Ecological Mitigation Recommendations and Restoration Plan ...

C & D Landfill Ltd

Ecological Mitigation Recommendations and Restoration Plan for the Proposed Expansion of C and D Landfill Area – Revised March 2014

C & D Landfill Ltd

Ecological Mitigation

Recommendations and

Restoration Plan for the

Proposed Expansion of C

and D Landfill Area –

Revised March 2014

© Opus International Consultants Ltd 2014

Prepared By Opus International Consultants Ltd

Roger MacGibbon Hamilton Environmental Office

Principal 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

Principal Ecologist

Date: 4 March 2014

Reference: 3-55619.00

Status: Revised Final

| 6 September 2013 Opus International Consultants Ltd

Contents

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

2 Determination of area of stream channel and terrestrial habitat to be restored . 2 2.1 Permanent and ephemeral stream channel ...................................................................... 2 2.2 Terrestrial habitat ............................................................................................................. 3

3 Consideration of offset restoration options ........................................................ 6 3.1 Restoration focus and philosophy ..................................................................................... 6 3.2 Riparian restoration potential within catchment ............................................................. 7 3.3 Riparian restoration potential in adjacent catchments .................................................... 8 3.4 Potential terrestrial compensation sites ........................................................................... 9

4 Proposed ecological compensation package ...................................................... 11

5 Offset compensation / restoration specifications .............................................. 13 5.1 Staging of restoration works. .......................................................................................... 13 5.2 Planting and site preparation specifications ................................................................... 14 5.3 Other restoration requirements ...................................................................................... 24

6 Conclusions and Recommendations ................................................................. 26

7 References ....................................................................................................... 28

8 Appendix 1 – Landfill staging ........................................................................... 29

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1 Introduction

A construction, demolition and cleanfill materials landfill (C&D Landfill) has operated at 50 Landfill

Road, Happy Valley, Owhiro Bay, Wellington, since the mid-1970s. An extension to the landfill is

proposed within a valley to the north and west of the current landfill. Resource consent applications

were lodged with the Greater Wellington Regional Council (GWRC) and Wellington City Council

(WCC) in 2009. An unnamed stream, currently partly culverted (referred to as ‘C&D Landfill Stream’

or Demolition Gully Stream), runs along the base of the valley.

An Assessment of Ecological Effects was carried out by Wildland Consultants in 2012 which

described the biota present upstream of the culvert that currently carries Landfill Stream water

beneath the existing landfill, and the environmental and ecological issues associated with the

proposed extension of the landfill. After review by GWRC, further assessment of the stream using

the SEV (Stream Ecological Valuation) method was requested to determine the nature and size of

the restorative works sufficient to mitigate the effects of the proposed gully filling and loss of a section

of stream.

Opus International Consultants produced the SEV in October 2012, and this has since been updated

in October 2013 to take into account changes to the proposed extent of new landfill area and

comments made by external technical reviewers.

This “Ecological Mitigation Recommendations and Restoration Plan” addresses three aspects of

ecological mitigation/compensation associated with the proposed extension of the C and D Landfill:

1. Offset compensation for the area of stream habitat lost, as calculated by the SEV;

2. Offset compensation for the loss of significant indigenous habitat (as defined in the GWRC

Regional Policy Statement, Policy 23);

3. Restoration of the proposed landfill site once landfill operations have been completed.

It is proposed and accepted by the C and D Landfill Managers that the extended landfill area, once

filled and completed, will be restored by planting with a cover of native trees and shrubs. In

addition, it is recommended that off- site restoration activity is undertaken to compensate for the

permanent loss of stream habitat that will occur when the landfill area is filled and the time lag

between when the significant vegetation within the proposed landfill area is cleared and when the

site can be rehabilitated post-landfill.

Uncertainty was expressed in the Wildland AEE report about the practicality and ecological outcome

of attempting to re-establish a habitable stream over the completed fill. We concur with this view

and believe that because of the considerable uncertainty of success associated with any attempt to

re-establish an overland stream that is suitable for habitation by aquatic fauna the option of

undertaking mitigation off-site is the safer option.

The SEV process is a commonly used tool to calculate the amount of offset stream channel to be

restored when existing stream habitat is lost. There is no similar equation or well-established

precedent to determine the amount of terrestrial habitat to be restored offset as compensation for

the loss and delayed replacement of indigenous habitat on an existing site. In the sections below we

propose a restoration package of planting and stream works that will provide appropriate

ecological compensation for the stream and terrestrial habitat lost.

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2 Determination of area of stream channel and

terrestrial habitat to be restored

2.1 Permanent and ephemeral stream channel

The revised SEV report has been used as the basis by which the area of stream likely to be lost

with the landfill extension is translated into a calculation of the area that needs to be restored

as compensation. The revised SEV study has found that 646 metres of permanently flowing

stream length and 599 metres of ephemeral stream channel1 and/or seepage areas would be

lost or affected by the expansion of the landfill site as it is now proposed. When this length is

multiplied by the average stream width (0.75m for the permanent stream and 0.30m for the

ephemerals) 665 m2 of stream area was calculated to be impacted (see Table 1).

Table 1: Stream area likely to be lost with the landfill expansion and calculated SEV

restoration compensation (Opus 2013)

Length

affected

Average

width

Area

impacted

Restoration

Area (ECR

5.38)

C&D Landfill

stream

646m 0.75m 485m2 2,607m2

Ephemerals/seeps 599m 0.30m 180m2 967m2

TOTAL 1,245m n/a 665m2 3,574m2

The SEV process generates an Environmental Compensation Ratio (ECR) which enables an

estimate of the stream area that should be restored to be calculated. The restoration area

calculated by SEV as compensation for the loss of permanent and ephemeral stream areas in

the C and D Landfill area equates to 3574m2 of stream surface area (generated by a ratio or

multiplier of 5.38). The offset stream restoration proposed in sections below has been

formulated to provide this amount of ecological compensation. It is important to note, however,

that the SEV process has not been designed to cater for ephemeral streams and seeps. The

ephemeral channels were not allocated their own SEV value because most were dry at the time

of assessment; the 5.38 multiplier used for the permanent stream compensation has been

applied to the ephemeral channels in the absence of any other value and is likely to greatly

exceed what would be considered “reasonable” compensation for the ephemeral stream

channels.

From an ecological perspective, stream habitat includes both the aquatic habitat (water

column) and the immediately adjacent riparian habitat. To differentiate the areas of

stream/riparian habitat being lost from the terrestrial vegetation being lost we have defined the

riparian habitat to be the stream channel plus a strip 20 metres each side of the permanently

1 Following communications with other ecologists we have included all ephemeral stream channels, including those that appear to remain dry most of the year, into the tally of stream channels that require offset compensation. This has increased the length of ephemeral stream affected from 415m to 599m.

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flowing channel, and the stream channel plus 10 metres each side of the narrower ephemeral

channels. The restoration effort applied to the offset compensation for the stream area lost will

be applied in the same fashion, that is, restorative works will extend up to 20 metres each side

of permanent streams being restored and up to 1o metres each side of ephemeral channels

being restored. The upper reaches of the ephemeral channels and seepage areas will have a

much narrower effective riparian margin than 10 metres and it is expected that restoration

effort will be adjusted to suit the conditions at each restoration site.

2.2 Terrestrial habitat

In total 13.1 ha of land surface will be disturbed when the proposed landfill extension is fully

utilised (Table 2). This area has been measured as “flattened out” land area, rather than as

measured on a 2 dimensional map, and so represents the actual land area on the ground. All

subsequent references to areas of land lost and land to be restored use this flattened out

equivalent. [Note that the total proposed landfill area measured two dimensionally on a map

totals 9.75 ha compared to 13.1 ha flattened out].

Table 2: Stream and riparian areas likely to be lost by the proposed landfill extension

Area to be lost

Permanent stream and riparian habitat

(20m each side of stream)

3.4 ha

Ephemeral streams and riparian habitat

(10m each side of stream)

1.3 ha

Terrestrial area (beyond the riparian zones) 8.4 ha

TOTAL 13.1 ha

When the permanent and ephemeral stream areas and their riparian margins are deducted, 8.4

ha of terrestrial land area will be affected by the proposed landfill.

The Wildland’s AEE report (Wildland Consultants 2012) identifies ten terrestrial vegetation

and habitat types across the proposed landfill area and allocates a relative ecological ranking

for each as summarised below:

1. Mahoe (Melicytus ramiflorus) – mamaku (Cyathea medullaris) – wineberry

(Aristotelia serrata) – tree hebe (Hebe parviflora) – nikau (Rhopalostylis sapida)

forest.

Ecological value: Moderate – high

2. Mahoe (Melicytus ramiflorus) – kawakawa (Macropiper excelsum) – manuka

(Leptospermum scoparium) – tree hebe (Hebe parviflora) – mamaku (Cyathea

medullaris) forest.

Ecological value: Moderate-high

3. Mahoe (Melicytus ramiflorus) / kawakawa (Macropiper excelsum) forest.

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Ecological value: Moderate

4. Indigenous scrub – gorse (Ulex europeus) scrub / pasture grassland.

Ecological value : Moderate-low

5. Gorse (Ulex europeus) / pasture grassland.

Ecological value: Low-moderate

6. Pasture grassland.

Ecological value: Low

7. Buddleja and other weeds.

Ecological value: Low

8. Concrete.

Ecological value: Negligible

9. Bare earth and/or waste debris.


10. Track.


We have calculated the area of each vegetation/habitat type likely to be lost when the proposed

landfill is at its full extent (Table 3) to provide a picture of the type and nature of the terrestrial

habitat compensation that should be provided. Only the proposed landfill area the lies on

“terrestrial” land is included (ie. it excludes the areas that lie within the riparian zones that have

been discussed in section 2.1 above). Table 3 excludes types 7, 9 and 10 because the areas

occupied by these types are negligible.

Table 3: Habitat types and area on the terrestrial land proposed for landfill

Area to be lost

Vegetation/habitat type 1 0.70 ha







TOTAL 8.4 ha

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Not all of the land and vegetation being lost to the proposed landfill has significant ecological

value. Applying Section 6 (c) of the RMA, which requires the protection of areas of significant

indigenous vegetation and significant habitats of indigenous fauna, and Policies 23 and 47 of

the Regional Policy Statement for the Wellington Region (2013) we believe that vegetation

types 1, 2, 3 and 4 as described by Wildlands (2012) contain significant biodiversity values and

their loss should therefore be compensated for.

Policy 23 provides five criteria to be used to determine indigenous ecosystems and habitats

with significant indigenous biodiversity values. The criteria are: representativeness, rarity,

diversity, ecological context and tangata whenua values. If any one of the criteria is relevant

then the habitat type is deemed to be significant. Of the criteria, perhaps the most relevant to

the Wellington City region and particularly the southern city area, is the ‘context’ criteria.

Mature gorse is a very important nurse species for the natural regeneration of native flora in the

Welllington City area (more so than other parts of the country) and wherever native

successional species are regenerating in a substantial manner under the gorse canopy the value

of the habitat should be considered significant.

Vegetation type 5, described as “nearly pure gorse with only a few indigenous shrub species”,

and types 6 (grassland), 7 (weeds), 8 (concrete), 9 (bare earth and/or waste debris), and 10

(tracks) are considered not to provide significant biodiversity values and therefore

compensation for these areas is not considered necessary.

Consequently, the terrestrial area that will be lost and will require offset compensation amounts

to 4.5 ha.

2.2.1 Calculating the terrestrial area to be restored

Unlike the SEV method for evaluating compensation for stream habitat loss, there is no

accepted quantifiable formula in common use to calculate the area of offset restoration work to

appropriately compensate for the loss of terrestrial indigenous habitat. SEV uses a 1.5

multiplier (ie. restoration must cover 1.5 times the area of the habitat being lost) for stream

habitat restoration, and multipliers ranging up from 2 have been used on some projects (eg

NZTA highway projects).

In the C and D Landfill situation, the site will be restored back to full native tree and shrub

cover at the conclusion of the consent period (which does not and cannot occur with NZTA

projects). In recognition of the restorative work that will be undertaken on the site at its

conclusion, it is considered appropriate that offset compensation for the removal of terrestrial

habitat containing significant biodiversity values should occur on a one for one basis, ie. 4.5 ha

of offset restoration work.

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3 Consideration of offset restoration options

3.1 Restoration focus and philosophy

Several well established ecological restoration principles have been applied in developing a

compensation package for the C and D Landfill extension proposal.

3.3.1 Retain/enhance existing ecological values

A generally accepted “working” philosophy for restoration ecology is to focus on retaining and

enhancing the most significant ecological values present in an area, site or waterbody. The most

significant ecological value present in the greater Owhiro Stream catchment (which

Landfill/Demolition Gully Stream is a tributary of) is the presence of a persistent native fishery.

Owhiro Stream is listed in Table 16 of the Wellington Regional Policy Statement as a ‘river with

significant indigenous ecosystems’ . It triggers three significance criteria:

The stream and all of its tributaries provide habitat for threatened indigenous fish species

(koaro, redfin bully and longfin eel);

The stream and all of its tributaries provide habitat for 6 or more migratory indigenous fish

species;

Owhiro Stream provides inanga spawning habitat (within the reach of tidal influence).

The landfill operations within the C and D Landfill catchment have affected and reduced the

value of the habitat for native fish species for several decades but, despite this, several species

continue to use Landfill Road stream (above and below the current landfill area) as habitat. The

extension of the C and D Landfill area will reduce the upper tributary habitat available for

native fish. Consequently, the focus of offset restoration effort should be directed at enhancing

the suitability of the catchment habitat that will remain accessible to native fish and, if possible,

opening up new habitat suitable for native fish. This philosophy has been adopted in the

restoration recommendations below.

3.1.2 Within catchment focus

The preferred approach to compensatory restoration is to attempt to find suitable offset

ecological compensation sites within the catchment. In hilly areas such as the Owhiro Stream

catchment plant and animal communities tend to centre on river catchments; so to retain the

resilience of these communities it is a sound principle to first look to undertake restoration

within the same catchment from which habitat is being lost.

3.1.3 Attempt to replace like with like.

Another generally advocated ecological compensation principle is to attempt to replace like

with like, or as close as possible to it.

With the restoration package outlined below we have attempted to find and propose restoration

sites that, through restoration, could be enhanced to a similar successional state to the areas

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being lost. This has not always been possible because of the limited sites available that have

potential for restoration and are on land that is likely to be available for restorative works and

managed to compliment the restoration. In the Owhiro Stream catchment / south coast area of

Wellington this has reduced potentially suitable land to Council administered land because no

private land has been offered where future access and appropriate future management can be

guaranteed.

3.1.4 Restoration sites must be accessible and manageable

Restoration sites that are not easily accessible invariably do not receive the post-planting

management and maintenance attention required to achieve high plant survival and effective

weed and pest control. This applies especially when restoration labour consists of local

volunteers but also applies to restoration works undertaken by professionals.

3.1.5 Build on areas of existing high value

It is a recognised ecological restoration principle that restoration usually reaps the best returns

when effort is directed at fewer but larger areas and also when restoration is appended to

existing established biodiversity sites rather than in isolated locations. Applying this principle,

we propose that the terrestrial offset compensation for C and D Landfill is appended to

proposed riparian/stream restoration works and/or to existing high value biodiversity areas.

3.2 Riparian restoration potential within catchment

3.2.1 Potential within-catchment riparian restoration areas

One of the major challenges in developing an appropriate mitigation package for the proposed

expansion of the C and D Landfill site has been the lack of accessible stream channel and

margin within the catchment or immediately adjacent to it that would benefit from restoration.

Despite this, two areas within the greater Owhiro Stream catchment have been identified as

suitable for restoration and appropriate as compensation sites for the stream area likely to be

lost with the landfill extension. They are:

1. Parts of the Owhiro Stream downstream of the confluence with the Landfill Road

stream tributary;

2. The Landfill Road Stream itself between the confluence with Owhiro Stream and the

upstream culvert that passes under the existing landfill;

The gully tributaries that flow from the south into Landfill Road Stream were also considered as

possible sites for riparian restoration but after discussion with Wellington Region and

Wellington City ecologists these tributary valleys were not included because the feeling was

they had already formed a well-established regenerating native canopy and would be better left

undisturbed.

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(a) Owhiro Stream – lower channel

The lower reaches of Owhiro Stream have been identified as a suitable compensation location

for restorative attention despite lying at a lower altitude than any of the stream sections being

lost from the proposed landfill site. This is because the stream is in a moderately degraded state

and therefore has greater potential for restoration, and also because it serves as an important

passageway for native fish species to move upstream and restoration will improve its value as

fish habitat. As stated in a section above, Owhiro Stream has been identified by the Regional

Council as a ‘river with significant indigenous ecosystems’.

Much of the main Owhiro Stream channel upstream of the confluence with Landfill Road

Stream has been restored by local community groups while the headwater tributaries that feed

into the Owhiro from the northwest have a good covering of regenerating native vegetation

along the riparian margins that is best left undisturbed. Little opportunity for restoration

exists along the tributaries that flow into Owhiro Stream from the east. Much of this side of the

catchment is now culverted and those tributaries that remain as natural surface flows have a

reasonable covering of regenerating native species.

(b) Landfill Road Stream

The Landfill Road Stream downstream of the landfill has reduced potential for restoration

because of the close proximity of Landfill Road on one side, however, after some thought and

discussion with Wellington City Council ecologists it was felt that enhancement planting of the

south side of the Landfill Road stream channel, and the north side where room exists, would

improve the quality of that section of waterway and improve the ability of native fish to move

into the gully tributaries that flow into Landfill Road stream from the south (downstream of the

landfill area). The addition of sedges (Carex spp.) to the banks at and just above base flow

levels will also provide enhanced fish and fish spawning habitat.

3.3 Riparian restoration potential in adjacent catchments

The Haape Stream catchment to the immediate west of the Owhiro catchment (see figure 2),

and to a lesser extent, the Waipapa Stream catchment further to the west, are the only adjacent

catchments that bear some ecological similarity to the Owhiro catchment (such as providing

access from Cook Strait for migratory fish and steep entrenched gully headwater), and which

are not completely modified by residential development. They are also the only two adjacent

catchments that lie almost entirely on land administered by Wellington City Council. The

stream catchments further west lie at least in part on private land and so were not considered

for restoration because access and future appropriate management could not be guaranteed.

Catchments to the east of Owhiro Stream are heavily modified by residential development (with

much of the drainage carried in culverts) and are not suitable for restorative planting.

The catchment to the north – north-west of Owhiro is the well-publicised Karori sanctuary that

has been enclosed by a pest exclusion fence and has been intensively managed for a number of

years to restore indigenous biodiversity.

3.3.1 Waipapa and Haape Stream catchments

Healthy natural regeneration is occurring along the main stem of both the Haape Stream and

the Waipapa Stream catchments. For this reason and because of the steep nature of the slopes

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that drop down to these streams, additional restoration planting of the main stream riparian

margins is not recommended except possibly for a few small sites in the mid reaches of Haape

Stream. However, there are several upper catchment and ephemeral tributaries that flow down

to Haape Stream (see figure 4), that have grass dominated channels and gorse dominated

flanks that would benefit from restorative planting and would serve as suitable compensation

sites for the ephemeral stream channels and seeps being lost for the C and D landfill site.

Haape Stream catchment also has potential to be opened up for native fish habitation. The

NIWA fish database shows no records of fish species in Haape Stream. While some fish species,

especially eels and possibly koaro, may exist in the catchment a small dam structure or weir

that exists near the mouth of the stream (Figure 1) is likely to serve as a barrier to most

migratory fish species. Eels will be able to climb around the weir and species such as koaro that

are very capable climbers may also be able to move past this structure, however most other

native fish species (such as inanga) are poorer climbers and will be prevented from moving into

the middle and upper catchment. The addition of a fish ladder, or better still the removal of the

weir and reinstatement of the natural stream channel, would provide new habitat for several

native fish species. This is proposed in the ecological compensation package outlined below.

3.4 Potential terrestrial compensation sites

A greater selection of terrestrial restoration options exists within the Owhiro Stream catchment

and in adjacent catchments than exists for riparian and stream restoration. To add greatest

value to the restorative works that are undertaken we have proposed that the terrestrial

compensation work should lie adjacent to and extend from the proposed riparian restoration

sites and/or add to existing high value riparian sites.

Sites have also been selected to provide a range of successional stages so that the species

planted align reasonably closely with those that will be lost. For example, approximately 2.1 ha

of more diverse mahoe canopy forest (vegetation types 1, 2 and 3 – table 3) will be lost , so

restoration sites have been chosen where the same successional species can be planted or,

wherever possible more advanced successional species can be planted. For the lower quality,

less diverse vegetation types being lost mid successional species will be planted into sites with

mixed gorse – native plant assemblages.

The details of the proposed areas and species mixes can be seen in the next sections.

Figure 1: Haape Stream dam

structure that could have a fish

ladder appended to facilitate fish

passage

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Figure 2: Location of Haape Stream and

Waipapa Stream relative to the location of

the proposed C and D Landfill Extension

Haape Stream

Waipapa Stream

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4 Proposed ecological compensation package

Following walk through surveys of the Owhiro Stream, Landfill Road Stream, Haape Stream and

Waipapa Stream catchments, appraisal of other catchments using aerial maps and botanical

information, discussions with regional ecologists and community conservation volunteers,

consideration of feedback from consultant and council ecologists, and consultation with the C and

D Landfill managers, a proposed ecological compensation package has been compiled . This

package includes the following:

A. Permanent and ephemeral stream offset compensation

The SEV methodology has the objective of achieving “no net loss of area-weighted stream

function” (Storey et al 2011) with environmental compensation preferably taking place within

the same catchment as the impacted site.

It has been calculated that ecological compensation needs to be undertaken on 3574m2 of

stream channel to provide full compensation for the permanent and ephemeral stream

channels that will be lost with the landfill extension.

The location of the proposed stream restoration works is detailed in Table 4, and mapped in

figures 3, 4 and 5.

Table 4: Proposed sites of stream and riparian restoration to compensate for stream area

lost from the proposed landfill area

The stream area proposed for restoration along Owhiro Stream and Landfill Road Stream

equates approximately to the permanent stream area that will be lost with the proposed landfill

extension, and the Haape Stream tributaries equate approximately to the area of ephemeral

stream lost.

Restoration will consist of weed removal and planting of up to a 20 metre wide margin on each

side of the permanent streams (Owhiro and Landfill Road Streams), and up to 10 metres each

side of the ephemeral Haape Stream tributaries. This equates to riparian restoration areas of

approximately 2.6 ha along Owhiro Stream and 3.4 ha along Landfill Road Stream, and 6.9 ha

along the Haape Stream tributaries.

Stream

Length

available

Stream

Average

width

Stream

Area

available

Riparian area

to be restored

(m2) *

Owhiro Stream 650m 2.5m 1625m2 26,000 m2

(2.6 ha)

Landfill Rd

Stream

850m 1.0m 850m2 34,000 m2

(3.4 ha)

Haape Stream

tributaries

3450m 0.30m 1035m2 69,000 m2

(6.9 ha)

TOTAL 4950m n/a 3510m2 12.9 ha

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B. Significant terrestrial vegetation offset compensation

As discussed in section 2.2 above, 4.5 ha of terrestrial offset area needs to be restored to

compensate for the ecologically significant habitat that will be lost with the landfill extension. It

is proposed that this area of terrestrial restoration is undertaken in the tributary valleys that

flow into Haape Stream (see figure 4), building on and expanding the riparian restoration

planting that has been proposed for this area.

Species such as Coprosma propinqua, rangiora (Brachyglottis repanda), Hebe parviflora,

Hebe stricta, tauhinu (Ozothamnus leptophyllus), cabbage tree (Cordyline australis) and

coastal flax (Phormium cookianum) can be planted in the upper valley areas where pockets of

rank remnant pasture grass and larger pockets of gorse occur. Pockets of mahoe and mixed

native shrub-small tree canopy exist further down in several valleys and these zones are ideal

for interplanting with later successional species, such as pigeonwood, kowhai, titoki, totara,

nikau and lacebark that are now uncommon in this area.

C. Provision of fish passage

It is likely that few fish species other than eels and possibly koara can move past the weir that

blocks Haape Stream. Removal of the weir or provision of fish ladders would open up in excess

of 80 hectares of stream habitat for native fish. It is proposed that C and D Landfill either

install a fish ladder system at the weir to enable climbing native fish species to move upstream

or, if the required resource consents are able to be procured, remove the concrete weir and

restore the original alignment of the stream channel, thereby opening up the catchment to all

native fish species. The fish habitat made available by removal of the weir (or even installation

of a fish ladder) would greatly exceed that being lost as a result of the landfill extension.

Assuming a fish ladder or re-alignment of Haape Stream occurs, the main Haape Stream

channel would be a suitable location for the release of native fish that will have to be captured

and translocated from the landfill stream area prior to commencement of the landfill extension.

D. Completed site rehabilitation

Upon completion of the landfill and/or at the conclusion of the consent period, the landfill area

surface should be revegetated with appropriate native tree and shrub species. It is likely that

the completed landfill surface will be open and exposed and probably well drained, so hardy,

fast-growing colonising / early successional plant species will need to be planted. It is

recommended that a planting and maintenance plan is prepared by an experienced restoration

ecologist prior to the conclusion of the consent period.

The lateral drainage channels that are proposed for construction around the outer edges of the

landfill area will eventually carry the main stream and tributary headwater flows from above

the landfill platform and so can be expected to flow all or most of the year. With this being the

case, these channels can be expected to generate some ecological value although the extent and

nature of this will not be known until the landfill is underway.

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5 Offset compensation / restoration specifications

The following information provides broad restoration specifications for each of the proposed

restoration areas, and an outline of the potential staging of the restoration works. It is

recommended that more detailed restoration schedules are developed in advance of each stage of

works.

5.1 Staging of restoration works.

A plan has been developed for the utilisation of the landfill and this has been translated to

represent the amount of stream-riparian area and significant vegetation that will be removed

with each stage of works, as is shown in Table 5. Three stages of fill are proposed and can be

viewed in Appendix 1.

It is recommended that restoration work occurs in phases that reflect the staging of the landfill.

This has been calculated and represented in Table 6. For example, 1.2 hectares of permanent

stream will be lost in stage 1N of the landfill. When the SEV multiplier and the 40 metre

riparian buffer are applied this equates to 2.10 ha of riparian restoration work that will need to

be done along the margins of Owhiro and/or Landfill Road Streams. Land fill stage 1N also

requires 0.2 ha of ephemeral stream margin restoration and 0.85 ha of terrestrial restoration

works (of which 0.66 ha is higher value enhancement planting and 0.19 ha is lower value

revegetation planting). It may not be practical to follow the exact staged restoration schedule,

especially if the requirement is for a very small amount of restoration in any one year, but the

objective should be to undertake the restorative works approximately as the Table 6 schedule

suggests.

Work on each restoration phase should commence at the commencement of each landfill stage.

Table 5: Proposed staged clearance of riparian and significant vegetation from the landfill site

1N 2 3 Total

Permanent stream

removal

1.2 ha

35%

0.59 ha

17%

1.62 ha

48%

3.41 ha

Ephemeral stream

removal

0.04 ha

3%

0.44 ha

35%

0.78 ha

62%

1.26 ha

Terrestrial habitat

removal

(vege types 1-3)

0.65 ha

31%

0.79 ha

37%

0.69 ha

32%

2.13 ha

Terrestrial habitat

removal

(vege type 4)

0.20 ha

8%

0.42 ha

18%

1.74 ha

74%

2.36 ha

TOTAL 2.09 ha 2.24 ha 4.83 ha 9.16 ha

14


Table 6: Schedule of restorative work to match the staged utilisation of the landfill

1N 2 3 Total

Owhiro and

Landfill Road

Stream restoration

2.10 ha

35%

1.02 ha

17%

2.88 ha

48%

6.00 ha

Ephemeral stream

restoration

0.20 ha

3%

2.42 ha

35%

4.28 ha

62%

6.90 ha

Terrestrial habitat

restoration

(vege types 1-3)

0.66 ha

31%

0.79 ha

37%

0.68 ha

32%

2.13 ha

Terrestrial habitat

restoration

(vege type 4)

0.19 ha

8%

0.42 ha

18%

1.75 ha

74%

2.36 ha

TOTAL 3.15 ha 4.65 ha 9.59 ha 17.39 ha

5.2 Planting and site preparation specifications

5.2.1 Owhiro Stream margins – maximum planting area 2.6 ha

The areas along Owhiro Stream that are accessible and suitable for riparian attention are shown

in Figure 3.

All three areas are administered by Wellington City Council. There are approximately 685

metres of stream length within these three areas but there are small patches of recent and

remnant native plantings scattered through them so it has been estimated that there is likely to

be about 650 metres of site suitable for restoration. If any of the proposed Owhiro Stream

margin is not available or suitable (ie. opposed by local residents) for restoration planting an

equivalent alternative area within the Haape Stream catchment should be restored instead.

The width of riparian margin available for planting varies between 5 and 20 metres on each

side of the stream in all three areas. Wherever possible planting should be extended as far as 20

metres from the stream edge.

Restoration objective

The principal objective of riparian restoration along the lower Owhiro Stream is to improve the

quality of the aquatic habitat for native fish and macroinvertebrates, and to enable these

organisms to move freely to the remaining upper tributaries that flow into C and D Landfill

Stream below the landfill area. This will be achieved by:

Removing weed species and replacing them with appropriate native riparian margin plant

species;

Removing rubbish and debris from the sections of stream channel requiring it;

15


Planting up to a 20 metre width of native tree, shrub and sedge species on each side of the

stream channel, wherever possible, to create a good level of shade over the channel (which

will enable summer water temperatures to be kept within fish-tolerable range) and to

provide a good supply of food material to the water body;

Plant native sedges along the small flood plains that remain at the water’s edge to create

zones suitable for fish spawning;

Undertaking a 5 year weed control and plant maintenance programme;

Where possible, remove any full or partial barriers to fish passage;

Improve the visual appeal of the stream margin.

Site preparation

All groundcover weeds and introduced shrub species should be cleared from the planting zone

prior to planting. Non-native trees that are not invasive in nature should be retained to provide

bank and slope stability and protection to the newly planted native trees and shrubs. At a later

stage when the plantings have become well established, the trees can be poisoned or ring-

barked which will result in their gradual disintegration without causing significant damage to

the surrounding plants. Tree poisoning or ring barking should not be undertaken where there is

public access as large branches can drop unexpectedly.

Along most parts of the Owhiro planting zone, gorse is more scattered and does not form a

dense canopy. However, if there are areas where gorse is well established and forms a dense

canopy, or it is playing an essential role in slope stabilisation, then it is recommended that

access lines are cut through the gorse at 3 metre intervals and plants planted at 1.5 to 2 metre

spacings along the lines. This retains the sheltering and slope stabilising benefits of the gorse.

The material cut from species that can sprout vegetatively from shoots and branches should be

removed from the site, but if this is not possible then this material should be stockpiled on site

(but well away from the stream) and sprayed repeatedly with herbicide until all material is

dead.

Where grasses are predominant, glyphosate herbicide should be used to clear planting squares.

Species to be planted

Hardy, fast growing native shrub and small tree species should be planted at 1.5 to 2 metre

spacings over most of the width of the riparian strip, and where the stream banks allow it

sedges, flax, and toetoe can be planted on or just above the water’s edge. Carex sedges can be

planted at 1 metre spacings but the flax and toetoe should be spaced at 1.5 to 2 metres.

One metre plant spacings are advocated by some for native shrub and small tree planting but

planting this close is not recommended except with sedges along stream banks. Several of the

species listed below have spreading canopies which if planted too close together can lead to

mortality amongst the slower growers. In addition, in riparian areas within the flood zone

plants located too closely together can hold back flood water and lead to localised flooding.

16


Figure 3: Proposed lower Owhiro Stream riparian

restoration areas (encircled in solid red)

N

Area 1

Area 2 Area 3

17


Recommended species (all plants should be ecosourced):

a) Stream banks :

Carex secta (on the water’s edge at base flow levels)

Phormium tenax (flax) above the normal flow level

Austroderia fulvida (toetoe) above the normal flow level

b) Flood terraces and the rest of the riparian zone:

Hebe stricta (koromiko) Coprosma robusta (karamu)

Leptospermum scoparium (manuka) Pittosporum eugenioides (lemonwood)

Aristotelia serrata (wineberry) Cordyline australis (cabbage tree)

Plagianthus regius (ribbonwood) Pittosporum tenuifolium (kohuhu)

Pseudopanax arboreus (five finger)

A PB 2 or PB 3 plant grade is recommended for this planting. Upright growing plants should

have foliage that extends a least 40cm above the bag and the root systems should be well

formed. Plants grown in 1 litre pots may be acceptable for faster growing species.

Post-planting maintenance

Gorse and problem weed regeneration will be vigorous so regular herbicide releasing will be

required to give the native plants sufficient head start. Spray releasing will be required twice

per year (pre-and post-Christmas) for the first 2 to 3 years and then annually until year 5.

Native plants are very susceptible to herbicides of any nature. All spraying should be

undertaken only when there is little wind and non-residual sprays such as glyphosates pose less

risk than more potent chemicals. Gorse control may require residual herbicides but if these are

used extra care is required to ensure none comes in contact with the native plants either by

wind drift or by movement through the soil. Gorse and other woody weed species can be

effectively controlled by applying herbicide paste to freshly cut stumps.

Cost estimate

Table 7: Likely cost of establishment per plant and hectare

$ cost/plant $ cost/ha (Assuming 2500plants/ha)

Site preparation $1.00-2.00 $2500-5000

Plant purchase $2.50 -3.50 $6250-8750

Plant freight $0.50 $1250

Planting labour $1.50 $3750

Maintenance (5yrs) $5.00 $12,500

TOTAL COST $10.50-12.50 $26,250-31,250

18


Allowing for the existing natives (planted and natural) on this section of the stream, the

retention of some trees, and an available riparian margin that along some stretches is less than

20 metres, it is estimated that about 5000 plants will need to be planted in this zone.

Performance measures

It is recommended that an appropriate measure of success would be 80% canopy closure in the

areas planted 5 years after planting. Growing conditions are relatively favourable in this area

(fertile soils, year round water and sheltered) so achievement of 80% canopy closure is realistic

in 5 years whereas on some of the higher elevation slopes in Haape Stream this may take 10

years.

5.2.2 Landfill Road Stream margins – maximum planting area 3.4 ha

The riparian planting zone for this area extends along the south bank of Landfill Road Stream

from where Landfill Road Stream flows out of the culvert that carries it to the south side of

Landfill Road virtually to the junction of Landfill Road and Happy Valley Road. It also includes

the narrow bank on the northern side of the stream that site between the stream and the road.

The area consists of moderately steep banks that drop to the base stream level some of which

already has scattered planted native shrubs, some small delta areas within the channel, steep

gorse covered slopes along much of the southern side, interspersed with less steep areas with

mixed native and gorse cover, and one large gully fan at the base of the most eastern tributary

that has a solid mahoe canopy.

850 metres of stream length are available to restore, with 20 metres of margin along most of

the southern side and 5 to 6 metres of margin between the road and the stream on the northern

side (figure 4).


The restoration objective for Landfill Road Stream is similar to that for Owhiro Stream, that is,

to improve the quality of the aquatic habitat for native fish and macro-invertebrates, and to

enable these organisms to move freely to the remaining upper tributaries that flow into Landfill

Stream from the south. This will be achieved by:

Removing invasive weed species (apart from gorse) and replacing them with appropriate

native riparian margin plant species;

Planting up to a 20 metre width of native tree, shrub and sedge species on the south side of

the stream channel and 5 metres on the north side to create a good level of shade over the

channel and to provide a good supply of food material to the water body;

Plant native sedges along the small deltas that exist at the water’s edge along portions of

the stream to create zones suitable for fish spawning;

Carry out enhancement planting on the fan delta where the eastern-most tributary joins

Landfill Road Stream;

Undertaking a 5 year weed control and plant maintenance programme;

Improve the visual appeal of the stream margin.

19


Site preparation

Gorse is the predominant weed in this area. On some less steep sections individual gorse plants

or small groups of mature gorse plants sit in amongst native regeneration – there should be

removed and the gaps planted. Elsewhere, especially on the steeper faces gorse predominates –

here gaps should be cut in the gorse at 2 to 3 metre spacings for natives to be planted. All gorse

plants should not be removed because they play an essential role in maintaining bank stability.

Gorse stumps should be painted with contact herbicide as soon as they are cut.


As for Owhiro Stream, hardy, fast growing native shrub and small tree species should be

planted along the banks wherever spaces can be found for them, and where the stream banks

allow it Carex secta can be planted on or just above the water’s edge. Flax and toetoe are too

large to be used in this narrow stream channel as the will crowd the channel and induce

flooding.

The mahoe dominant canopy on tributary fan delta should not be disturbed more than is

necessary to insert more advanced successional species into the gaps. Any gorse or weed plants

should be removed and the gaps filled with natives and existing native plants may need to be

trimmed to make room for interplanting. The aim is to insert native species at, on average, 5

metre intervals to improve the species diversity of this zone.

Recommended species (all plants should be ecosourced):

a) Stream banks :

Carex secta (on the water’s edge at base flow levels)

b) Steeper and more exposed southern slopes:


Leptospermum scoparium (manuka) Aristotelia serrata (wineberry)

Olearia paniculata Hebe parviflora

c) Lower, more sheltered slopes and banks:


Leptospermum scoparium (manuka) Pittosporum eugenioides (lemonwood)

Aristotelia serrata (wineberry) Cordyline australis (cabbage tree)

Plagianthus regius (ribbonwood) Pittosporum tenuifolium (kohuhu)

Pseudopanax arboreus (five finger)

d) Eastern tributary fan delta:

Cordyline australis (cabbage tree) Plagianthus regius (ribbonwood)

Pittosporum tenuifolium (kohuhu) Pseudopanax arboreus (five finger)

Pittosporum eugenioides (lemonwood) Hedycarya arborea(pigeonwood)

Fuchsia excorticata (tree fuchsia) Sophora microphylla (kowhai)

The species listed above should form the majority of each plant mix however there is opportunity to

plant a range of additional species especially those that are now locally uncommon. PB2 and PB3

grade plants should be used for these plantings

20



Regenerating gorse and problem weeds should be prevented from becoming established in the

clearings created for each plant by twice yearly spray releasing for the first 3 years, and then

once yearly for the next 2.

Cost estimate

Plant costs will be similar to that stated for Owhiro Stream above.

It is estimated that between 4000 and 5000 plants will be required to restore this 850 m

section of stream.


80% canopy closure of planted areas by year 5 is an achievable performance target.

5.2.3 Haape Stream Tributary margins – maximum planting area 6.9 ha

Several tributary ephemeral streams flow into the lower, middle and upper sections of Haape

Stream and a number of these have grass dominant riparian margins in their middle and upper

reaches, with gorse dominant faces above the riparian zone. Rank grasses, remaining from the

sheep farming activities of the past, still occupy the damp seep and stream channel areas that

are not suitable for gorse. There is potential to introduce hardy native coloniser species to these

areas to increase the plant diversity.

Well in excess of the required 3450 metres of ephemeral stream channel suitable for restorative

planting exist in several gullies on the lower, middle and upper Haape Stream catchment

(figure 5). The aim is to plant natives into a 10 metre wide riparian margin on each side of the

channel and further widen the planting with additional terrestrial compensation planting (see

5.2.4 below).

Most of the gullies can be accessed by vehicle track from above which will assist with the

logistics of getting plants and planters to site.


The restoration objective for the Haape Stream tributary plantings is to improve the diversity of

the riparian zones in the gullies by planting hardy native coloniser and early successional

species into the areas dominated by grass and gorse, and mid successional species into the

areas of more established mahoe canopy. This will be achieved by:

Removing any scattered invasive weed species (other than gorse);

Planting hardy early successional shrubs, flaxes and sedges into open patches dominated by

rank grasses. Wet seeps should be avoided and left in rank grass.

Interplanting early successional native shrub species into existing gaps where gorse exists

within the riparian margin; the aim being to minimise the ground and gorse disturbance;

Interplanting mid-successional species into more mature native stands where natural gaps

in the canopy occur.

Undertaking a 5 year weed control and plant maintenance programme.

21


Figure 4: Landfill Road Stream showing

proposed riparian restoration areas (in

yellow)

Landfill Rd Stream

channel

22


Figure 5: Haape Stream and tributaries showing

riparian (yellow line) and terrestrial (blue

shaded) restoration areas

23


The planting of the grassy wet seepage areas within Haape Stream catchment is not

recommended because rank grass serves as an excellent filter to intercept surface runoff

containing sediment and reduce sheet erosion. Blanket planting of native shrubs will shade out

the grasses and potentially create a period of increased soil erosion risk until the native shrubs

establish a canopy and extensive root system. Patch planting introduces a greater diversity of

plants to the gullies and a future seed source for these species to spread gradually.

Mid-successional plant species can be planted into the stands of mahoe where natural gaps in

the mahoe canopy exist.

Site preparation

Site preparation will consist of herbicide spraying of grass areas to create the planting patches,

trimming of gorse to widen existing gaps, and cutting and stump painting gorse to create gaps if

insufficient gaps exist.


The aim is to plant patches of 10 to 20 native plants at 1.5 to 2 metre spacings with patches at

least 10 metres apart.

Recommended species:

a) Upper areas of the gully where the mahoe canopy is less well established and not as tall:

Hebe parviflora Leptospermum scoparium (manuka)

Olearia paniculata Phormium cookianum

Coprosma crassfolia Coprosma propinqua

b) Lower reaches where the mahoe is more established and the site more established:

Cordyline australis (cabbage tree) Plagianthus regius (ribbonwood)

Pittosporum tenuifolium (kohuhu) Pseudopanax arboreus (five finger)

Pittosporum eugenioides (lemonwood) Hedycarya arborea(pigeonwood)

Fuchsia excorticata (tree fuchsia) Sophora microphylla (kowhai)

In the more sheltered lower reaches there may be potential for successionally advanced species,

such as nikau and totara, and potentially locally threatened species such as Clematis afoliata

and Melicytus obovatus, to be incorporated into the planting mix. PB2 and PB3 grade plants

should be used for these plantings. All plants should be ecosourced.


Regenerating gorse and problem weeds should be prevented from becoming established in the

clearings created for each plant by twice yearly spray releasing for the first 3 years, and then

once yearly for the next 2.

Cost estimate

Individual plant costs will be similar to that stated for Owhiro Stream.

24


It is estimated that between 7000 and 9000 plants will be required to restore these tributary

stream channels.


80% canopy closure of planted areas where contiguous stands are planted is unlikely to be

achievable until year 10 because of the exposed and low fertility nature of much of this steep

catchment.

5.2.4 Terrestrial plantings – maximum planting area 4.5 ha

The 4.5 hectares of terrestrial planting that needs to be undertaken should occur in the Haape

Stream catchment to extend and complement the riparian plantings proposed in the sections

above.

The planting in these areas will be a mix of mid successional species where there is a reasonable

amount of well-established mahoe – mixed native cover, and early successional species where

grass predominates and/or where there is a scattered gorse cover. An appropriate mix of the

species listed in the sections above should be selected to match local site conditions. The

species to be used and the planting specifications will be the same as those stated above for

enhancement planting.

The number of plants required in these three areas is likely to amount to between 6000 and

8000.


Planting should be undertaken to achieve 80% canopy cover of natives within 10 years of

planting.

5.3 Other restoration requirements

5.3.1 Fish ladder or passage

The construction of a fish ladder at the Haape Stream weir is likely to cost in the order of $1000

and can be installed relatively quickly with little impact.

The alternative, and preferred, option of removing the weir and realigning the stream will require a

resource consent, an engineering plan, sediment management consideration, and several days of

excavator operation. No attempt has been made to cost this option but it would provide

considerable ecological benefit to the region’s native fishery if it was implemented.

5.3.2 Species translocations

Native fish

In addition to the ecological compensation responsibilities, there will be a need to capture,

translocate and release any native fish in the streams that are to be affected by the proposed landfill

expansion. A translocation plan will need to be produced in consultation with the Department of

Conservation, Wellington Regional Council and local iwi, and approvals for fish transfer will be

25


required from the Ministry of Primary Industries (MPI) pursuant to regulations 17, 18 or 22 of the

Freshwater Fish Farming Regulations 1983 and/or section 26ZM(2) of the Conservation Act 1987

for a fish transfer.

The fish translocation plan will need to include the following:

The stream(s), and the reaches within each stream, into which the captured fish are to be

released, plus approval from the landowners through which the streams run;

A detailed methodology for the capture, transport and release of all native fish species to be

transferred, including method of capture, timing of capture, method of transfer, and timing

and method of release.

Reptiles and frogs

Translocation will also be required for any indigenous reptiles or frogs (if any) that may occupy the

riparian and terrestrial habitats within the zone of the proposed landfill expansion. While no

lizards or frogs were recorded in surveys undertaken by Wildland Consultants, this does not rule

out the possibility that lizards are present. It is recommended that reptile surveys are undertaken

on land proposed for disturbance immediately prior to disturbance to determine the location of any

reptiles. Any detections should then be followed by trapping efforts to capture and remove these

animals.

A permit under the Wildlife Act is required to capture, transfer and release any native vertebrate

animal (including all frogs and reptiles), and a lizard management plan must be prepared as a

condition of the permit. The plan needs to be consistent with the new DOC lizard relocation permit

conditions, and should include:

The location(s) to which the lizards are to be moved to;

The proposed relocation and monitoring techniques to be used;

Evidence of consultation with local iwi.

A separate application for capture and release will be required if threatened or at-risk lizard or frog

species are located on the site. The exact details of a capture and release exercise for different

species, common or threatened, cannot be determined until more accurate knowledge of the

species involved and their abundance is known.

26


6 Conclusions and Recommendations

This report has been produced to recommend an ecological mitigation package as compensation

for the length of stream and riparian vegetation that will be lost with the proposed extension of C

and D Landfill area at the head of Landfill Road, Wellington. The report content is additional to the

Stream Ecological Valuation (SEV) Report produced by Opus in 2012 and its review in 2013 and

the Assessment of Ecological Effects produced by Wildland Consultants earlier in 2012.

The valley proposed for filling with the landfill extension is steep sided and clothed with a cover of

regenerating native trees and shrubs. The stream and tributaries at the base of the valley are

described in the Wildland report as having high ecological values, exhibited by the presence of

several native fish species and a healthy macroinvertebrate population.

The SEV undertaken and revised by Opus found that 1245 metres of stream length would be lost or

affected by the extension of the landfill. This is made up of 646m of permanent stream channel and

599m of ephemeral channel. The SEV Ecological Compensation Ratio for this stream loss is

3547m2 , which means that 3547m2 of stream channel must be restored as offset compensation.

In addition, 4.5 ha of significant terrestrial vegetation will be lost from the landfill area. Because

the completed landfill will be revegetated with native trees and shrubs at the conclusion of the

consent period it is recommended that the compensation for the significant terrestrial vegetation

lost should occur at a ratio of 1 to 1. That is, 4.5 ha of terrestrial vegetation will need to be restored

in addition to the stream/riparian areas.

Three restoration sites have been recommended for the riparian compensation with the emphasis

being to enhance the value of the waterways for native fish and macroinvertebrates. 650 lineal

metres of Owhiro Stream, 850 metres of Landfill Road Stream, and 3450 metres of the ephemeral

tributaries flowing into Haape Stream have been identified as the most appropriate sites for

stream/riparian restoration.

It is proposed that the 4.5 ha of terrestrial restoration is appended to the proposed riparian

plantings n the Haape Stream catchment. This will serve to create larger more diverse areas of

native plant regeneration which in turn should support greater aquatic diversity.

It is also proposed that the restoration package include the installation of a fish ladder at the Haape

Stream weir (or removal of the weir if approvals for this can be obtained) which will open up 80ha

of stream catchment to several fish species that have not had access for many decades. Because the

(re-)establishment of fish access to the Haape Stream catchment will be of significant ecological

benefit, the cost of construction of the fish ladder or removal of the weir should be deducted from

the total cost of the offset mitigation package set for C and D Landfill.

In conclusion, it is our recommendation that the ecological compensation restoration plan detailed

above be adopted and the restoration package include the following items:

1. C and D Landfill should appoint an experienced restoration manager to oversee the

restoration works.

2. Production, and peer review (by a suitably qualified ecologist), of detailed restoration plans

prior to each section of restoration work commencing.

27


3. Offset restoration work to be undertaken at a rate equivalent to the rate at which the new

landfill area is disturbed, with restoration planting commencing as close to the

commencement of land disturbance as is practicable (recognising that it can take three

years to collect ecosourced seed and grow plantable grade plant stock).

4. Restoration / mitigation progress to be reported to Wellington City Council and Greater

Wellington Regional Council on a regular basis.

5. Production of a fish translocation plan by a suitably experienced ecologist, and

procurement of approval from MPI to capture, transport and release fish;

6. Capture, transport and release into Haape Stream of all native fish found in the stream area

that is to be lost to the new landfill;

7. Production of a lizard management plan by an experienced ecologist and procurement of a

Wildlife Act permit for the capture, transport and release of native lizards;

8. Capture of all native lizards found in the area to be cleared of vegetation and transport and

release into an area with appropriate habitat (probably the Haape Stream catchment). Tthis

is likely to require preliminary surveys of the proposed landfill area and the release sites to

determine the size and nature of the reptile populations.

9. Installation of a fish ladder at the Haape Stream weir (or removal of the weir) provided the

cost of that work is deducted from the restoration obligations.

28


7 References

Neale, M.W., Storey, R.G., Rowe, D.K., Collier, K.J., Hatton, C., Joy, M.K., Parkyn, S.M., Maxted,

J.R., Moore, S., Phillips, N., Quinn, J.M. 2011. Stream Ecological Valuation (SEV): A User’s

Guide. Auckland Council Technical Report 2011/001.

Opus International Consultants Ltd. 2012. C and D Landfill Ltd.: SEV Stream Assessment.

Opus International Consultants Ltd. 2013. C and D Landfill Ltd.: SEV Stream Assessment -

revised.

Park, G. 1999. An inventory of the surviving traces of the primary forest of Wellington City.

Wellington City Council. Wellington.

Stark, J.D., Boothroyd, I.K.G., Harding, J.S., Maxted, J.R., Scarsbrook, M.R. 2001. Protocols for

sampling macroinvertebrates in wadeable streams. New Zealand Macroinvertebrate

Working Group Report No. 1. Prepared for the Ministry for the Environment. Sustainable

Management Fund Project No. 5103.

Storey, R.G., Neale, M.W., Rowe, D.K., Collier, K.J., Hatton, C., Joy, M.K., Maxted, J.R., Moore, S.,

Parkyn, S.M., Phillips, N. Quinn, J.M. 2011. Stream Ecological Valuation (SEV): a method

for assessing the ecological functions of Auckland streams. Auckland Council Technical

Report 2011/009.

Wildland Consultants Ltd, 2012. Assessment of Ecological Effects for a proposed expansion of C&D

Landfill, Happy Valley, Wellington. Contract Report No. 2438b. Wildland Consultants Ltd,

Porirua.

29


8 Appendix 1 – Landfill staging

Opus International Consultants Ltd Opus House, Princes Street Private Bag 3057, Waikato Mail Centre, Hamilton 3240 New Zealand t: +64 7 838 9344 f: +64 7 838 9324 w: www.opus.co.nz

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