maintenance and operations guidelines for planning, design...

Maintenance and Operations Guidelines

for Planning, Design, Construction and

Handover of Capital Projects in the

Auckland South Area Motorway Network

October 2013

M&O Guidelines for Capital Projects - Revision 5

This document has been prepared for the benefit of the NZ Transport Agency (NZTA). No liability is accepted

by this agency or any employee or sub-consultant of this agency with respect to its use by any other person.

This disclaimer shall apply notwithstanding that the report may be made available to other persons for an

application for permission or approval or to fulfil a legal requirement.

Quality Assurance Statement

Project Manager: Bruce Chappell

Prepared by: Rob Lorden, Peter Mitchell, Andrew Stevens, Tek

Chin, David Ashby, Cliff Wickham, Vic Ollerenshaw, Jim Baker,

David Rendall, Grant Gordon, Dale Logan, Rick Gardner, Trevor

Yeoman, Phil Stewart, Mike Marsden, Carol Bannock, Kathryn

Campbell

Reviewed by: Bruce Chappell, NZTA Auckland Capital Projects and

Highway Network Operations personnel

Approved for issue by: Tony Fisher

Revision Schedule

Rev.

No Date Description Prepared by Signature Reviewed by Approved by Signature

1. Oct 09 Issued for NZTA

review/approval See above

B. Chappell T. Fisher

2. Jan 10 Amended and

issued for use B. Chappell


3. Aug 10 Amended and

issued for use See above


4. Sep 10

Capital Project

deliverables and

timing amended

B. Chappell


5. Oct 13 Amended and

issued for use B. Chappell



Contents

1. Introduction ......................................................................................................................... 1

1.1 Background.......................................................................................................................................... 1

1.2 Capital Projects Breakthrough Workshop .............................................................................................. 1

1.3 Maintenance and Operations Guidelines for Capital Projects ................................................................. 2

2. Asset Classes........................................................................................................................ 4

3. Asset Management and Whole of Life Value ........................................................................... 5

3.1 Highway Asset Management Cycle ........................................................................................................ 5

3.2 Whole of Life Value .............................................................................................................................. 5

4. Health and Safety .................................................................................................................. 6

5. Consenting ........................................................................................................................... 7

6. Project Deliverables and Timing ............................................................................................ 8

7. RAMM and As-Built Data ..................................................................................................... 10

7.1 RAMM Data ........................................................................................................................................ 10

7.2 As-Built Data ................................................................................................................................ 11

8. Pavements and Surfacing .................................................................................................... 12

8.1 Whole of Life Cost Considerations ...................................................................................................... 12

8.2 Planning and Design Considerations ................................................................................................... 13

9. Structures ........................................................................................................................... 15

9.1 Whole of Life Cost Considerations ...................................................................................................... 15

9.2 Planning and Design Considerations ................................................................................................... 15

9.2.1 Drainage ..................................................................................................................................... 15

9.2.2 Structure Inspections .................................................................................................................. 17

9.2.3 New Structure Components ......................................................................................................... 17

9.2.4 Other Considerations .................................................................................................................. 17

9.2.5 Over-Weight Vehicles .................................................................................................................. 19

9.2.6 Over-Dimension Vehicles ............................................................................................................ 19

9.2.7 Safe Maintenance Inspection Access Considerations .................................................................... 20

9.3 Handover Considerations ................................................................................................................... 20

9.3.1 Production of all As-Built Information and Bridge Data System (BDS)............................................ 20

10. Traffic Assets ................................................................................................................... 21

10.1 Whole of Life Cost Considerations .................................................................................................... 21

10.1.1 Lighting .................................................................................................................................... 21


10.1.2 Barriers ..................................................................................................................................... 22

10.2 Planning, Design and Construction Considerations ........................................................................... 23

10.2.1 Lighting .................................................................................................................................... 23

10.2.2 Barriers ..................................................................................................................................... 25

10.2.3 Line Marking ............................................................................................................................. 26

10.2.4 Signage .................................................................................................................................... 27

10.3 Other ............................................................................................................................................... 28

11. Traffic Operations ............................................................................................................ 29

11.1 Traffic Operations Assets and Issues ................................................................................................ 29

11.2 Traffic Signals .................................................................................................................................. 32

11.3 ITS Equipment .................................................................................................................................. 32

11.3.1 Whole of Life Considerations ..................................................................................................... 32

11.3.2 Operational Requirements ......................................................................................................... 32

11.4 ITS Hardware.................................................................................................................................... 33

11.4.1 Full Body CCTV Cameras ........................................................................................................... 33

11.4.2 Emergency Motorway Telephones (EMT) .................................................................................... 33

11.4.3 Lane Control Signals ................................................................................................................. 34

11.4.4 Vehicle Detection Systems ......................................................................................................... 34

11.5 Structures and Roadside Furniture .................................................................................................... 34

11.5.1 ATMS Cabinets .......................................................................................................................... 34

11.5.2 CCTV Poles ............................................................................................................................... 35

11.5.3 Gantries .................................................................................................................................... 35

11.5.4 Services .................................................................................................................................... 35

11.6 Handover Procedures ....................................................................................................................... 36

11.6.1 Procedure ................................................................................................................................. 36

11.6.2 Documentation ......................................................................................................................... 36

11.6.3 Spares Handover ....................................................................................................................... 36

12. Corridor Assets ................................................................................................................ 37

12.1 General ............................................................................................................................................ 37

12.2 Whole of Life Cost Considerations .................................................................................................... 38

12.3 Planning, Design and Construction Considerations ........................................................................... 40

12.4 Management of Pest Plants ............................................................................................................... 43

12.5 Asset Owner‟s Manual ...................................................................................................................... 46

12.6 Vegetation Handover ........................................................................................................................ 46

12.7 Other Items ...................................................................................................................................... 46

13. Stormwater Management .................................................................................................. 47

13.1 Stormwater Management Assets ....................................................................................................... 48


13.2 Whole of Life Value Considerations ................................................................................................... 49

13.3 Planning, Design, Construction, and Handover Considerations .......................................................... 50

13.3.1 General ..................................................................................................................................... 50

13.3.2 Planning ................................................................................................................................... 52

13.3.3 Design ...................................................................................................................................... 53

13.3.4 Construction ............................................................................................................................. 66

13.3.5 Handover .................................................................................................................................. 68

Appendices .................................................................................................................................. 1

Appendix 1 - Corridor Assets ..................................................................................................................... 1

Appendix 2 Safe Mowing Slopes ............................................................................................................... 1

Appendix 3 - Corridor Assets Photo Examples ........................................................................................... 1

Appendix 4 - The Real Costs of Mowing Grass (A Guide for Assessing Whole of Life Cost Considerations) ... 1

Appendix 5 – Other Corridor Considerations .............................................................................................. 1

Appendix 6 - Graffiti Management ............................................................................................................. 1

Appendix 7 - Asset Owner‟s Manual – Landscaping .................................................................................... 1

Appendix 8 - Asset Owner‟s Manual – Stormwater Management ................................................................. 1

M&O Guidelines for Capital Projects - Revision 5 Page 1

1. Introduction

1.1 Background

Auckland Motorway Alliance (AMA) was established as an Maintenance and Operations (M&O) Alliance for the

Auckland South network area in the Auckland Region of NZTA. The Alliance participants are New Zealand

Transport Agency (NZTA), Fulton Hogan Ltd, Beca Infrastructure Ltd, Opus International Consultants Ltd,

Resolve Group Ltd with Armitage and Auckland Harbour Bridge as (sub-Alliance participants).

The Auckland South network has had many Capital Projects undertaken between 2000 and 2013. Several

projects are currently underway (2013) and planned for the next decade. Interfacing with Capital Projects is

essential to ensure best for network outcomes occur during planning, design, construction and handover.

1.2 Capital Projects Breakthrough Workshop

A Capital Projects breakthrough workshop was held on Monday 6th April 2009 that identified several gaps that

exist between current and desired outcomes from the various stages of Capital Projects. The workshop

established means to close these gaps. The table below presents the workshop initiatives established.

Gap Breakthrough Initiatives

Little structure around handovers and maintenance

during construction.

Create and implement an agreed structure.

Specifications and standards for maintenance during

construction.

Review these and propose improvements.

Liaison issue for maintenance during capital project. Create M&O contact person for each Capital Project.

Expectations of stakeholders:

Existing Capital Projects

Future Capital Projects

Actions to meet expectations:

Document and close out existing projects

M&O involvement at planning, design,

documentation, construction and handover stages

Stakeholder liaison AMA to be involved at various stages

Poor understanding of asset life and asset demands.

Design staff with little or no background in M&O.

No whole of life costs.

No evaluation of congestion costs for project stage or

for future maintenance activity.

Solution to all these gaps is to produce a complete

Maintenance and Operations Guidelines to

accompany the usual Capital Project Design

Standards, Manuals and Guidelines that will

emphasise whole of life evaluation requirements.

NZTA to promote M&O issues in Capital Projects.

Lack of interest in what is being handed over and

associated documentation required

Regular project interfacing to audit M&O issues.

No practical completion issued until project finished:

- schedule an item with large sum for this, or

- withhold payment to progressively release

Early resolution of maintenance boundary issues

once assets are known in Capital Projects.


The breakthrough initiatives generated can be encapsulated in three action items:

Complete M&O Guidelines for Planning, Design, Construction and Handover of Capital Projects in the

Auckland South Area Motorway Network by October 1 2009 and have NZTA mandate the use thereof.

Establish M&O contact person to act as liaison portal with Capital Projects.

To actively engage with Capital Projects during planning, design, construction and handover stages.

1.3 Maintenance and Operations Guidelines for Capital Projects

This document has been prepared as the M&O Guidelines for Planning, Design and Construction of Capital

Projects in the Auckland South Area Motorway Network.

This is a unique opportunity to contribute to the processes in planning, preliminary design, detailed design,

Principal‟s Requirements, specifications, construction and handover of Capital Projects.

By defining processes and outcomes with Maintenance and Operations considerations, for each stage of a

Capital Project, whole of life issues and value for money can be included.

Mitigation of risk of undesirable outcomes for post project handover Maintenance and Operations activities

can also occur.

Data for production and review of these Guidelines has come from several sources:

Planning and Capital Project personnel in NZTA

Highway Network Operations personnel in NZTA

Existing NZTA documentation aligned to M&O outcomes for capital projects

AMA participants

All traditional entities (Client, Design Consultant, Construction Contractor, Maintenance Consultant and

Maintenance Contractor) are represented by the AMA participants. This captures a knowledgeable group with

experience across all stages of Capital Projects.

NZTA has published an existing standard document, Asset Management Guide for Project Design, Standard

Professional Services Guideline PSG/3 - Asset Management Guide, Version 1, March 2009 which shall be used.

These new M&O Guidelines for Capital Projects are “Auckland motorway centric”, in that it represents the M&O

requirements for the Auckland South area motorway network in particular. These Guidelines are in addition to

NZTA‟s standard document.

The following table outlines the M&O inputs at various Capital Project stages:


Capital Project Stage Asset Type M&O Inputs M&O Personnel Input or Advice

Planning and

Consenting

Depending on project. Delivery – maintenance issues and relative costs.

Asset Management – conceptual design issues.

Feasibility, Conceptual

and Preliminary Design

and Consenting

Depending on project. Delivery, Asset Management, Traffic Operations.

Tender Stage for

Detailed Design

Document input requirements

with respect to whole of life

value and demonstrating value

for money in decision making.

Delivery, Asset Management, Traffic Operations

Detailed Design and

Consenting

All asset classes likely to have

input requirements.

Delivery, Asset Management, Traffic Operations.

Preparing Principal‟s

Requirements and

Project Specifications

All asset classes likely to have

input requirements.


Site Handover to

Capital Project

Nil Delivery

Construction All asset classes likely to have

input requirements.


Data Delivery All asset classes likely to have

some data requirements.

Delivery, Asset Management, Information

Management

Site Handover to M&O All asset classes likely to have

M&O inspection requirements

Asset Management, Delivery, Traffic Operations

The focus of these Guidelines is to provide recommendations in the following areas:

Consideration of maintenance and operating costs during planning and consenting stages of capital

projects

Whole of life value for money in selecting asset class components

Design and construction of assets that lead to safe, effective and efficient maintenance activities

Users of these Guidelines should discuss issues requiring clarification with the organisations responsible for

the current M&O and/or asset management contracts on the network.

In these Guidelines the term “network Maintenance and Operations organisations” is used to define the current

single or multiple organisations contracted by NZTA to undertake network Maintenance and Operations.


2. Asset Classes

The Auckland South network comprises numerous asset classes, each with specific maintenance requirements:

Pavements and Surfacing

Structures

o Overpass and underpass bridges of various materials and forms

o Large diameter culverts

o Tunnels and associated buildings

o Retaining walls

o High mast lighting

o Noise walls

o Stormwater structures

o Weigh stations and associated buildings, facilities and pavements

Stormwater management assets

o Surface water collection, conveyance and disposal

o Waterway and network crossings (e.g. culverts)

o Management devices (e.g. treatment systems)

Traffic assets

o Street lighting

o Signage

o Pavement delineation

o Barriers

Corridor assets

o Noise walls and fences

o Vegetation

o Urban design features

o Graffiti coatings

Intelligent Transportation System assets

o Cameras

o Emergency telephones

o Variable message signs

o Lane signal units

o Traffic signals

o Fibre optic backbone

Electronic Weigh in Motion detection equipment

Mechanical and electrical equipment in tunnels


3. Asset Management and Whole of Life Value

3.1 Highway Asset Management Cycle

Many organisations are involved in the highway asset management cycle:

Management at national and regional level (NZ Government and NZTA specifically)

Network planning (NZTA, consultants)

Design (NZTA, consultants, contractors)

Construction (NZTA, contractors, consultants)

RAMM database updates (NZTA, contractors, consultants)

Operations (NZTA, consultants, contractors)

Performance monitoring (NZTA, consultants, contractors)

Condition monitoring (NZTA, consultants, contractors)

Maintenance (NZTA, contractors, consultants)

Rehabilitation (NZTA, contractors, consultants)

Replacement (NZTA)

Revocation (NZTA)

Asset management auditing (NZ Government)

Each capital project is an intrinsic part of the highway asset management cycle. Capital projects occur over a

relatively short time frame in the total asset management cycle, typically around 5 to 15 years for planning

and creation, in an asset Maintenance and Operations life of perhaps 50 to more than 100 years. The

outcomes of the planning and creation stages of a highway asset have a major influence on Maintenance and

Operations costs over the total asset life.

3.2 Whole of Life Value

Providing whole of life value in decision making is a fundamental requirement for sound asset management

decisions. This process should occur throughout all steps in the highway asset management listed above.

The requirement for whole of life value in decision making is a recurring theme in these Guidelines. Typically

whole of life value can be assessed and provided by:

Liaison with network Maintenance and Operations organisations for assessment input advice.

Consideration of more than one option in design for asset types and associated components.

Use of net present value cost analysis, capital plus M&O costs, to determine best whole of life value option.

Include operational costs, such as delay costs to highway users in analysis of maintenance requirements for

options, NZTA Economic Evaluation Manual provides methodology and data.

Striving for consistency and compatibility of asset components, determine what is used elsewhere on the

network and the advantages and disadvantages of different component types, refer network Maintenance

and Operations organisations for relevant data.

Including allowance for spares and availability of such in the assessment, understanding that some asset

types have short life spans, e.g. ITS assets may have 5-10 year lives with limited spare availability.

Design to include allowance for future use, e.g. for ITS and utility services include installation of ducting.


4. Health and Safety

Network Maintenance and Operations activities provide health and safety challenges for both staff involved in

such activities and road users.

Capital project planning and design has a role in the whole of life management of health and safety risk

associated with Maintenance and Operations activities. This can be achieved by:

Rigorous adoption of Safety in Design principals.

Incorporate crime prevention through environmental design (CPTED) provisions in the design process.

Liaison with network operation and maintenance organisations with respect to:

o Design elements, or lack thereof, considered to be hazards for Maintenance and Operations activities

or for the road user, e.g.

manholes in shoulder or traffic lane areas

lack of access to stormwater treatment devices

steep areas or areas adjacent vertical drops that require maintenance.

o Providing safe access and consideration of potential dis-benefits of such, e.g. fixed ladders for

structures access could be used by graffiti vandals.

Liaison should occur through planning, scheme assessment, preliminary design and detailed design stages

to identify and mitigate potential hazards.

Including health and safety of road users and Maintenance and Operations staff in whole of life cost

considerations for asset type and component options, e.g. traffic barriers are a hazard that protects road

users from a hazard, is there an alternative to remove both hazards?

Demonstrating that the design option selected minimises maintenance interventions. Liaison with M&O

personnel will likely be required to satisfy this requirement.

Identifying how each asset component will be maintained and demonstrating that maintenance can be

undertaken in a safe manner. Liaison with M&O personnel will likely be required to satisfy this

requirement.


5. Consenting

During the planning, scheme assessment, preliminary design and design stages of Capital Projects designation

and resource consenting authorities often require a level of detail on asset types and locations that can lock

the project into early Maintenance and Operations requirements. These consent requirements and associated

conditions may have considerable whole of life cost implications. Agreement may be reached without due

consideration of alternative options that satisfy requirements and offer better whole of life value.

The organisations responsible for network Maintenance and Operations have considerable experience in asset

types, options and the associated whole of life costs. It is recommended that organisations responsible for

the planning, scheme assessment, preliminary design and design stages of Capital Projects seek advice from

organisations responsible for network Maintenance and Operations during consent stages to ensure that what

is being agreed to reflects consideration of whole of life value.

Consideration needs to be given to the conditions that require on going inspection and reporting. In addition

to the safety of access, special attention should be given to the appropriateness of the frequencies, type and

consequences of non-compliance of monitoring agreed to.

An example of this might be the concept of utilising soakage pits in the motorway shoulder in an area with a

predominance of subsurface rock, combined with limited corridor width for stormwater disposal. This option

may offer least capital cost, and an easy path for consenting, however to ensure adequate treatment of

stormwater to required quality standards the provision of devices with a three monthly inspection and cleaning

cycle can sometimes be required. The sum of capital cost and traffic management and cleaning costs over 25

years determined by net present value analysis for the stormwater system could well prove to be higher than

an alternative conventional conveyance system to alternative treatment devices that do not require traffic

management to maintain.

Capital Projects should aim to have one Maintenance and Operations resource consent, and this should align

with the project Environmental Management Plan.


6. Project Deliverables and Timing

A list of project deliverables for the organisations responsible for network Maintenance and Operations, and

the timing of such are included in the table below. This deliverable list and delivery dates should be included

in Capital Project documentation.

Deliverable Item Deliverable Date

Project geometric design, in digital version, as Autocad

or Shape File, for NZTA RAMM network model

updates.

As soon as available, but not later than 3 months

before Practical Completion.

Structural data (bridge data) for NZTA bridge database

system (BDS), to enable permits to be issued for

overweight/over dimension vehicles.

As soon as available, but not later than 1 month

before opening of structure.

Operational consents and their conditions. As soon as agreed for operation and maintenance

planning and budgeting.

Producer statements. Not later than Practical Completion.

Certificate for Public Use. Before opening of structures.

Digital As Built drawings, as Autocad and pdf file. Draft before Practical Completion. Final not later

than 3 months after Practical Completion.

RAMM data for all assets collected by NZTA qualified

RAMM data collectors.

Maximum 1month after Practical Completion.

Stage 4 Road Safety Audit date.

Note, M&O traffic safety personnel may provide the

project audit team with known safety deficiency data

for the area and will also observe the project audit.

Audit carried out not later than 1 month after

Practical Completion. Advise date of audit to

organisations responsible for network M&O 2 weeks

in advance of audit date to allow audit observance.

Joint inspections programme with network

Maintenance and Operations personnel.

Minimum 1 month before permanently opening any

section of the Works.

ITS equipment operations manuals.

Minimum of 1 month before any section is opened

to traffic.

10% working spares for all ITS assets installed are to

be supplied to maintenance contractor organisations

Not later than Practical Completion.

Asset Owner‟s Manual including M&O requirements for

asset components and code of compliance certificates.

Draft not later than Practical Completion. Final

maximum 3 months after Practical Completion.

Snag/Defects Lists At practical completion and maintained and updated

weekly by project personnel until completed and

signed off.

Maintenance boundaries and agreements.

Responsibility lies with NZTA Project Manager.

Draft - not later than Practical Completion. Final -

maximum 3 months after Practical Completion.


The organisations responsible for network Maintenance and Operations prefer all project deliverables to be

delivered as digital versions, and not hard copy.

It is recommended that Capital Projects create a suitable secure document storage area for such deliverables

that is accessible for project personnel, relevant NZTA staff and relevant staff from the organisations

responsible for network Maintenance and Operations, to enable:

Timely deposit of deliverables, with version control

Relevant personnel to view progress on deliverables

Simple file transfer to occur, with version control

Tracking of deliverable progress against delivery programme.

Should the Capital Project be unable to create and maintain such a document storage area, the organisations

responsible for network Maintenance and Operations will create a web-based site for this purpose.


7. RAMM and As-Built Data

7.1 RAMM Data

A summary of asset information required for updating the RAMM system follows.

These criteria are designed to assist Capital Project Managers in specifying the timely capture of such data and

in the approved format.

A fundamental issue for NZTA is to decide whether to require Capital Projects or the organisations responsible

for Maintenance and Operations of the network to undertake the RAMM data capture for the project. Currently

this responsibility lies with Capital Projects.

To enable RAMM data for Capital Projects to be collected, and Route Positions of assets recorded correctly,

the Capital Project will require highway and ramp route stations, and interchange and ramp identification

numbers to be fixed and agreed in accordance with the NZTA Manual SM051, Location Referencing

Management System (LRMS).

The Capital Project contract will identify what responsibilities, if any, the project has with establishment of

the LRMS system for the project. The Capital Project is encouraged to liaise at an early date with the

network Maintenance and Operations organisations, to identify roles and responsibilities and to ensure

establishment of the system occurs well in advance of project opening to enable RAMM data collection to

be carried out before project opening.

RAMM data is to be submitted to the accredited individual for RAMM upload in the approved NZTA forms

that can be obtained from the NZTA Asset Management RAMM Manager – due to constant updating of

these forms it is essential that the latest forms are obtained from the source listed.

RAMM data may also be provided in a digital format using Pocket RAMM databases, although spreadsheet

format is preferred. Pocket RAMM data could be collected and stored in an off-line “dummy” database

before being exported for upload to RAMM to occur by the accredited individual.

All RAMM data collectors shall be certified to NZTA Level 1.

All asset fields for new items, highlighted in yellow, shall be completed, unless otherwise agreed by the

NZTA Asset Management RAMM Manager. If fields are left blank, without permission, data is likely to be

rejected.

Project Managers are to ensure that project boundaries are understood and that all asset information within

these boundaries is captured. Exact start and end RPs (ERPs) will need to be clearly defined to ensure

assets are accurately captured, as well as a clear understanding of Increasing and Decreasing sides of the

route in the case of divided carriageway sections.

This requires the network Maintenance and Operations organisations to produce a Network Update Form

(NUF) with details of a route change (see LRMS Manual).


The Network Update Form (NUF) should be prepared prior to opening, with the detailed data being

provided at latest 1 month after Practical Completion.

Only once an NZTA official RAMM receipt has been received can the project be signed off as complete.

The Capital Project may consider negotiating the shifting of RAMM data responsibilities to the network

Maintenance and Operations organisations if this is deemed more effective or efficient.

7.2 As-Built Data

As-Built data is critical for M&O organisations to understand the extent and location of assets and to enable

planning and compilation of long term forward works programmes for budget purposes.

Final As-Built data should be delivered not later than 3 months after Practical Completion of the project.

Design geometric drawing data in the form of plans, long-sections and cross-sections should be delivered

at least 3 months prior to Practical Completion to enable establishment of the LRMS system and update of

the NZTA network model for RAMM data to be recorded against.

NZTA should ensure project handover documentation requirements are clearly defined in project

documentation, with delivery timeframes, and adequate leverage in the MSQA and construction contracts to

ensure delivery occurs on time.

Suggestions are a minimum Lump Sum amount (say 1% of Contract total) in the project tender scheduling to

ensure the RAMM and As Built data work is given due attention and not ignored or recorded poorly.


8. Pavements and Surfacing

8.1 Whole of Life Cost Considerations

Pavement concepts and designs should consider the following:

Referring to the latest NZTA Pavement Design Guideline Document or Standards for good advice on

pavement types and associated risks.

Undertaking whole of life cost analysis for the evaluation of design options using the risk based evaluation

procedures in the NZ Supplement for the Austroads Pavement Design Guide.

When undertaking risk based evaluation of pavement options ensure risk factors assigned to pavement

type options are agreed with NZTA (as at 2013 there are many projects in NZ where this methodology has

been used, refer to the network Maintenance and Operations organisations or David Alabaster of NZTA).

For construction and maintenance costs evaluation remember to consider the additional cost of traffic

management for maintenance activities that is applicable to the class of road being designed.

For maintenance costs unit rates and traffic management costs refer to the network Maintenance and

Operations organisations, RAMM database historical costs, NZTA asset management staff, and/or Roading

New Zealand (RNZ) or its member organisations for advice related to road class and location.

Consider performance of existing pavements and structural type when evaluating risk for options.

Avoid designing grassed or landscaped medians as the mowing or vegetation maintenance operation is

both unsafe for personnel and expensive due to traffic control requirements. Grassed or vegetated

medians have been shown, long term, to result in rutting and localised ponding in the median, loss of

support at wire rope or steel barrier posts, and potential for water ingress into pavement sides.

Consider polymer binders in surfacings to provide extended life in heavy or very heavy traffic situations

and/or high stress areas.

Consider epoxy asphalt surfacing to provide best whole of life value.

Consider the practicalities of providing specialist surfacings that may require high maintenance costs to

satisfy consent conditions, e.g. 80 mm thick two layer OGPA surface for noise mitigation may initially be

cheaper than a noise fence, however long term replacement interval frequency and cost for the 80 mm

thick layer to perform as consented, may result in a noise fence being a more cost effective solution.


8.2 Planning and Design Considerations

Projects tender documentation should require the maintenance responsibility for existing pavements to

extend as far as the project temporary signage as the organisations undertaking Maintenance and

Operations for NZTA are unable to work within Capital Project managed sites.

Gated median cross over points are useful when full closures in one direction are required during

maintenance or emergency activities. Detours during full carriageway closure can result in road user stress

or fear, significant additional travel time for vehicles and congestion in local areas. Having the option of a

gated crossover with temporary barriers in a contra-flow traffic arrangement would provide a more

efficient option for traffic management and emergency vehicles. Suggested spacing of gated median

crossovers is one per kilometre, however this will depend on the alignments of opposing carriageways.

If existing pavements are being utilised in the final design, check the stiffness of the existing pavement

(Falling Weight Deflectometer deflection and curvature) and determine whether rehabilitation or upper

pavement stiffening is required to provide the design life required and compatibility with new pavements.

If widening of existing pavements is being undertaken then the pavement widening should match the

stiffness (deflection and curvature) of the adjacent pavement unless a stepped transition zone of adequate

width is created to mitigate potential for longitudinal cracking at the interface, or alternatively the existing

pavement is rehabilitated to have similar stiffness characteristics as the new designed pavement.

If widening of existing pavements is being undertaken then the existing pavement depth and subsurface

drainage characteristics should be determined to ensure that the new design does not create ponding of

subsurface water within the existing pavement area. Examples are new impermeable pavement types

constructed to subgrade level and located adjacent to and downslope of existing pavements with a

granular drainage layer, which would then require a subsoil pavement drain at the new/old interface.

If cement bound pavements are an option, consider what measures are to be included in design and/or

construction techniques to mitigate slab warping and/or reflective cracking in the pavement surfacing.

Consider local aggregates and contractor construction and maintenance capabilities in design options.

Minimum constructed thickness of dense graded and stone mastic asphalt layers should be in accordance

with the latest version of NZTA M/10 specification, currently (2013):

o A minimum of 3 times the mix nominal size for dense graded mixes (old TNZ mixes)

o A minimum of 3.5 times the mix nominal size for asphaltic concrete mixes (AC mixes)

o A minimum of 4 times the mix nominal size for stone mastic asphalt mixes (SMA mixes)

The nominal mix size is the sieve size that 90% of the graded aggregates will pass. Pavement designers

should design to thicker than the minimum thicknesses above to allow for construction tolerances, and

specify the minimum constructed thickness for each layer appropriate for the design.

Minimum constructed thickness of open graded porous asphalt mix layers should be a minimum of 3 times

the mix nominal size.


Thin asphalt layers, <45 mm, can be significantly permeable. When used over unbound granular layers,

design to include adequate waterproofing below the asphalt layer, to maintain water resistance and

associated shear strength in the unbound granular layer, in the form of sufficient chip seal layers and/or

bitumen emulsion added to the basecourse aggregate:

o For dense graded, asphaltic concrete or stone mastic asphalt mixes over unbound granular or

modified aggregate basecourse pavements a minimum of 2 l/m2 residual binder under the asphalt

o For open graded porous asphalt mixes over unbound granular or modified aggregate basecourse

pavements a minimum of 3 l/m2 residual binder under the asphalt

Consider all areas from which water might enter a pavement:

o The sides, subsurface flow from batter slopes

o Unsealed shoulders in super-elevated sections

o Through the surfacing (thin asphalt surfacing and chip seals are not waterproof), and particularly

through paving joins and cracked areas

o Upward from the subgrade (springs or capillary rise)

In wide motorway sections, with greater than 3% longitudinal gradient, water within the pavement will tend

to flow along the alignment rather than across it. In steep areas (greater than 5% longitudinal gradient)

unbound or modified granular pavement saturation, and hydrostatic or hydraulic forces, can occur leading

to loss of shear strength during wet weather and traffic loading. Pavement water can flow upward through

the surfacing, noticeable when the pavement surface dries out. Design flushable herring bone subsoil

pavement drains at regular intervals at the top of the subgrade layer, across the water flow direction, to

provide periodic release of the entrapped pavement water. Ground and pavement water flow modelling is

recommended to mitigate risk of saturation levels rising above 80% in any unbound pavement layers.

Pavement subsoil systems shall have:

o The ability in the future to utilise inspection cameras within the pipe to check condition

o The ability to clean the subsoil out by water jetting (entry points and the ability to get a pressure

water hose up the subsoil drain)

o Concrete surrounds on any outfalls to embankments to prevent damage by maintenance vehicles

o Vermin grills on outlets to prevent nesting by rodents

Review potential aquaplaning issues where the carriageway is widened or the geometry is changed such

that the drainage path length is increased. Refer stormwater section in this document.

Provide adequate and maintainable drainage systems with positive drainage to prevent water ingress, and

remove water from, permeable pavement layers.

Where edge beams are used in unbound granular layers, check whether the depth of these will affect

pavement layer drainage. In the case where such edge beams are constructed to subgrade level provide

large pavement layer drains to remove trapped water.


9. Structures


Standardisation, where possible, for all structure joints to reflect best practice and operational knowledge

from the network Maintenance and Operations organisations, to reduce outages, and the need for resetting

and tightening of holding down components.

No abrupt changes in longitudinal grade at joint locations. Longitudinal profile should follow design

geometrics, and a maximum joint roughness of 50 NAASRA counts should be achieved.

Review of component design to allow for fatigue long term.

At concept design stage consider reducing the number of joints required.

Allow for future inclusion of structural fittings for increased post tensioning to allow increased loading.

Whole of life review of future capacity requirements for both traffic services and pedestrians.

Consider whole of life value if considering partial prestress in design, which may allow cracking to occur

with associated future maintenance and operation cost issues (refer to network Maintenance and

Operations organisations for data on experience with poor performing examples that saved capital cost but

added considerably to M&O costs).

9.2 Planning and Design Considerations

9.2.1 Drainage

Standardisation of components, where possible, for surface drainage to aid efficient cleaning and repair.

Review of access to secondary drainage system adjacent to structures, e.g. soak pits or treatment devices,

to address potential damage during access and to facilitate effective cleaning and structural inspection.

Appropriate inlets to ensure structure deck catchment capacity is adequately addressed for predicted

return periods with appropriate mainline capacity.

Design of a water catchment for under joint collection and reticulation to main storm water systems should

be self cleaning and easily maintained. The installation should be able to cope with the expected flows and

direct them into the drainage system.


Main surface drainage should be captured before the structure‟s expansion joint and not be required to go

over or through the joints.

All catchpit grates to have a frame, and not required to be bolted down with small fine threaded bolts.

No scupper drains that need blowing or washing out. If installed they should be self cleaning.

Finger joints to have drainage channel with access for cleaning. Hanging rubber skirts to have a cross fall.

Avoid the installation of drainage systems and elements that require safety belt or specialist access. E.g.

Newton No.1 Bridge drainage channel is outside the MB5 Barrier.

Avoid level drainage pipes.


Consider providing a system without sumps on the structure, only surface grates to prevent debris

blockage of pipes, and provide all sumps and treatment devices off the structure in an area with easy

access.

9.2.2 Structure Inspections

Allow for access staging to carry out general and detailed inspections to be permanently attached to major

structures (e.g. on the new Newmarket Viaduct).

Construct access manholes in box sections on all concrete structures to allow permanent lockable access

for internal inspection processes.

Internal reticulation of lighting and power outlets with the appropriate security for structures where

internal inspections and maintenance work may be required.

Bird proofing should be installed where there is the possibility of pigeons or birds nesting/roosting or

gaining access to the internal services and boxes.

9.2.3 New Structure Components

Sweeping and maintenance of joints needs consideration in joint design as detritus accumulates in rubber

expansion sections and reduces life.

Appropriateness of coatings for lighting columns, holding down bolts and bearings, side protection review.

Joints should be programmed to be reset possibly within defects liability period, if required, after elastic

shortening and creep.

Holding down bolts should have sufficient component room to allow operational movements to take place

without stress.

9.2.4 Other Considerations

Allowance for projected utility services components and associated maintenance access requirements.

All of carriage way and associated shoulder areas should be accessible by the rubbish sweeper.

All bridge joints to be steel edged with concrete or similar nosing. This prevents damaging the joints when

resurfacing.

Concrete nosing to be cast integrally with joint steel edge component.


Do not use epoxy type material for nosing.

Three or four bolts to be used on guardrail posts. This aids installation and repairing when required.

No necked bolts unless specifically treated and installed e.g. galvanised and greased.

No small recesses that overlap on to substantial components e.g. a panel sitting on an abutment, this can

create maintenance issues.

Investigate appropriate clearance for structures both on network and Local Authority underpasses. The

height clearance of adjacent or nearby structures is not a reason to compromise required height clearances

on new structures.

Full consideration for side security protection for both pedestrians and underpass motorists with the

installation of debris screens appropriate for the particular environment.

Appropriate design of screens to allow access by maintenance staff and other stakeholders (e.g. Local

Authority and Railway).

Review side protection requirements particularly when bridge is being widened or modified.

Avoid recesses that create maintenance problems.


Sealed Over Joints. These are shown in the design of bridges where the movement is very small and

sometimes where the movement is practically zero. It is important to prepare the joint correctly before

sealing or asphalting over the top. The use of products such as Polymer Modified Bitumen, PMB 400, or

geogrid is not satisfactory because this will lead to cracking of the surfacing. It is necessary to cover the

joint before surfacing with a high-strength multi-laminate tape bandage that is held in place by priming or

by self-adhesive action. Design surfacing thickness to handle movement expected.

When widening bridges the same joint type as existing shall be used at existing joint locations.

Naming of new structures. Project designers to check with NZTA that the new name proposed does not

duplicate existing names, e.g. the network has three Hillcrest bridges and three Puhinui Stream

bridges. This confusion can be avoided at design stage before names are added to project drawings.

Plants being placed near structures may obscure the structure and cause future damage, e.g. plants that

creep and grow to fill the voids in exposed aggregate panels. In a very short time the architectural features

on the walls can be obscured. The gaps allowed for expansion and movement can fill and resulting forces

may damage the panels. If the whole face is covered by plants that adhere to the wall, the ability to do

competent inspections will be severely compromised without a large vegetation removal job. Ensuring this

does not occur requires structural designers to specify in project documentation that landscape planning,

design and planting must avoid using plants that cause problems to structural elements.

9.2.5 Over-Weight Vehicles

Unless otherwise specified bridges shall be designed to carry HN-HO-72 loading in accordance with the

NZTA Bridge Manual.

Design shall not restrict overweight vehicles to certain travel paths over the structure

Additionally, consider local effects of the footprint of individual overweight axles on components.

The over-weight design shall include all relevant components of the bridge including:

o Foundation and sub structure

o Superstructure

o Approach embankments and all associated extra retaining structures

9.2.6 Over-Dimension Vehicles

Where specified, the bridge shall also be designed to carry specific over-dimension vehicles.

All bridges shall be designed and detailed to allow the passage of over-dimension (6m high and 10m wide)

and over-weight vehicles either over or under the structure as specified in the Principal‟s Requirements.

In particular the following issues shall be addressed:


o Deck width and vehicle tracking swept path

o Clearance dimensions of 10m wide by 6m height

o Where it is necessary for roadside furniture to be removed to allow passage of vehicles design of all

such items shall allow for easy removal and replacement

9.2.7 Safe Maintenance Inspection Access Considerations

Safe access for maintenance inspection workers is important.

Where access will not be from bridge decks or footpaths safe access tracks should be provided as follows

The following recommended drawings are from Department of Conservation track details

o Refer to http://www.doc.govt.nz/documents/about-doc/role/policies-and-plans/track-

construction-maintenance-guidelines.pdf

o The track formation shall be shaped to achieve the required track width and to ensure the track

longitudinal grade is within the required maximum limits

o The required walking surface width shall be between 1200 and 750 mm

o The maximum gradient on any track shall not exceed 1V to 4H (25%) for distances up to 15 m length

o No vegetation shall be planted within 1 metre of inspection tracks

o Surface with 50 mm thickness of compacted well graded aggregate

9.3 Handover Considerations

9.3.1 Production of all As-Built Information and Bridge Data System (BDS)

Live load and overweight capacity calculations should be formally handed over at least one month prior to

opening of the structure to loading. These should be incorporated as a deliverable in the Contract

schedule.

Production of all structural data on the standard forms for the Bridge Data System (BDS) to allow

assessment of effects of passage of overweight vehicle from the first day of operation. Complete BDS

forms, in line with NZTA Bridge Maintenance Manual database operations requirements, shall be provided

to the network Maintenance and Operations organisations one month prior to opening the structures to

public traffic.

http://www.doc.govt.nz/documents/about-doc/role/policies-and-plans/track-construction-maintenance-guidelines.pdf

http://www.doc.govt.nz/documents/about-doc/role/policies-and-plans/track-construction-maintenance-guidelines.pdf


10. Traffic Assets


10.1.1 Lighting

LED lighting

All capital projects are to consider using LED streetlight luminaries. LEDs offer substantial advantages over

existing technology by way of increased „lamp‟ life and energy savings while at the same time reducing

maintenance due to the virtually eliminating of traffic control required for cyclical lamp replacement and

the environmental costs of lamp disposal. Capital projects should undertake a whole of life cost analysis to

determine the business case for installing LED luminaires. The organisations responsible for maintenance

and operation can assist with cost parameters for this analysis.

LED‟s offer better light cut off, which reduces light overspill nuisance to any adjacent property, they have a

lower upward waste light, and have better uniformity than other lamps, particularly in wet conditions.

LED lighting technology is improving exponentially, is becoming widely used and more affordable. Over the

next 15 years it is most likely that the current Auckland South network HID luminaires will be replaced with

LED. Currently (2013) there are 9 different types of luminaries present on the network. This creates stock

control issues for maintenance due to having to carrying spares for many different products. It is preferred

to have fewer types of luminaires for lighting consistency and more cost effective long term maintenance.

The organisations responsible for maintenance and operation will advise recommended LED luminaries.

HID lighting

If new LED lighting cannot be installed by the project then use HID luminaires, as recommended by the

organisations responsible for maintenance and operation of the network, and High Pressure Sodium Twin

Arc 55,000 hour lamps. This will simplify stock control procedures (product availability, purchasing orders,

programming etc.) for the existing HID luminaries.

If HID lighting is adopted then design spacing for streetlight column locations should, where possible,

allow for future upgrade to LED.

Control Monitoring System - use this technology for remote control of lamps to allow dimming for

efficiency, asset management decisions with respect to life of lamp and carbon footprint monitoring.

Locating lighting columns in the median with double outreach arms is preferred to that of shoulder located

columns. An overall lantern mounting height of not less than 12 metres. Median location removes a road

side hazard (barrier or pole), essentially eliminates pole strikes by vehicles and allows easier future

widening of the pavement.


If median lighting installation is unachievable one safe parking area/bay (refer to the drawing below) per 40

lighting columns (20 lighting columns either side of a parking area/bay) should be designed and

constructed. Those bays will also benefit other utility services and road users such as ITS, vegetation,

signs, barriers and other maintenance crews. Bays can also be used by police and as emergency stop areas.

o Parking area plan view:

o Pavement design for the parking area:

All existing lighting related hardware must be replaced with new within capital project area. Do not reuse

existing lighting hardware.

10.1.2 Barriers

For new concrete barriers preferred minimum reveal is 40 mm, to allow at least one pavement surfacing

overlay (standard permits 0 mm minimum to 80 mm maximum).


10.2 Planning, Design and Construction Considerations

10.2.1 Lighting

Slip base height. Ensure correct slip base height in design and installation.

Consider location/design of aprons/structures/slopes of drainage infrastructure relative to barriers and

slip bases, so that vehicle characteristics/behaviour is not changed prior to impact. Location of base of

pole relative to swale drains can be wrong if the drains erode or are re-graded and the slip base

height/performance is compromised.

Vehicle approach angles and relative height of underside of vehicle need to be considered as one side of

the vehicle in a side drain can create a scenario where the vehicle sump is too low to clear the slip base,

resulting in a safety failure. Consider locating poles behind barriers on ground mounted stubs if a median

location is not possible.

Ground stub and shear base protection. To comply with NZTA requirements both stubs and shear bases

require corrosion protection whether or not they are founded in concrete.

Lighting assets such as concrete foundations and area around them (lighting poles, high masts, Montrose

boxes and any other lighting related hardware) shall be designed and shaped to direct water away from the

base of the assets.

Consider location of Montrose (or similar) boxes and power supply infrastructure. Locate outside of the

clear zone or protect with barrier. Include a protected hard stand for maintenance vehicles to stop safely.

Mature vegetation shall not encroach within 1 m of lighting assets (lighting poles, high masts, Montrose

boxes and any other lighting related hardware).


A clear access pathway to the lighting assets (lighting poles, high masts, Montrose boxes and any other

lighting related hardware) from safe parking areas is to be provided.

Careful attention to boundary lines between NZTA and Local Authority should be given for column

placement and cable circuits to allow for easy demarcation (for details refer to organisations responsible

for maintenance and operation of the network for Maintenance Boundary Agreements).

Mitred outreach arms are preferred for NZTA network.

All street lighting materials used on NZTA network area are to be manufactured and installed to the latest

version of the following standards and guides:

o NZTA standard M/26 and appendices;

o NZTA technical memorandum TM-2007 (12/2011).

A requirement for street lighting columns and materials from approved NZTA suppliers only.

The column must comply with the manufacturer‟s specifications for outreach and attachments.

The pole numbering system has to comply with existing NZTA system. The project is to supply final

lighting design to the organisations responsible for maintenance and operation of the network to obtain

correct numbers for each pole.

Review lighting levels where carriageway is widened to ensure compliance with modern standards, as

existing lighting may be deficient in the modern context.


Lighting column cover plates in median. Use the design adopted for Manukau Harbour Crossing project to

standardise cover plates. Refer to organisations responsible for maintenance and operation of the network.

Ensure cover plates for light poles on, or outside of, bridge edge barriers face in towards the road to avoid

the need for cherry picker vehicle access for maintenance inspections.

Consider lighting level at interchanges and intersections carefully.

Integrate lighting, traffic signals and street names at interchanges and intersections on joint use poles to

minimise the number of poles, reduce clutter and maximise visibility to signal displays.

Level of Service (LOS) of the existing lighting operation needs to be maintained during the entire

construction period by the project. Refer to organisations responsible for maintenance and operation of

the network. During construction, attention is required to ensure that a high standard of illumination is

provided. Night time is a high risk period on motorways and in particular road work sites. Design

documentation is to show what appropriate level of lighting is to be provided during construction.

10.2.2 Barriers

Ensure Length of Need requirements are met at the start of all barriers.

Ensure full run-out provision for the length of guardrail selected.

Test level requirements for bridges to be agreed and implemented (generally TL5 for motorway bridges).

Ensure sufficient deflection available behind barrier to any lighting columns or other infrastructure.

Create a hard stand area behind the trailing end of side barriers with sealed access from the shoulder:

o If the location has other infrastructure and/or assets that require regular access (check with the network

Maintenance and Operations organisations)

o That is suitable for VMS signs and maintenance vehicles (in areas where VMS signs may be deployed)

Refer to section Corridor Assets (Landscaping) for low maintenance considerations around barriers.

Ensure major hazards with high severity for errant vehicles are protected even if the object is outside the

clear zone, e.g. ponds, gullies, bridge piers and abutments.

Gated median cross over points are useful when full closures in one direction are required during

maintenance or emergency activities. Detours during full carriageway closure can result in significant

additional travel time for vehicles and congestion in local areas. Having the option of a gated crossover

with temporary barriers in a contra-flow traffic arrangement would provide a more efficient option for


traffic management and emergency vehicles. Suggested spacing of gated median crossovers is one per

kilometre, but dependent on adjacent carriageway alignment.

10.2.3 Line Marking

In accordance with NZTA Specifications P/30 and M/24, NZTA Auckland Local Procedure Manual and (with

some local exceptions) the Manual of Traffic Signs and Markings.

All motorway and rural edge lines to have audio tactile profile (ATP) ribs at 500 mm centres.

All motorway lane lines to have ATP ribs at 250 mm centres.

All rural road yellow centrelines to have ATP ribs at 500 mm centres.

Motorway ramp edge and lane lines do not require ATP ribs.

Use 150 mm wide edge lines at ramps (not the 100 mm wide as per Manual of Traffic Signs and Markings).

Consistency on the network is important and standards regularly change. Please check line marking

designs with the network Maintenance and Operations organisations to ensure network consistency.

There shall be no scar/shadow/ghost marking on the surfacing upon the completion of capital project. Any

line removal during the construction period shall be carried out according to the NZ Roadmarkers

Federation Line Removal Guide: www.nzrf.co.nz/techdocs/Line-Removal-Guide.pdf .

Project specifications should refer contractors to the Regional Practice Manual for temporary lane

delineation, and avoid line removal if possible:

http://www.aucklandmotorways.com/SitePages/INFORMATION%20-%20CONTRACTORS.aspx .

Projects shall specify that removed lane marking scars ar not permitted on final surfacing (whether surface

is new or existing at completion). The use of temporary orange lane marking tape was approved in 2013.

http://www.nzrf.co.nz/techdocs/Line-Removal-Guide.pdf

http://www.aucklandmotorways.com/SitePages/INFORMATION%20-%20CONTRACTORS.aspx


10.2.4 Signage

Consistency of sign size is important. Generally, all small ground-mounted signs are to be 750mm to

900mm in diameter of width. Larger or smaller signs used are to be consistent with other network

treatments.

All ground mounted signs to be mounted 2.0 to 2.5m from ground to bottom of the sign.

Pay attention to signs spacing, order and height at on and off ramps. Use Manual of Traffic Signs and

Markings for layout spacing and order of signs.

All dedicated ramp signs e.g. no walking/no cycling, motorway begins, motorway ends, wrong way, are to

be mounted 1.0 to 1.5m from ground to bottom of the sign.

Protect all high-mounted gantry or large-structure-mounted signs with Dew Guard.

Protect all small-ground-pole mounted signs with Graffiti Guard.

Ensure all minimum height clearances are provided at overhead signs.

Use wide observation angle material on all Motorway Guide Signs.

Correct use of sign sheeting (High Intensity versus Diamond versus Fluoro)

Fluoro-yellow to be used on all vulnerable user signs.

MOTSAM provides a combination of requirements and guidelines for signage. There are various criteria that

need to be satisfied when finding the ideal location for a sign. Often, space is an issue.

Consider that too many signs create visual clutter and reduce a motorist‟s ability to take-in information.

Whilst ensuring messages are adequately displayed, consider carefully the spacing of signs and the number of

signs designed at one location.

Make every attempt to provide a sign so that a motorist can easily „pick it out‟ from the visual environment.

Check signs are located sensibly, for the benefit of road users, and, if necessary, agree with NZTA local

variations to MOTSAM for this purpose.

We want to avoid creating the clutter shown below, as the motorist will likely be put off reading any message:


10.3 Other

Refer to the Safety Deficiency Database and CRS Studies to identify all previously identified deficiencies.

Wherever possible design should seek to address and rectify existing issues to modern standards.

The network Maintenance and Operations organisations will supply traffic safety deficiency information

from databases upon request.

The network Maintenance and Operations organisations expect to be advised of all traffic safety audits and

fitness for purpose inspections in order to ensure that:

o Safety auditors are aware of recorded existing safety deficiencies

o The network Maintenance and Operations organisations can participate as observers in safety audits

Congestion of signs at Hobson St on-ramp


11. Traffic Operations

A concept of Traffic Operations needs to be developed at the planning stage of capital projects. This concept

will need to be reviewed and updated as a Capital Project progresses. The network Maintenance and

Operations organisations can assist with this.

The definition of Capital Projects in the traffic operations context is that a capital project involves any addition

or significant alteration to the asset. This definition needs to include addition of Intelligent Transportation

System (ITS) kit, communications facilities. These traffic operations projects are often delivered by staff

outside of the capital projects team in NZTA Auckland region, and are often funded from outside of those

project allocations e.g. from national allocations. Many of the ITS projects can significantly impact the existing

assets and have a resultant effect on traffic performance and performance of existing ITS assets. The network

Maintenance and Operations organisations can offer valuable advice which will allow a better „project‟ to be

delivered.

The network Maintenance and Operations organisations need to provide balanced advice, and not just focus

on one aspect. Recent (2009) examples of where improved safety has been achieved with little thought about

on-going costs and operational traffic efficiency include SH01 Ellerslie Panmure Highway Interchange

roundabout lane marking, and the contra-flow provisions at the Johnson Hill Tunnels (SH01 Orewa to Puhoi

section).

Joint Traffic Operations Centre (JTOC) has a Service Level Agreement (SLA) with NZTA and Auckland Motorway

Alliance (2009). There are various operational requirements in addition to concerns related to the ITS Assets.

11.1 Traffic Operations Assets and Issues

Below is a list of Traffic Operations Assets and related issues that require Maintenance and Operations

considerations:

Whole of life cost considerations in design and specification of assets

Emergency telephones.

Lane control signals.

Variable Message signs.

o Permanent

o During construction for motorist advice

CCTV coverage.

Traffic Detection and Counting Infrastructure (existing and required).

o Includes maintenance locations

Accessibility for maintenance.


Cabinet location.

Cabinet access and modification protocols.

Electrical compliance certification (and other compliance issues).

Gantry design and location (access, ability to work above live lanes for routine maintenance, security).

ITS specification and location.

Connection to communications (available bandwidth/fibres, standards and processes).

Design for ITS maintenance; accessibility, ease of maintenance, avoiding the need for temporary traffic

management (TTM) for routine activities.

Supply of critical spares and ongoing provision of consumables.

Design for traffic flow (especially merges).

Incident response provision.

Constructability (especially TTM).

Traffic flow and TTM requirements, and methodology during construction

o Impacts on ramp signal operations – both directly and due to changed traffic flows

o How will the new facility be opened?

Traffic Signal Design (TMU).

Maintenance and defect liability periods.

Warranty provisions and response times for defect rectification

o Manufacturer/installer requirements during warranty period

Maintenance requirements (especially where maintenance period is not concurrent with Defects Liability

Period).

Type Approval of ITS items (Factory Acceptance Test and Site Acceptance Test requirements), compatibility

with existing NZTA assets.

Level of Service and requirements for maintaining operations of existing assets.

Third party suppliers and requirements (e.g. TelstraClear for the fibre communications backbone).

Graffiti prevention requirements.

As Built and handover requirements (e.g. file types, prior to practical completion).


Commissioning strategy and programme, including staged completion requirements

o Signal commissioning , acceptance and fine tuning (including ramp signals)

o Publicity and communications

Provision for Over-Dimension vehicles.

Provision for NZ Police activities (Patrols, Commercial Vehicles Investigation Unit and Booze Bus operation)

in the form of concrete Police Pads.

Emergency stopping shoulders.

Emergency procedures (both during construction) and after opening

o Detour routes

o Contact staff

o Responsibility matrix

o ATOMS procedures

Maintenance and Operations Manual – Content, as part of Asset Owner‟s Manual, draft not later than

Practical Completion and final maximum 3 months after Practical Completion

o ATOMS briefed and ATOMS systems operational prior to opening to traffic, including staged

completions

o Call-out lists

o Detour routes changed/identified (manuals updated by network Maintenance and Operations

organisations)

o Design assumptions document (to assist development of detailed operating procedures in the future)

o Risk register – asset and operational.

Asset data handover (including RAMM, warranties, maintenance schedules, supplier details).

o SNAG closeout process prior to, and following opening to traffic, e.g. final clean-up prior to handover

to remove construction detritus

On-going service agreements for installed kit and items.

Maintenance boundaries defined.

Speed limits locations agreed to allow gazetting prior to removal of TTM.

Motorway / State Highway declarations – requirements of NZTA to allow these to occur in a timely manner.

Operational Involvement and/or review of Stage 3 and 4 safety audits to ensure operational aspects

considered.

Access keys and arrangements for ITS assets.

Public Transport routes identified and allowed for in temporary and permanent works (incl. TTM).

Refer to the network Maintenance and Operations organisations for guidance/requirements on the above.


Design for temporary traffic management aspects during construction needs careful and appropriate

consideration. Examples are:

When is it acceptable to reduce lane widths to 3.1m

Removal of line markings

Sight screens

Appropriate storage of plant and materials on site

11.2 Traffic Signals

Consultation with NZTA Highway Network Operations traffic and safety personnel during planning, design

and construction

Preparation of traffic signal controller software, 6 week lead time

11.3 ITS Equipment

11.3.1 Whole of Life Considerations

When designing a deployment of ITS field equipment the whole life of the equipment must be considered, the

deployment of unsupported equipment types and systems can significantly impact on-going costs and

reliability, as do maintenance access issues.

It is important that there is consistency of hardware and communication protocols being integrated in the field

and that the equipment is the current model and is supported by the manufacturer and more than one local

supplier.

If a new type of equipment is proposed it must go through type approval testing by NZTA and the network

Maintenance and Operations organisations to ensure compatibility with existing systems and functional

requirements for operations.

It is acknowledged that the ITS field is driven by constant technical advances and thus the network

Maintenance and Operations organisations can provide guidance for any issues that the contractor may

perceive.

It is very important to provide safe maintenance access for ITS installations as the sites are often critical to the

safe operation of the road corridor and rapid access to the asset without the requirement of traffic

management.

11.3.2 Operational Requirements


During the design phase it is critical that the Joint Traffic Operations Centre and the network Maintenance and

Operations organisations are consulted on the proposed locations of new equipment to ensure that the

equipment locations are both serviceable and provide JTOC with an asset that fits its requirements for use.

11.4 ITS Hardware

11.4.1 Full Body CCTV Cameras

Full Body CCTV Cameras should meet the minimum specifications below:

Pelco D/P protocol compliant

Camera C/CS mount

Camera = ½ CCD

Lens C/CS Mount

Lens =/> 200mm

Focal length F1.8 – F1.2

Camera heater function

Wiper function

Camera environmental attributes meets NIWA area requirements.

Video output = PAL

Video Resolution =/> 540 TVL

Min Lux rating =/> 1.2 @ F1.2 colour

Camera housings =/>IP55

Remote receiver configuration

Remote/Site camera configuration

11.4.2 Emergency Motorway Telephones (EMT)

Network Maintenance and Operations organisations currently only support Clearsonics GSM VCE Emergency

Telephones due to the EMT self-testing services provided by the Clearsonics Wayphone manager environment.

When deploying EMTs the following issue must be addressed:

Solar power with battery backup is the preferred power supply

A single button for operation on the front panel

Should be lighting column mounted or pedestal

The user should have free unobstructed access from the road

Offset between phones to be 1200m +/- 200m unless otherwise required due to road design such as

bridges or tunnels

EMTs must be installed at junctions

Pedestal phones to be sheer base

Phone colour is to be Dulux X15 Orange

Phone lettering and numbering to be advised by the network Maintenance and Operations organisations

For pedestal mounted phones please contact the network Maintenance and Operations organisations for

standard plinth drawings.


The network Maintenance and Operations organisations will supply SIM cards for all new phones and will

undertake configuration of the new phones and head end system.

Allow 28 days for the supply of SIM cards and 7 days for phone and head end configuration.

11.4.3 Lane Control Signals

UPS must be fitted in local control cabinets

Entry into sign and connectors must be unobstructed for maintenance purposes

Sign must be serviceable with the requirement to remove the sign from its mounting

11.4.4 Vehicle Detection Systems

Radar.

At present radar detection devices are not supported by NZTA however they may be deployed as temporary

measures to collect data from a road environment which may be changing due to lane reconfiguration during

construction.

Inductive Loops.

All loop reinstatement and new site installations to meet NZTA Specification, TNZ P/28 November 2006 for all

specification requirements with the exception of loop layout dimensions appendix drawing 1.

Clarification of details and or requirements can be taken up with the network Maintenance and Operations

organisations in regards to dimensions for TDM, ATMS and TMS loops.

All loop locations and Toby boxes to be marked on site, use of a Reflective Road Pavement Marker (contact

network Maintenance and Operations organisations for colour of RRPM) to highlight the centre line of the

loops and Toby box if at different locations; RRPM to be placed on the LHS of carriageway edge beam or

suitably visible location.

11.5 Structures and Roadside Furniture

11.5.1 ATMS Cabinets

The network Maintenance and Operations organisations promote the use of a standard ATMS cabinet which is

proven in the field, details of this cabinet are available from the network Maintenance and Operations

organisations upon request.

Cabinet details are as follows:

Cabinet colour to be Karaka Green

Anti graffiti coating


Electrical warning stencilling to be administered to all cabinets

Fibre optic radiation stickers to be administered to all cabinets where fibre optic is present

19‟ internal racking

Padlock security

The network Maintenance and Operations organisations to supply replacement padlocks when transitioning

to maintenance phase

Front and rear door access

1m clear access around the cabinet to be provided

Fibre optic splice trays are ATG-8

An equipment shelf is to be provided for the mounting of non 19' rack mount equipment

19' fan shelves to be installed in sites where significant heat exposure or reduced air flow is expected

Transmission equipment to be specified by the network Maintenance and Operations organisations or

NZTA

IMV Match 1500RM UPS or suitable alternative to be installed in node, LSU and VMS cabinets.

UPS to be SNMP compliant

ABB distribution box with RCD protection to be installed in all cabinets

All cables to be glanded

All cable entries to be covered upon completion of cable works

All cabinets to be subject to electrical Certificate Of Compliance

“Half” or “Mini” cabinets are not supported by the network Maintenance and Operations organisations

Further details for plinths and cabinet standards are provided by network Maintenance and Operations

organisations upon request

11.5.2 CCTV Poles

Poles must be of a folding type unless otherwise required

Installation to consider the weight of the CCTV camera to ensure correct balance and fixings

Poles to be slip base

Standard poles are to be 15m (including lightening rods)

Poles to meet New Zealand standards for galvanisation

Pole to be a maximum of 10m from the ATMS cabinet

11.5.3 Gantries

Gantries must allow unimpeded access for the maintenance crew

Gantries must be secured against unauthorised access

Gantry handrails and toe boards must comply with the New Zealand building code

Maintenance access to the walkway must not be from a cherry picker or other elevated platform

Internal access to all electric signs must be from the back

Internal sign access must not be impeded by the gantry structure

11.5.4 Services

Ducting and Pits.

Pits are to be standard NZTA pits


Pits to be suitable for application, where required trafficable pits are to be installed.

Pits and conduits cleaned, unblocked prior to hand over

Pits are to be secured

All ducts are to be supplied with draw strings

Ducts to have long radius bends.

Duct entry into pits to be sealed

Ducts to be installed as per NZTA standards

Accurate As Built information for all ducts and pit locations to be provided

11.6 Handover Procedures

11.6.1 Procedure

Preparation of traffic signal controller software, 6 week lead time

The network Maintenance and Operations organisations request that 2 months advanced notice of

proposed handover be given to allow for site inspections (minimum of 1 month before opening of any

section).

Network Maintenance and Operations organisations will report to NZTA issues found during inspections.

Inspection of signals and commissioning to be attended by JTOC representative.

Maintenance arrangements. Preference is to hand signals to area signal maintenance contractor as quickly

as possible. Only defects and warranty issues would be referred back to the construction contractor.

Training can take up to 8 weeks due to shift work patterns.

Support agreements are to be established prior to project closure.

Maintenance call-out procedures are required before opening.

11.6.2 Documentation

As-built drawings (refer to network Maintenance and Operations organisations for specifications)

Relevant manuals and technical documentation for all hardware

Operations manuals required 1 month before opening to traffic

Completed FAT documents

Completed SAT documents

All items to be entered into RAMM, data collection by NZTA accredited RAMM data collectors

GPS references for all sites

COC documents for all electrical installations

Complete details system configurations

Source code for any PLC or programmable devices.

11.6.3 Spares Handover

10% working spares for all items installed to be supplied to maintenance contract

Critical spares to be identified and suitable level of spares to be purchased

A list of all spares to be handover is to be supplied, including serial numbers, manufacturer‟s details,

product suppliers and any current warranties.


12. Corridor Assets

12.1 General

The following are design guidelines for capital projects‟ corridor assets. Corridor assets include vegetation

including grass between the shoulder and the boundary and vegetated/grassed median and gore areas. Other

assets include the anti-graffiti coatings used to facilitate the prompt removal of graffiti from surfaces and

protect them from inappropriate graffiti removal techniques. .

Corridors should be designed to make driving on motorways a pleasant experience for our customers. This

experience is subjectively judged by our customers by the appearance of vegetation within the corridor and

the management of graffiti and litter. Urban design elements and other visual features also contribute to this

experience where present. Journey delays caused by lane or shoulder closures required to carry out corridor

maintenance adversely contributes to our customers‟ experiences and reduces network efficiency.

Internally corridor management costs (mainly vegetation, graffiti, litter and traffic management) are a

significant portion of the network maintenance and operation organisations‟ annual maintenance budget.

These maintenance costs can be significantly reduced by good design. Key opportunities include:

Not creating grassed areas that need to use weed eaters or require attenuators or traffic control to

maintain.

Ensuring all grassed areas can be safely maintained with a tractor mower without requiring lane or

shoulder closures.

Avoiding creating small grassed areas where time spent off-loading and reloading the mower

represents a significant portion of the mowing time for that area.

Finding alternative methods of maintaining large and wide grassed areas as part of a project.

Careful selection of plant species recognising their ultimate size, particularly when planting near to

the shoulder, and their on-going maintenance requirements. (Flax stamens encroaching into live

lanes is an avoidable issue).

Ensuring that soil conditions are sufficient to sustain plant growth to 80% + establishment before

project maintenance handover(Soil compacted by construction activity is a poor growing medium).

Making allowances for safe access for all regular network activities including inspections.

Recognising the “intangible” costs of customer journey delays during

mowing operations and including these in the whole of life considerations.

Reducing the opportunities for graffiti offending by using CPTED principles

and protecting selected structures from damage by applying anti-graffiti

coatings.

The following Appendices provide additional details.

Appendix 1 specifically addresses whole of life issues for vegetation and has a section on whole of life

considerations which can be used as a designer‟s checklist.

Appendix 2 specifically addresses safe mowing slopes.

Appendix 3 is a separate document containing photo examples of good and not so good historical

design practices.

Appendix 4 discusses the real costs of mowing grass.



Because of the nature of the corridor there is a strong overlap between design and whole of life

considerations. The whole of life consideration below, are intended to deliver value for money to NZTA from

well-designed projects.

12.2.1 General

Carry out a Maintainability Review to demonstrate that corridor whole of life costs have been

considered in the design and that the design represents value for money for NZTA. This should

include, but not be limited to, any necessary traffic control and intangible costs such as customer

journey delay times (i.e. include all costs in the review).

Show that all regular network maintenance activities within the corridor can be safely carried out

without significant traffic control (e.g. attenuators) by designing safe maintenance access locations.

12.2.2 Grassed areas

No grassed medians.

No grassed areas that can only be effectively

maintained by weed eating or spraying.

Produce a Mowing Plan showing that all grassed

areas are able to be safely tractor mown (2m

wide tractor) without requiring significant traffic

control such as lane or shoulder closures (or the

use of attenuators) to mow and off-load and

re-load mowers.

o Ensure safe tractor mower turning areas

are provided, particularly on slopes.

(See Appendices 2 and 4).

o Include mower off-loading and

reloading costs and traffic control and

customer journey delay costs, when

considering grassing verses

landscaping options.

Consider alternative options such as leasing for wide large grassed areas. (e.g. large areas > 9m

from edge line.) This should be considered as part of a whole of life design.


12.2.3 Vegetation

The landscape designer‟s checklist included as Appendix 1 should be used. The following are some of the

key points. Photos of badly designed vegetation are included in Appendix 3.

Landscaping design based on achieving low maintenance solutions for 50 + years. Avoid plants with

short lifespans (e.g. Whau) unless part of a two stage process.

Vegetation handed over includes existing vegetation which should be pest plant free (See below).

Designers should ensure that vegetation when fully grown will never:

o Encroach into live lanes and shoulders (e.g. flax stamens)

o Encroach onto footpaths and cycleways (trip hazard)

o Obscure sight lines when fully grown (safety issue)

o Cause future problems with neighbouring properties (Customer issue)

Consider planting 1% of rare plant species. The network maintenance and operation organisations

have details of species that may be appropriate for Auckland.

12.2.4 Cut batters/exposed slopes

Cut batters/exposed slopes should be carefully designed

and if necessary sown or otherwise protected to ensure

that they do not incur excessive maintenance costs from

constant sediment discharges that without regular

maintenance would encroach into live lanes.

Acidic slopes that are low in nutrients are particularly high

maintenance. (Photo right)

Excessive erosion causes premature consumption and

failure of stormwater treatment ponds resulting in high

and otherwise preventable maintenance costs to maintain.

Excessive erosion uncovers boulders which can fall onto the carriageway below.

12.2.5 Graffiti

Graffiti is managed on site during the construction period to at least NZTA Levels of Service standards

(graffiti allowed to remain will make future reoffending more likely).

Anti-graffiti coatings must be applied in accordance with NZTA‟s Q/4 standard and verified by the

project, not the applicator.

A full CPTED design review is undertaken and includes graffiti opportunities including:

o Planting in front of at risk surfaces considered.

o At risk surfaces identified and protected and/or hardened.

12.2.6 Noise barriers/walls

Place structure on or immediately adjacent to the boundary so

as to have no gap between wall and boundary for over the

fence rubbish dumping.

Design structures for a 50 year + design life. I.e no plywood.

Allow for ground settlement under walls where not placed in

ground. (Gaps allow noise through.)

Where urban design features are used on walls, ensure that

any vandalism including graffiti vandalism is able to be

repaired at minimal cost.

Use NZTA‟s Noise Barrier Design Guide


12.2.7 Urban design features

Low maintenance with minimal opportunities for vandalism including graffiti vandalism.

The aesthetic appearance with time needs to be considered. E.g. use of nano-technology or photo-

catalytic concrete may maintain the visual appearance of concrete for longer.

The on-going maintenance requirements and product associated risks should be fully considered

before accepting new products as appropriate for a motorway environment. On-going maintenance

requirements include addressing the risk of accidental or deliberate damage including graffiti and

vehicle fires (A car fire recently damage four acrylic panels). A recommended maintenance regime and

spare inventory should be included in the Asset Owner‟s Manual. The full recommended spares

inventory should be on hand during the DLP and supplied in full to NZTA on handover.

12.3 Planning, Design and Construction Considerations

12.3.1 General

Carry out a holistic design, considering all expected maintenance

requirements, when designing landscaping and locating assets. E.g. Bad

placement of signage poles in grassed areasprevents tractor mowing

access.

Include entire area from boundary to boundary and include existing

vegetation and the removal of pest plants even if areas are not included

in project landscaping. This reduces the risk of future control costs.

Design a defined edge between shoulder and vegetation/grass to keep

the edge looking tidy.

CPTED and IPTED (Injury prevention through environmental design)

reviews carried out on wider corridor. This includes all NZTA assets.

Agree the maintenance boundary at an early opportunity. Others (e.g. Auckland Transport) who will

be responsible for maintenance may have different requirements from NZTA such as planting

alongside cycleways.

Avoid special maintenance agreements with adjacent owners that require a different level of service

than the adjacent corridor.

Include safe pull off areas for all regular maintenance activities and possible Police use.

12.3.2 Grassed areas

Mower off-loading / re-loading areas identified on plans for all proposed and existing grassed areas.

No grass designed that requires weed eating or spraying

to maintain.

No grassed medians or gore areas unless they can be

safely maintained without traffic control.

Ensure all grass slopes are safely mowable – (refer

Appendix 2 Safe mowing slopes). Identify safe areas for

tractors to turn in a Mowing Plan.

Vegetation and other assets within grassed areas able to

be safely mown around by tractor mower.


Avoid small grassed areas if tractor mowers have to be off-loaded and re-loaded to mow.

Rationalise existing grassed and landscaped areas within project boundaries.

Avoid planting grass immediately adjacent to galvanised assets (weed spray issues with galvanising –

whole of life for galvanised pole).

Stormwater swale areas also need to be considered planted swales are preferred).

Area/soil specific grass mixes should be identified and used, ensuring weed species are not used e.g.

paspalum.

Grass can be handed over as a separable portion. E.g. after full growth has been established and it

has been maintained for two years under the DLP in accordance with the NZTA Levels of Service

criteria.

12.3.3 Vegetation

Carry out a design review to confirm

o No vegetation is planted that will

obscure NZTA signage when fully

grown.


obscure pedestrian sight lines when

fully grown.


ultimately cause safety issues such as

flax and flax stamens close to live

lanes, or reduce the effectiveness of

barriers.

o No vegetation is planted that will be

an environmental issue e.g. invasive.

o Flaxes are not planted so close to

footpaths and cycleways so as they

grow to become trip hazards.

o Any weed mat if required is

biodegradable within 2 years.

o No cabbage trees are planted close to

grassed areas. (Mower clogging and blocked catchpit issues.)

o Plants with short lifespans (e.g. Whau) are not used unless part of a two stage landscaping

process.

o Vegetation/trees close to boundaries will not cause overhang, root or other problems for

adjacent properties for the foreseeable future.

o Projects will be handed over pest plant free. This include free of pest plants in established

vegetation.

o Vegetation when fully grown will not exacerbate red light running. E.g. by obscuring on-

coming traffic at off ramps.

o Area/soil specific planting is identified and used.

o Imported soil/mulch will be free of contaminants. These are often present in cheaper

products.


o Soil testing has been carried out. Vegetation on cut batters is designed mindful of what it is

planted in. Failure to do so results in erosion leading to premature consumption of

stormwater treatment capacity and high maintenance costs to prevent silt from encroaching

into the carriageway. Particularly where there are acidity and low fertility issues.

o Vegetation is designed to be handed over 80% + established for entire project area at the end

of the Defects Liability period. The network outcomes contractor will not be required to carry

out work to establish project vegetation unless separately funded and agreed.

12.3.4 Graffiti

Use only approved coatings http://www.aucklandmotorways.com/SitePages/FAQ%20-

%20What%20Anti-

Graffiti%20products%20are%20approved%20for%20use%20on%20the%20Auckland%20Motorways.aspx

As-built for coatings in RAMM format.

Adherence anti-graffiti coating is a historical issue. NZTA Q/4 to be used for coating applications.

Project to confirm standard met.

12.3.5 Cycleways and walkways

Carry out CPTED and IPTED reviews.

Security measures/motorway fences are provided between the public walkway and the motorway.

Such fences should prevent access to the motorway but allow activities on an adjacent cycleway to be

seen from the motorway (for CPTED reasons).

Auckland Council/Auckland Transport comments should be considered with unresolved issues

identified in the Asset Owner‟s Manual.

12.3.6 Noise barriers/walls

50 year plus design life. No plywood walls.

Colours if used should have long “no fade” life. Guarantees should be provided from manufacturers.

Replacement material should be easily sourced and at a reasonable price.

Guarantees should include cost of traffic control. (TC can cost more than the painting.)

Must be anti-graffiti protected.

No complicated to repair features.

http://www.aucklandmotorways.com/SitePages/FAQ%20-%20What%20Anti-Graffiti%20products%20are%20approved%20for%20use%20on%20the%20Auckland%20Motorways.aspx




12.4 Management of Pest Plants

12.4.1 Introduction

NZTA is required to control pest plants on their land through Auckland Council‟s Regional Pest Management

Strategy (RPMS). Motorways can act as vectors for pest plant spread and there is risk of new pest plant

populations establishing through materials being brought on site e.g. clean fill harbouring pest plant seed.

Auckland Council and NZTA have agreed upon 32 species (listed in Table 1) of pest plant to be controlled by

NZTA on the network. A pest plant management plan approved by Auckland Council is co-ordinated by the

network maintenance and operation organisations Network Operations. The plan recognises that to

successfully control pest plants and comply with the RPMS, NZTA needs to manage pest plants on all the land

they administer. There also needs to be consistency in NZTA‟s approach to pest management and in

addressing potential cross boundary issues.

Capital works project sites can harbour pest plants. Generally, designation land part of a Capital Works lies

under the control and management of the Capital Works team, while Network Operations maintain any

motorway that is still being used by the general public as part of the state highway network. To ensure NZTA

are compliant with the RPMS during both Capital Works and Network Operations it is recommended the

following protocol is implemented.

12.4.2 Pest Plant Protocol

Design

Under Rule 18.2.1.1 c. in Auckland‟s RPMS, NZTA shall not distribute by any means, any species listed in

Auckland Council‟s pest plant management plan or otherwise act in such a way to encourage or cause the

propagation or multiplication of any species listed in their agreed management plan. There are a number of

species that have been used in highway landscaping design in the past that are listed in the RPMS. These

include Agapanthus (Agapanthus praecox; A. orientalis) and English Ivy (Hedera helix species). Capital Works

projects are to ensure species specified in the RPMS are not included in any landscape designs. It is

recommended exotic species similar in appearance to known pest plants are not included in landscape

planting plans to avoid confusion e.g. Canarian ivy used on SH20 has caused a number of complaints from the

public thinking it is English ivy.

Any exotic species proposed to be deliberately introduced is to be investigated to ascertain whether there is

any environmental risk associated with it. Some species that are recognised as environmental weeds in some

parts of New Zealand are not necessarily listed as pest plants in Auckland‟s RPMS e.g. saltwater paspalum

(Paspalum vaginatum). Although this species is not in the RPMS it is a known threat to estuarine environments.

Construction

The following management actions are recommended to incorporate into Capital Works landscaping practices:

Pest plants are to be controlled using methods approved by Auckland Council as per their pest plant

control guidelines found on the Auckland Council website.

The use of herbicides is to be in keeping with NZS: „NZS 8409:2004 Management of Agrichemicals‟. Rules

in PARP:ALW Chapter 4a which target discharge to air are to be adhered to.


Steps are to be in place to reduce weed spread, including managing excavation and placement of

potentially contaminated fill (e.g. pest plant seeds or fragments that could establish in new areas). This

may entail controlling pest plants before earthworks begin.

Once handed over to Capital Works, the responsibility for maintaining the area pest-free is the Capital

Works project team unless otherwise agreed between Capital Works Project Team and NZTA.

Inspections are to be undertaken by the Capital Works team at regular intervals, no less than twice yearly,

ideally early spring and autumn to enable required control to be programmed and undertaken then.

Any follow up pest control required shall be specific to the species of plant being eradicated and is to

adhere to the methods approved by Auckland Council.

Any materials brought on to site (e.g. aggregate, fill, chip mulch) are to be free of pest plant contaminants

that are able to potentially germinate and establish. Quality Assurance is to be managed by Capital Works.

Defects Liability and Maintenance Period:

The defects liability period is a critical time for pest plant management as open areas are vulnerable to pest

plant establishment.

It is recommended Capital Projects include a clause in all landscape contracts that pest management across

the sites designation and works area is included in the defects liability and maintenance period programme.

On handover to NZTA Network Operations, the Capital Works team shall provide the following information:

The start date and finish date of the defect liability and maintenance period.

The desirable outcome of the defects liability and maintenance period in relation to pest plant

management as stated in the NZTA Principals Requirments for the Capital Works project (for example, no

pest plants within the designation and no non-target damage to desirable plants).

It is recommended defect liability periods are for the projects landscaping in their entirety, rather than

separated into individual landscape plots for ease of handover and associated maintenance. Ideally this is to

be discussed with NZTA and Network Operations, and agreed upon at the beginning of the project.

To ensure pest plant infestation is minimised it is recommended a clause be written into landscape contracts

that specifies that pest plant species are not to be present in the plant stock/ mulch. The contract should also

specify that the Contractor is responsible for pest plant control for at least two seasons after the

planting/application of mulch or for a period of time agreed upon by NZTA.

During the defects liability period all landscaped areas will be inspected 6-monthly by NZTA. Any landscaped

areas that still fall within the defects liability period of a Capital Works project that require pest management

will be noted. The Capital Works contact will be informed and pest management is expected to be undertaken

within 2 weeks of notification or an otherwise agreed time between NZTA and the Capital Works team.

A formal handover process is to be agreed upon including but not limited to dates stipulating the defects

liability and maintenance period, and when inspections are to be undertaken. It is recommended the Capital


Works team contact the NZTA at least 6 months before handover to Network Operations. Ideally inspections

should be undertaken in late Summer/early Autumn which allows any remediation planting to be undertaken

in the most favourable planting season (June – August).

During handover of the Capital Works project to the Network Operations the landscape and grassed areas are

to be inspected for pest plants by NZTA. Subject to the Principals Requirements generally all Capital Works

areas are to be pest plant free from the start of the alignment to the end of the alignment, boundary to

boundary within the designation and encompassing all NZTA property. If pest plants are present the Capital

Works team are to control these to the satisfaction of NZTA.

Table 1: Pest plants to be controlled on the Auckland South network

Common Species Scientific Name

Agapanthus Agapanthus praecox (A. orientalis)

Blue morning glory Ipomoea indica

Boneseed Chrysanthemoides monilifera

Broom (wild broom) Cytisus scoparius

Brush wattle Paraserianthes lophantha

Buddleia Buddleja davidii

Cape ivy Senecio angulatus

Castor oil plant Ricinus communis

Chinese privet Ligustrum sinense

Climbing asparagus Asparagus scandens

Cotoneaster Cotoneaster glauphyllus, C. franchetii

Climbing dock Rumex saggitatus

Crack willow Salix fragilis

Elaeagnus Elaeagnus x reflexa

Giant reed Arundo donax

Gorse Ulex species

Grey willow Salix cinerea

English ivy Hedera helix species

Japanese honeysuckle Lonicera japonica

Japanese spindle tree Euonymus japonicus

Jasmine Jasminum polyanthum

Lantana Lantana camara

Madeira vine (Mignonette vine) Anredera cordifolia

Mile-a-minute Dipogon lignosus

Monkey apple Syzygium smithi

Montpellier broom Teline monspessullana

Moth plant Arauja hortorum

Pampas grass (common and purple) Cortaderia selloana, C. jubata

Tree privet Ligustrum lucidum

Sexton‟s bride Rhaphiolepis umbrellata

Spanish Heath Erica lusitanica

Sweet pea shrub Polygale myrtifolia (not including. Cv. “Grandiflora”).

Wild ginger Hedychium gardnerianum

Woolly nightshade (tobacco plant) Solanum mauritianum


12.5 Asset Owner‟s Manual

Refer to Appendix 7 for more detail. Needs to include:

A summary of all on-going corridor related consent requirements and reasons behind them.

Identification of special interest features such as wahi tapu areas, blessing stones and other similar

features that would not otherwise be known. Names of the key stakeholders involved should be supplied,

especially where there would be an issue if NZTA removed or changed the feature.

Special agreements such as with adjoining owners (Hopefully no agreements).

Other NZTA specified requirements in Standard Professional Services Guideline PSG/15 - Asset Owner's

Manual. Version 3, March 2011.

12.6 Vegetation Handover

Vegetation should be handed over as a new asset at the end of the vegetation DLP without any immediate

remedial actions being required of the network outcomes contractor. Specifically, unless otherwise agreed:

Vegetation at handover should be 80%+ established canopy coverage for new landscaping and established

for existing vegetation at the end of the Defects Liability Period (DLP). A five year DLP is recommended.

The DLP may need to be extended or alternative handover arrangements made where vegetation is not

established at handover.

Vegetation should be handed over for the total project area rather than in separable portions.

Grass may be treated as a separable portion with a different DLP. Grass needs to be weed free at

handover.

Vegetation handed over should include all vegetation between the NZTA/network outcome contractor‟s

maintenance boundary and the shoulder including existing vegetation i.e. not just the landscaping

provided by the project.

There should be no Pest Plants handed over.

12.7 Other Items

Padlocks need to be 'motorway padlocks'. Refer to the network maintenance and operations organisations

for type and source and registering of such.

Route Stations and Route Positions need to be measured and have signs installed before the road opens.

As well as the maintenance and operations organisations, the Police also require this information.


13. Stormwater Management

“Customers First” - Customer engagement for the Transport Agency Highway Asset Management Plan

identifies a number of values and bottom line expectations of the state highway network. These values are

grouped into three categories:

safer journeys;

efficient and reliable journeys;

social and environmental responsibility

Good stormwater management assets should deliver on these values in all areas of need, particularly with

respect to risks such as unsafe surface flooding, asset durability and resilience, network vulnerability, the

ability to deliver timely operational monitoring and maintenance by good safe off road access to stormwater

assets, and the need for delivery of environmental compliance (legal requirement), etc. The delivery of

holistically good stormwater management assets and outcomes also requires good consideration of other

risks and opportunities throughout the delivery lifecycle such as water quality, biodiversity, ecology, cultural,

social, and amenity values. This is broadly reflected in the network Stormwater Asset Management Vision:

To provide informed customers and stakeholders with the positive legacy of a world class, safe, efficient, and

optimised stormwater management asset that delivers the right level of service, and best practice to avoid,

remedy or mitigate adverse environmental effects.

Throughout the asset lifecycle, many factors can significantly influence Capital Project outcomes and values.

Often overlooked (or not respectfully considered) is that the operational life delivery of stormwater asset

dwarfs the planning, design, construction, and handover phases of these Capital Project assets in terms of the

associated life timeframe and delivery costs.

Firstly it is important to recognise that motorways are nationally significant and critical (National Significance

Criticality Rating 1). Motorways are also unique for the sheer volume of traffic, and some principals that may

be considered „fit-for-purpose‟ for stormwater assets at say local roads or highways in a rural context are

different to some of the principles that most importantly apply for the Auckland Motorway network. For

example there is no such thing as simply pulling over to the side of the road to deliver operational

management. For strict safety reasons, often timely and costly temporary traffic management (TTM) is

essentially required for what may seem on the surface to be the simplest of operational needs.

The intent of this section of the Maintenance and Operations Guidelines is to help capital projects achieve

positive outcomes and deliver values that are important for good operational management of stormwater


assets such as available and reliable function, whole of life value for money, and safety (people, plant, and the

environment).

Fundamentally, good Stormwater Management outcomes that need to be safely delivered at the Auckland

Motorway network broadly fall into two primary categories:

The „right‟ Level of Service (e.g. no unsafe assets or unsafe motorway surface flooding, network availability

and resilience for flood flows);

Environmental Compliance (i.e. delivery of legal compliance against conditions of Resource Consents

including physical issues such as erosion, sediments, contaminants & ecological health).

The target audience is all personnel involved in delivery of Capital Projects throughout the asset management

lifecycle for the NZTA stormwater management asset including; planners, designers, contractors, MSQA staff,

and importantly the end asset owners (i.e. the Transport Agency). All personnel involved in the development

and delivery are encouraged to be inherently outcome focused and develop a strong sense of „ownership‟.

Throughout the project life:

always challenge yourself to think about the legacy of the asset (positive, safe, sustainable and resilient)

think about the stormwater implications on the efficiency and reliability of the State Highway network

think about how customers and stakeholders (including yourself) will value/perceive the stormwater asset

ensure robust evaluation of whole of life outcome implications, and value for money

think about holistic health of stormwater management assets (environmental, social, cultural, financial)

13.1 Stormwater Management Assets

There are three primary types of stormwater management asset that provide different service and outcome

needs. These assets are of different material types, all with different deterioration rates and performance

capabilities. These assets all have unique operational delivery needs (i.e. monitoring and maintenance activity

needs vary). The three primary types of Stormwater Management Assets are: (See Operation and Maintenance

Schedule at Appendix 8) are:

Type 1 - Surface water collection, conveyance, and disposal: This is the means of getting stormwater off the

motorway surface (e.g. median drains, slot drains, catchpits), conveyance (e.g. pipes, manholes, open

channels, pump stations, entryway crossing, secondary flows), and discharge disposal (e.g. streams, soakage

to ground, pipe networks).

Type 2 - Waterway and Network Crossings: Where the motorway crosses a major waterway or regional

reticulation network (e.g. major culverts at streams, local council pipe, or coastal waterway). The asset

typically includes elements such as the pipe barrel, headwall/wingwall, erosion and scour protection, energy

dissipation, and ecological provisions such as fish passage, and landscape planting.


Type 3 - Stormwater Management Devices: Water quality (treatment), and quantity (attenuation) devices such

as swales, ponds, basins, sediment tanks, proprietary treatment devices;

13.2 Whole of Life Value Considerations

Delivery of a robust whole of life value in decision making is critical for good stormwater management

outcome requirements. Considerations include:

Demonstrate full consideration of stormwater operational implications throughout life (Preliminary

Feasibility, Planning, Design, Construction, MSQA, Operations, Renewal and/or Disposal). Also see Section

- Asset Management and Whole of life Value.

Consider the implications of Resource Consent conditions on maintenance and operation costs that occur

during the planning, design, and construction delivery stages. Look for solutions and agree consent

conditions (with the the network maintenance and operation organisations Stormwater Asset Manager) that

have low operational monitoring and maintenance time and cost implications.

Ensure that a robust evaluation of options is undertaken. This is generally best supported by a value

analysis matrix (e.g. a transparent weighted multi criteria evaluation) including a rigorous assessment of

whole of life operation and maintenance costs, including temporary traffic management, safety permitting

and costs (e.g. confined spaces entry), activity delivery (people and plant), and costs associated with

delivery of compliance with consent conditions, etc.) Whole of life value assessment (robust lifecycle

analysis) should demonstrate holistic value for money. As part of this process the 50 year operational

monitoring and maintenance costs should be included.

Never underestimate the whole of life costs associated with Temporary Traffic Management (TTM) for the

purpose of delivering operational activity needs at stormwater assets that do not have good safe off road

all weather access. For example TTM for a ramp closure typically costs about $2,500 per night, and the

TTM for a mainline closure typically costs about $4,000 per night.

It is preferred that the network maintenance and operation organisations Stormwater Asset Manager be

engaged to provide inputs for robust 50 year life considerations and the operational monitoring and

maintenance requirements.


13.3 Planning, Design, Construction, and Handover Considerations

To ensure that optimal outcomes are achieved for the stormwater management asset there are a number of

considerations that should be addressed during the development and delivery of the stormwater management

assets.

A number of considerations are general and relate to all phases of the asset lifecycle, whilst some points are

more specifically pertinent and influenced at the planning, design, construction, or handover phases of Capital

Project delivery. This section is not comprehensive or exhaustive and is simply intended to provide a guideline

to help ensure that improved stormwater management operational outcomes are achieved. Fundamentally, it is

important to always be mindful that the two primary drivers for the stormwater management asset are to

deliver the right Level of Service such as structural integrity, safe condition of assets, available performance

(e.g. pavement surface drainage, flood protection), and to effectively and efficiently deliver Legislative

Compliance (e.g. comply with conditions of resource consent) throughout the asset lifecycle.

13.3.1 General

Some common considerations for good operational outcomes for the stormwater asset development and

delivery lifecycle include:

a. Informed engagement (i.e. consultation and approval) of the Stormwater management solutions is desired,

including copies of the project life reporting documents (preliminary feasibility reporting; scheme

assessment reporting, assessment of environmental effects, preliminary and detailed design reporting,

peer review reporting, & construction reporting). Good consultation with the network maintenance

organisations will help to ensure the effective transfer of knowledge (especially the delivered „intent‟) and

to capture of appropriate information in the stormwater asset owners‟ manual (including operational review

by the Auckland Motorway stormwater asset manager as part of Consent sign off process).

b. To help ensure that good and safe positive legacy outcomes are achieved for the stormwater management

asset, it is important to carefully consider every element of the total stormwater management system being

developed and delivered (collection & conveyance network; major waterway & network crossings; treatment

devices). The network maintenance and operations organisations stormwater asset manager can offer

guidance and advice for all elements of the stormwater management asset throughout the lifecycle.

c. Compliance - Ensure that all general conditions, specific conditions and advice notes of the Resource

Consents are adhered to throughout the capital project delivery, and ensure that linkage of relevance to the

future operational requirements is captured for the stormwater asset owners‟ manual. Ideally the statutory

„requirements‟ (consent conditions) will facilitate the delivery of a consistent and pragmatic regime for

intelligently aligned cyclic monitoring and maintenance. Also see Section – Consenting.

d. Less is more. Consider opportunities to minimise the extent of asset whilst delivering the required

outcomes (e.g. if space is available, rather than say a traditional catchpit/manhole/piping stormwater


system, that swales can provide the collection, conveyance, and treatment objectives as a single and simple

asset which is easy to monitor and maintain).

e. Consistency (and compatibility) of asset elements, standards, and specifications. Consistency reduces the

need for specialised tools, resources, and personnel for effective operational monitoring and maintenance

activity to be delivered. Avoid „special‟ or „bespoke‟ assets that require unique operational needs or

knowledge - Keep it simple and intuitive. Assets with monitoring and maintenance activity needs that are

familiar to maintenance operators stand a much greater chance of being delivered well.

f. Consider all aspects of safety (e.g. clear zone requirements, road users, operational staff during monitoring

and maintenance activities, neighbours, emergency services). Safe off road access is important due to the

time required to maintain some assets such as periodic pond cleaning, or the time taken to replace sand

media in a sandfilter. It is however important to carefully weigh-up consumption of land viable for

treatment (often limited by designation footprint, or available hydraulic head limitations) versus the

provision of the off-road access. Also see Section – Health and Safety, and the below section for

stormwater Safety in Design.

g. Stormwater management solutions should adhere to good principles of crime prevention through

environmental design (CPTED). In context this includes minimising the risk of vandalism, judicious

landscape planting at ponds, thoroughfare control at major culverts and waterway crossings (e.g. consider

risks associated with culverts adjacent to private properties, parks and reserves);

h. Access for ease of monitoring and maintenance. Delivery of operational monitoring and maintenance of

the Auckland motorway network is normally undertaken at night (when visibility is poor) to best manage

the motorway network efficiency (i.e. customers/drivers do not want to be stuck in traffic while

maintenance is delivered). Sometimes maintenance is also delivered in wet conditions. Hence good safe all-

weather access (24/7) is required. Avoid assets where operational monitoring and maintenance needs to be

undertaken within the carriageway area and requires temporary traffic management. Avoid locating

stormwater assets at median or gore areas due to the operational challenges of safety exposure and safe

access (e.g. swales, sediment vaults, soakage disposal, and filtration treatment devices, etc. at medians

cannot be accessed for maintenance activity without costly TTM). Assets are best located outside of the

carriageway area. Also, best practicably avoid solutions that require specific permitting or operational

activities (e.g. working at heights or confined spaces activity)

i. Consider emergency incidents such as the capacity of the stormwater assets/system to contain, intercept,

or isolate environmental incidents like unsafe spills, or flooding). Ideally the stormwater management

system should include mechanisms to inherently contain oil, grease and other floating contaminants, as

well as to provide an isolation capacity of 20m3 (e.g. consider the event of a petrol tanker spill, or say a

truck load of milk powder or cement entering the stormwater network and receiving environment).

j. Secondary flow paths (SFPs) are critical. Ensure that SFPs are robust (i.e. durable and safe for peak design

discharges). SFPs should be secure in perpetuity (e.g. easements), and reflected on as-built information

(i.e. mapped). Take good account of the potential implications of other assets on intended secondary flow

paths (e.g. fences, noisewalls, and bridge piers, etc. can interfere with intended SFPs.

k. Debris blockage will impair performance of the network. All elements of the delivered stormwater

management asset need to be given essential assessment for the reliability and functionality of

performance. Assets that minimise the risk of blockage occurring through accumulation need consideration

(i.e. appropriate protection gills at pond outlets, and waterway culverts).

l. Aesthetics. It is important that the network always looks great. A good stormwater management asset

should best blend with nature (e.g. swales, waterways, and ponds to be of „naturalised‟ appearance) or be

hidden (e.g. below ground pipe networks, or treatment vaults). Avoid solutions attractive to graffiti artists,

or assets that can create unsafe distractions to drivers.


m. Spend mental time at the asset. Imagine the completed asset and the full range of conditions encountered

during a lifetime of operational monitoring and maintenance. Think about factors such as daily conditions,

night maintenance activities, wet weather, drought, the asset after a month of operation, after a year, ten

years, fifty years, safety of users and operators, aesthetics, health of vegetation, ecological health, risks of

failure such as pollution, erosion or flooding.

n. Risk management - Through the planning, design, and construction phases, all operational risks, liabilities,

and opportunities must be effectively managed (hazard/risk register). From day one, develop and manage

an outcome focused risk and opportunity strategy for level of service and compliance outcome

requirements and needs. All elements of the stormwater risk register should include the likelihood,

consequence, and operational monitoring and management strategy.

13.3.2 Planning

It is critically important to recognise that whilst at the early planning phases proposed stormwater solutions

are often simply developed to sufficiently demonstrate that a technically and physically viable solution can be

achieved (for the purpose of supporting resource consent processing – at which time the conditions for

design, construction and future operation are often set).

The planning phase of Capital Projects is critically important to ensure that good legacy outcomes can actually

be delivered by the latter „lifecycle‟ phases of the project (i.e. design, construct and operate). For example if

land requirements have not been adequately identified and secured at the project planning stage (so that the

stormwater assets can be pragmatically delivered within designation) there will be latter challenges and issues

like high costs for ancillary works such as significant earthworks, retaining walls, or „structural‟ solutions (e.g.

large concrete vaults). Inadequate „space‟ also means that some fundamental outcome values such as good

safe all weather off road access cannot be effectively achieved (resulting in high future costs for temporary

traffic management, etc.). Good planning sets the foundation to delivering and achieving good stormwater

management operational outcomes and values.

It is also important to recognise that often the „foundation‟ set at the planning phase of capital projects carries

through the latter delivery phases (e.g. a conceptualised pond at planning more often than not results in a

conceptually similar pond being built). Good robust stormwater planning cannot be understated nor

underestimated. Some important principles include:

a. The high level philosophy and objectives for the stormwater management system needs to provide a best

practicable option (BPO) to avoid, remedy or mitigate adverse environmental effects. The Resource


Management Act states: “Every person has a duty to avoid, remedy or mitigate any adverse effect on the

environment arising from an activity. . .” Section 77 (2) of the Land Transport Management Act 2003

(LTMA), also includes that adverse environmental effects be avoided or managed with the (BPO). This

includes important consideration of whole of life operational monitoring and maintenance.

b. Consider opportunities for an integrated and centralised approach to manage Stormwater quality and

quantity issues. Maximise the value of water management systems through partnerships with others, and

avoid piecemeal systems which require multiple operational establishments).

c. Ensure that works will not induce or result in an increase to pollution, erosion or flood risks on the

upstream and downstream properties. OM intervention for renewals or improvements (resulting from sub-

standard capital project delivery) is not cost effective. Robust and resilient stormwater solutions need to be

delivered during the project design and construction lifecycle. Best practicably mimic the predevelopment

hydrologic regime and setting, to deliver outcome objectives which are aligned with the issues, values, and

opportunities of the receiving environment (e.g. post development discharges to mimic predevelopment

flow rates and volumes to manage erosion and/or flood risks).

d. Future-proofing: Ensure that designs are future-proofed for the maximum probable development (MPD) for

the catchment. In some cases council plans do not accurately reflect the „likely‟ or „potential‟ MPD (e.g. for

sites adjacent to the urban limit). Also consider positioning of all stormwater assets with respect to future

road widening or development projects.

e. Challenge operational conditions of consent to ensure that all conditions enable effective and efficient

delivery of operational needs to satisfy legal responsibilities. Aim for consistent, simple, and meaningfully

measureable conditions. Ideally at the planning stage all operational conditions associated with the future

operations and delivery of the stormwater management assets should be reviewed and agreed with the

network maintenance and operation organisations Stormwater Asset Manager.

f. Signoff on conditions as they are satisfied (don‟t wait until project completion), and all compliance

„updates‟ should be recorded at CSVue

13.3.3 Design

For all elements of the design of stormwater management assets associated with capital projects, the

practicality of all future operations (monitoring and maintenance requirements) should be carefully considered

in the context of the network (e.g. consider that traffic volumes often >100K vehicle per day). Reliable

functionality and a capability to pragmatically deliver and achieve compliance is the essence of good

stormwater management operational outcomes. As simple as it may seem, it is important to ensure that the

asset can actually be accessed to enable physically monitoring and maintenance (some existing assets from

capital projects cannot). Accordingly all planning, design, construction, and handover deliveries should be

reviewed and approved by the network maintenance and operation organisations Stormwater Asset Manager.

Standards and Level of Service

i. Ensure that appropriate engineering standards are applied. Aside from NZTA Minimum Standards (Z

series), few NZTA Stormwater Instruction Standards, Policy, Interim Standards (or standard drawings)

are documented or available (aside from 1977 NRB Highway Surface Drainage), and the design

expectations or „requirements‟ are often not clearly defined. NZTA need a stormwater engineering

standards document (current default to Austroads).

ii. Being a nationally significant and strategic network the Auckland South network needs to be safe and

trafficable during extreme storm events (up to the 1% AEP critical storm event). This includes the need

for design tide levels and rainfalls to include appropriate allowances for factors such as storm surge

and climate change.


iii. The maximum surface water depth at any point on any running lane, including merge, diverge and gore

areas, during a 50% Annual Exceedance Probability (AEP) 5minute duration rainfall event should not be

greater than 4mm above the top of the surface texturing. As per NZTA TM-2502 - 'Preferred method of

calculating surface water runoff in NZ' - Surface Drainage should be evaluated in accordance with the

RRL method documented in the 1977 MOW document - Highway Surface Drainage Design Guide for

Highways with a Positive Collection System. This document is based on the formula developed by the

Road Research Laboratory (RRL) in 1968 for the UK Ministry of Transport. The Galloway or any other

method should not be used. In situations where this standard cannot be achieved, such as super-

elevation development, specific departure is required. Normal crossfall on all pavements of 3% should

be maintained wherever practical. Where it is impractical to maintain a 3% crossfall then specific design

should be undertaken to ensure that the pavement remains free from surface water.

iv. When reviewing departure requests to the surface drainage standard, some additional considerations

that need to be demonstrated before acceptance of the departure include:

Good practical diligence and consideration of the surface drainage system where the potential

consequences of aquaplaning failure present elevated risk profile (e.g. elevated safety risk of

aquaplaning at zones of acceleration/braking and bends).

Scope to modify the pavement crossfall or superelevation to encourage more efficient and effective

surface drainage.

Pragmatic consideration of the travel direction and the significant impact that wheel drag has on

where unsafe surface water results. Ensure that catchpit systems immediately 'downstream' (travel

direction) of the risk sites also have good reliable inlet efficiency (e.g. enlarged catchpits or

slot/grated trench drains).

Redundancy needs be adequately considered (for blockage). Note - a catchpit with 50% blockage does

not necessarily mean that the remaining 50% inlet 'efficiency' is available. At grade often even lesser

blockages (as low as 10-20%) can mean that all water 'skips' past the intended collection catchpit.

Carefully consider the risks associated with the nature of landuse and landscape at the contributing

catchment in context of catchpit blockage and reliability of inlet efficiency.

Merge and diverge gore areas tend to accumulate pollutants - more so than standard running

shoulders. The reliability of inlet efficiency at these zones needs good consideration because they are

often difficult to safely access for routine maintenance. Enlarged inlets provide a good longer term

and reliable level of service against unsafe surface flooding.

Consider if additional slot/trench drainage and/or say double, back-entry, or super catchpits rather

than standard single catchpits improve the situation. Note - there is very little difference in capital

project turn out cost, yet significant performance increase in the reliability of asset function. For

strip/slot/grated trench drains, the ACO HiFlo PowerLok TraffikDrain system is preferred.


v. Sufficient collection and conveyance capacity should be provided so that the shoulder flows do not

encroach onto trafficable lanes during a 5% AEP 10 minute duration rainfall event. The depth of

shoulder flow should not exceed 100mm depth and its velocity should not exceed 2m/s.

vi. In a 1% AEP 10 minute duration rainfall event one lane of a multi-lane section of carriageway may be

covered with water that is no more than 100mm deep and its velocity should not exceed 2m/s. On a

single lane link road in the same event, at least 2m of carriageway should be kept free of stormwater

greater than 4mm depth.

vii. At super elevated areas the design should include for the collection of stormwater adjacent to the

normal centreline. No stormwater from the uphill side of the carriageway should be allowed to flow

across the pavement of opposing lanes of traffic or, in the case of multiple on/off ramps, across the

pavement of traffic on adjacent carriageways.

Durability

i. All elements of the Stormwater Management asset should be designed to provide adequate durability.

Culverts >3.4m2 should be in accordance with requirements in the TNZ Bridge Manual and relevant

material design codes. All mainline crossing culverts should be designed with a minimum design life

expectancy of 100 years. The surface collection and conveyance network, and management devices

should be designed with a minimum life expectancy of 50 years.

ii. Where culverts or piping material, other than concrete, is proposed (e.g. multi plate or metal pipes)

demonstrate the adherence to the longevity criteria by assessing whole of life value in design, including

the costs for providing and maintaining adequate protection against corrosion and/or abrasion

throughout the life of the structure.


iii. Also consider the resilience of materials e.g. StormBoss Pipe - Although product literature refers to

material as 'plastic' it is made from Polypropylene. Polypropylene is not self-extinguishing in the event

of fire

iv. Structures should be sufficiently durable to ensure that without reconstruction or major renovations,

they continue to fulfil their intended function throughout the design life.

v. All Streetware (e.g. lids, trench gratings, catchpits grates) must be NZTA approved and D Class (400kN)

vi. All exposed steel (e.g. scruffy domes, grates) must be either stainless steel or HD galvanised (to AS/NZS

4680)

Network Design

i. The stormwater management system should be via gravity systems (except tunnels).

ii. All pipes within the local road network should have a minimum diameter of 225mm. For all other pipes

the minimum diameter is 300mm except lines crossing the carriageway, in which case a minimum

diameter is 375mm dia.

iii. Reticulated networks should be self-cleansing (consider pipe grade, flow rates and network tractive

forces). The minimum water velocity in the stormwater conveyance network (e.g. channels and

pipelines) should be 0.6m/s at a flow arising from half the 50% AEP critical storm.

iv. All new pipelines crossing the road should cross as directly as is practicable, and in no case, should the

angle between the longitudinal direction of pipeline and the centreline of the road be less than 40o

(degrees).

v. A maximum pipe run should be 90m, or as required to suit change in pipe direction, or grade and to

suit inspection structures such as manholes and catchpit locations (or rodding/flushing points for

subsoil drainage).

vi. No access covers (e.g. catchpits and manholes) should be situated within the trafficable flexible

pavement lanes. See following case:

Stormwater Access Structures (Manholes) at Pavement Surfaces

Unsafe pavement failure around

Manhole situated in trafficable

lane

Frame failure where traffic

loosening has caused the lid to

settle too deep into the frame

Flying manhole lid – A serious

safety risk


Dangerous - Manhole frame,

pavement, and lid failure

Manholes at bridge underpass.

Very difficult for safe access

Level differential >35mm.

Acceptable tolerance 25mm

Good reasons to avoid stormwater access structures at trafficable pavement surfaces include:

Safety – The risks associated with failing or collapsing lids; broken or flying manhole covers; loose

loads „bumped‟ by uneven surface; motorcyclist safety e.g. when manhole lids polish and become

slippery;

Comfort of ride – Pavement is smoother without structural „lids‟ in trafficable lanes. Acceptable

pavement tolerance (differential levels) is less than 25mm;

Asset Deterioration – Manholes situated in the heavily trafficked Auckland Motorway lanes typically

experience lid/frame failure within 10 years (some fail more frequently, and some a bit less).

Frames loosen over time with heavy traffic which allows the lid to settle becoming more susceptible

to kicking out of the frame;

Noise – Avoid the clunking sound, or „tyre slap‟ when manhole lids are trafficked;

Access – It is difficult to conveniently and safely access manholes in traffic lanes for routine

operational activities without specific and costly TMP/TC for lane closures;

Cost savings and whole of life value. Every 5-8 years when new pavement surfacing is required, the

additional work associated with resetting manhole lids to match new surfacing/paving level

tolerances costs $2-3k per manhole (additional time, milling efficiency, TC, resource, etc, to

modify riser rings and re-set the lids/frames). A significant whole of life value results from burying

manholes (approximately $20,000 cost savings per manhole over a 50 year life). If a manhole is

buried and an infrequent incident or event occurs that requires access to the manhole, then

effective identification, exposure, and reinstatement of the lid can be achieved for less than $5k;

Night maintenance and CCTV

work activity delivered under

time pressure of full TTM

closure

Pavement „frittering‟ at

manhole situated in trafficable

surface

Working at night under full TTM

closure - routine inspection

Cracked frame. Frame failure

can occur suddenly resulting in

a loose lid

The view inside a typical

manhole.

Ready for burial. Manhole ready

beneath new pavement surface


All new stormwater access structures (manholes) should be sited away from trafficable pavement

surfaces (ideally at least 5m from the edge of seal). If structures cannot be sited outside of the

trafficable surfaces then the structures should be buried below the structural pavement, as follows:

Bury the manhole lid (cover) at a minimum depth of 75mm from surface (to minimise risk of long

term reflection of structure at surface). For structural asphalt pavements the buried lid level needs

to be matched to the level of bottom of the layer below the surfacing layer e.g. if your pavement

has 30mm OGPA surfacing and a 50mm AC 14 structural layer below this, then the lid level will

need to be 80mm below the final surface.

Lid and Frame should be a Heavy Duty Class „D‟ (400kN) non-roc type.

Insert plastic protection lugs at the manhole lifting points to prevent pavement material filling the

key-slot. This will facilitate any future exposure and lifting needs.

Internally the connecting pipe must be concrete benched or equivalent (to top of pipe height) and

finished to a high standard. This helps to minimise the risk of any internal snagging/blockage from

occurring, and also helps to facilitate alternative access for flushing, rodding, and CCTV activities

The exact co-ordinates of buried lids must be accurately recorded for 'as-built' drawings and for

NZTA RAMM/GIS data updates (include co-ordinates, barrier off set and depth from surface

dimensions). We need to know where buried lids exist e.g. so in future we don‟t hit the lids with

milling machines, and for the infrequent possibility that in future the manholes need to be exposed

and accessed for operational purposes.

To re-set and bury the lid will require clean cut of surface, and cut-down and/or resetting of the

MH riser or removal and resetting of the frame riser rings. MH Lids must be reset (in concrete)

Plastic blocks used as frame

riser rings - NOT ok

Plastic blocks used as riser rings

up close – Not good

Too many manhole frame riser

rings. Always use lowest

common denominator for riser

thickness

Manhole frame is not set

concentrically with manhole

lid. „Flipping‟ can occur

Submerged manhole cover at

traffic lane – Inadequate

secondary flow path

Manhole lid collapse only

prevented by steel sheath pins

To bury a manhole below the pavement surface, several criteria must be satisfied, namely:


1. The asset must have a 'clean' contributing network. e.g. if the stormwater discharged through the

asset comes from an open drain or channel at vegetated land, there can be an increased risk of

discharge containing debris that can cause blockage (e.g. branches. sticks). In this case effective

upstream debris grilles are required. If the contributing stormwater network only serves pavement

surface discharge it will be free from material that typically presents a snagging or blockage risk.

2. The asset must have good viable alternative access for routine operations at all connecting pipe

assets i.e. flushing and/or CCTV activities for connecting pipe assets can be effectively

delivered from other connecting manholes, catchpits, or inlet structures.

3. A secondary flow path with a positive outfall must exist. e.g. if a blockage were to occur, would it

result in ponding over the manhole asset that would be difficult to manage if the manhole is buried

below the pavement surface (e.g. imagine emptying a dirty bath if you couldn‟t find or get to the

plug hole)

4. Internal pipe networks must not have acute angles, otherwise future operations from alternative

location cannot be undertaken (e.g. flushing long networks through an acute angle is not possible)

5. If any of the aforementioned governing criteria cannot be satisfied then the manhole asset (and

associated network) must be located outside of the trafficable pavement surfaces.

Note: Projects that are widening based should take good account of the stormwater management asset

condition and durability and should demonstrate the whole of life value assessment of network

renewal, versus modifications to retain the network (including access structures) within the trafficable

lanes.

The preferential hierarchy for the location of stormwater access structures (manholes) is:

>5m off carriageway (future-proofed)

<5m off carriageway

On shoulder

In lane (buried)

In lane (not buried) Unusual circumstances with no viable alternative. For this last resort the

access should not be within the zone of typical wheel tracking to reduce risks.

vii. Slot or catchpit grating covers should be attached by a removable hinged system, or fastening systems

that do not require specialised tools to open. For example do not use fastenings such as small fine

threaded bolts (these may work on a brand new clean asset system, but during night works on a dirty

system it is very difficult to re-attach such gratings). Consider the direction of traffic flow for hinge

orientation.

viii. Additional catchpits, slot/trench drain, or other suitable inlet collection systems should be placed at

gore areas or low points to best manage the risk of unsafe surface flooding.

ix. All catchpits should have sumps at least 400mm deep (below the invert of the outlet pipe level). These

provide good pre-treatment benefit reducing the frequency of maintenance at treatment devices.

Sumps also help to minimise the migration of sediments into often flat pipe networks where gradual

sediment accumulation can become bedded and cement-like.

x. Any catchpit siphons should be removable to facilitate flushing, rodding, and CCTV inspections.

xi. Swales should provide a discrete trafficable section (e.g. a 3m wide strip of gobi-block or rip-rap lining)

to enable maintenance vehicles to safely traverse across the swale without causing damage to the

profile or invert (e.g. to avoid wheel rutting).


xii. Also see Section – Structures – Bridge Drainage.

Stream and Waterway Crossing Design

i. Where any proposed culvert serves a permanent watercourse that contains existing or potential future

ecological values (e.g. upon restoration) in addition to meeting the hydraulic requirements for passing

design flows, culverts should be designed to include features for the provision of ecological connectivity

for the passage of aquatic and terrestrial fauna

ii. To mitigate erosion at the interface between natural streams and culvert headwalls, wing-walls and

structures, appropriate debris control, erosion control and energy dissipation measures must be

incorporated. Also consider contractions and expansions of the streams at the proposed culverts in

order to manage local scours, erosion and increases of flood levels.

iii. Consider the safety risks associated with culverts adjacent to private properties, parks and reserves

where grills are required.

Stormwater Devices

i. Ensure that any below ground structures have safe access and best optimise the ability to safely

perform operational monitoring and maintenance activities without the need to enter the system (e.g.

grated tops over sediment chambers, and suitable size manhole access over the forebay zone as well as

the filter bed for filter system (e.g. sandfilters or StormFilters), observation access platforms at pond

outfalls).

ii. Ponds should have dewatering facilities to incrementally draw down the water levels to pond forebay

and base level for the purpose of delivering maintenance operations. Carefully consider dewatering

orifice sizes relative to practical draw down time

iii. All stormwater management devices (i.e. ponds, filters) should have a flow bypass facility to facilitate

the timely delivery of routine operational activities (e.g. desludging) as well as emergency procedures

(e.g. spill containment/isolation).

Stormwater Landscaping (also refer to Corridor Assets)

Good landscaping associated with „green‟ stormwater management assets such as swales and ponds can make

a big difference to the delivery of good whole of life outcomes and values.


Consider the types of landscape species best suited to the delivery of operational function of the stormwater

management asset such as:

i. Safety is a significant issue. Good consideration must be given to what delivering safe landscape means

for stormwater assets at busy motorways (e.g. consider proximity to traffic lanes before specific

temporary traffic management is required (at a financial and network efficiency cost)

ii. Maintenance costs associated with landscape maintenance of stormwater assets are high. Good

consideration of whole of life value for money is critical when selecting and specifying suitable plants

(e.g. maintaining grass costs about 6-9 times more than maintaining established landscape.

iii. Consider the life of landscaping in its intended form before rehabilitative maintenance is required (e.g.

how long before landscaping passes it‟s use by date and removal/replacement is required). Good plant

selection for stormwater management assets is critical.

iv. Drought and inundation tolerant species are often important at „green‟ stormwater assets. Motorway

landscaping is manually watered (due to safety and cost considerations). When plant species associated

with stormwater assets become inundated, mortality must not result. Saline tolerant landscape plant

species are important at coastal locations (consider coastal inundation and wind spray resilience).

Consider the mortality of certain species. It is not desirable when whole stands of vegetation die-off in

quick succession i.e. avoid overly sensitive species that can suddenly die-off and cause blockages at

stormwater assets. Apodasmia similis (Oioi) is an example of a good resilient plant for stormwater

management asset outcomes.

v. Simplicity of planting is important e.g. „fancy‟ landscape quickly becomes operationally „lost‟ hence do

not specify a multitude of plants when a couple of key species will reliably deliver the outcomes needed.

Low growth and hardy landscape plant species are preferred. For motorways the simplicity and

commonality of planting is important to reliably achieve a good sustainable landscape outcome. Fewer

and greater consistency of plant species also enables increased operator awareness and capability of

delivering the right landscape maintenance activity at the right time. Landscape planting that is familiar

and intuitive to maintenance operators also stands a much greater chance of being well maintained.

vi. NO stormwater landscape planting should be delivered at confined or isolated areas that can only be

safely accessed with TTM and closures (COPTTM standard). Planted medians are very costly and unsafe

to maintain to the right level of service. For example stormwater treatment swales must not be

positioned at medians or locations where safe off road access cannot be achieved.

vii. Infiltration type stormwater devices are not desirable for the Auckland South network due to the rate of

clogging that is caused by the sheer amount of CRAP (Crude Road Accumulated Pollutants).

Raingardens, and biofiltration assets clog very quickly which can increase the risk of surface flooding

and compromise fundamental level of service needs (i.e. no unsafe surface flooding). Infiltration assets

are not a good whole of life solution and should not be used for stormwater management in the

Auckland South network.


viii. Swales are a great stormwater management asset. Landscaped stormwater swales deliver better

outcomes than grassed swales. See below case:

ix. Avoid the use of deciduous trees at locations where catchpit or system blockage can result in level of

service issues such as flooding, Deciduous trees are a major problem with respect to the sheer volume

of organic mass that can very quickly accumulate causing major problems at stormwater assets (e.g.

catchpits matting and blocking very quickly requiring high seasonal maintenance cost/frequency to

manage unsafe surface flooding risks). Provide good buffer planting for safety (barrier) at pond

perimeters,

x. Good clearance of landscape planting to stormwater structures is desirable. Some plants too close to

manholes and catchpits can result in structural damage (root growth), and landscape planting can

quickly hide the assets (e.g. a manhole in the motorway corridor can be „lost‟ in overgrown plants

within a matter of months/years presenting operational time and cost implications – whole of life).

xi. Pine needles are very problematic at stormwater inlets. Pine needles create dense and fine mesh

matting that can quickly render a standard catchpit „blocked‟. Consider stormwater inlet specifications

where pine trees are in proximity.

xii. No large trees should be planted at ponds that are sited on embankments, or perched ponds where

dying roots can generate „piping‟ failure issues through the dead root zones. Piping can compromise

the structural/geotechnical integrity of the dam/embankment creating a safety risk (of bund failure).

xiii. Mature specimen trees should be planted at the northern aspect of streams, ponds and wetlands to

provide shading that will manage thermal impacts (i.e. of „heated‟ motorway runoff) and ecological

habitat (e.g. flora/fauna/fish passage). Where waterbody shading is needed to ensure the delivery of

consent compliance requirements (i.e. discharge temperatures less than 20.3 degrees), then trees

should be established from the time of handover (i.e. a seedling planted today may not provide the

necessary shading and stormwater temperature management needs for 20 years when grown).


xiv. At shallow ponds ensure that planting is selected to best minimise the risk of weed and algae blooms

that are often induced by thermal and contaminant loading effects.

xv. Ensure appropriate wetland plant species are incorporated into a pond of good bathymetric design, to

ensure that environmental compliance requirements can be achieved. Wetland plants that generate

excessive biomass are not considered particularly good for stormwater management assets as the

biomass will consume the stormwater quantity management capacity (e.g. reduced channel cross

sections and capacity), or stormwater quality improvement performance (e.g. ponds may require

increased frequency of maintenance in order to retain sufficient water quality volume for the treatment

performance needs).

xvi. Carefully consider the use of bark mulch for landscaping at areas contributing runoff to the stormwater

management network. The stormwater assets are regularly adversely affected by bark blocking channels

and catchpit inlets. Excessive bark mulch washed off the landscape areas often appears in ponds

consuming the water quality and quantity management capacity of the asset (increased frequency and

nature of maintenance needed). Use good stabilising agents if bark mulching,

xvii. New Zealand Flax or Phormium tenax and Phormium cookianum (maori name harakeke and wharariki

respectively) are a very hardy and perennial plant that can look great. Caution must however be applied

in selection of the right location the species in proximity to stormwater assets. Flax is very hardy (and

even harder to remove when it becomes overgrown at pipe inlets and outlets) and the root mass can

damage traditional stormwater infrastructure such as culvert headwalls and wingwalls).

xviii. Loose placed round river run rocks should be avoided in stormwater landscape features. These rocks

can be a safety risk (when run over by tyres they become missiles).

xix. Good established vegetation is very important during an „earthworks‟ establishment phase e.g.

landscape planted swales and permanent ponds can be subject to excessive sediment loading during a

landscape establishment phase, resulting in smothering of the target planting and premature

consumption

xx. Compliance with conditions of resource consents is a legal responsibility. Any landscape planting that is

linked to conditions of consent (e.g. a consented swale with an „approved‟ OM document referring to


specific plants) must be effectively conveyed to the Auckland Motorway Alliance to ensure operational

delivery.

Safety in Design (SiD)

Safety = Zero Harm to People, Plant, and the Environment. Stormwater Management Assets present a range of

potential hazards. Good SiD can help to minimise risk. Hazards include: Drowning; Collisions; Confined

Spaces; Congestion; Falls; Contamination; Loss of Control. Importantly a robust risk assessment of proposed

assets should be undertaken in accordance with AS/NZS 4360:2004; AS/NZS ISO 31000; NZTA Z/44.

Stormwater asset reliability, availability, and functionality helps to achieve reduced operational exposure to

safety risks. Consider system functionality to deliver the fundamental Level of Service (e.g. surface flooding,

local flooding, regional flooding). Also ensure that critical asset evaluation is undertaken with consideration of

robust and resilient lifeline needs (consider network vulnerability).

Whilst the below may be „duplicated‟ elsewhere in the stormwater section of the OM guideline the following

points can be considered as useful checklist for a safety in design assessment of proposed stormwater

management solutions and important operational outcome values.

i. Access: Safe, All Weather, Off-Road Access (24/7)

ii. Access: Timing for activity delivery e.g. consider that some activity delivered at night to manage

network congestion under reduced visibility

iii. Access: Confined Spaces access for operational activity e.g. clearance and facilitation of access set-up

like tripod

iv. Access: into Assets e.g. larger lids for sedimentation, spill containment, treatment vault access, etc

v. Access: Inlets and Outlets (e.g. main culverts) - Asset type and location with access to enable

operational delivery

vi. Access: Ladder Rungs in Structures - Consider positioning for confined spaces entry


vii. Access: Enable visual monitoring e.g. vault treatment systems that can be monitored and inspected

safely from ground; safe access to pond viewing position. Safe access to Pond outlet structures is

important for monitoring purposes

viii. Access: Consider Asset ownership versus maintenance boundary versus legal responsibility (e.g.

conditions of consent)

ix. Condition: Integrity - Premature failure of assets (e.g. collapsed culvert)

x. Condition: Durability - Different assets and elements of assets have different failure rates (deterioration

and consumption)

xi. Condition: Material Selection e.g. marine environments, or corrosive environments

xii. Condition: Robust lid fittings i.e. often manhole lids not well specified for frame fastening

xiii. Condition - Some assets may be in a poorer condition than was verified by preliminary investigation or

data records

xiv. Condition: Loose rocks e.g. consider grouting to secure

xv. Distractions - Some assets can look 'wrong' and be distracting.

xvi. Drowning: Water levels and proximity to deep water influences safety risk profile (e.g. in adjacent

ponds, waterways, harbour, etc - risk of drowning and falls)

xvii. Environment: Compliance - Planning and Design interface to ensure that construction and operational

conditions will not result in exposure to safety risks

xviii. Environment: Spill and Pollution - Incorporate contaminant management into design (e.g. half siphon at

catchpits, containment vaults, treatment devices)

xix.

xx. Falls: Heights - Some assets can present fall risk e.g. headwalls, wingwalls, retaining walls, etc, may

need safety rails and or ladders to facilitate operational access

xxi. Falls: No Landings in Deep Manholes owing to impediment to confined spaces entry

xxii. Flooding: Surface Flooding - aquaplaning/loss of control

xxiii. Flooding: Secondary Flow Paths - Reliable and available secondary flow paths

xxiv. Flooding: Consider implications of limit state events (e.g. what if 0.2% AEP storm occurs)

xxv. Flooding: Bridge Deck Drainage e.g. unsafe surface flooding; waterfalls created by passing vehicles;

xxvi. Flooding: Severe Storms During Construction and operation - environmental risk and human safety risk

(operators and motorists)

xxvii. Security: e.g. loose of flying bits such as slot drain covers; fencing if drowning hazard; grating covers

and debris/safety grill if public access

xxviii. Security: Failures from outside corridor/designation (e.g. ponds uphill, flood debris causing blockage at

culverts)

xxix. Security: Surcharging at pressure lines - e.g. manholes popping and flipping


xxx. Security: Fastenings - e.g. risk of assets failing e.g. small screws to fasten assets are not wanted

xxxi. Security: Utilities - appropriate clearances e.g. proximity to power assets.

xxxii. Security: Unidentified Assets - encounter assets not identified by investigation and exploratory works

(e.g. power assets; culverts)

xxxiii. Security: Vandalism: Apply CPTED principals - Crime prevention through environmental design;

consider security of manhole and catchpit grates at say cycleways

xxxiv. Trafficability: Location of Assets e.g. No structure within trafficable lanes

xxxv. Trafficability: Frangibility - consider proximity to shoulder and position within corridor designation

xxxvi. Trafficability: Traversable assets (e.g. catchpits and roadside channels/access). Consider approach

Safety e.g. direction of hinged grates, kerbs form, traversable assets

xxxvii. Trafficability: Safe Slopes - Consider trafficability; and slip potential e.g. pond batter slopes

13.3.4 Construction

Several factors through the construction phase of a capital project delivery can influence the legacy outcomes

and values achieved for the stormwater management assets. These include:

Erosion and Sediment Control (E&SC)

The earthwork and construction stage of capital projects, present significant risk to the safe, reliable, and

compliant operational delivery of motorway stormwater management asset.

Good E&SC is fundamental and can have a significant and positive implication on the safety

(people/plant/environment) outcomes associated with delivery of the motorway stormwater management

assets.

i. During construction and earthworks, ensure that industry best practice is applied for the management

of E&SC measures (e.g. Auckland Council TP90). Good adherence to this guideline helps to ensure the

longevity of the stormwater asset performance (e.g. filtration and infiltration characteristics of

treatment systems will be best preserved by minimising the scope for premature clogging and

consumption).

ii. Consider the implications of transitioning between an earthworks site (TP90) versus a permanently

stabilised site with permanent stormwater level of service and compliance is important. Without good


stabilisation (e.g. established vegetation) of the earthworks, premature consumption of the permanent

stormwater assets occurs.

iii. Good E&SC helps to manage risks such as blockage to motorway stormwater inlets (e.g. sediment laden

catchpits causing unsafe surface flooding), and the premature consumption of critical stormwater

assets (e.g. consumption of roadside channels by sediments can cause surface water to enter traffic

lanes presenting an unacceptable safety risk, and ponds can become prematurely consumed by

sediments requiring „out of cycle‟ and often costly operational activities.

iv. Good established vegetation is very important during an „earthworks‟ establishment phase. E.g.

Vegetated swales and permanent ponds can be subject to excessive sediment loading during a

landscape establishment phase, resulting in smothering of the target planting.

Temporary traffic management (TTM)

Good TTM = Reduced Incidents = Safer Outcomes - During the construction and delivery of capital projects,

good TTM can have a significant and positive implication on the safety (people/plant/environment) outcomes

associated with stormwater management.

It is also very important to recognise that because most motorway maintenance and operational activity is

delivered at night (when visibility is poor) and risks to operators are high, during wet weather visibility gets

worse and safety risks increase. Good consideration of stormwater management for TTM activity helps reduce

the likelihood of incidents at capital project work sites as well as the Auckland Motorway network. Factors to

consider include:

i. Consider the positioning of TTM relative to stormwater inlets and outlets. For example sign stand

footings (and sandbags) often collect debris and CRAP (Crude Road Accumulated Pollutants) that can

cause runoff to spill onto trafficable lanes, and barriers can block or reduce runoff and flows from

reaching the intended inlet, outlet or to follow intended secondary flow paths). Positioning of signs

downstream of catchpit inlets and concrete barriers with underdrainage are good TTM measures.

ii. Rain and stormwater runoff can obscure signs and road markings (and „temporary‟ road markings)

leading to driver confusion. This issue is compounded at Capital Project sites where risks are highest

and „normal‟ operating conditions are altered.

iii. Stormwater runoff and flows can be concentrated by temporary barriers (meaning regular primary and

secondary flow paths are not viable). This can result in unsafe depths of surface water at trafficable

lanes. Consider barrier positioning and drainage needs. Maintain good Primary and Secondary Flow

Paths (consider regular and high flow routes).

iv. Concentrated runoff and flows from constructions sites can wash gravel onto the road causing safety

risks to drivers, vehicles, and the environment.


v. „Temporary‟ pavements during construction can cause unsafe surface flooding e.g. without the „final‟

pavement layer catchpit frames may be „perched‟ resulting in water ponding on the temporary road

surface which can cause aquaplaning and „splashing‟ that obscures drivers vision.

vi. Consider the durability and resilience of all TTM measures to withstand high flows (e.g. to avoid

washouts).

vii. Good TTM includes maintaining the TTM assets for stormwater risks such as blockages and being

prepared for reactive/unscheduled activity (if things go wrong during extreme rainfall storms this will

help to ensure timely action). Further, because every project is different and continuously evolving it is

important monitor the conditions (i.e. monitor and observe if stormwater runoff during storms is

causing problems due to TTM activity). If unsure, engage with the site environmental manager,

stormwater engineer, and/or the network maintenance and operation organisations Stormwater Asset

Manager.

Construction Delivery

“Built it once – built it right” - Whilst generally delivering and constructing stormwater assets is in accordance

with designers plans and specifications, during the construction and delivery of capital projects, good

consideration of certain construction „factors‟ can make a significant and positive implication on the safety

(people/plant/environment), reliability, and resilience of the stormwater management assets. Some factors to

consider include:

i. Decommissioning of existing stormwater management infrastructure made redundant by new works

should be appropriately treated in a manner that will prevent any future deformation or loss of support

to the pavement or any other structure (e.g. remove redundant or fill with 5MPa flowable fill backfill).

ii. Epoxy cement grout (or similar) at cut RC surfaces to ensure that spalling and prematuring aging does

not occur (e.g. too often pipe joints at manholes and catchpits have not been „end‟ treated which

results in reinforcing rust and concrete spalling that results in joint failure)

iii. During construction secondary flow paths should be well maintained. Any secondary flow paths

interrupted by the temporary works should accommodate the effects caused by the works (e.g. safe and

efficient management of disposal to the receiving environment).

iv. During project construction delivery, proactive monitoring and maintenance are considered to be in the

best interest of NZTA and the Contractor. The quality of the stormwater management assets should not

be compromised by the activity or inactivity of others (e.g. sub-contractors).

v. The stormwater management asset should always look great including during the defect liability period

(e.g. consider the separable portion of landscaping associated with ponds or grass swales).

13.3.5 Handover

Some important considerations and needs for the successful handover of stormwater management assets from

Capital Project planning/design/construction status to operational delivery of the assets include:

a. Asset Owners Information: The draft stormwater AOM (including asset information data) and a

familiarisation briefing should occur at least one month prior to Practical Completion. This will enable

adequate time for handover meeting, project snag and document review, for the final AOM to be supplied

before Practical Completion, and for Auckland Council sign off as approved. The network maintenance and

operation organisations require hard and electronic copies of the AOM Document (MS Word format) and

Drawings (CAD and PDF). Refer to Appendix 8 for the Stormwater Management AOM requirements.


b. Asset Information Data: NZTA format RAMM and spatially compatible digital format data to include

fundamental asset management data including what, where, condition, design performance for quality and

quantity. Also see Section – RAMM and As-Built Data.

c. Handover Condition: Verification of the condition including CCTV records and inventory record/reporting

sheets. This includes that appropriate maintenance is undertaken prior to the handover (i.e. flush, clean

and CCTV network that is utilised by the finished solution). Handover to include operational monitoring

inspection, and maintenance activity closure forms at the time of handover. It is important to note that a

„new‟ asset should be just that – a NEW asset. Too often the assets received (historically) have been very

poorly maintained or consumed, and are not to an adequate commissioning standard for handover to

operations.

d. Special Tools and Parts: Any special tools or parts (e.g. manhole or penstock keys, fish passage moulds) to

be supplied prior to opening.

e. Handover Meeting(s): A joint inspection and meeting to debrief on the specific operational monitoring and

maintenance, as well as any defect liabilities for the stormwater management asset should be held at least

six (6) weeks prior to opening. Depending on findings there may be important need for a second meeting

for issue closure. This should occur at least two (2) weeks before opening.

f. It is critical that any planning, design, and construction conditions are satisfied and closed off by capital

projects prior to handover for operational activity. With the current compliance chronology, the operational

ownership (legal) cannot be fully owned by operations until the preceding delivery consent conditions have

been signed-off.


Appendices


Appendix 1 - Corridor Assets

Whole of Life Consideration - Corridor Vegetation

The following comments are based on achieving whole of life value for the corridor from all projects and

avoiding unnecessary on-going NZTA maintenance costs, and customer costs arising from loss of network

efficiency from lane/shoulder closures needed to carry out cyclic and programmed maintenance and

inspection activities.

Consult the network maintenance and operation

organisations for more specific advice if required.

Significant traffic control (TC) refers to the use of

two to three attenuators. Attenuators are costly

compared to the activity they are protecting (e.g.

mowing, litter removal), cause loss of network

efficiency and potential safety issues from lane or

shoulder closures. Up to three attenuators are

required.

The design of corridor vegetation and the placement of other

corridor assets within the corridor such as guard rails, barriers,

lighting columns, gantries and signs should be jointly considered as

part of a holistic corridor design.

For example, placing signs in the middle of a tractor access route

can prevent tractor mowing and requires weed eating to be carried

out in an area that can otherwise be mown (51% of the grass

maintenance budget is spent on weed eating).

The following whole of life comments are based on recent and

historical projects. They support other NZTA documentation

relating to landscaping and noise barriers. They are in effect a

designer‟s checklist. Some of these comments may not be

appropriate for a particular site. It is the designer‟s responsibility

to come up with a design that represents value for money for NZTA

based on whole of life principles by taking in all site specific

considerations for a particular project.

Reference to photos refers to photos in Appendix 3.


Whole of Life Cost Considerations

When designing corridors, consideration should be given to the following:

Landscaping Designer‟s Checklist 1. Landscaping should be designed as part of a holistic design for the project that considers the

placement of signs, barriers and other assets within the corridor before deciding on landscape themes

and selecting plant species. This will

a. Avoid plants growing to full height and encroaching into live lanes, over barriers and

guardrails, obscuring signage and other adverse impacts from poorly placed and/or selected

planting. The designer should specifically address this matter when selecting plant species.

b. Allow access to the corridor for mowing and other regular maintenance and inspection

activities.

2. Specific attention should be given to avoiding planting flax in areas where flax stamens will grow to

considerable heights and encroach into live lanes. (Photos 1 and 10)

3. Avoid cabbage trees near to grassed areas as their leaves clog mowers .

4. Landscaping designs should be for a 50 year plus period taking into account where plants will grow to

in that time. This particularly includes consideration of how wide flax will grow to in 50 years when

placing flax behind guard rails. Digging out of flax is expensive and avoidable. (Photos 1, 10 and 27)

5. Plants with short lifespans such as Whau should be avoided unless part of a two stage design or a

plant that self seeds with tough seedlings that can grow in challenging places before it dies such as

comprosma robusta.

6. Two stage planting programmes should be clearly identified. Costs to bring landscaping up to full

establishment after the end of the DLP should be clearly identified and funded from the project

through suitable arrangements.

7. Landscaping should consider all areas within the motorway boundary other than pavements and not

just areas where landscaping is planned. This includes medians and gore areas. It should include

impermeable solutions for areas unable to be effectively landscaped (e.g. red oxide concrete in narrow

gore areas.

8. Planting in front of barriers and guard rails should only be used where there will be no safety risk

from vehicles striking the vegetation and crossing over the guard rail or barrier. Definitely no

planting of flax in front of guard rails.

9. The landscape design should allow for areas to safely park vehicles during regular operational and

maintenance activities without requiring significant traffic management. This includes mowing,

inspection activities for stormwater, IT assets and structures. This could be combined with

consideration of safe areas for incident management and Police bays. This can be achieved by gaps in

guardrails and barriers.

10. If required, only biodegradable weed mat lasting no more than two years, should be used.

11. The edge of the shoulder adjacent to landscaping/grass should have a defined edge.

12. Vegetation planted in medians and similar areas such as gore areas requiring on-going maintenance

should be avoided unless they can be safely accessed without any significant traffic management.

(Photos 2, 3, 4, 5 and 7)

13. Where vegetation is planted in median and gore areas, it shall be designed so that it will require no

regular maintenance (other than occasional weed spraying) once the vegetation is 80% + established

and handed over to the network outcomes contractor at the end of the Defect Liability Period.

14. The designer should ensure that the landscaping will not cause future adverse impacts on

neighbouring properties such as overhanging branches.

15. The landscaping design should be integrated with the stormwater vegetation design including swales.

(Photo 29)


16. There should be no need to use attenuators for TC for any foreseeable landscape/grass maintenance

or any other regular activity on the corridor..

17. Pest Plant removal programmes where required should be established and implemented at the earliest

opportunity. The network maintenance and operation organisations can give specific advice.

18. Materials brought to site such as plants, mulch, fill, aggregate shall be free of contaminants including

anything that is potentially able to germinate. This will require suppliers to be carefully chosen.

19. No vegetation is planted that will be an environmental issue e.g. invasive

20. Landscaping should address or make allowance for biodiversity. The network maintenance and

operation organisations have a biodiversity strategy that supports NZTA‟s Environmental Plan.

21. The landscaping plan should clearly identify and locate special interest areas such as time capsules,

grave sites, special blessing stones, urban sculptures, trees and, taniwha areas.

22. The landscape design shall be included in the CPTED review for the project. (Landscaping can reduce

the opportunities for graffiti offending and other antisocial behaviour. Planting in front of at-risk

fences reduces the likelihood that they will be tagged.)

23. Landscaping also needs to consider all activities taking place within and adjacent to the effective

corridor including the CPTED needs of cycleways.

24. Flaxes planted close to footpaths are trip hazards and should be avoided. (Photo 27)

25. Vegetation should not impact on Safe Stopping Sight Distances particularly on curves. Drivers can see

over barriers but when the plants behind them grow higher than the barriers sight lines are reduced

and accident rates increase.

26. Vegetation should not exacerbate red light running at, for example, off ramps by compromising sight

lines to opposing traffic on side roads or disguising the presence of side roads.

27. Trees and plants should be placed so as to not overhang areas to be mown when they are fully grown.

28. Species should be selected after consideration of where they will grow to be in 50-100 years,

especially where planted near to shoulders, guard rails and boundary fences.

Grass

29. No grass should be planted in the median.

30. Grass should be sufficient distance away from the live lane as to not require any significant (i.e.

attenuators) to mow unload or reload. This distance requires due consideration being given to area

specific safety concerns including deceleration and acceleration needs of maintenance vehicles.

31. Grassed areas should be specifically designed so that they can be safely and efficiently mown with a

tractor mower. No narrow areas (<2m) or square corners in grassed areas. Minimal reversing

required to mow area.

32. Special attention should be given to tractor safety issues when designing mowing run around trees

and other plantings on grass slopes

33. Ideally mowers should be able to get to the next area without needing to access the motorway (and

requiring TMP). Access is often prevented by small gullies. Lengthening a culvert and covering can

sometimes provide access from one area to the next.

34. Recommendations on maximum slopes are included as Appendix 2.

35. There should be no grass that requires weed eating to maintain. This will require the landscape

design to be coordinated with the designs for the placement of signs and other infrastructure in the

corridor.

36. Grassed areas should be a reasonable area for effective mowing i.e. no small isolated areas of grass

that cannot be mown from another grassed area. (Loading and unloading a mower on a truck takes

20 minutes and sometimes requires attenuators.).

37. How mowing round signs, gantries, trees and other corridor assets will be carried out needs to be

considered. (Teardrop landscaping is one option).

38. Grass mix should be specifically designed for the site conditions.


39. Drainage needs to be included where necessary to avoid mud tracking onto the carriageway from

grass mowing, following wet weather.

40. Non-motorway access for mowing may be appropriate in some areas.

41. No grass between noise walls and boundaries unless there is a big gap with access at both ends.

42. There should be a Mowing Plan produced to demonstrate that the above has been incorporated into

the design.

Other Corridor Considerations

43. Noise barriers should be constructed with a 50+ years design life. Ideally they should be sited on the

boundary as maintaining between the back of a barrier and a boundary is difficult.

44. If unavoidable, narrow areas behind noise walls should have appropriate maintenance access for

spraying.

45. There needs to be a separate graffiti management plan for protecting all at risk surfaces. The

landscaping plan, and other project plans, will influence the extent of graffiti protection necessary.

46. Only approved anti-graffiti coating products shall be used. Refer the network maintenance and

operation organisations‟ website for details.

47. Graffiti coatings are very sensitive to surface preparation and ambient conditions. They need to be

applied in accordance with the manufacturer‟s instructions. This has been an issue on previous

projects with incorrectly applied and possibly diluted coatings peeling off shortly after handover. It is

recommended that projects use the same QA as used for structural coatings e.g. use NZTA (TNZ) Q/4

Standard. The project should confirm that the Q/4 standard has been met, i.e. not the applicator.

48. CPTED reviews (including IPTED reviews where appropriate) should be carried out on all designs.

Consideration of graffiti opportunities should be included. This includes structures, (e.g. avoid

creating areas on the end of piers for taggers to stand on - Photo 18)

49. Urban design features should require minimal maintenance including repainting. They also may need

to be anti-graffiti coated.

50. New products e.g. acrylic panels need to be chosen mindful of their on-going maintenance

requirements and their susceptibility to graffiti and other vandalism.

51. Where not already covered under existing agreements, maintenance boundaries should be agreed at

the earliest opportunity in accordance with the principles of the current maintenance agreement

(draft) with Auckland Transport.

52. Special on-going maintenance agreements with adjacent owners should be avoided wherever

possible. A recent project agreed a monthly mowing frequency with an adjoining property. This is a

much higher standard than would otherwise be required and requires a special trip to mow.


Appendix 2 Safe Mowing Slopes

Summary

Slopes in this document are expressed as Vertical to Horizontal i.e. 1 in 3 =1 Vertical to 3 Horizontal.

The safety of operators and the travelling public are key issues when designing grassed slopes, as well as

whole of life considerations. Considering the following and assuming well planted and established slopes,

recommended criteria and comments for slope design are:

No grass should be planted if weed eating to maintain it is needed due to access or slope considerations.

NZTA Std Professional Services Guideline PSG/3 - Asset Management Guide Version 1, March 2009 should

be used. It says “Ride-on mowers require slopes less than four horizontal to one vertical“, (IV in 4H).

Slopes steeper than 1 in 3 are strongly discouraged because of safety and efficiency reasons. These slopes

should be planted with plants that require minimal maintenance

Slopes need to be even with no bumps or holes/soft-spots/rutting/obstacles to mow around, particularly

when getting up to slopes of 1 in 3.

Safety in design should be a key consideration, (for mower operator and highway users).

This report only addresses safe slopes. Whether or not designing grass slopes represents value for money for

NZTA where compared against planting, is not addressed in this Appendix.

Recommended criteria for safe slopes (in order of preference)

Slope Slopes with Runoff Areas Slopes with drop hazards Comment

<1in 12

General consideration of

mowing requirements

General consideration of mowing

requirements.

NZTA levels of service

likely to be met

1 in 7

to

1in 12

General consideration of

mowing requirements.

Slopes to be specifically designed

for mowing runs (e.g. tractor turn

areas, obstacles to mowing such

as vegetation, poles, evenness of

slope, avoidance of need for

tractor to go close to edge.

Produce tractor mowing plan.


unlikely to be met for

slopes with drop hazards

when slopes wet.

Separation from the top of

the drop needs to be

considered.

1 in 4

to

1 in 7

Slopes to be specifically

designed for mowing runs.

Produce tractor mowing

plan (e.g. consider tractor

turn areas, obstacles to

mowing such as vegetation,

evenness of slope, poles,

safe runoff areas.)

No grass generally and preferably

planted but considered on a case

by case basis mindful of mowing

safety issues and whole of life

considerations.


unlikely to be met when

slopes wet - even with

runoff areas.

Slopes need to be well

constructed with no

bumps or hollows.

1 in 3

to

1 in 4

Only where unavoidable and

practical.

Subject to criteria above.

No grass Steeper than the 1 in 4

that NZTA PSC/3

recommends for tractor

mowers.

Planting recommended

>1 in 3 No grass No grass

Purpose


The purpose of this Appendix is to recommend guidelines for the steepness of mowing slopes that can be

applied to the design of Capital Project corridors.

Considerations

These grassed slope guidelines consider:

Health and Safety

o Operator

o Motorists (from tractors rolling onto live lanes)

Slope types

o Slopes with drop hazards such as retaining walls at the bottom

o Slopes with safe run-off areas at the bottom

Compliance with NZTA‟s Levels of Service

Consistency with NZTA PSG/3 re slopes for tractor mowers

Mowable grass is one slope treatment option. For some slopes vegetation will be a better option.

Irrespective of how a grassed slope is designed, the mower operator determines whether slopes are mowable

depending on the conditions on the day.

Document Limitations

This document only addresses safe slopes, i.e. Just because a slope can be mown, it does not mean that it is

necessarily appropriate to plant it in grass based on whole of life considerations.

Whole of life costs are specific to a particular project and include:

Whole of life costs

o Construction costs

Planting, impermeable fill such as red oxide concrete, or grassing

Retaining walls (with drops) or steeper slopes

Other considerations

o On-going maintenance costs

Mowing

Associated costs such as transporting, offloading/loading

Traffic management such as attenuators or coning

Intangible costs (that are real to our customers).

Interruption to customer journeys

Increased safety risks from lane closures

Journey Ambiance

Other project specific considerations

Slopes with run off areas


Mowing runs for all slopes including slope with drop offs, need to be considered for safety, whole of life and

practical reasons.

Slopes between 1 in 3 and 1 in 7 with safe runoff areas at the bottom are only safely mowable in dry

conditions such as typically after two weeks without rain in winter. This often prevents compliance with the

NZTA levels of service.

In addition slopes between 1 in 3 and 1 in 7 with safe runoff areas can only be safely maintained if there are

no impediments to mowing the whole slope. Having to manoeuvre around isolated trees can be very

dangerous when the tractor is required to turn uphill. There are simple design solutions to avoid these issues.

For this reason any slope greater than 1 in 7 needs to be carefully designed (including the placement of all

infrastructure including vegetation in it) giving due consideration to the tractor mowing plan. The slope

opposite BP Silverdale is a good example of such a steep slope designed for mowing as it has no trees or other

obstacles to mow round – Picture 1.

Slopes flatter than 1 in 7 with safe runoff areas at the bottom are safely mowable in almost all conditions

(other than following recent rain) and usually able to comply with NZTA‟s levels of service.

Slopes less than 1 in 12 are ideal but are still slippery when wet.

Picture 1 – Slope opposite BP Silverdale

Slopes with drops

Slopes with drops should not be steeper than 1 in 7 and ideally less than 1 in 12. With no runoff areas there is

no factor of safety and tractors could end up in a live lane and/or over the drop. Wet grass can be

deceptively slippery and cause slippage even on relatively flat slopes. (See article on following page and note

the slope.)

Slopes with drops should be included in a tractor mowing plan. This includes ensuring that the tractor will be

able to safely manoeuvre close to the edge of the drop.

General

All slopes should be carefully designed taking into consideration safety, drop hazards, whole of life and other

issues.

The safety of mower operators is a key issue when designing slopes. Mowers rolling onto live lanes are also a

consideration where the toe of a steep bank finishes close to the shoulder, or there is a drop hazard (e.g.

retaining wall) adjacent to the shoulder.

Tractors will roll over through a combination of;

slippery/wet conditions,


bumps and hollows/soft spots (e.g. caused by water seeping out of a slope),

imperfect or eroded slopes,

turning on slopes,

small loss of pressure in the downhill tractor tyre, and

operator error including speed.

Where this occurs on a slope, this could result in a mower rolling onto the live lanes if there is no runoff area.

Where this occurs above a drop hazard, it could also have other serious ramifications depending on the nature

of the “drop”.

Mowers can roll or slip/slide down a slope. Slippery slopes above vertical drops are a specific safety issue. See

the attached Herald article on a recent mowing accident.

It is the steepest part of the slope, not the average slope that needs to be considered.

A mower with a 1.5 m wide wheel base dropping the lower wheel into a 200 mm hole on a 1 in 3 slope will

increase the slope to 1 in 2.14. The same effect will occur with a 200 mm bump on the uphill side. Even at

slow speed this may result in a mower rolling.

Bumps are not easy to see when mowing as they are often covered in grass.

Having to manoeuvre around trees, signs and other obstacles on slopes can potentially cause a mower to tip

where uneven surfaces are present. Turning to go uphill is particularly dangerous.

Grassed slopes are cheaper to construct than planted slopes. This does not mean that they are the best

option for NZTA.

Steep slopes can be hydro seeded with specific grass species and do not require mowing or regular

maintenance.

Access to mow slopes adjacent to swales may require some form of crossing to protect the swale.


Miscellaneous Reference Material - NZTA Requirements

(Standards of Professional Services Guidelines PSG/3 – Asset Management Guide Version 1 March 2009.)

Ride on mower manufacturers‟ recommendations

Manufacturers are reluctant to recommend a maximum slope. John Deere say “There are too many

variables to specifically state what degree of slope can be "safely mowed".


Appendix 3 - Corridor Assets Photo Examples

Issue 1. Planting of Flax – Safety

Good Design

Features

Design Improvement Opportunities/Comments

Flax too close to barrier and stamen over live lane. (Stamens can grow to 5

metres and damage cars and wing mirrors, if not removed.)

Unnecessary money spent removing stamens including TC costs. Customers also

adversely affected by full or partial lane closures.

In a few years many guard rails will not work as designed because of the flax

pushing behind them. Flax will also encroach onto the live lane.(middle photo).

Significant issue for several sections of network.

Sight distance around curve restricted, unable to see tail of queue (middle photo)

Obscuring signs (middle photo).

Stamen heads

in live lane


Issue 2. Grass Maintenance - Medians

Good Design Features Design Improvement Opportunities/Comments

Aesthetically

pleasing.

Edging between

shoulder and

vegetation/grass.

Median grass unable to be accessed by tractor mower. Note

lighting column in middle of median.

Lane closures needed to maintain.

Attenuators needed to get in and out.

Grass behind barrier on right too wet to tractor mow because of

ground drainage system discharges and is weed eaten.

Light poles in berms not conducive to mowing.

Sign on the right of photo also impedes mowing runs.

Issue 3. Grass Maintenance - Medians


Long length of

grass to mow

without “fiddly

bits”.

Attenuators required to make lane closure to enable mowing.

Very long queues (several kilometres) caused by reducing two lanes

into one lane at off peak times (Fast lane blocked).

Area around wire barrier sprayed.

Sealed or low maintenance strip under barrier that allows visual

inspection of barrier.

Over time soil around posts erodes and/or is pushed up by

Auckland‟s shrinking/expanding clays.


Issue 4. Median Maintenance


Easy to main median.

Aesthetically pleasing

Low maintenance costs.

Lighting column on barrier (right photo).

Issue 5. Grass Maintenance – Network efficiency and safety issues


Mowers able to be safely

loaded and off loaded

without TC.

Attenuators needed for lane closure to mow grass

because of design.

Tree requires mowers to access live lane with TC to

get around it.

Design so as to be mown without attenuators. .being

required. E.g. provide space behind tree.

Design with space beside tree so that mowers do not

need to be within 5m of a live lane.


Issue 6. Grass Maintenance by Weedeating


Large grass area unable to be accessed by tractor mower.

Very inefficient to maintain.

Provide safe access for mower in design.

Issue 7. Plants by wire barriers


Looks attractive to motorists.

Reduced headlight glare.

Potential safety issue if species planted allows

vehicles to be uplifted over barrier. Address with

smaller plants.

Also an issue if plants encroach into live lane or

affect sight lines.

Hides damage to barrier system. Requirement is

for all cables to be visible.

Impermeable solutions such as red oxide would

reduce maintenance costs and allow wire rope to

be visible.


Issue 8. Red oxide concrete gore areas

Good Design Features Design Improvement

Opportunities/Comments

Looks attractive/tidy.

Minimal maintenance.

No TC necessary to maintain vegetation.

Issue 9. Provide access for expected maintenance and inspection activities

Good Design Features Design Improvement Opportunities

Looks attractive.

Access provided.

Minimal disturbance/distraction to traffic.

Minimal TC to access.

Small area of grass to maintain.

Grass has since been replaced by

vegetation.


Issue 10. Vegetation obscuring signs


Left photo

Access provided for roadside

cabinet.

Vegetation looks good.

Left photo

Vegetation will soon obscure sign.

Trimming or removing such vegetation is an

unnecessary expense.

Holistic design will avoid this issue.

Right photo –

sign obscured.

see previous comments about flax.

Issue 11. Safe slope mowing


Looks attractive.

Run off area for tractor mower.


edge of shoulder.

No attenuators needed to unload and

mow.

Steep slope with hazards to negotiate –

safety issue for mower.

Grass struggling to grow.

Drainage obstacle to avoid in middle of

photo.

Landscape positioning could have been

designed mindful of tractor mowing runs.



Good Design Features Design Improvement

Opportunities/Comments

Slope relatively even with minimal deviation of cross

slope mowing runs.

Obstacle at right of picture relatively easy to avoid.

Safe runoff area at bottom.



Requires weed eating.

No tractor access.

Obstacles (raised manholes) to go round if tractor

mown was possible.




Looks good (from motorists‟

perspectives (i.e. not camera

position).

Tractors able to be offloaded

and grass mown without the

need for attenuators.

Good tractor runoff area.

Mowing grass on slope requires tractor to turn on

slope when the landscaped area is reached (White

line). Teardrop shaped landscaped area would make

mowing safer, particularly when grass slippery.

Swale needs to be able to be mown or crossed to mow

grass behind swale, without tractor damaging swale.

This may require drainage.

Large area of grass to mow.

Slippery in winter months to mow.

Issue 15. Access for mowing


Could have been designed for access to large grass area.


Issue 16. Access for mowing

Before (behind sign)

Weed Eating

40-60 man-days P.A.

Tractor

No tractor mowing.

based on 5 visits a year

After (Behind sign after

sign raised)

Weed Eating

5 man-days P.A.

Tractor

7.5 - 10 hours P.A.

based on 5 visits a

year.


Grass able to be mown behind sign

because sign height was raised to

allow for tractor mower. (Before sign

raised, grass behind it had to be

weed eaten).

Signs should be placed and designed for

tractor access where appropriate.

Two legged signs can often be raised to allow

a tractor to pass, three legged signs make it

more difficult because of the reduced space

between the legs.

Area between barrier and poles difficult to

mow.

Issue 17. Access for Mowing


No access for tractor mowing large area of

grass.

Grass planted under guard rail.


Issue 18. Access for mowing and cost reduction opportunities


NZTA land between fences is grazed.

I.e. reduced mowing costs and revenue

from grazing.

Access over stream/low point is

possible for tractor. (In many places

the tractor has to reverse out and

reload and unload to get to the other

side of the stream/low point. Often one

additional culvert pipe is all that is

needed to cross such areas.

Flax adjacent to grass is a mowing issue (Same for

cabbage tree leaves).

Would be better if the concrete edge was behind

the wooden posts.

Issue 19. CPTED Design review


Simple design modifications would have

prevented platform for graffiti offenders to

stand being created.

Attenuators/lane closures/cherry picker needed

to remove – i.e. very expensive to remove.


Issue 20. Edge Maintenance



Grass unable to be accessed by tractor

mower.

Area maintained by spraying under mobile

operation (Lane closures).

Low growing shrubs could be planted or

mower access provided if wide enough.

Plantings generally deter taggers.

Issue 21. Edge Maintenance


Aesthetically pleasing.

Metal posts in concrete for guard rail –

easier to fix when hit than wooden posts.

Sign not impeding mower.

Grass able to be accessed by mower.


Issue 22. Safe Access


Good access for mower

unloading/loading.

Good grass mowing runs.

Not too many mowing impediments.

Able to be used by Police, and others on

motorway business.

Note shoulder used as bus lane.

Mowing close to live lane by sign requires

TC.

Median maintained by spraying. Less

spraying would be required if median was

e.g. red oxide concrete or hotmix.

Issue 23. Pedestrian Sight Lines


Planting has significantly reduced

pedestrian sight lines from crossing

point.

Similarly open sight line at intersections

reduce bicycle crashes and red light

running crashes .


Issue 24. Noise Walls/Barriers – Whole of Life – Concrete vs Timber


Concrete meets NZTA

design life requirements

of 50 years plus.

Concrete looks good.

Timber has short design life 5-10 years?

Top of timber walls need to be protected by sealant and

capping beam. Photo 3 above shows unprotected top of

new timber wall allowing water ingress. Note some

vertical boards have begun to crack after a few years.

Concrete Noise Wall Timber/Plywood Noise Wall

Top of Timber/Plywood Noise Wall

Timber/Plywood Noise Wall


Issue 25. CPTED - NZTA Noise Walls/Barriers – Graffiti removal


Looked good before it was tagged. NZTA‟s Noise wall is aesthetically maintained

by Auckland Council.

Painting out graffiti with multi coloured stripes

requires a lot of paint tins for volunteers to

carry.

Issue 26. Design review – Trip hazards


Aesthetically pleasing Flax planted too close to footpath and will

significantly encroach onto the footpath and

become a trip hazard.

Front row of flax will need to be removed once

it encroached on the path.


Issue 27. Grass maintenance by spraying


Fence poles in concrete strip (right

photo.

Grass behind barrier and between fence is

maintained by spraying. (Left photo).

Some form of surfacing between shoulder and

fence would make it look tidier and be easier to

maintain. (both photos).

Issue 28. Grass maintenance


Unable to access with tractor mower.

Boggy for weed eating team to work in.

Landscaped swale would be a better option.

E.g. Oioi


Appendix 4 - The Real Costs of Mowing Grass (A Guide for Assessing

Whole of Life Cost Considerations)

Summary

This document addresses the frequently asked question of how much a year it costs to mow a square metre of

grass on the network. There is no simple cost per m2/year for grass mowing, the cost is a function of:

How it is cut (tractor mower or weed eaten).

Whether temporary traffic control (TC) is required (not needed, 2 to 3 attenuators, or coning).

Whether there is a large area that can be mown without needing to constantly relocate or there are

discrete and fiddly small areas.

The NZTA mowing specification for the area (Type 1, 2 or 3) which determines the mowing frequency.

(The type of grass also determines the mowing frequency).

Area specific plant and labour rates.

Intangible costs such as the customer delay costs resulting from TC (e.g. lane and shoulder closures).

Ideally grass should be able to be mown by a tractor mower with no Traffic Control (TC) being required. Based

on the following, the least efficient mowing rate (tangible costs) is 154 times more than the theoretical most

efficient mowing rate.

Intangible costs also need to be taken into consideration. Queues several kilometres long can result when

two lane sections of the southern motorway are reduced to one lane to mow median grass. Safety and

journey ambience also need to be considered, especially safety on curves.

The alternative to grass is usually impermeable treatments such as red oxide concrete, or more commonly

landscaping. Landscaping is not specifically addressed in this Appendix other than to note that typically

landscaping costs $15-20/m2 to establish up to 80% canopy coverage which is slightly higher than the

highest annual rate above to mow/m2.

Grass also has considerable but usually lesser costs to establish which must also be considered.

The following provides guidance as to a methodology for calculating likely whole of life mowing costs.

Conclusions

1. Tractor mowing large grassed areas without TC being required is the most efficient way of mowing.

2. Weedeating grass is very inefficient compared to tractor mowing.

3. TC where required adds significant costs.

4. Whole of life costs are based on practical considerations for any specific site including site specific

rates. E.g. some clay sites may require significant treatment before anything can be planted in them.

5. Site specific analysis of mowing runs needs to be applied to completed designs to ascertain an

efficiency percentage to use to calculate annual mowing costs if the tables below are used.

6. Determining whole of life costs for grass mowing may require discussions with mower operators, TC

qualified persons, grass type specialists, persons able to calculate the intangible costs including

customer delays and cost estimators.

7. This document is a suggested methodology which can be applied to any area of highway corridor by a

project designer. The ratios in the table below are indicative of the experience to date.


The Real Costs of Mowing Grass Purpose

Considerable maintenance money is spent inefficiently maintaining grassed areas on the network because of

poor attention to whole of life considerations in project designs. Associated traffic management not only

incurs additional costs but also adversely impacts on our customers‟ journeys.

The following is intended to be a guide for designers to assist them in calculating annual and whole of life

mowing costs for their projects.

Costs used in this Appendix

The mowing costs used in the Summary are for example purposes only and are not indicative of any particular

area. Designers will need to calculate area specific costs to use in their whole of life calculations.

Introduction

The purpose of this document is to quantify grass mowing cost ratios for weed eating and tractor mowing to

assist capital project designers to calculate whole of life costs for capital projects. This in turn will assist

designers to produce value for money designs for NZTA based on whole of life costing principles.

This is a generic methodology based on the network maintenance and operation organisations‟ experience of

maintaining grass. Designers will need to apply area specific common sense, rates and knowledge.

Mowing refers to tractor mowing and weed eating in this Appendix.

The following is based on current experience noting that low-grow grass techniques and other initiatives may

reduce mowing frequencies and hence overall maintenance costs. Boggy flat grassed areas also need to be

considered as labour intensive methods such as weed eating may be needed to maintain them.

Background

The analysis in this document is based on general observations and current experience to assist designers in

determining whole of life costs for NZTA based on value for money principles and expressed as ratios

compared to a day tractor mowing efficiency (defined below). Site specific designs reinforced by common

sense practical considerations need to be applied to all project designs.

Currently (2013) 51% of network grass maintenance costs are for weed eating. Most of these costs could have

been avoided through greater attention to whole of life design considerations. Tractor mowing costs could

also have been significantly reduced by greater consideration of TC requirements and unloading/loading areas

in the design.

There are various treatment options for any section of motorway corridor that need to be considered. This

includes determining which areas should be landscaped, which areas should be grassed and which areas are

set aside for other purposes such as hard filled access areas, Police Bays and narrow gore areas.

Considering how those areas will be maintained and how much it will cost to maintain before finalising the

corridor treatments is essential.

Day efficiency

For the purpose of this document, mowing teams spending 5.5 hours (69%) out of 8 hours/day physically

mowing or weedeating is considered to be a very good day (i.e. achieving theoretical maximum efficiency) and

used as a 100% efficiency benchmark. Getting to site, offloading and reloading mowers, travel between sites,

manoeuvring mowers for the next run, safety breaks and maintenance requirements are not included in the

5.5 hours above.


In practice mowing efficiency on the motorway probably varies between 10% and 80%. 80% efficient would be

achieved where large areas of grass are mown such as on the large grassed areas on SH1 between Lonely

Track and Silverdale with unloading and reloading only occurring a small number of times. For example, 80%

efficient would be 80% of 5.5 hours, i.e. 4.4 hours, spent mowing grass at normal speed. 10% efficiency would

be achieved in the many small fiddly grassed areas intermittently spaced along the carriageway, without good

access, requiring TC and typically using weed eaters.

General

Grass is mown as per NZTA

Specifications where it is safe to do

so. There are three service levels

that apply to the motorway.

Typically grass is mown 5 to 8 times

in an average year. (Six times a

year is used in this document.)

Where there is a grass interface with

undefined landscaped areas such as

trees and shrubs planted in grassed

areas/slopes, the areas around the

vegetation are unable to be mown

and require specific weed spraying

3 to 4 times a year to maintain

where no defined edge exists.

(See brown areas in Picture 1)

Tractor Mowers

5½ hours of mowing at normal speed out of an 8 hour day is considered for this document to be very good

and is regarded as 100% efficient. (Tractor mowers typically mow at 7km/hr.)

Assuming a typical 1.8m wide cut, this equates to 12,600 m2/hr or 69,300 m2 per very good day (5.5 hours

mowing). Some tractors can mow wider say 4m but are not considered in this document as they are more

suited to a sports field type environment.

Tractor mowers are usually taken to site on a trailer on the back of a small truck and take 20 minutes to load

and unload.

Tractor mowers mow across slopes in a motorway environment.

Travelling between grassed areas is not counted as mowing.

Weed Eating

Over the course of a day, one experienced person can cover an average of 10 m2/min or 600 m2 per hour.

This equates to 13,200 m2/day for a four man crew (current practice) based on 5½ hours effective weed

eating per person. The remaining 2½ hours allows for refuelling, safety breaks and other on-going activities

during the mowing operation.

Weed eating is 5 times more expensive per m2 than a tractor mower (without considering TC).

Picture 1: Vegetation showing brown areas free from weeds spraying


Tangible costs

Figures used in this section are highlighted and italicised in the table below.

The relative costs of the various scenarios are presented in the table below. The table compares a theoretical

100% efficient very good day cost (Cost Ratio = 1) to other costs expressed as ratios. For example, using

weed eating and TC (coning) at 10% efficiency has a cost ratio of 154, i.e. it costs 154 times more to maintain

this grass than grass mown with a tractor mower at 100% efficiency and not requiring TC.

Mowing large areas with a tractor mower able to be taken to site and offloaded without TC is the most efficient

way to mow grass. At 100% efficiency (a very good day), it is eight times more efficient than using weed eaters

without TC and 15 times more efficient than using weed eaters with TC (coning).

Tractor mowing (one mower) with TC (2 or 3 attenuators) is about five times more costly than without TC.

Using two mowers under the same TC reduces overall mowing costs/m2 by about 30-40%. I.e. Mowing costs

the same but TC costs halved under ideal conditions. This is common practice for larger areas.

Relative cost to tractor mowing

with no TC 100% 90% 80% 70% 60% 50% 40% 30% 20% 10%

Tractor - no TMP

(one tractor) 1.0 1.1 1.3 1.4 1.7 2.0 2.5 3.3 5.0 10

Tractor – Attenuators 5 6 6 7 9 10 13 17 26 52

Weed eating - no TMP

(four Persons) 8 9 10 12 13 16 20 27 40 81

Weedeating -Cones 15 17 19 22 26 31 38 51 77 154

Intangible Costs

None of the above takes into account any consideration of the following and sometimes considerable

intangible customer costs.

The intangible cost of mowing results mainly from the delays to our customers‟ journeys and safety

implications when lanes are closed and shoulders in a high speed environment. Mowing the grass median on

the northbound two lane section of the southern motorway mid-afternoon, can cause queues of several

kilometres as it is reduced to one lane. Up to three attenuators can be required to mow motorway grass.

There are usually no significant delay or safety implications (intangible costs) when no TC is required.

Considerations include:

Delay costs/loss of network efficiency costs (e.g. lane and shoulder closures)

Additional safety risk (safety issues/distractions from lane and shoulder closures.)

Visually attractive landscaping can make a better contribution to NZTA‟s Customers First (SHAMP)

strategy than grassed areas (Journey ambiance).

Field crew safety (using mechanical plant/weed eaters on steep and sometimes slippery slopes has

inherent dangers. Operators sometimes need to be harnessed.)

Delay costs are as per NZTA‟s Economic Evaluation Manual (Section A4.3 Composite values for travel time and

congestion.) The urban arterial figure for travel time during the daytime inter-peak (when grass is usually

mown) is $17.95/hr, e.g. 40,000 person minutes of delay (i.e. 4000 people delayed 10 minutes) at average

rate of $17.95/hr multiplied by 6 times a year =$71,800/ year.


Safety considerations from lane and shoulder closures are less able to be defined but nevertheless are

important to consider, especially on curves.

Other Costs

Spraying around trees in the middle of grassed areas is required about 3 or 4 times a year. (See Picture 1

above.)

Landscape, assuming landscaping is 80% established on handover, is sprayed 1-2 times a year.

Swales

Grassed swales need to be carefully designed so they can be maintained without tracking mud onto the

carriageway if they are to be mown with a tractor mower.

If swales are to be mown, then appropriate access needs to be provided. Swales surrounded by barriers and

vegetation cannot be tractor mown.

For an (vegetated) Oioi swale 3-5m wide that has been well established with no Convolvulus or Kikuyu

present, maintenance would require one to two visits per year and completing 1000m of maintenance in a day

using two persons and a vehicle.

Intangible costs - Delayed Customers/year 17.95$

Based on six mowing runs 1 2 4 6 8 10 15 20

Number of persons 1000 1,795$ 3,590$ 7,180$ 10,770$ 14,360$ 17,950$ 26,925$ 35,900$

2000 3,590$ 7,180$ 14,360$ 21,540$ 28,720$ 35,900$ 53,850$ 71,800$

4000 7,180$ 14,360$ 28,720$ 43,080$ 57,440$ 71,800$ 107,700$ 143,600$

6000 10,770$ 21,540$ 43,080$ 64,620$ 86,160$ 107,700$ 161,550$ 215,400$

8000 14,360$ 28,720$ 57,440$ 86,160$ 114,880$ 143,600$ 215,400$ 287,200$

10000 17,950$ 35,900$ 71,800$ 107,700$ 143,600$ 179,500$ 269,250$ 359,000$

Minutes per mowing run

Delay Costs per mowing year (six runs)


Appendix 5 – Other Corridor Considerations

Stormwater/drainage

All-weather tracks provide ideal access to ponds (SH01 Orewa to Puhoi has some good examples).

Swale drains need to have grass strike and be stable when the road is opened. Otherwise, there is high

potential for erosion (and thus non-compliance with consents), and the drainage capacity may be

compromised.

Consider the effectiveness of unique stormwater solutions. The easiest things to maintain are those which

are accessible and consistent.

If maintenance of stormwater assets is complicated, or the process is unclear, this will make consent

compliance difficult.

General maintenance

Service lids in or near the carriageway mean that access is difficult. Putting these behind barriers and/or

away from live lanes will help.

Locate road furniture (such as signs and cameras) behind barriers where possible. This gives them added

protection, and also makes maintenance safer, cheaper and easier.

The harder it is to maintain, the less likely that the project will reflect well on its designers and

constructors.

Consider how complicated the maintenance is for any one item? Consider that there will be many

personnel changes over the asset life, and it will not be possible for each individual to be trained by the

designer or constructor.

Consider whether “unique solutions” such as special light poles or barriers are necessary. They may be

more expensive to maintain, and replacements may be more difficult to source when needed.

If you have to abseil/helicopter in to install something, then the network Maintenance and Operations

organisations will have to do the same to maintain it.

Any documents provided should be ready for use „as is‟ – i.e. the network Maintenance and Operations

organisations should not have to add anything further. For example, maintenance checklists are great,

and ideally the crews will be able to take copies and use them right away. Consider the audience of these

documents – not everyone is a designer and field crews prefer clear work instructions with diagrams.

Maintenance should only require standard or readily available equipment, e.g. lid lifters and other plant.

Be reasonable with equipment requirements – e.g. it should not require ten strong men or a Hiab just to lift

the lid on a stormwater device.


Appendix 6 - Graffiti Management

Objectives

To reduce opportunities for graffiti vandalism in an holistic design process

To coat selected surfaces with approved products by approved methods at the time of construction

To have QA processes in place to ensure the above is achieved

To promptly and efficiently remove all graffiti vandalism starting with the contractor‟s establishment on

site without adverse impacts on structures, travel efficiency, safety, and other client objectives.

Graffiti is one on the main causes of dissatisfaction with the motorway network. It needs to be removed

quickly. Graffiti requiring traffic management (TM) is generally done on a once a week basis when two

attenuator trucks are regularly booked. Graffiti therefore can stay in public gaze for up to a week which can

lead to complaints. Work has to be carried out at off peak hours under lights.

Graffiti is purposely placed where the public can see it. Graffiti complaints start when construction activities

begin. E.g. the contractor‟s shed.

Protection coatings should be in accordance with NZTA requirements. Refer to NZTA and the network

Maintenance and Operations organisations. This is applied to both quality of product and application.

Currently, 2009, there is one approved product for the network, and for new capital projects the network

operation and maintenance organisations will carry out coating application for capital projects.

Designing Capital Projects should be a holistic process based on whole of life considerations. This includes

consideration of:

What structures will be graffiti protected?

o Natural/clear protected coatings

o Painted protected coating – e.g. NZTA grey

o Painted e.g. acrylic paint

o No protection

How do we respond when e.g. unprotected barriers are graffiti vandalised?

o During construction

o After handover

How will quality be confirmed?

o Random testing?

o Contractor‟s QA records?

Lifespan of protective coatings above 5-10 years at best?

o Non-complying products/application methods gives shorter lifespans

How will access be obtained e.g. we do not want TM

o Being able to safely park is good.

o Removing graffiti over motorways is expensive

Consideration of other access issues:

o E.g. access to the 17m high wall on SH20 Mt Roskill extension project

Painting over graffiti

Removal of graffiti during construction through inappropriate methods has resulted in structural damage

(e.g. high pressure water blasters quickly remove graffiti from concrete but can also damage concrete)

Alternative Coatings


A methodology has been established (2009) to evaluate alternative coatings to the approved product. The

network Maintenance and Operations organisations can advise on the procedures for this evaluation and the

independent assessment process involved.

Assisting Graffiti Vandals to ply their trade

New Bridge over motorway

Cost to remove graffiti in above photograph:

Remove graffiti $50 basic removal cost plus:

o Height access equipment e.g. cherry picker

o Two attenuators

o Loss of NZTA image /complaints while graffiti present – Up to a week

o Potential traffic delays

Total Cost can be significant – consider this with design alternatives.

There are potentially a number of design alternatives that could have been used, and meet other objectives

e.g. safety of maintenance operations.


Appendix 7 - Asset Owner‟s Manual – Landscaping

General

This section amplifies the general highway requirements of Z/15, PSG/15 and PSF 3g in respect to operation,

renewal and maintenance of corridor assets. This includes consideration of similar activities related to other

assets likely to be carried out at the same time such as maintenance of landscaping surrounding stormwater

management ponds and maintenance of swales.

The following should be included in the AOM or referred to in the M&O Manual (as appendices to AOM).

Contents

The AOM should be written to inform the client and their maintenance contractor of any issues, agreements,

and conditions that are relevant to the ongoing maintenance of the assets that a good maintenance contractor

familiar with NZTA standards would not be expected to know. (E.g. It was agreed with Council that a higher

maintenance standard would be applied to the section of highway between „a‟ and „b‟ because …..)

It should be assumed that the maintenance contractor will have one team covering “vegetation maintenance”.

It should be clear in the AOM what attributes will require vegetation maintenance and include the maintenance

as line items in the programme above. E.g. roundabouts with planting will require vegetation maintenance

and maybe plant replacement over the 20 year period of the Plan.

The manual writer should consider how the maintenance contractor will maintain the assets and provide a 20

year vegetation forward works/maintenance programme with costs based on the whole of life analysis used in

determining the landscaping design. This will be used to update the client‟s Asset Management Plan. Any

assumptions used should be clearly stated. E.g. Drainage maintenance is carried out at the same time as

corridor vegetation maintenance.

The above information should be provided in excel format to enable it to be aggregated.

The Attributes in PSG/15 should be used as a guide for headings noting that other headings may be required

for a particular project.

The ongoing maintenance requirements of the other Attributes including aesthetic assets also need to be

included. This includes graffiti and “wow” factors.

The following should be included or referred to in the M&O manual:

A schedule of all surfaces at risk from graffiti vandalism and their treatments.

Clear identification of non structural assets attached to structural assets. E.g. fancy panels

Boundary noise design details e.g. dB(A) Leq 24 hrs at boundaries

All agreements other than consents as covered above which have ongoing potential relevance such as

agreements regarding fence maintenance with individual owners and Councils.

Reasons why particular species have been planted, e.g. being a consequence of a consultation process.

Information to assist repair of special features which may suffer some form of vandalism, such as the

reptiles at Gillies Ave ramps SH01, e.g. where to get the tiles from.

Financial data.

a. Estimated M&O costs for managing the landscaped area as above

b. Valuation data


Appendix 8 - Asset Owner‟s Manual – Stormwater Management

Asset Owners‟ Manual (AOM)

It is most important that the delivery intent of the stormwater management asset (e.g. specific planning,

design, & construction considerations) is conveyed to the operator and that the document is reviewed and

approved by the operators (as well as the consenting authority). The document should provide focus on the

exceptions or any special/unique elements and project specific operational requirements. Also consider the

“boots to suits” scenario for asset ownership and operations when preparing the operators manual and

information. Maintenance and Operations field staff prefer clear work instructions with diagrams to outline the

routine maintenance activity requirements. Good quality plans and drawings are great (i.e. a full set of

„accurate‟ as-builts drawing is essential). The Stormwater Management information should be presented in a

specific Operational Monitoring and Maintenance document as part of the total AOM, and should provide a

clear linkage to other asset elements (e.g. corridor landscape, and structural elements).

Key Content

Purpose. Outline of intent;

Document Status (e.g. draft; final) including QA verification;

Document Application (implementation & review statements);

Project Overview (executive summary, introduction, and key background information);

Site Plan. Overview and specific including points of operational access;

Ownership – Maintenance Boundaries. Clearly defined (and shown on schedule and plans) particularly for

pipe networks or management devices that are shared with others like councils or adjacent developers.

Include definition of the operational interface (roles, responsibilities, and any agreements);

Collection and Conveyance System (All key parameters for the basis of design, and the operational

objectives, what, where, condition, design performance, and functionality, including description of any

system specific regular & reactive intervention practices);

Waterway Crossings/Major Culverts (All key parameters for the basis of design, and the operational

objectives, what, where, condition, design performance, and functionality, including description of specific

regular & reactive intervention practices) Include clear linkage to the bridge and structures management

plan;

Stormwater Management - Treatment & Attenuation (All key parameters for the basis of design, and the

operational objectives, what, where, condition, design performance, and functionality, including description

of specific regular & reactive intervention practices);

Monitoring and Maintenance Action Schedule (basis of design for the nature & frequency for regular and

reactive, including interventions, and emergency procedures);

Emergency Procedures (specific procedures, and network interception/isolation/containment points for

managing environmental incidents such as spill, from within the motorway designation to the receiving

environment);

Risk & Opportunity Management Strategy/Register. Through the planning, design, and construction phases,

an awareness of operational risks, liabilities, and opportunities will be raised and considered. A risk

register including the likelihood, consequence, monitoring, and operational management strategy should

be supplied;

Contact details for key personnel associated with delivery and intended operation of the Stormwater

Management Asset. This should include Project Manager, Designer, Contractor, Council, NZTA, Emergency

Services, any specific Special interest parties (e.g. DOC).


Key Appendices

Consents (Resource and Building) and conditions of consents including reporting linkage to operational

requirements and/or environmental agreements (e.g. special conditions) to facilitate the delivery of

„compliance‟. Include ARC approval of the Operational Monitoring and Maintenance Documentation.

Plans showing mapped catchment zones of permeable and impermeable runoff discharging to the asset

(i.e. areas draining to the collection and conveyance network, areas and parameters of catchments

discharging to major waterway and network crossings, and areas draining to stormwater treatment devices;

As-built plans of all elements of the stormwater management asset including associated structural

elements (e.g. catchpits, pipe network) and „natural‟ elements (e.g. swales, ponds, waterways). Include

clear identification of all elements of the stormwater management system (new and existing network).

Flood maps should be produced to show the extent and level of ponding (.e. upstream of culvert

structures). The flood maps for the zone of works shall be drawn contour plans with contour lines at

maximum 0.2m intervals.

Specific landscaping planting plans, schedule & specifications (e.g. Swales, Ponds, Biodetention, Riparian

Margins, Special Areas of Biodiversity). Include clear linkage to corridor management plan;

Mapping of any known Cultural features in relation to the stormwater management asset (e.g. wahi tapu,

taonga, waterways identified as traditional sources of food);

Schedule of specific asset inventory, valuation, & condition. The schedule is to uniquely identify existing

and new stormwater asset that constitutes the total stormwater asset for the zone of works. This should

also include any assumptions on design life, and valuation;

Asset valuation schedule.

Specific operational monitoring and maintenance checklists (i.e. any proprietary or bespoke devices or

procedures);

Engineering Standards (any departures and associated design and approval information);

Specifications (e.g. for special soil/sand mixes; unique materials or asset items);

Photos for record of condition and to present asset element situation (e.g. devices, ponds, waterways,

discharges, special features);

Special Terms and Conditions (e.g. any specific Council proformas for Stormwater);

Any producer statements (e.g. for multi-plate culverts, or proprietary treatment devices).

Any agreements and conditions (e.g. permits, service agreements, landowner consents)

Stormwater Asset Schedule

The following schedule contains motorway stormwater assets.

M&O Guidelines for Capital Projects – Revision 5 Page 3

Stormwater Management Asset - Schedule, and Operational Monitoring & Maintenance Overview

Asset

Category

Ref.

Asset Elements Unit Quantity

(4)

Standards &

Guidelines (5)

Typical

Monitoring

Frequency (6)

Typical

Maintenance

Frequency

(7)

General Overview Description of Monitoring & Maintenance Works

(8)

1 Collection and

Conveyance Network

(1)

a Slot/gore Drains m NRB 1977 &

Austroads

6 month 1-2 years Visual monitoring assessment during regular drive over and any

apparent blockages, accumulated debris, vegetation or damage to be

cleared and made good (sweep/flush as required). Include Traffic

Barrier slot flushing. The inventory verification record required is to

include location, type (materials & size), and general condition rating.

b Surface channel (e.g.

vee channel, or dish

channel drains)

m NRB 1977 &

Austroads

6 month 1-2 years Visual monitoring assessment during regular drive over and any

apparent blockages or damage to be cleared and made good

(sweep/flush as required). Note: Does not include 'traditional' Kerb and

Channel, or edge nib works, which are considered part of the

pavement & surfacing solution. K&C is only used at Motorway

interchange areas typically at the local road interface (lower speed

environments). The inventory verification record required is to include

location, type (materials & size), and general condition rating.

c Catchpits No. NRB 1977,

Austroads, &

Local

Authority

Standards

6 month 1-2 years Visual monitoring and inspection records (as per the network

Maintenance and Operations organisations catchpit schedule

supplied). Vacuum clean, flush and clear as required. Catchpits types

include single, double, side entry, superpits, maxpits, splay pits,

recessed catchpits, and manhole-type cess pits. The inventory

verification record required is to include location, type (materials &

size), and general condition rating.

d Pipes (<225mm) m CPAA &

Austroads

2-5 years as required CCTV monitoring, inspection, flush, clear and make good as required

(reactive). The pipe network inventory verification record required

needs to include size, material, and condition rating.

e Pipes (225mm-

600mm dia)

m CPAA &

Austroads





f Pipes (> 600mm dia) m CPAA &

Austroads




g Manholes/Junctions No. Austroads Annual 2-5 years Visual monitoring inspection, vacuum, flush, clear and make good as

required (reactive). The manhole inventory verification record required

needs to include size (including depth), pipe connections, and

condition rating.

h Waterways

(ephemeral)

m Austroads 6 month Annual Visual monitoring inspection for erosion, scour, debris blockage and

overgrown vegetation. Make good. The inventory of the ephemeral

waterways (seasonal flowing waterways) needs to include the location,

details of the general profile and condition.

i Waterways

(perennial)

m Austroads 6 month Annual Visual monitoring inspection for erosion, scour, debris blockage and

overgrown vegetation. Make good. The inventory of the perennial

waterways (flowing all year round) needs to include the location,

details of the general profile and condition.

j Artificial Channels m Austroads 6 month 2-5 years Visual monitoring inspection for debris blockage, erosion, scour or

damage. Make good. The inventory of the artificial channels (e.g.

concrete drains, gabion wall drains) along the motorway alignment

needs to include the general profile and condition.

k Entryway Crossings

(SH Access)

No. Austroads 6 month 2-5 years Visual monitoring inspection for debris blockage, erosion, scour or

damage. Make good. The inventory of the culvert/crossing systems

(i.e. State Highway driveway access locations crossing waterways/open

channels within the designation - none allowed at Motorway) needs to

include details of the location, crossing description, and condition

rating.

l Pipe Inlets No. various 6 month Annual Visual monitoring inspection for debris blockage, erosion, scour or

damage. Make good. The inventory of pipe inlets needs to include

details of the location, inlet description, physical dimensions, and

condition rating.

m Pipe Outlets No. various 6 month Annual Visual monitoring inspection for debris blockage, erosion, scour or

damage. Make good. The inventory of pipe outlets needs to include

details of the location, outlet type description, physical dimensions,

and condition rating.

n Erosion Protection sq.

m

Austroads,

MOW &

various

6 month Annual Visual monitoring inspection for debris blockage, erosion, scour or

damage. Make good. The inventory of specific erosion protection

measures needs to include details of the location, type description

(e.g. rip-rap, geogrids, reno matress, and gabions), physical


dimensions, and condition rating.

o Energy Dissipation No. Austroads,

MOW & USBR

6 month Annual Visual monitoring inspection for debris blockage, erosion, scour or

damage. Make good. The inventory of specific energy dissipation


(impact type energy dissipaters, specific masonry block work, or rip-

rap), physical dimensions, and condition rating.

p Tidal Control (valves

or gates)

No. various 6 month Annual Visual monitoring and operational inspection (e.g. check gate hinge

operational and grease if required, as well as check seal and repair or

make good as required). The monitoring inspection needs to include

clearing of any debris, overgrown vegetation, and observations of any

damage. The inventory of tidal (non return) gates or valves to include

details of the location, type description (e.g. Hume-king, Baycast,

Tideflex, and specific design), physical dimensions, condition rating.

q Soakage Disposal No. ACC/MCC

Soakage

Design

6 month Annual Visual monitoring and inspection records (as per the network

Maintenance and Operations organisations 'soakage disposal' schedule

supplied). Vacuum clean, flush, clear, and rejuvenate as required. The

inventory verification record required needs to include location, type

(e.g. rockbore, manhole, and chamber), physical dimensions and

condition rating.

r Secondary Flow

Paths

No. Austroads 6 month Annual Visual monitoring inspection for erosion, scour, debris blockage,

overgrown vegetation, or obstructions. Make good by clearing and

reinstating a stable flow path (or notify if say new fence or earth

filling). The inventory of Secondary Flow Paths (SFPs) needs to include

the location, details of the general profile and condition. Insufficient

information is currently available to identify all specific locations.

Locations are to be marked up on GIS base plan as part of 'delivery'

briefing information.

s Pump Stations No. various Quarterly Annual Visual monitoring and inspection records (as per the specific the

network Maintenance and Operations organisations Pump Station

schedules supplied). The monitoring inspection needs to include

specific operational inspections, clearing of any debris, and

observations of any damage. Make good. Specific Pump Station

inventory and rating information to be verified. The network pump

stations are: SH1 Mt Wellington Highway; SH16 Newton Eastbound;

SH22 Butchers Rd Underpass at Paerata.


t Bridge deck drainage m none 6 month Annual Visual monitoring assessment during regular drive over and any

apparent blockages, accumulated debris, vegetation or damage to be

cleared and made good (sweep/flush as required). Include Traffic

Barrier slot flushing. The inventory verification record required is to

include location, type (materials & size), and general condition rating.

Currently covered by Structures team. Develop system with Structural

team to define optimal operational monitoring and maintenance

procedures.

o others? tbc tbc tbc Others (miscellaneous). Specific asset and management requirements

to be confirmed (asset type, quantity, dimensions, standards,

condition, monitoring & maintenance requirements, and inventory

details).

2 Major Waterway &

Network Crossings(2)

Major Culvert Crossings (Waterways and Local Authority Pipe Network)

a Culverts No. Austroads &

MOW

6 month as required Visual monitoring and inspection records (as per 'Waterway & Network

Crossing' schedule supplied). Clear and make good as required

(reactive). The culvert inventory verification record required needs to

include size, material, and condition rating.

b Headwall (i.e.

upstream)

No. Austroads &

MOW

6 month as required Visual monitoring inspection for debris, erosion, scour, overgrown

vegetation, or structural damage. Clear and make good as required.

The inventory of culvert inlet headwalls needs to include details of the

location, type (prefab or specific) inlet description (e.g. massblock,

gabions, and geogrid), physical dimensions, and condition rating.

c Debris Grill No. Austroads &

MOW

6 month Annual Visual monitoring inspection for debris, overgrown vegetation, or

damage. Clear and make good as required. The inventory of debris

grills needs to include details of the location, type, materials, physical

dimensions, and condition rating. At upstream limit some culverts

have debris grills either attached at headwall, or within stream.

Inventory records to verify

d Wingwall (i.e.

downstream)

No. Austroads &

MOW

6 month as required Visual monitoring inspection for debris, erosion, scour, overgrown

vegetation, or structural damage. Clear and make good as required.

The inventory of culvert wingwalls needs to include details of the

location, type (prefab or specific) inlet description (e.g. massblock,

gabions, and geogrid), physical dimensions, and condition rating.

e Energy Dissipation No. Austroads &

MOW

6 month 5-10 years Visual monitoring inspection for debris, erosion, scour or damage.

Make good. The inventory of specific energy dissipation measures

needs to include details of the location, type description (impact type


energy dissipaters, specific masonry block work, or oversized rip-rap),

physical dimensions, and condition rating.

f Junction Chambers No. 6 month as required Visual monitoring inspection, clear and make good as required

(reactive). The junction chamber inventory verification record required

needs to include, location, type, size (including depth), and condition

rating.

g Fish Passage No. ARC TP131 &

NIWA

6 month as required Visual monitoring inspection for accumulated debris, erosion, scour or

damage. Clean and make good. The inventory of fish passage


(e.g. submerged invert, grouted rip-rap, baffle blocks, timber blocks),

and condition rating.

h Erosion Protection sq.

m

Austroads,

MOW & USBR

6 month 1-2 years Visual monitoring inspection for debris, erosion, scour or damage.

Make good. The inventory of specific erosion protection measures

needs to include details of the location, type description (e.g. rip-rap,

geogrids, reno matress, and gabions), physical dimensions, and

condition rating.

i others? tbc tbc tbc Others (miscellaneous). Specific asset and management requirements



details).

3 Treatment Devices

(Quality and/or

Quantity Control)(3)

ARC TP10

a Oil & water

separators (API type)

No. ARC TP10 &

API

3 month Annual Operational monitoring and maintenance requirements as per the

network Maintenance and Operations organisations schedule supplied

b Sandfilters (first

principle design)

No. ARC TP10 3 month Annual Operational monitoring and maintenance requirements as per the


c Vaults (sediment

and/or storage)

No. ARC TP10 3 month Annual Operational monitoring and maintenance requirements as per the


d Swale m ARC TP10 3 month 3 month As per schedule supplied. Note: Routine Swale maintenance (i.e.

mowing, vegetation clearing); is covered by procedures outlined by

corridor vegetation management and network strategy (consents and

compliance) team, which include grass length requirements (typical

50mm-150mm length), and tolerances for vegetation management

practices such as mowing, and spraying.

e Vegetated Filter Strip sq. ARC TP10 3 month 3 month As per schedule supplied. Note: Routine Swale maintenance (i.e.


m mowing, vegetation clearing); is covered by procedures outlined by

corridor vegetation management and network strategy (consents and

compliance) team, which include grass length requirements (typical

50mm-150mm length), and tolerances for vegetation management

practices such as mowing, and spraying.

f Biodetention (e.g.

raingardens, or tree

pits)

No. ARC TP10 3 month 3 month Operational monitoring and maintenance requirements as per the


g Infiltration Practices

(e.g. trenches, or

basins)

sq.

m

ARC TP10 3 month Annual Operational monitoring and maintenance requirements as per ARC

TP10 schedule supplied

h Ponds (e.g. wet

pond, or dry

detention pond)

No. ARC TP10 3 month 5-10 years Operational monitoring and maintenance requirements as per the


i Wetland No. ARC TP10 3 month 5-10 years Operational monitoring and maintenance requirements as per the


j others? tbc tbc tbc Others (miscellaneous). Specific asset and management requirements



details).

Proprietary

Treatment Devices

(Quality Control

Only)

k Catchpit Filter

Systems (i.e.

Enviropods)

No. Supplier

Spec and

ARC

Certification

3 month 3 month Operational monitoring and maintenance requirements as per

suppliers specification and schedule (unless approved departure).

Inventory needs to verify the location, type, and condition rating.

Enviropods supplied by Stormwater 360 & Hynds. Neither are fully

TP10 compliant (i.e. to 75% TSS removal efficiency). Exist at some

parts of the network as part of the best practicable option (BPO)

treatment train.

l Sand Filters No. Supplier

Spec and

ARC

Certification

3 month Annual Operational monitoring and maintenance requirements as per


Inventory needs to verify the location, type (e.g. SF2000), physical

dimensions, and condition rating. Proprietary sandfilters are supplied

by Humes and Hynds.


m StormFilters No. Supplier

Spec and

ARC

Certification




StormFilters are supplied by Stormwater 360, and are approved as ARC

TP10 compliant.

n HumeCeptors No. Supplier

Spec and

ARC

Certification



Inventory needs to verify the location, type, physical dimensions, and

condition rating. Supplied by Humes. Not approved as ARC TP10

compliant (i.e. to 75% TSS removal efficiency)

o CDS (continuous

deflective

separation)

No. Supplier

Spec and

ARC

Certification




condition rating. Supplied by Skellerup. Not approved as ARC TP10

compliant (i.e. to 75% TSS removal efficiency).

p UpFlo Filter No. Supplier

Spec and

ARC

Certification




Supplied by Hynds, and are approved as ARC TP10 compliant for roads

with less than 20,000 VPD.

q Cleansall No. Supplier

Spec and

ARC

Certification




condition rating. Supplied by Hynds. Not approved as ARC TP10

compliant (i.e. to 75% TSS removal efficiency). Gross Pollutant Trap

(GPT) only.

r Downstream

Defender

(hydrodynamic

vortex separator)

No. Supplier

Spec and

ARC

Certification




condition rating. Supplied by Hynds. Not approved as ARC TP10

compliant (i.e. to 75% TSS removal efficiency)

s others? tbc tbc tbc Others (miscellaneous). Specific asset and management requirements



details).

Notes

1 Pavement subsoil drains (TNZ F/2 type) are not included in the stormwater management collection and conveyance system and are considered to be part of the


pavements and surfacing solution.

2 For waterways with a cross-section area up to 3.4m2 (Above 3.4m2 is covered by Bridge Structures)

3 Most stormwater management improvement devices on the network are unique designs to address specific local/regional issues such as water quality, erosion

management, flood protection, and receiving environment management. A range of operational requirements apply to each system in order for the devices to retain

their functionality and to deliver legislative responsibility. Whilst NZTA are currently developing specific guidelines for a nationally consistent approach to

Stormwater Management Device Design, the ARC TP10 guidelines currently take precedence at the network (consent compliance)

4 Total quantum to be determined. See comprehensive Stormwater Management Asset - Schedule and Specification for route specific information (i.e. available Capital

Project & RAMM information zones).

5 A range of standards and guidelines apply to the various elements of the stormwater management asset. NZTA do not have comprehensive Engineering Standards

for Stormwater Management (default Austroads). THE NZTA Stormwater Treatment Design Standards (Draft July 08) should be considered for the Auckland Motorway

Network, however in the interim the regional requirements will take precedence (e.g. TP10, TP90, TP124, TP131)

6 The monitoring frequencies stated are required for a minimum period of two years at which time it is anticipated that based on inspection records a pragmatically

refined frequency and nature of activity can be applied. Treatment Devices inspection records will form the basis for applying for a managerial approved variation to

'agreed' frequencies.

7 Actual maintenance requirements are triggered by findings of the monitoring inspections. The nominated typical frequency of maintenance activities (e.g. Sand

replenishment, or StormFilter cartridge media replacement) is distinct from the routine cyclic maintenance (e.g. vegetation, litter and debris removal).

8 Inventory verification inspection is required for all asset elements.

maintenance and operations guidelines for planning, design...

Documents