ruakura interchange alteration to designation · 2014. 9. 18. · 2-31695.00 | 29 august 2014 opus...

Waikato Expressway: Hamilton Section

Ruakura Interchange Alteration to Designation Assessment of Ecological Effects

Waikato Expressway: Hamilton Section

Ruakura Interchange

Alteration to

Designation

Assessment of Ecological Effects

© Opus International Consultants Ltd 2014

Prepared By Opus International Consultants Ltd

Stephanie Large, Ecologist

Hamilton Environmental Office

Prepared By Trevor Connolly, Ecologist

Opus House, Princes Street

Private Bag 3057, Waikato Mail Centre,

Hamilton 3240

New Zealand

Reviewed By

Telephone: +64 7 838 9344

John Turner Facsimile: +64 7 838 9324

Date: 29 August 2014

Reference: 2-31695.00

Status: Final

Approved for

Release By

Dave Heine

Opus Team Leader

Ruakura Interchange Ecological Assessment i

2-31695.00 | XX July 2014 Opus International Consultants Ltd

Contents

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

1.1 Overview ............................................................................................................................ 1 1.2 Background ....................................................................................................................... 1 1.3 Context .............................................................................................................................. 3 1.4 Proposal ............................................................................................................................ 6 1.5 Scope of Ecological Assessment ........................................................................................ 8

2 Methodology ...................................................................................................... 9

2.1 Flora .................................................................................................................................. 9 2.2 Terrestrial Fauna ............................................................................................................... 9 2.3 Aquatic Habitats and Fauna ............................................................................................. 9

2.4 Stormwater ...................................................................................................................... 13

3 Criteria for Assessment of Ecological Significance and Related Relevant Policy 13 3.2 Threatened Species Criteria ............................................................................................ 15

4 Ecological Description .......................................................................................16

4.1 Flora ................................................................................................................................ 16 4.2 Terrestrial Fauna ............................................................................................................. 17 4.3 Aquatic habitats and Fauna ............................................................................................ 18

5 Assessment of Significance .............................................................................. 29 5.1 Significant Indigenous Vegetation .................................................................................. 29

5.2 Significant Habitat of Indigenous Fauna ........................................................................ 29 5.3 Significant Natural Areas (SNA’s)................................................................................... 29

6 Assessment of Ecological Effects ...................................................................... 30 6.1 Flora ................................................................................................................................ 30 6.2 Terrestrial Fauna ............................................................................................................. 30 6.3 Aquatic Habitats and Fauna ........................................................................................... 30 6.4 Stormwater Effects .......................................................................................................... 31

7 Avoidance, Remediation and Mitigation of Effects ........................................... 35 7.1 Avoidance of Adverse Ecological Effects During Construction ...................................... 35 7.2 Mitigation of Adverse Ecological Effects ........................................................................ 35

8 Conclusions ...................................................................................................... 38

9 References ....................................................................................................... 39

Ruakura Interchange Ecological Assessment 1

2-31695.00 | 29 August 2014 Opus International Consultants Ltd

1 Introduction

1.1 Overview

The New Zealand Transport Agency (the Transport Agency) proposes to alter the existing

designation for the Hamilton Section of the Waikato Expressway (Hamilton Section) and obtain

additional resource consents from Waikato Regional Council (WRC) in order to construct, operate

and maintain the Ruakura Interchange and connecting roads. The Ruakura Interchange was omitted

from the recent round of alterations to the designation, whilst the Transport Agency awaited the

Board of Inquiry’s decision on the Ruakura Development Private Plan Change, by Tainui Group

Holdings.

1.2 Background

1.2.1 Roads of National Significance

In May 2009, the Government Policy Statement on Land Transport Funding (GPS) was released,

which identified seven Roads of National Significance (RoNS), which are considered by the

Government to be New Zealand’s most important transport routes requiring significant development

to reduce congestion, improve safety and support economic growth. The Waikato Expressway is one

of the seven RoNS.

The purpose of listing particular roads as nationally significant was to ensure these priority roading

projects are fully taken into account in the development of the National Land Transport Programme.

The Government expects that planning for the future development of the land transport network

should reflect the importance of these roads from a national perspective and the need to advance

them quickly.

1.2.2 Waikato Expressway

The Expressway will extend from the Bombay Hills in the north to just south of Cambridge. The

Expressway has been divided into 12 sections. It is expected the Expressway will:

» Improve economic growth and productivity for Auckland, Waikato and Bay of Plenty through

more efficient movement of people and freight between Auckland, Hamilton, Tauranga and

Rotorua;

» Improve the reliability of the transport network by providing a more robust and safer road

network between Auckland, Hamilton, Tauranga and Rotorua;

» Reduce travel times between Waikato and Auckland; and

» Support the growth strategy for the central Waikato.

1.2.3 Hamilton Section

The Hamilton Section is located on the eastern side of the city of Hamilton. The Hamilton Section

adjoins the recently completed Ngaruawahia Section to the north, and the existing Tamahere

Interchange to the south. It is approximately 22km in length. Figure 1-1 shows the scope of the

Hamilton Section.



Figure 1-1: Proposed Scope of Works - Waikato Expressway Hamilton Section



1.3 Context

1.3.1 Current Designation and Resource Consents

The Hamilton Section was first designated in 2005, following an appeal before the Environment

Court in 2004. In October 2013, the Transport Agency lodged Notices of Requirement (NORs) to

alter the designation in a number of discrete locations. Applications for resource consent to

construct, operate and maintain the Hamilton Section were also lodged at that time. Both resource

consents and NORs were heard by independent Commissioners at a joint hearing in April/May 2014.

The Commissioners’ decision on the resource consents was notified on 1 July 2014, granting all

consents applied for, subject to conditions. A recommendation from the Commissioners was

released on 30 June 2014 with respect to the NORs. The recommendation was that the NORs be

granted subject to a set of recommended conditions. On 8 July 2014, the Transport Agency

accepted the recommendation with only minor modifications. Two appeals have been made by

submitters, one in relation to Alteration U, and the other in relation to Alteration Z.

1.3.2 Ruakura Structure Plan (RSP)

Boundary changes between Hamilton City Council (HCC) and Waikato District Council (WDC) have

meant that a significant area of land at Ruakura is now within the jurisdiction of HCC. The

development of this land is identified in a number of high level documents including: the Hamilton

Urban Growth Strategy, the Access Hamilton Transport Strategy and the Waikato Proposed Regional

Policy Statement.

To enable the progressive development of this area, the Ruakura Structure Plan (RSP) was developed

and notified as part of the Hamilton City Proposed District Plan (PDP) in December 2012. The RSP

(as notified) includes an inland port, freight and logistics hub and other industrial land. The inland

port as proposed in the RSP has an intermodal facility so that freight can be transferred to and from

road and rail. The RSP also provides for research and innovation activities, and residential areas for

an eventual population of approximately 1,800 households, including the development of a

neighbourhood centre.

Submissions and further submissions have been received on the RSP, however hearings and a

decision have been deferred, pending the outcome the Ruakura Private Plan Change (PPC).

1.3.3 Ruakura Private Plan Change (PPC)

Tainui Group Holdings Limited (TGH) is the predominant landowner affected by the RSP. It was

identified that rules in the Hamilton District Plan: Waikato Section (as transferred over from the

WDC’s District Plan) prohibit any application being made for urban development within this area.

Given that the WDC rules are currently operative, they continue to apply until the PDP (including

the RSP) is made operative. Given the potential for lengthy delays, TGH have sought a PPC for what

is known as the Ruakura Development, through the Environmental Protection Authority (EPA). The

PPC affects some, but not all, of the land subject to the RSP.

The PPC does not re-zone any land, rather it proposes to adopt mechanisms providing an overlying

‘schedule’. This allows a range of activities to be undertaken in identified areas, as well as existing

rural activities.

The key aspects of the PPC are as follows:



A new ‘Schedule 25H Ruakura’ inserted into Chapter 25: Rural of the PDP, which provides a

Ruakura Logistics Area (incorporating the Inland Port), Ruakura Industrial Park Area,

Knowledge Area, Residential Areas and Open Space Areas along with indicative roads (refer to

Figure 1-2 below).

Amendments to the Prohibited Activity rules to enable the planning and development of the land

covered by Schedule 25H, including the future roading network.

On 31 July 2013, a ministerial direction was released, referring the PPC request to a Board of Inquiry

(BOI) which was held over a number of weeks during May/June 2014. On 5 August 2014, the BOI

issued its draft decision approving the PPC, subject to a number of amendments to the proposed

objectives, policies and rules, as they would apply to the Ruakura Development. Comments on the

draft decision close during the week commencing 1 September 2014, and a final decision is due on

11 September 2014.

The PPC will enable development to occur in the interim, but it is intended that the PPC will also be

incorporated into the framework of the PDP, once the PPC has been confirmed. Accordingly, the

RSP contained within the notified PDP is likely to be superseded by the Board’s decision on the PPC.



Figure 1-2: Ruakura Schedule Area as approved by the BOI in its draft decision



1.4 Proposal

1.4.1 NOR – Alteration to Designation

The Transport Agency is now proposing to alter the designations for the Hamilton Section to

include a new interchange at Ruakura and encompass associated connecting roads (being the

relocated and the existing Ruakura Road). The scope of the designation sought is shown in Figure

1-3 below.

Figure 1-3: Diagram of Proposed Alteration to Designation

The altered designation includes the following:

» Widening of the existing Expressway designation to accommodate the Ruakura Interchange

ramps, connecting roundabouts, and stormwater wetland;

» Closure of the existing Ruakura Road either side of the Expressway and consequently

shortening of the proposed bridge over the East Coast Main Trunk (ECMT) rail line;

» Retention of the existing Ruakura Road either side of the closure at the Expressway in order to

provide continued property access to residents on Ruakura Road, including access to Percival

and Ryburn Roads as currently provided;

» Relocation of Ruakura Road between the Ruakura Road/Silverdale Road intersection and the

existing Ruakura Road near the Vaile Road intersection to connect with the proposed Ruakura

Interchange, including:

Existing Ruakura Road/Silverdale Road intersection closed, with Silverdale Road terminating in

a cul-de-sac (road retained for access) and creation of a new signalised relocated Ruakura



Road/Silverdale Road intersection that will also provide a key access point to the Ruakura

Development Logistics Area;

New relocated Ruakura Road/Existing Ruakura Road (west) priority controlled tee intersection;

A signalised intersection along the relocated Ruakura Road to provide a second key access point

to the Ruakura Development Logistics Area;

Provision of a tee intersection where the relocated Ruakura Road meets the existing Ruakura

Road (east);

Upgrading the existing Ruakura Road, largely within its existing boundaries, between the new intersection with the relocated Ruakura Road (east) and the Ruakura Road/SH26 intersection (this will include shape correction of the roadway, carriageway widening, provision of a footpath and drainage improvements;

Extension of the designation to cover the existing Ruakura Road (from the intersection with the

relocated Ruakura Road up to SH 26) so upgrading works can be undertaken;

Provision for the relocated Ruakura Road to pass either over or under the Expressway; and

Provision for stormwater attenuation and disposal from the relocated Ruakura Road and

Ruakura Interchange.

Detailed designation plans are provided as Appendix C to the NOR.

1.4.2 Resource Consents

The Transport Agency is also seeking additional resource consents from the WRC to construct,

operate and maintain the connecting roads (being the relocated and existing Ruakura Road). The

interchange ramps and associated earthworks are covered by the existing consents granted 1 July

2014. Water and discharge permit applications will be lodged with the WRC shortly.

1.4.3 Existing Environment

The Resource Management Act 1991 (RMA) requires an assessment of the actual and potential effects

on the environment of allowing the activity (s104(1)(a)). This report forms part of that assessment.

Consideration therefore needs to be given to what defines the existing environment, as this is what

the effects of the proposal will be assessed against.

1.4.3.1 Waikato Expressway

The Hamilton Section of the Waikato Expressway designations pass to the east of Hamilton City in

a generally north-south direction and enable the construction of a four-lane Expressway and

associated on/off ramps to connect with the local road network (excluding the Ruakura Interchange).

The development of the Expressway is also supported by a number of consents granted by the WRC.

For the purpose of assessing this NOR, the Expressway as currently designated is considered part of

the existing environment.

1.4.3.2 West of the Expressway

The land immediately to the west of the Expressway is currently zoned Rural in the Hamilton District

Plan: Waikato Section. This area adjoining the Expressway is in pasture, with scattered dwellings

and farm buildings. The Waikato University is located to the west of Silverdale Road, and is

surrounded by residential development. There is also residential development to the east of



Silverdale Road, which juts out towards the Expressway and is bounded by a gully (Nevada Road).

North of Ruakura Road is an area of land zoned Country Living, which contains a cluster of

approximately 30 rural residential dwellings.

The environment immediately to the west of the Expressway is subject to a PPC, which a BOI has

approved in its draft decision. Consideration of this NOR by the territorial authority should be in

the context of the future development enabled by the PPC. The need for the Ruakura Interchange is

a direct result of development occurring in this area in accordance with the PPC. Without the PPC

proceeding, the Agency would revert back to the approved north facing ramps at SH26, unless an

alternative justification was provided for establishing an interchange at Ruakura.

It is reasonable to assume that the existing environment for the purpose of assessing the effects of

this NOR will consist of the land use activities indicated in Figure 1-2 of this report, and supported

by the BOI decision. The BOI has already heard evidence in relation to the associated effects of these

land use activities and their ruling on the PPC has taken such effects into consideration. It is for this

reason that for the purposes of the overall effects assessment the PPC has been adopted as the

existing environment.

1.4.3.3 East of the Expressway

The land to the east of the Expressway is zoned Rural in the Waikato District Plan. The portion of

land between the ECMT and Davison Road is characterised by large open paddocks and scattered

buildings, including some dwellings. From Davison Road south, there is significantly more rural-

residential development. The Dairy NZ/LIC site is located on the corner of Ruakura Road and SH26.

Ruakura Road itself is identified as an Arterial Road in the Waikato District Plan (WDP). The

function of Arterial Roads is described in the WDP as roads that1:

» Form a strategic network of regional importance

» Provide for the collection and distribution of goods significant to the regional economy

» Rural roads that typically provide for more than 2,500 vehicle movements per day

» Include rest areas; and

» The through traffic function predominates.

1.5 Scope of Ecological Assessment

A detailed assessment of the ecological effects of proposed activities within the existing designation

can be found in the Assessment of Environmental Effects for the Hamilton Section (Connolly &

Turner, 2013) that accompanied Notices of Requirement (NORs) to alter the designation and

applications for resource consents lodged in October 2013. The proposed alterations to designation

which are the subject of this application result in additional potential ecological effects over and

above those associated with the existing designation and activities covered by resource consents that

have already been granted. This ecological report provides an assessment of those effects.

A key issue requiring assessment is the effects of the proposed changes to the NOR on the population

of black mudfish (Neochanna diversus) known to inhabit the Ruakura Road drain. At the time of

lodgement of resource consent applications in October 2013, resource consents for crossing the

Ruakura Road drain were not required as it was proposed to span the drain with the Ruakura Road

bridge. The proposed bridging resulted in no loss of instream habitat and no significant effects on

1 Refer Table 7 of Appendix A: Traffic (Waikato District Plan, April 2013).



the mudfish population. However, the implementation of the RSP will result in the shortening of the

proposed bridge over the East Coast Main Trunk (ECMT) rail line. This will result in a section of the

Ruakura Road drain being piped (approximately 65m) and consequently a requirement to reassess

the effects of the Project on the mudfish. For details regarding the stormwater design for the Ruakura

Interchange Designation Alteration, refer to Appendix H of Volume 2 (Burke, 2014).

This ecological assessment therefore provides a detailed assessment of the potential effects of the

Ruakura Interchange Designation Alteration on black mudfish, an assessment of the effects on other

additionally impacted ecosystems and their associated flora and fauna, as well as effects of the

additional stormwater discharge which will be generated as a result of this project.

2 Methodology

2.1 Flora

A walkover vegetation survey which included the entire area of the proposed alteration to

designation was carried out on the 29th of January 2014. Further vegetation surveys were carried

out during fish surveys, between the 27th of June and the 10th of July, 2014.

2.2 Terrestrial Fauna

2.2.1 Birds

Incidental bird observations were recorded on the site visit conducted on 29th of January 2014.

2.2.2 Bats

A desktop assessment of relevant literature documenting the presence of native bats within the

area was undertaken, including Boffa Miskell Ltd and the surveys undertaken by McQuillan (2013).

2.2.3 Lizards

Given the habitat present and the results of the surveys undertaken in the immediate vicitnity by

Boffa Miskell (2013), lizard surveys were not undertaken as it was considered highly unlikely that

any threatened species would be present. Therefore assessment of effects on herpetofauna was a

desktop exercise based on previous records, including the assessment of effects relevant to reptiles

made as part of the Waikato Expressway: Hamilton Section ecological AEE.

2.3 Aquatic Habitats and Fauna

A desktop assessment of relevant literature documenting the presence of native fish species was

undertaken. A walk over survey was carried out to assess the habitat condition of the watercourses

which will be affected by the Ruakura Interchange Designation Alteration.

2.3.1 Black Mudfish (Neochanna diversus) Survey

The NIWA New Zealand Freshwater Fish Database was searched for records of fish species found

within the vicinity of the Ruakura Road drains. To supplement this, a survey was undertaken at

several sites. Drains exhibiting suitable habitat were identified for black mudfish sampling. Five sites

in total were sampled for black mudfish (Figure 2-2). Four of the sites were on Ruakura Road, with



the fifth located within farmland (owned by Tainui Holdings Ltd.) adjacent to Davison Road. The

drain located adjacent to the Silverdale Rd roundabout was not sampled as it was completely dry.

Figure 2-1: Black mudfish sampling sites

Gee minnow traps have proved to be the most effective means of capturing both juvenile and adult

mudfish (Ling et al, 2009). Six fine meshed steel gee minnow traps were used at each site according

to the protocols of Ling et al. (2009). Figures 2-2 to 2-6 show gee minnow trap locations for each of

these sample sites.

Each site was sampled over two consecutive nights between the 28th of June and the 8th of July. The

traps were set between 0900h and 1100h each day, left overnight and checked the following morning.

Fish caught were identified, measured and released near the point of capture. Over the 3 weeks prior

to survey, there was an average of 8.9mm of rainfall per day (NIWA cliflow database).



Figure 2-2: Sample site 1





2.4 Stormwater

Relevant stormwater information was obtained from Opus Stormwater Engineers and the

stormwater design assessment (Burke, 2014).

3 Criteria for Assessment of Ecological

Significance and Related Relevant Policy

3.1.1 Significant Indigenous Vegetation and Significant Habitat of

Indigenous Fauna Assessment Criteria

3.1.1.1 Resource Management Act 1991

Determination of the ecological value of a habitat and its associated species is a critical part of

assessing the significance of the ecological impact associated with the Ruakura Interchange

Designation Alteration (the Project). Section 6(c) of the Resource Management Act 1991 (RMA)

requires the protection of significant indigenous vegetation, and significant habitats of indigenous

fauna. This is to be recognised and provided for by local authorities as a matter of national

importance. Consequently, the identification of sites that are representative of significant indigenous

vegetation and significant habitat of indigenous fauna is an important part of assessing ecological

values and determining the significance of ecological effects.



3.1.2 NZTA’s Environmental Plan

NZTA’s Environmental Plan (June 2008) establishes an environmental policy for state highways and

outlines specific actions to improve NZTA's environmental performance enabling the integration of

environmental and social considerations into all aspects of state highway planning, construction and

maintenance. Section 2.7 of the Environmental Plan which deals with ecological resources states the

following objectives:

“E1 Promote biodiversity on the state highway network.

E2 No net loss of native vegetation, wetlands, critical habitat or endangered species.

E3 Limit the spread of plant pests”.

3.1.3 Assessing ecological Significance Within the Waikato Region

The criteria for identifying significant indigenous vegetation and significant habitat of indigenous

fauna within the Waikato Region are contained in Appendix 3 of the Operative Regional Policy

Statement (October 2000) and section 11A of the Proposed Regional Policy Statement (February

2013). While the criteria are similar in both documents, there are some proposed modifications. For

example criteria in Appendix 3 of the Operative Regional Policy Statement states:

“It is vegetation or habitat that is currently habitat for indigenous species or associations of

indigenous species that are:

Threatened with extinction; or

Endemic to the Waikato Region”.

Whereas, the Proposed Regional Policy Statement (February 2013) states:

“It is vegetation or habitat for indigenous species or associations of indigenous species that are:

classed as threatened or at risk, or

endemic to the Waikato region”

Sites which meet these criteria can be further assessed and ranked in terms of their level of

significance using the Guidelines to Applying Regional Criteria and Determine Level of Significance

(Environment Waikato & Wildland Consultants Ltd. 2002). Criteria 3 of the Guidelines states that

habitat is Nationally Significant if it provides:

….”habitat for an indigenous species which is under serious threat in the categories Nationally

Critical, Nationally Endangered, Nationally Vulnerable, Serious Decline, or Gradual Decline”.

As an example, longfin eel (Anguilla dieffenbachii) are classified as ‘At Risk – Declining’ (Goodman

et al., 2014) and are found in the Mangaonua Stream. They are also likely to be present at least

seasonally in other streams and drains along the Ruakura Interchange Designation Alteration,

including the Ruakura Rd drains. Application of Criteria 3 of the guidelines would mean that this

and many other streams, farm drains and stormwater ponds along the alignment (and throughout

the Waikato Region) would automatically rank as Nationally Significant habitat based on the

presence of longfin eel. However, as longfin eel is still one of the most widely distributed species in

New Zealand, the automatic ranking of every artificial or highly modified waterway it inhabits as



Nationally Significant, without consideration of the rarity of the habitat type in a regional or national

context, can become problematic. That is not to say that these species are not significant or their

decline a matter of concern, or that where there are impacts they should not be mitigated; however

the widespread and common nature of their potential habitat is such that, under Criteria 3, few

waterways in New Zealand can avoid being categorised as Nationally Significant, from the most

pristine mountain stream to farm and roadside drains which are impacted by pollution. It is

unrealistic for all waterways to be managed as ecologically Nationally Significant.

This problem has also arisen elsewhere in New Zealand. When developing criteria for identifying

rivers and lakes with significant indigenous ecosystems in the Greater Wellington Region, in part

using the presence of ‘Threatened’ and ‘At Risk’ fish species, Warr et al. (2009) excluded longfin eel

from their assessment criteria because it was recognised to be one of the most widespread and

common fish in the region.

This issue was raised and discussed in the Waikato Expressway: Hamilton Section AEE (Opus, 2013).

Rather than re-visit the issue in any further detail, in this report we acknowledge the presence of

longfin eels where they have been recorded, assess the potential ecological effects of the proposed

Ruakura Rd interchange on all fish species found including longfin eels, and suggest mitigation of

effects. However for the reasons stated above, criteria 3 needs to be applied with caution and requires

that the significance of sites based on the presence of at risk or threatened species needs to take into

account other contextual information.

3.1.4 Waikato District Plan

The Waikato District Plan identifies areas of significant indigenous vegetation and significant

habitats of indigenous fauna by assessment against the criteria listed in Appendix OC of the Plan.

These criteria were taken from Appendix 3 of the Waikato Regional Policy Statement. An area is

significant if it meets one or more of these criteria, as determined by a suitably qualified person.

3.1.5 Significant Natural Areas – Hamilton City Council

The Proposed Hamilton City District Plan protects significant indigenous vegetation and significant

habitat of indigenous fauna through the identification and protection of Significant Natural Areas

(SNAs). The sites are identified on the Planning Maps and are listed in Schedule 9C: Significant

Natural Areas in Volume 2, Appendix 9. The significance of a site is based on the ecological

significance of its indigenous vegetation. Sites were assessed using criteria for determining

significant indigenous vegetation and significant habitats of indigenous fauna contained in the

Regional Policy Statement (2000).

3.2 Threatened Species Criteria

The New Zealand Threat Classification System, originally developed in 2002, classifies New

Zealand’s native flora and fauna in terms of their risk of extinction (Molloy et al., 2002). Lists of

threat status of a broad range of taxa were developed between 2001 and 2005 (Hitchmough, 2002;

Hitchmough et al., 2007). The classification system was reviewed in 2007, resulting in several new

threat categories, and redefinition of some existing categories (Townsend et al., 2008). Based on this

new system, several taxonomic groups have been reassessed and results published in a number of

papers which now supersede the relevant sections of Hitchmough et al. (2007), including: vascular

plants (de Lange et. al., 2013), bats (O’Donnell et al., 2013), birds (Robertson et. al., 2013),



herpetofauna (Hitchmough et al., 2013), amphibians (Newman et al., 2009) and freshwater fish

(Goodman et al., 2014).

Where appropriate, in assessing the significance of individual species reference will be made to

Hitchmough et al. (2007) and papers covering the different taxonomic groups that have been

subsequently reassessed following Townsend et al. (2008).

4 Ecological Description

4.1 Flora

The proposed alteration to designation impacts upon a highly modified environment, including a

dairy farm, roadside drains and predominantly exotic ornamental vegetation.

The riparian margins of the Ruakura Road drains are dominated by exotic grasses and common weed

species, including ryegrass (Lolium perenne), blackberry (Rubus fruticosus), chickweed (Stellaria

media) and clover (Trifoium repens). Exotic trees line parts of the drain network, particularly along

the eastern section of Ruakura Rd.

The intensively farmed landscape within the alignment supports no natural ecosystems. The land is

flat or gently undulating and mainly in pasture used for grazing dairy cattle. For the most part it is

extremely open with very few mature trees or hedgerows.

The only locations where there are appreciable numbers of mature trees are at and around the

existing Silverdale Road roundabout. At this location, there is a loose grouping of large deciduous

and coniferous exotic trees. Most of the trees are English oak Quercus robur (up to 100cm diameter

at breast height - dbh) or holm oak Quercus ilex (up 200cm dbh – including a triple stemmed

specimen).

There is a loose grouping of exotic trees around the property located at 488 Ruakura Rd, and along

the road reserve boundary. The trees include acacias, eucalypts, copper beech (Fagus sylvatica

‘Purpurea’), Lombardy poplar (Populus nigra ‘Italica’) and English oak. The latter species is up to

70cm dbh with most other specimens in this location of much smaller diameter. There is also a

variety of exotic garden shrubs and also cabbage tree Cordyline australis.

Extensive ornamental trees (mostly exotic, with scattered natives) are found on private property

lining the eastern section of Ruakura Rd between 449 Ruakura Rd and the Ruakura Rd/Morrinsville

Rd intersection, however these lie on private property and will not be affected by the proposed

alignment. Exotic species along this section include hedgerows of she-oak, specimens of silver birch

and copper beech and phoenix palms (Phoenix canariensis). Native species include hedgerows of

tarata (Pittosporum eugenioides) and kohuhu (P. tenuifolium), and several garden plantings of

totara (Podocarpus totara), rimu (Dacrydium cupressinum), titoki (Alectryon excelsus), although

none are mature.

There are no mature indigenous trees within the proposed alteration to designation and no

indigenous plant communities.




4.2.1 Birds

Based on observations made during several site visits, the bird species present within the designation

alteration area are common native and exotic species, typical of highly modified landscapes. Species

recorded during site visits were: harrier Circus approximans, welcome swallow (Hirundo tahitica),

silvereye (Zosterops lateralis), house sparrow (Passer domesticus), goldfinch (Carduelis carduelis),

greenfinch (Fringilla chloris), starling (Sturnus vulgaris), myna (Acridotheres tristis) and magpie

(Gymnorhina tibicens). It is unlikely that the habitats within the proposed alteration to designation

this landscape provides significant habitat for threatened bird species.

4.2.2 Bats

The very open nature of the landscape means that most of the area within the alteration is unlikely

to be used with any frequency by long-tailed bats (Chalinolobus tuberculatus). The only locations

with the potential to hold roosting and/or feeding bats are the stands of mature trees around the

Ruakura Road/Silverdale Road roundabout and the mature trees around the property at the

proposed junction with Ruakura Road to the east of the Expressway. However, the Hamilton City

Bat Survey 2011-2012 (Le Roux & Le Roux, 2012) found no bats in the parks surveyed to the north

of Cobham Drive and to the east of Galloway Street. This included surveys of the University Campus

(c.500m from the Silverdale Road roundabout) and Chelmsford Park (within 1.5k of both stands of

trees). A subsequent survey by McQuillan (2013) recorded a single bat pass in September 2013 at the

Ruakura Research Centre using a hand-held detector, indicating at least sporadic use of the area by

bats. Surveys of the Ruakura Research Campus and Chelmsford Park by Boffa Miskell using

automatic bat detectors (ABM’s) in January 2014 recorded no bat passes (Dave Slaven pers. comm).

Two of the ABM’s were placed within 250m and 500m of the Silverdale Road roundabout

respectively. The bat surveys that have been undertaken around this area to date suggest that bat

usage of the area is sporadic. These results are consistent with bat surveys of the Hamilton and

Cambridge Sections undertaken by Opus International Consultants Ltd which has found that bat

activity is low or non-existent in open landscape away from substantial stands of mature trees and/or

gully habitat. The results of the various surveys suggest that it is unlikely that the trees around the

Silverdale Road roundabout or property adjacent to Ruakura Road will be regularly used by roosting

or feeding bats.

4.2.3 Herpetofauna

The Waikato Expressway: Hamilton Section AEE noted lizard species and native frog species records

from the DOC BioWeb Herpetofauna Database, from within 25km of the proposed Ruakura

Interchange. These are listed in Table 4-1, along with records of exotic frogs found within the same

area.



Table 4-1: Reptile and Amphibian records from the DOC BioWeb Herpetofauna Database within 25km of Hamilton

Common name

Scientific name Conservation threat status (Hitchmough et al., 2013; Newman et al., 2009)

Recorded locations Year of last record

Hochstetter’s frog

Leiopelma hochstetteri

At Risk – Declining Mt Pirongia, Mt Maungatautari 2004

Auckland green gecko

Naultinus elegans At Risk – Declining Te Pahu, Huntly, Ngaruawahia, Paterangi, Pirongia

1984

Speckled skink Oligosoma infrapunctatum

At Risk – Declining Ngahinapouri 1968

Pacific gecko Dactylocnemis pacificus

At Risk - Relict Te Pahu, Mt Maungatautari 2004

Forest gecko Mokopirirakau granulatus

Not Threatened (Partial Decline)

Mt Pirongia, Te Tapui, Mt Maungatautari

2010

Copper skink Oligosoma aeneum Not Threatened Various sites throughout area 2007

Rainbow skink Lampropholis delicata

Introduced and naturalised

Hamilton City 2007

Green and Golden Bell Frog

Litoria aurea Introduced and naturalised

Various sites throughout area 2009

Southern bell frog

Litoria raniformis

Introduced and naturalised

Hamilton City 2003

Those gecko species recorded in the DOC Herpetofauna database are arboreal species that favour

relatively high quality forest and/or manuka (Leptospermum scoparium)/kanuka (Kunzea

ericoides) habitat, although pacific gecko is known to inhabit rock piles and creviced clay banks.

Hochstetter’s frog is even more restricted in its range to only a few sites of relatively intact mountain

forest habitat, and will not be present. Farm debris, rank grass and wood pile habitat that is present

is likely to favour native copper skink and exotic rainbow skink. Exotic green and golden bell frogs

and southern bell frogs are likely to be present.

Evidence presented to the recent Board of Enquiry for the Ruakura Development Plan Change by

David Slaven (2014) detailed results of a manual hand-search for lizards carried out within the Plan

Change area which lies adjacent to the proposed Ruakura Interchange. Lizards species found were

copper skink and rainbow skink, while frog species were green and golden bell frogs and southern

bell frogs. These species are all commonly found throughout the Waikato landscape and are likely to

be present within the Ruakura Interchange footprint where suitable habitat exists. It is unlikely that

other skink species are present however this cannot be discounted.

4.3 Aquatic habitats and Fauna

4.3.1 Habitats Affected by Construction

The location of watercourses which are directly affected by the Ruakura Interchange Designation

Alteration are displayed in Figure 4-2, and descriptions are detailed in Table 4-3.



Figure 4-2: Sections of waterways assessed within this report are shown in green

Table 4-3: Location of affected watercourses and culverting lengths

Section Location Effect Approximate length

A From the property located at 488 Ruakura Road to the intersection of Ruakura Road and State Highway 26

2 culverts (west)

110 m, 70 m

B To the west of Ruakura Road and Holland Road intersection to 319 Ruakura Road

1 culvert

65 m

C A short 100m section of roadside drain adjacent to the Silverdale Road roundabout

- -

D Two farm drains located within the farmland adjacent to Ruakura Road (farmland owned by Tainui Holdings Ltd).

2 culverts 140 m, 20 m

The drains along Ruakura Road which are affected by this proposal are intermittent, meaning

seasonally wet (Sections A and B), ephemeral, wet for a short period after rain (Section C) and

permanent (Section D). It is unlikely that native fish species apart from eels and mudfish inhabit the

drains. A description of the habitat and aquatic fauna associated with each section of waterway is

detailed below.



Section A:

The drains within this section are intermittent and are in a highly degraded state. Along the western

side of Ruakura Rd, a significant amount of refuse was observed within parts of the drain, with an

oil slick also observed. A photo of a section of the drain system can be seen in Figure 4-9. There is

minimal connectivity between the sections of drain on the western side of the road, with swales

dividing the drain at various points. Vegetation is predominantly rank grass within the drain channel

and along the banks.

On the eastern side of the road, drains are also divided by short, narrow culverts running underneath

driveways; the drains here are very incised, with very little riparian vegetation of any kind. Many

sections were dry at the time of fish survey, despite consistent rain in the weeks beforehand. Many

connecting culverts are perched. The sections of drain within the designation are highly impacted by

varying degrees of management ranging from periodic mechanical clearance to control of weeds

using agrichemicals. The wet channel width within these drains is narrow (approximately 300-

600mm) and the water depth is shallow (approximately 0-200mm). The overall condition, low water

levels (even during winter when other drains in the area are near capacity) and lack of connectivity

of these sections of drain is such that they are unlikely to provide significant habitat for aquatic life.

Section B:

This section of drain includes some culverted sections. Riparian vegetation varies in composition. In

parts the vegetation is relatively dense and intact, and although it is mostly weeds and rank grass, it

contributes shade to the wet channel. The depth of the drains vary, being approximately 500-

600mm, and the wet channel width approximately 1-1.5m at time of survey. The drains within this

section are intermittent.

A fish survey has been carried out in close proximity to this drain by Clark (2014). This fish survey

was undertaken in the drain which lies between Ruakura Road and Ryburn Road (running

underneath the railway line). Clark (2014) found 1 black mudfish (Neochanna diversus), 4 shortfin

eels (Anguilla australis), and 1 juvenile banded kokopu (Galaxias fasciatus). Clark (2014) suggested

this area may provide occasional habitat for banded kokopu and giant kokopu (Galaxias argenteus),

but permanent populations of either species are unlikely to be present as all of the drains surveyed

were intermittent, and the area may also provide habitat for permanent populations of shortfin and

longfin eels (Clark, 2014).

Within Section B, one recording of a longfin eel was also documented on the NIWA Freshwater Fish

Database in 1996, the location is shown on Figure 4-3. This section of drain is intermittent, which

decreases the quality of habitat for longfin and shortfin eel, however they may be present at least

seasonally. The amount of dense riparian vegetation along this section of drain increases the quality

of habitat for aquatic fauna.

Section C:

The short section of roadside drain adjacent to the Silverdale Road roundabout was dry at the time

of the survey carried out on the 19th of June 2014 and does not appear to be connected to any of the

other surface drains in the near vicinity i.e. sections of drain along Ruakura Road. The sections of

drain within the designation appear to be highly impacted by varying degrees of management

ranging from periodic mechanical clearance to control of weeds using agrichemicals. There is no



overhanging vegetation. This section of drain is ephemeral and only contains water for short periods

after rainfall. For these reasons the quality of habitat for aquatic fauna is very low.

Section D:

This section comprises two sections of drain, located within farmland and both are fenced off from

stock. The water within the drains was fast flowing and is likely to be permanent. The drains

contained extensive macrophyte growth. Water depth was approximately 200-300mm, and wet

channel width was approximately 400-800mm. Rank grass lines the banks of the drain. A fish survey

was undertaken by Clark (2014) in a Mangaonua Stream tributary which is connected to one of the

drains in Section D (closest to the Mangaonua Stream). No fish were found in this survey.

For the reasons listed above the quality of habitat for aquatic fauna is low, however longfin and

shortfin eel may be present at least seasonally.

4.3.2 Receiving environment

The waterway that will receive future stormwater discharges from the proposed Ruakura

Interchange area includes a tributary to the Mangaonua Stream (Figure 4-2). Macroinvertebrate and

fish survey was carried out within the Mangaonua Stream tributary by Clark (2013) at the

approximate site of discharge proposed for the Ruakura Interchange. Results of the

macroinvertebrate survey were analysed using the macroinvertebrate community index (MCI) of

Stark et al (2007), revealing an MCI score of 91.71 and an SQMCI score of 4.19, indicating water

quality in the Mangaonua Stream tributary was ‘fair’, with ‘probable moderate pollution’. No EPT

taxa were present, and only 7 taxa were represented overall. This indicates a macroinvertebrate fauna

that is adapted to survival in highly impacted environments of low water quality. A fish survey was

also carried out, however no fish were found.

Water samples gathered by Clark (2013) within the tributary at Silverdale Road, approximately

1.5km downstream from the discharge site, indicated elevated levels of nitrogen and phosphorus,

exceeding levels required to limit algal growth, and microbial pathogens at levels above ANZECC2

recommended guidelines for contact recreation or livestock watering. Given the agricultural nature

of the upper catchment this waterway was expected to continue to receive inputs of turbidity,

suspended sediment, faecal bacteria and nutrients, causing low clarity, frequent algal blooms and

resulting in water unsuitable for human contact or livestock consumption (Clark, 2013).

These results indicate the Mangaonua Stream tributary is currently in a poor ecological condition.

4.3.3 Black Mudfish

Fish records were obtained from the NZ Freshwater Fish Database (FFD) and results are shown

below in Table 4-3, with locations of recordings in Figure 4-4.

2 ANZECC 2000, Australian Water Quality Guidelines for Fresh and Marine Waters, Australian and New Zealand Environment and Conservation Council, Kingston



Table 4-3: Results of the FFD search conducted on the 25th of June 2014

Year Catchment Locality Map East North

Species common name:

Species scientific name:

1982 Waikato River Ruakura Road drain s14 2715800 6379100 Black

mudfish Neochanna diversus







1996 Waikato River Ruakura Road drain s14 2715900 6378900 Longfin eel Anguilla dieffenbachii

Figure 4-4: Map showing the results of the FFD search conducted on the 25th of June 2014

4.3.4 Habitat Condition of Black Mudfish Sampling Sites

The Ruakura Road drain is a deeply incised linear artificial waterway. For the most part the drain

runs alongside Ruakura Rd although several ephemeral tributaries extend into the adjacent

paddocks in places. Riparian vegetation along the section in which mudfish sampling took place

consists almost exclusively of exotic pasture grasses and weed species, with several large trees

interspersed. A habitat description of each sample site is as follows:

4.3.4.1 Sample site 1 (Section B)

Incised banks, with riparian vegetation consisting of cocksfoot (Dactylis glomerata) and common

weed species including broad-leaved plantain (Plantago major), narrow-leaved plantain (Plantago



lanceolata), clover, chickweed and dandelion (Taraxacum officinale). Little to no shade provided by

overhanging plants. Some emergent weed growth within the water column. Water depth was

approximately 400-500mm, wet channel width was approximately 1m, and substrate composed of

silt/mud.

Figure 4-5. Drain habitat at site 1.




Water column shaded at the western end of this section by several large macrocarpa (Cupressus

macrocarpa) and tarata; riparian vegetation is relatively dense and intact and is composed of

blackberry, Japanese honeysuckle (Lonicera japonica) and several sedges (Carex sp.) which also

provide shade. Some growth of Ranunculus sceleratus within the water column, with rubbish

(plastic bottles) present in places. Water depth was approximately 500-600mm, wet channel width

was approximately 1-1.5m, and contained a silt/mud substrate.

Figure 4-6: Drain habitat at site 2.



4.3.4.3 Sample site 3 (Section D)

Drain running through pasture, less incised than the Ruakura Rd drains. Stock excluded from the

drain by fencing. Extensive R. sceleratus growth in the water column providing shade. Docks (Rumex

sp.) and cocksfoot line the banks, while the stream bed is sediment-covered. Water depth was

approximately 200-300mm, wet channel width was approximately 400-800mm, and contained a

silt/mud substrate with some gravels. The drain contained extensive macrophyte growth in places

and was fast flowing.





Extensive weed growth within the water column which appears to have been sprayed with herbicide.

Riparian vegetation is cocksfoot, common weeds and some blackberry, with several invasive acacias

(Acacia sp.) in isolated places. Two acacias had been recently windblown and were lying across the

drain at the time of visit. An extensive oily sheen was visible on the water surface. Water depth was

approximately 300-500mm, wet channel width was approximately 1-1.2m, and with a silt/mud

substrate.




4.3.4.5 Sample site 5 (Section A)

This section of drain is very incised and water depth too shallow for gee-minnow traps to be used for

the most part, however six sites of sufficient depth were located. A large amount of refuse was seen

in the drain. Riparian vegetation is dominated by cocksfoot with common weeds interspersed. Large

trees are present within adjacent paddocks including shea-oak (Casuarina cunninghamiana) and

silver birch (Betula pendula). Water depth was approximately 0-200mm (the drain was dry in some

places), wet channel width was approximately 300-600mm, and the substrate contained silt / mud,

with extensive leaf litter and rubbish.


4.3.5 Black Mudfish Survey Results

Results of the mudfish surveys are presented in Table 4-10. Mudfish were found at site 2 only. 6 black

mudfish were trapped, and the size range of fish caught included both juveniles and adults,

suggesting there is a permanent population, and that local conditions support both adult fish and

spawning habitat.

The NZ FFD holds several records of mudfish within the Ruakura Road drains, and in several other

drains within 700m of the affected area of works for the proposed re-alignment. The results of this

survey confirm that black mudfish remain present in the Ruakura Road drain within 100m of

proposed works.



Table 4-10: Results of the black mudfish surveys at 5 sites within the Ruakura Interchange designation alteration

Date: Location: Trap number: Species: Length (mm):

26/06/2014 Site 1 - 0 fish caught -

27/06/2014 Site 1 Trap 3 Mosquitofish (Gambusia affinis) -

01/07/2014 Site 2 Trap 5 Black mudfish (Neochanna diversus)

100


70


120


60


50


50

01/07/2014 Site 2 Trap 6 Mosquitofish (Gambusia affinis) -










5 Assessment of Significance

5.1 Significant Indigenous Vegetation

5.1.1 Regional

No indigenous vegetation was found that would trigger the criteria for significance under the

Waikato Regional Council Proposed Regional Policy Statement (2013).

5.1.2 District

The Waikato District Plan identifies areas of significant indigenous vegetation by assessment against

criteria derived from the Waikato Regional Council Proposed Regional Policy Statement. No

indigenous vegetation was found that would trigger the criteria, as per Section 5.1.1.

5.2 Significant Habitat of Indigenous Fauna

5.2.1 Regional

According to the criteria contained in the Waikato Regional Council Proposed Regional Policy

Statement (WRC:PRPS) (2013), Section B (location shown on Figure 2-1) triggers Criterion 3:

“containing indigenous species which are classed as threatened, at risk, or data deficient” (black

mudfish and longfin eel – both classified ‘At Risk - Declining’ (Goodman et al. 2014)).

Given that Section D is a permanent waterway, longfin eel may be seasonally present. This section is

therefore classified as significant habitat of indigenous fauna under the WRC:PRPS.

Section C is ephemeral and was dry at time of survey. Therefore no significance criteria are triggered.

Section A is highly degraded and large portions of the drain are disconnected and ephemeral. For

these reasons no significance criteria are triggered.

5.2.2 District

The Waikato District Plan identifies areas of significant habitat of indigenous fauna by assessment

against criteria derived from the Waikato Regional Council Proposed Regional Policy Statement. No

significant habitat of indigenous fauna was found that would trigger the criteria.

5.3 Significant Natural Areas (SNA’s)

There are no Significant Natural Areas identified within the Ruakura Interchange Designation

Alteration area for the Proposed Hamilton City District Plan 2012 and the Waikato District Proposed

District Plan (2012). However, an SNA has been identified near the alignment at Chelmsford Park,

at the very head of a smaller offshoot of the Mangaonua Gully (SNA 13.1). The small stream flowing

from this gully head is referred to further in this report as Mangaonua Stream tributary. This

connects further to the Mangaonua Gully -Silverdale SNA (13.2) further downstream. The SNA

values for both areas appear to be based mainly around vegetation (e.g. Astelia grandis populations

and good quality regeneration; C. Beard, pers. comm.). Although the alignment will not directly

affect this area, a stormwater wetland is planned for construction nearby to drain into this gully head.



6 Assessment of Ecological Effects

6.1 Flora

Indigenous vegetation within the proposed alteration to designation is confined to a few individual

plants and exotic trees found alongside the drains and within several areas of plantings within

residential gardens. Consequently there is no significant indigenous vegetation within the proposed

designation footprint and the ecological effects of the loss of this vegetation will be less than minor.


It is highly unlikely that the area of the designation alteration supports significant habitat for

indigenous terrestrial fauna, although stands of mature trees around the Silverdale Road roundabout

and property adjacent to Ruakura Road may provide sporadic habitat for long-tailed bats. The

activity levels that were found in surveys of long-tailed bats in the surrounding area as detailed in

Section 4.2.2 suggest that these trees are not used as roosting sites and therefore the ecological effects

will be minor.

6.3 Aquatic Habitats and Fauna

Several sections of open drain will be converted to culvert as a result of works. Approximate lengths

are as follows:

Section A: 180m – Not significant habitat

Section B: 65m – Significant habitat (for black mudfish and longfin eels)

Section D: 160m – Minor significance (potentially for longfin eels)

Total length of drain to be converted to culvert is approximately 405m. Of this, 65m is significant

habitat of indigenous fauna (Section B). Section D is a permanent watercourse, which has some

prospect of providing regular habitat for native fish. Section A is highly degraded and large portions

of the drain are disconnected and ephemeral, and no significant habitat of indigenous fauna is

present.

6.3.1 Effects on Eels

All of the waterways that will be affected are intermittent (i.e. they hold water during wet portions

of the year, but are dry for periods) with the exception of the farm drain within Section D, which is

likely to be a permanent waterway. Eels may use the drains within Sections B and D for migratory

purposes. Given the flat gradient of the culverts to be installed, eel passage is unlikely to be impeded

provided that culverts are correctly installed. However adverse effects may include potential

mortality during the construction phase.

6.3.2 Black Mudfish

Black mudfish (Conservation Threat Status Classification ‘At Risk - Declining’ (Goodman et al.

2014)) are cryptic in nature and this makes them difficult to survey. As a result their existence is not

widely known, and their distribution is probably underestimated (Ling, 2001).



The drain within Section B (Figure 2-1) provides significant habitat for black mudfish, one of the few

known habitats at the south-eastern end of Hamilton City.

The drains within Section A are highly degraded and there is poor connectivity to the drains located

within Section B. No black mudfish or any other fish species were found during our surveys in this

section, and it is unlikely that black mudfish are present.

Section C is an ephemeral drain and was dry at the time of survey. Surveys were conducted following

a period of consistent rainfall, which suggests that it is dry for most of the year and mudfish are

unlikely to be present.

The section of drain located on farmland (within Section D) is fenced off from stock, contains

substantial macrophyte growth, and swift-flowing water. No black mudfish were found at this site.

This supports results found by Clark (2013) who sampled a nearby drain in the same system, finding

no fish at all present. It is unlikely that black mudfish are present within this drain.

The adverse effects on black mudfish include a loss of habitat in Section B due to the construction of

a 65m long culvert, and potential mortality during the construction phase. Black mudfish

populations within the Waikato are rare, particularly at the south end of Hamilton City. In this

context the effects of culverting on the population remaining in this section of drain are more than

minor.

6.4 Stormwater Effects

6.4.1 Adverse Effects of Construction Phase

Earthworks associated with the cuts and fills necessary for the Project, and in-stream works, have

the potential to result in increased sediment discharges to the watercourses in the Project corridor.

Fine sediments have the potential to cause a range of adverse effects on streams and rivers and

contribute to sediment accumulation downstream. Most of these effects have been well documented

and best practices control measures for avoiding and mitigating effects have been developed and are

now standard practice on construction projects. The control measures for this Project will be

managed through the preparation and implementation of an erosion control and sediment

management plan (ECSMP) prepared in accordance with WRC’s Erosion and Sediment Control -

Guidelines for Soil Disturbing Activities (January 2009). An ECSMP has previously been prepared

for the Waikato Expressway: Hamilton Section Project and will also be used for the Ruakura

Interchange Project. It will be attached to the applications for resource consents.

It is recommended that all culverts are designed and installed to permit fish passage. Recovery and

relocation of native fish encountered during culvert installation should also be undertaken. Fish

recovery and relocation procedures will be developed for the Waikato Expressway: Hamilton

Section, and it is considered appropriate to use this procedure for the Ruakura Interchange

Designation Alteration also.

Providing that the ECSMP and fish relocation procedure is effectively implemented, the risks to

aquatic life should be effectively minimised during the construction phase.

6.4.2 Adverse Effects of Contaminants Entering Watercourse

Stormwater runoff from roads typically contains a number of contaminants including; sediments,

hydrocarbons, lead, copper, and zinc. In sufficient concentrations these contaminants can cause



adverse effects on fish and invertebrates. An NZTA funded study (Shaver and Suren, 2011) assessed

the ecological effects of contaminants generated by highway runoff. This study found that for five of

six streams monitored, there was little evidence of the stream being affected by runoff from the state

highways, despite high traffic volumes. All streams were in good ecological condition and were found

to be unassociated with stresses attributed to urban runoff. In the one stream which did show

changes to the invertebrate communities as a result of road runoff, the changes were regarded as

minor at most (Shaver and Suren, 2011). Traffic behaviour at the Ruakura Interchange will differ to

those sites assessed in the study by Shaver and Suren (2011). A higher level of braking and

accelerating will result in higher levels of contaminants in the runoff. However the treatment

approach for the stormwater in the Ruakura Interchange Designation Alteration includes the use of

roadside swales as well as wetlands which provide a higher degree of treatment than the grassed

ditches in the Shaver and Suren study, where runoff flowed into roadside drains or ditches. The

constructed wetlands and grassed swales aim to remove pollutants and mitigate ecological effects

downstream by storing and slowly releasing runoff.

Considering the results of this study, the high level of treatment that stormwater will undergo in the

swales and constructed wetlands, and the poor state of the aquatic habitat within the receiving

environment, it is considered that the effects of contaminants on aquatic ecology will be minor.

6.4.3 Potential Long Term Effects of Pulsed Discharge

The creation of impervious surfaces that are associated with roads and urbanisation increases the

amount of stormwater runoff associated with a given rain event. Due to the lack of soakage associated

with impervious surfaces compared to that which typically occurs when rain falls on soil surfaces

stormwater is conveyed much more rapidly and directly into watercourses. This can result in

increased channel scour and changes in channel morphology with consequent adverse effects on

instream aquatic life and riparian vegetation. Typically the most severe effects are found in urban

environments where there is no stormwater attenuation and where the cumulative effects of many

impervious surfaces leads to substantial changes in stream hydrology, even during modest rainfall

events.

In order to attenuate stormwater flows associated with state highways and also treat stormwater for

contaminants NZTA prepared the Stormwater Treatment Standard for Highway Infrastructure

based on industry best practice at the time. The Standard was issued in May 2010 and this has been

adopted for the design of stormwater systems for this Project.

Planted stormwater ‘wetlands’ and attenuation swales have been proposed to treat and attenuate

stormwater runoff from the interchange. These devices provide surface storage of stormwater and

remove pollutants through the process of biofiltration and sedimentation. Where practical, grassed

conveyance swales will provide a degree of pre-treatment as part of a treatment train. The

stormwater wetlands will have a permanent surface water area that will be at least 3% of their

contributing catchment area, and will be designed with sufficient storage capacity to maintain

hydraulic neutrality for the two and ten year ARI storms (average return interval). The 100 year ARI

storm flow will be attenuated to 80% of the pre-development discharge rate to prevent these

extremely intense, and infrequent storms from generating larger flows in the lower catchment. As

the stormwater management devices need to attenuate the runoff generated by the 100 year ARI

storm, no road water will be bypassed around them.

In a routine storm event, run off will be captured, detained, and released over a 24 hour period in a

process of extended detention. Extended detention will detain more than 90% of the runoff



generated on an annual basis, and the first 34.5mm of rainfall that collects within the interchange.

While flow will be attenuated to predevelopment rates, a larger volume of stormwater will be

discharged over a longer duration ‘pulse’. Extended detention will reduce the magnitude of these

pulses to mitigate streambed erosion in the downstream catchment (G.Jarvie, pers.comm.). Further

to this, the scale of increase in duration of pulse of this discharge, over and above that which will be

produced by stormwater from roads on the Waikato Expressway: Hamilton Section, is likely to be no

more than minor.

It is considered that the potential ecological effects of the pulsed discharge deriving from the Ruakura

Interchange are likely to be no more than minor.

6.4.4 Potential Effects of Stream Bank Erosion

The ecological effects on aquatic biota of stream bank erosion that will potentially result from the

increased duration of pulsed discharge are difficult to quantify. Precise ecological effects of such

erosion is currently unknown. In his evidence presented to the Waikato Expressway: Hamilton

Section Hearing, Dr Bruno David acknowledged the difficulties in attempting to quantify this3. Dr

David recommended NZTA should identify opportunities across their roading network to initiate a

robust monitoring programme similar in nature to that undertaken by Shaver & Suren (2011), that

would seek to measure such site-specific erosion-related ecological effects from discharges of this

scale; however in relation to the Hamilton Section project, he also acknowledged the difficulties in

establishing such a programme, particularly with respect to locating a suitable location to carry out

monitoring. Given the smaller scale of the Ruakura Interchange Designation Alteration in relation

to the Hamilton Section and the shared discharge point into the Mangaonua Gully it is not

considered that such an opportunity exists in the context of this Project.

Currently, the receiving habitat within the Mangaonua Stream tributary is in a poor ecological state,

with poor water quality as a result of inputs from the surrounding agricultural landscape. Clark

(2013) observed that many watercourses in the area currently regularly receive spikes in suspended

sediment. Within the Mangaonua Stream tributary, the macroinvertebrate community is currently

characterised by taxa that are adapted to survival in poor quality waterways.

Erosion mitigation measures for this project include detention and slow release of runoff through

wetlands and swales, and energy dissipation and scour protection at outlets where required. With

these measures in place, Opus stormwater engineers consider the issue of stream bed and bank

erosion within the receiving environment will subsequently be considered less than minor from a

hydrological perspective (Burke, 2014). Considering this, and the level of increase in volume of

proposed stormwater discharge to the Mangaonua Stream over and above that which will be

introduced from roads previously consented on the Hamilton Section, it is likely that ecological

effects from erosion will be minor.

6.4.5 Effects of Groundwater Interception on Gully Ecology

Hydrogeological investigations carried out for the Waikato Expressway: Hamilton Section AEE

(Connolly and Turner, 2013) determined that apart from a very small loss of water to evaporation

there should be no reduction in stream flows within the Mangaonua Stream as a result of effects of

3 Statement of Evidence Bruno David, Waikato Regional Council. Application for Resource Consents in respect of Waikato Expressway Hamilton Section. Applicant: NZ Transport Agency. 26th May 2014. Para 39.



construction on interception of groundwater. The very small loss due to evaporation is unlikely to

have any discernible impact on the ecology of the streams.

Spring seepages are a very common feature of the gullies in this area. It is difficult to accurately

predict the extent to which flows in spring seepages located in gullies to the west of the Expressway

might be reduced by the construction of the Ruakura Interchange. However, the effects are likely to

be localised and it is likely that additional reductions in flow to seepages in the Mangaonua Gully

resulting from construction of the Ruakura Interchange will result in less than minor adverse effects

on the ecology of the gully system, although minor changes to the ecology in the vicinity of the

seepages may occur over the longer term.

6.4.6 Summary of Stormwater Effects on the Receiving Environment

Effects of construction phase: An Erosion Control and Sediment Management Plan

prepared for the Waikato Expressway: Hamilton Section will be adopted for the Ruakura

Interchange Designation Alteration. Potential adverse construction effects on waterways

are expected to be minor.

Effects of contaminants entering receiving environment: Constructed stormwater

wetlands and grassed swales will provide a high degree of treatment, removing a large

proportion of road contaminants and sediment prior to discharge to the receiving

environment. Adverse effects of contaminants entering the receiving environment will be

less than minor.

Effects of increased duration of existing pulsed discharge: Larger volumes of

stormwater will be discharged to receiving environments, over a longer period following

rain events. The increase in duration of the pulsed discharges is expected to be minor. The

ecological condition of the receiving environment is currently poor. The increased level of

ecological effects over and above that of the Hamilton Section is likely to be minor.

Effects of stream bank erosion: Ecological effects are difficult to quantify, given the

small scale of increased pulse duration. However given the current poor ecological state of

the receiving environment and the small scale of the increase, the ecological effects of

stream bank erosion are expected to be minor.

Effects of groundwater interception on gully ecology: It is difficult to accurately

predict the extent to which flow seepages will be reduced by the Ruakura interchange.

Likely ecological effects on the gully ecosystem are expected to be less than minor, except

for minor localised long-term effects in the vicinity of the seepages.



7 Avoidance, Remediation and Mitigation of

Effects

7.1 Avoidance of Adverse Ecological Effects During Construction

The following measures are recommended to minimise effects on fish and stream habitat during

construction within the main gullies.

Fish recovery and relocation during the installation of culverts, and the re-alignment of the drain

within Section A. It is considered appropriate to utilise the procedures that will be developed for

fish recovery and relocation for the Waikato Expressway: Hamilton Section.

Careful management of the culvert construction and drain re-alignment construction process to

ensure that sediment discharge to the streams is minimised. This will be managed through the

Erosion Control and Sediment Management Plan, which has been prepared for the Waikato

Expressway: Hamilton Section, and will also be used for this Ruakura Interchange Project.

The culverts and any associated erosion control structures should be constructed in such a way

that does not impede the passage of fish either upstream or downstream.

7.1.1 Mudfish Management Plan

In order to avoid, remedy and mitigate adverse effects, a Mudfish Management Plan (MMP) should

be developed for this project. The MMP should include procedures for the capture and relocation of

mudfish associated with temporary and permanent drain diversions if required during construction.

Sediment removal activities in swampy lowland streams (or drains) have the potential to adversely

affect mudfish through habitat destruction, and removal and mortality (Hamill & Montgomerie,

2010). It is important that mechanical (or otherwise) clearance of the drain by Regional Council is

entirely avoided as mortality of mudfish will result. Populations of black mudfish are vulnerable to

extinction within roadside drains through herbicides, pesticides, drainage, or cleaning (Hicks and

Barrier, 1996).

7.2 Mitigation of Adverse Ecological Effects

The assessment of ecological effects determined that there will be minor adverse ecological effects

on flora and terrestrial fauna, and minor effects as a result of the stormwater discharges. However

potential for more than minor ecological effects has been identified for the loss of significant black

mudfish habitat and longfin eel habitat.

Table 7-1: Area of significant habitat that will be lost due to culverting

Length of culvert to be installed:

Channel width: Area:

Section B 65m 1.2m 78m2

Section D 160m 0.8m 128m2

Total: 225m - 206m2



It has been confirmed that Section B contains significant habitat for indigenous fauna, as surveys

have shown that black mudfish are present. Section D is a permanent watercourse and there is a

reasonable probability that is used by longfin eel. Although Section D has not specifically met the

test of significance as habitat, it is appropriate to take the conservative view and undertake mitigation

for this loss of habitat.

Although the drains within the Ruakura Interchange footprint are all artificial waterways that sit

within a highly modified environment, the more than minor effects of the project on ‘At Risk’ black

mudfish and longfin eel, and the effects on the habitat of these species requires mitigation. The

principle of biodiversity offsetting attempts to achieve no net loss of biodiversity in such situations

by quantifying the area to be impacted, and undertaking an appropriate form of mitigation at a scale

commensurate with that area. Offset mitigation must allow for factors such as the scale of values lost,

the presence of threatened species, and the potential time lag until the proposed mitigation provides

compensatory values4 5. The resulting calculation generally results in the requirement to mitigate an

area greater than that being impacted; this requires a ‘multiplier’ ratio of mitigation area to impact

area.

Total channel area lost to culverting is approximately 206m2. In terms of habitat compensation, we

suggest a ratio of 2 x area lost should undergo offset mitigation, to allow for lost habitat, installation

of culvert structure and time lag for establishment of the mitigation measures. This equates to a total

area of approximately 412m2.

In the first instance mitigation should take place in the same catchment as the impact is taking place.

It is appropriate to focus mitigation on improving the existing habitat for black mudfish and longfin

eel along Ruakura Rd. Riparian habitat that currently exists along the majority of Ruakura Rd is very

poor. Mudfish that were found during our surveys were limited to an area that is currently well

shaded, with significant overhanging vegetation including rank grass and weeds. Given the continous

nature of the drain, the historical presence of mudfish and longfin eel within the drain network to

the east, and the potential for improvement of riparian vegetation that exists, we recommend that

an appropriate response to loss of in-stream mudfish and longfin eel habitat through culverting is to

improve riparian vegetation in surrounding sections of the same drain, at a ratio of 2 x area impacted.

Mitigation of the adverse effects of the loss of significant habitat of black mudfish and longfin eel is

outlined below.

7.2.1 Riparian Planting Along Ruakura Road and Holland Road

Appropriate riparian planting would improve in-stream habitat for black mudfish and longfin eels

within the drain. Increased vegetative cover in the form of emergent or overhanging vegetation or

tree roots would enhance ecological values (Hicks and Barrier, 1996), providing food and shelter

(Ling, 2001). Appropriate planting would aim to improve the current poor quality of in-stream and

riparian habitat, and to increase the extent of suitable habitat available to the mudfish and longfin

eel populations in the drain, ultimately potentially providing improved habitat for other native fish

species. Sections of the drain to the west of the Expressway are earmarked for significant

development under the Hamilton City Council Private Plan Change which was approved for Tainui

ruakura interchange alteration to designation · 2014. 9. 18. · 2-31695.00 | 29 august 2014 opus...

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