INFRASTRUCTURE AND SERVICING REPORT

HOBSONVILLE POINT LAUNCH BAY - SUPERLOTS

PROJECT NO: 1204

DATE: SEPTEMBER 2017

DOCUMENT CONTROL RECORD

Client Marlborough Precinct Holdings Limited

Project Hobsonville Point – Launch Bay

Document Infrastructure and Servicing Report for Apartment Super lots

ISSUE

Date of Issue 18 September 2017

Revision A

Originator John Sia

Checked John Gardiner

Approved John Gardiner

Telephone (09) 579 5505

Facsimile (09) 579 5506

Email john.sia@candor3.co.nz

TABLE OF CONTENTS

DOCUMENT CONTROL RECORD ............................................................................................ 2

ISSUE ......................................................................................................................................... 2

TABLE OF CONTENTS ............................................................................................................. 3

1 INTRODUCTION ............................................................................................................... 4

2 EXECUTIVE SUMMARY ................................................................................................... 4

3 EXISTING SITE DESCRIPTION ........................................................................................ 4

4 EARTHWORKS ................................................................................................................ 5

5 SEDIMENT AND EROSION CONTROL ............................................................................ 5

6 ROADING ......................................................................................................................... 6

7 STORMWATER ................................................................................................................ 6

Stormwater reticulation network ........................................................................... 6

8 WASTEWATER ................................................................................................................ 7

9 POTABLE WATER SUPPLY ............................................................................................ 7

10 UTILITY SERVICES .......................................................................................................... 7

11 CONCLUSION .................................................................................................................. 7

APPENDIX A – DESIGN DRAWINGS & CALCULATIONS ....................................................... 8

Appendix A: Design Drawings & Calculations

1 INTRODUCTION This report has been prepared in support of the consent application for the development of six super lots and the creation of the associated apartments within Launch Bay, Hobsonville Point site (Lot 10 DP 4977622).

This is a subsequent application to the underlying approved Resource Consent (BUN60303085, LUC60303086, and SUB60067563) that approved the creation of 23 residential lots, six of which were designated as apartment super lots.

2 EXECUTIVE SUMMARY This report along with the appended plans and calculations have been prepared by Candor3 to support the consent application for the creation of six apartment super lots within the Launch Bay development (Lot 10 DP 4977622).

Based on work carried out to date there are no technical impediments to providing any of the necessary services to allow development of the apartments that is the subject of this report.

3 EXISTING SITE DESCRIPTION The proposed development is located in Launch Bay, at the eastern end of Hobsonville Point incorporating Hudson Bay Road and Marlborough Crescent. The full development site covers approximately 4.3Ha and is shown by the red outlines in Figure 1. Within the site there are six apartment super lots proposed (see drawing 01-100 H for details).

Hobsonville Point has been significantly redeveloped over recent years by the Hobsonville Land Company, with this precinct (Launch Bay) being part of the next phase of Hobsonville redevelopment. Resource Consents BUN60303085, LUC60303086, SUB60067563 and Engineering Approval ENG60302639 underlie the Launch Bay development.

All civil works and infrastructure within Launch Bay that support the subsequent apartment development is proposed to be constructed and installed by mid-2018. The infrastructure will be utilised to service the full development including the six apartment super lots.

To the East is The Landing, a reclaimed area including the passenger ferry terminal, car parking and local farmers market. The ferry provides regular links to Auckland CBD. The Upper Harbour Highway runs to the North, providing links to Albany and the North Shore, with access from Squadron Drive (within Hobsonville Point). Commercial and retail development is continuing within the local area as well as school and reserve facilities.

Figure 1 - Location of the Launch Bay development in Hobsonville Point.

The existing site typically flows from South to North, at varying but generally gentle grades.

The Landing is located to the East of Launch Bay, on reclaimed land at a lower level, some 5 metres below the development site.

Within the Launch Bay development, several existing buildings have been retained that will be renovated for future use. These existing buildings include the four officers houses (Lots 18 to 21) located along the north-east boundary of the site and the Catalina Hangar (Lot 1) building located at the south-west corner of the site. The existing Catalina Barracks on proposed lots 15 and 23 will be demolished in October 2017.

4 EARTHWORKS The apartments proposed for lots 2, 3 ,4, 15 and 17 will require excavation for underground basements. Subgrade excavation level has been assumed to be at 600mm below finished floor level of either the basement or ground level of the building where relevant.

The proposed Catalina Hangar Apartment (Lot 1) features an existing building that will be repurposed. As such, there will be negligible earthworks required as a basement is not being constructed. Access into the ground level of the apartment during construction will be from existing Launch Road.

The Launch Road West Apartment (Lot 2) involves the formation of a basement in close proximity to the existing boundaries. As such, it is assumed that in-situ bored reinforced concrete or driven piles will be installed along the perimeter of the basement walls at close centres prior to excavation in order to stabilise the adjacent land from displacement. A stabilised access ramp for excavators and trucks will then be formed from the existing road into the proposed basement at the approximate future basement ramp entry location. Loading of excavation spoil into the trucks will occur within the super lot boundary as the basement is cut down to 600mm below finished floor level.

The Launch Road East Apartment (Lot 3) involves the formation of a basement in close proximity to the existing boundaries. As such, it is assumed that in-situ bored reinforced concrete or driven piles will be installed along the perimeter of the basement walls at close centres prior to excavation in order to stabilise the adjacent land from displacement. A stabilised access ramp for excavators and trucks will then be formed from the existing road into the proposed basement at the approximate future basement ramp entry location. Loading of excavation spoil into the trucks will occur within the super lot boundary as the basement is cut down to 600mm below finished floor level.

The excavation for the basements of Lot 15 and 17 will be relatively straightforward with the excavations starting from the super lot - Marlborough Crescent boundary and daylighting towards the rear of the apartments. Similarly, for lot 4, the excavation for the basement starts at the super lot – Hudson Bay Rd boundary and daylights towards the eastern boundary of the apartment.

In total, the design of the six super lots requires approximately 40,900 m³ of cut to waste in order to form the foundations and basements for the apartments.

It is envisaged that the only material to be removed from site will be ‘clay’ as part of the basement and foundation excavations and topsoil that is stripped will be respread across the super lot soft landscaped areas.

5 SEDIMENT AND EROSION CONTROL A sediment and erosion control plan has been designed in accordance with the objectives in Auckland Council GD05. Indicative Sediment and Erosion Control plans are attached, refer to Drawings SK-001 to SK-003.

Due to the nature of basement construction and the proximity of the proposed basement walls to the super lot boundaries for super lots 2 & 3 the use of floating sump pumps will likely be required to drain ground water and stormwater runoff that forms within the basement during excavation. It is proposed that temporary decanting earth bunds (DEB) / sumps be formed within the basement excavation located close to cesspits

CP5/1 and CP9/1, floating pumps can then drain the clear water off the top of the DEB/Sump into the road cesspits or stormwater manholes.

The excavations for the basements of Lots 4, 15, and 17 daylight and therefore can utilise standard DEB devices before discharging the treated run-off across the adjacent stabilised surfaces.

Five decanting earth bunds, 320m of super silt fences and sediment laden flow cut off drains will be used to control sediment and erosion during earthworks. In addition, 85m of clean water diversion channel will be used to divert run-off away from basement excavation within lot 4 and 17.

All decanting earth bunds will be PAC batch dosed and will discharge to existing heavily vegetated areas above the coastal environment. However, as the majority of the Launch Bay site will have been stabilised (roads, footpaths, grassed lots), the levels of the silt generated from the basement and foundation excavation works are expected to be minimal.

The basements will be progressively stabilized on completion of earthworks to minimise time exposed and therefore minimise sediment loss.

6 ROADING As part of the Launch Bay subdivision development two new public roads will have been vested with Auckland Council (Road 1 – Hudson Bay Road & Road 2 – Marlborough Crescent). Refer to SUB60067563.

Launch Road will have been vested to Council by the Hobsonville Land Company, under a separate application.

The Launch Bay subdivision road layout and cross sections are shown within Drawings 03-200 to 03-227. The drawings also indicate where the proposed basement apartment entries will be located.

We propose the following vehicle access arrangements. These are shown as proposed vehicle crossings on the plans.

- Lot 1 from Launch Road (Existing)

- Lots 2, 3, 4, & 15 from Hudson Bay Road (Road 1)

- Lot 17 from Marlborough Crescent (Road 2)

Vehicle access to the following is shown on the drawings and is to be constructed by the owner or builder of the property.

- Lot 1 from Launch Road (Existing)

- Lots 2 – 4 from Hudson Bay Road (Road 1)

- Lots 15 – 18 from Marlborough Crescent (Road 2)

Appropriate traffic management measures will be implemented as required and will be in accordance with the Auckland Transport COPTTM.

7 STORMWATER

Stormwater reticulation network

The stormwater reticulation to be constructed under (SUB60067563) combine into a single outfall, which discharges into the tidal environment to the north east of the site.

The pipes have been designed to convey the 10 year ARI storm flow including climate change, in accordance with Auckland Council Code of Practice for Land Development and Subdivision (Chapter 4 – Stormwater), which will provide each of the super lots with a connection. The pipes are located in the proposed road reserve, local purpose reserves and within private property boundaries ranging from 1.46 m to 6.02 m deep. Drawings 04-100 to 04-103 show the pipe network layout and drawings 04-200 to 04-203 show the pipe long sections.

The reticulated network has been generally designed to accommodate for the stormwater run-off of the subdivision based on an 80% impervious area of the majority of the lots, and allowance has been made for 100% impervious are for apartment super lots 1, 2, 3 and 15. There are no capacity or infrastructure restraints preventing the apartments from being constructed.

The pipe flow capacities have been calculated using the Colebrook-White equation with a roughness coefficient of 1.5 mm. (See Appendix B for pipe flow calculations).

At the time of this infrastructure report being written the exact outfall structure had not been approved. However, discussions with Healthy Waters and Auckland Council as at 30.08.2017 indicated that an outfall design utilising a pipe drilled from manhole 1/2 to the base of the embankment discharging to a bubble up manhole (1/1 Outfall) would be the likely approved design.

8 WASTEWATER The wastewater reticulation network has been designed in accordance with the Watercare Water and Wastewater Code of Practice for Land Development and Subdivision (Version 1.5, May 2015) and approved under SUB60067563. Details of the proposed network are shown on Drawings 05-100 to 05-103. It is made up of 150 mm diameter PVC pipes at a minimum grade of 0.72 % with grades increasing at the end of lines to ensure a self-cleansing velocity is achieved. The wastewater reticulation ultimately will discharge into the existing wastewater line connecting to the existing pump station adjacent to the ferry terminal.

The Launch Bay reticulated wastewater network has been designed to cater for the projected 328 Housing Unit Equivalent (HUE) demand. There are no capacity or infrastructure restraints preventing the apartments from being constructed. A copy of the wastewater calculations are appended to the wastewater drawings.

9 POTABLE WATER SUPPLY The water supply network has been designed in accordance with the Watercare Water and Wastewater Code of Practice for Land Development and Subdivision (Version 1.5, May 2015.) and approved under SUB60067563. The proposed water supply network is shown on Drawings 06-100 to 06-103. It is made up of 150 and 100 mm diameter pipes set generally at 1.1 m outside the proposed boundaries.

Lots 1, 2, & 3 have the option to connect into either the 150mmØ watermain located along the northern or

southern boundaries of the super lots.

Lot 4 is able to connect to the 150mmØ watermain located along the south-western corner of the super lot.

Lot 15 is able to connect to the 150mmØ watermain located along the eastern boundary of the super lot.

Lot 17 is able to connect to the 150mmØ watermain located along the southern boundary of the super lot.

10 UTILITY SERVICES Power and telecom services will be provided for the development by Vector and Chorus respectively.

Vector and Electrix have been involved in the design of the Launch Bay subdivision development and have designed a transformer which will be sited within the south-western corner of Lot 105 and another transformer located in the Jimmy’s Pt walkway (located adjacent to the south-eastern corner of Lot 16). This will provide sufficient power for the 328 HUE based on 3kVA per HUE.

There are no capacity or infrastructure restraints preventing the apartments from being constructed.

11 CONCLUSION The engineering works for the Launch Bay development have been designed in accordance with the appropriate engineering standards stated under the Auckland Unitary Plan. This report along with the appended drawings and calculations supports the application for the development of the six apartment super lots.

APPENDIX A – DESIGN DRAWINGS & CALCULATIONS