, ACT 1:10 000 210161.9.574121(GDA/MGA 692398.7.6063959 Buffer Zone 25 m) An isolated stone artefactlocated on flat level ground near a small creek.

TUG7 - Located in Block 1607 Tuggeranong, ACT 1:10 000 210119.0.574435(GDA/MGA 692362.2.6064276 Buffer Zone 25 m) An open scatter of at least fourartefacts located on a small level rise 100 m from an ephemeral creek.


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TUG8 - Located in Block 1607 Tuggeranong, ACT 1:10 000 210506.9.575316(GDA/MGA 692768.1.6065149 Buffer Zone 25 m) An isolated stone artefactlocated on a small flat rise above an ephemeral creek.

TUG9 - Located in Block 1623 Tuggeranong, ACT 1:10 000 210674.576028(GDA/MGA 692949.6.6065857 Buffer Zone 25 m) An open scatter on at least five

artefacts located on a crest, 500 m from a creek.

TUG10 - Located in Block 1623 Tuggeranong, ACT 1:10 000 210933.576592(GDA/MGA 693218.6066414 Buffer Zone 25 m) An isolated stone artefact locatedon a small spur.

CLSC9 - Located in Block 1633 Tuggeranong, ACT 1:10 000 211660.8.580952(GDA/MGA 694036.6.6070759 Buffer Zone 25m) An open scatter of at least 17artefacts located on a lower slope.

CLSC10 - Located in Block 1633 Tuggeranong, ACT 1:10 000 211631.8.580789

(GDA/MGA 694004.3.6070597 Buffer Zone 25m) An open scatter of at least fiveartefacts located on a wetland spur.

CLSC11 - Located in Block 1633 Tuggeranong, ACT 1:10 000 211581.1.580712(GDA/MGA 693951.8.6070520 Buffer Zone 25m) An isolated stone artefact locatedon the lower slope of a spur.

CLSC12 - Located in Block 1642 Tuggeranong, ACT 1:10 000 211746.579547(GDA/MGA 694091.6069353 Buffer Zone 25m) An open scatter of at least 10artefacts located mid-slope on a spur.

CLSC13 - Located in Block 1642 Tuggeranong, ACT 1:10 000 211633.9.579097GDA/MGA 693971.8.6068904 Buffer Zone 25m) This site consists of an isolatedstone artefact.

CLSC14 - Located in Block 1642 Tuggeranong, ACT 1:10 000 211667.9.581372(GDA/MGA 693703.4.608392 Buffer Zone 25m) An open scatter of at least twoartefacts located on the lower slope of a spur.

CLSC15 - Located in Block 1642 Tuggeranong, ACT 1:10 000 211363.9.578792(GDA/MGA 693695.7.6068605 Buffer Zone 25m) An open scatter of at least 11artefacts located on the slower slope of a creek margin.

CLSC16 - Located in Block 1642 Tuggeranong, ACT 1:10 000 211711.9.580132

(GDA/MGA 694070.9.6069937 Buffer Zone 25m) An isolated stone artefact locatedon the upper slope of a spur.

RRF25 -ACT 1:10 000 210458.583500 (GDA/MGA 692884.6073331) This site is alow density scatter on the surface of a fire trail that passes through a shallowsaddle. Artefacts are apparent along approximately 70m of trail. It is likely thatthe site extends across most of the saddle feature. The local soils have moderatepotential to contain in situarchaeological material.

RRF26 -ACT 1:10 000 210274.584184 (GDA/MGA 692714.6074017) This sitecontains an estimated 30-50 artefacts extending along approximately 200m of firetrail in a wide saddle setting. The site extends through the saddle to a trail Tintersection south of an overhead subtransmission line corridor. Artefacts are


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apparent eroding from cuttings along the edge of the trail. Local deposit is mostlygravelly clay with some loamy soil in the saddle. The potential for additionalartefacts at the location is high.

RRF27 -ACT 1:10 000 210169.584132 (GDA/MGA 692607.6073969) This site is asmall low density artefact scatter extending along approximately 50m of fire trail on

a short spur crest. It is likely that the site extends into adjacent spur crestdeposits.

Figure 7: Heritage Items


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Eu r o p e a n H e r i t a g e

There are no previously recorded European historic sites within the study area.Unrecorded historic sites and features that may occur within the Williamsdale areainclude:

nineteenth-century structures such as farm dwellings, outbuildings andselectors and timber-getters huts, which may survive as archaeologicaldeposits and are most likely to survive on less developed rural properties

traces of agricultural processing or extractive sites such as dairies and quarries

access routes such as bridle paths and stock routes

old fence lines (such as post and rail fencing) along road easement boundariesand farm boundaries.

Within the nearby area, the Royalla Shearing Shed is listed in the ACT Heritage

Register. The shearing shed has also been identified in Sites of Significance in theACT Volume 4, Woden, Tuggeranong and Associated Areasas having localhistorical significance, as it provides a good example of the ingenuity of bushcarpentry

This sheering shed is immediately adjacent to the highway on the western side andnear the main entry to the Royalla rural residential estate. it is approximately 500mfrom the proposed subtransmission lines.

Reedy Creek Gorge (Block 65 Tennent) includes remnants of a hut built in 1881identified as having cultural heritage. This locality is on the western side of the

Murrumbidgee River and is therefore outside the study area.

2.1.6 Land Use

The land uses within the southern sector include grazing, agricultural uses andassociated rural dwellings.

The land uses within the central sector include grazing and agricultural uses, ruralresidential dwellings. Adjacent to the line route is nature park including Rob RoyRange.

The land uses in the northern sector are grazing and other agricultural use and

rural residential dwellings. The line is adjacent nature reserves.


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2.1.7 Landscape and Views

The landscape of the central sector is generally cleared agricultural land, crossed byGuises Creek and several other small intermittent creeks and gullies.

Views to the proposed lines from the Monaro Highway are generally limited due tothe distance between the lines and the road. The densely vegetated background ofthe Rob Roy Range has high visual absorption capacity which will enable the polesto readily blend into the background.

2.2 Description of the Region Surrounding the Project Site

The Williamsdale to Theodore subtransmission line route runs south to north alongthe foothills and basal slopes of Rob Roy Range and at its northern end passes

between Callaghan Hill and that range. The line route crosses several drainagelines and creeks including Guises Creek.

The region surrounding the study area comprises an undulating landscapeincorporating the slopes of the Rob Roy Range, the Murrumbidgee River valley andGuises Creek valley. (Figure 8 refers)

The predominant underlying geology of the study area is the middle SilurianColinton Volcanics which comprise tuff, dacite, shale, sandstone and limestonelenses. The Rob Roy Range is composed of Tuggeranong Granite which is a pinkgranite of Silurian/Devonian age.

Where native vegetation is present in areas surrounding the project site, thisconsists predominantly of open forest dominated by E. macrorhynchaand E. rossii,with a native shrub understorey and groundcover. Because of clearing for firewoodproduction during the early development of Canberra, the majority of the foresttrees are relatively young but there are some trees which would predate Europeansettlement. There are also some limited areas of remnant Yellow Box Red Gumgrassy woodland or scattered old remnant woodland trees which are regeneratingnaturally within introduced pasture.

The predominant land use in the immediate vicinity of the subtransmission lineroute is agricultural land including cattle and sheep grazing. The corridor between

the Monaro Highway and the nature reserves to the west contain eight (8)dwellings.


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Figure 8: Surrounding Region


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2.3 Current Land Use Policy and Lease Conditions of the Site

2.3.1 National Capital Plan

The object of the NCP is "to ensure that Canberra and the Territory are planned anddeveloped in accordance with their national significance".

The National Approach Route (the Monaro Highway) includes land within 200m ofthe centre line of the road. Special Requirements under the NCP apply to suchland. Development adjacent to Approach Routes must be of a type and qualitycomplementary to the role and status of the city. The proposed route as describedin this report is greater than 200m from the Monaro Highway.

Design policies of the NCP are concerned with achieving awareness of thesignificance of the approach route by the following:

marking the boundary of the ACT

establishing a clear and identifiable route from the boundary to the symboliccentre of the city

progressively formalising the design character along approach routes

enhancing views to recognisable and popular images of the National Capital

ensuring that the structure, detailing and signage is consistent.

A high voltage transmission line is defined under the NCP as a Public Utility, whichfalls within the broader land use definition of Administrative and Utility Services.

A Public Utility as defined by the NCP means the use of land for the following utilityundertakings:

a) headwork and network undertakings for the provision of sewerage and

drainage services or the reticulation of water, electricity, or gas except forgas manufacture and storage;

b) communication facilities, including Australia post facilities, Telecom facilities,television/radio broadcasting facilities and air navigation communicationsfacilities;

c)

municipal uses, including street cleaning depots, public toilets, parks andgarden depots, works depots and associated uses.

The proposed transmission line route crosses two Land use Polices under the NCP,being Rural and Hills Ridges and Buffers. Public Utility is permissible within bothRural and Hills Ridges and Buffers Land Use Policy areas.

Na t i o n a l Ca p i t a l O p e n S p a c e Sy s t em

The importance of the natural setting of the National Capital has been recognisedby the creation and formal adoption of the concept of the National Capital OpenSpace System (NCOSS). This system includes the distant mountains and bushlandsto the west of the Murrumbidgee River near the proposed subtransmission lineroute.


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The National Capital Open Space System (NCOSS) is intended to protect thenationally significant open space framework, visual backdrop and landscape settingfor the National Capital.

The route is outside the historic landscape significance and heritage values of theLanyon Bowl Area.

The route does traverse areas identified as Hills, Ridges and Buffers under theNational Capital Plan. The NCP states that hills and ridges are intended for multipleuses appropriate to the location and character of each area. Their continued usefor recreation, tourism and appropriate urban services must be in a mannerconsistent with maintenance of their environmental qualities.

The NCP requires that Hills, ridges and buffer spaces remain substantiallyundeveloped in order to protect the symbolic role and Australian landscapecharacter of the hills and ridges.

The range of uses permitted in the Hills, Ridges and Buffer Spaces part of theNational Capital Open Space System include Public Utility

Figure 9: Extract from National Capital Plan


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2.3.2 EPBC Act 1999

The project will be referred under the Commonwealth Environment Protection andBio-diversity Conservation (EPBC) Act, 1999 due to the potential to impact uponareas of Yellow Box Red Gum Grassy Woodland. Procedures under the EPBC Actwill be initiated and the EPBC assessment undertaken separately to the DA process.

2.3.3 Territory Plan

The Territory Plan provides the policy framework for the administration of planningof land under the jurisdiction of the Territory. The purpose of the Territory Plan isto manage land use change and development in a manner consistent with strategicdirections set by the ACT Government, Legislative Assembly and the community. Itmust not be inconsistent with the National Capital Plan. The Territory Plan includesbroad principles and po

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