Artillery Drive Stormwater Tunnel Runs into Issues

Geo-technical difficulties risk Budget over-run


One to keep an eye on for Papakura as this major storm-water project is very close to home and is urgently required with Papakura east and Papakura north extending through to east of Addison receiving a lot of new houses.

The storm water department of the Council are busy building a storm water pipeline (see agenda extract below) to take the increased amount of storm water triggered by new developments to Papakura’s east. This work was started thanks to the tireless work of former Councillor Calum Penrose in getting the necessary funds for the Artillery Drive storm water tunnel. However, it seems part of the project has run into geo-technical difficulties near the outlet which might trigger a project budget over run.


I noticed this from the Strategic Procurement Committee:

Strategic Procurement Committee

07 December 2016

Artillery Drive Stormwater Tunnel Project Variation

File No.: CP2016/23254


  1. To note an update on the Artillery Drive stormwater tunnel project.

Executive summary

  1. The construction of a stormwater tunnel at the Takanini Greenfield Special Housing Area has been identified as the best option to mitigate flood risks in the Artillery Drive area, and to enable further development under the Takanini Structure Plan.
  2. At its 15 December 2015 meeting, the Tenders and Procurement Committee awarded the construction contract for a stormwater tunnel at Artillery Drive to McConnell Dowell for $19,076,542.
  3. Construction has commenced, however, there have been delays due to unforeseen ground conditions. The length of the delay is not certain at this stage; however, mana whenua, the Papakura Local Board and surrounding communities will be notified as soon as this is confirmed.
  4. Additional funding is required for the project to be completed. It is recommended that the Strategic Procurement Committee approve the contract variation requested in the confidential section of this 7 December 2016 meeting.



That the Strategic Procurement Committee:

a)      note that the information contained in this report on the Artillery Drive stormwater tunnel project enables further transparency on the topic due for discussion in the public excluded section of the meeting.



  1. The Housing Accord and Special Housing Areas Act has been enacted to provide for the future growth of Auckland by facilitating specific areas of development within the Rural Urban Boundary. As an area identified for growth in previous planning documents, the Takanini Greenfield Area has been rezoned and announced as a Special Housing Area.
  2. However, the Central Papakura Integrated Catchment Management Plan identified a large floodplain which covers this land making it unsuitable for intensive development.
  3. Three separate stormwater projects have been developed to address stormwater concerns in this area: the Takanini Cascades (Takanini 2a/2b Conveyance Channel), Grove Road Box Culvert and the Artillery Drive stormwater tunnel projects.
  4. The Takanini Cascades project is currently being designed, and construction is expected to start on the Grove Road culvert in early 2017.

Project Description

  1. The Artillery Drive stormwater tunnel is approximately 1.1 kilometres in length and 2.5 metres in diameter. It will convey stormwater from the Upper McLennan Park Pond to the Pahurehure Inlet by Katavic Park.
  1. This tunnel will enable the diversion of the stormwater discharge from the future Takanini Structure Plan Area 2a and 2b away from the existing stormwater pipes through Old Wairoa Road and the central business areas, which are known to have very limited capacity. This will decrease the flooding extents upstream of the ponds and enable residential development in parts of the Takanini Greenfield Area.
  2. The tunnel sections are being constructed using a micro-tunnel boring machine, to minimise disruption to the community.
  3. The tunnel route is located on public land and a number of sites owned by Auckland Council, including McLennan Park, Old Wairoa Reserve, 78A Great South Road, and Katavic Park, Papakura.
  4. A map showing the tunnel alignment and shaft locations has been included as Attachment A.

Current progress

  1. The contractor has completed Shafts C and D, and is in the process of constructing Shaft E. The micro-tunnel boring machine has completed its journey from Shaft C to D and has laid 160 metres of pipe. The machine is now getting ready to tunnel from Shaft D to E (see Attachment A).
  2. Once the micro-tunnel boring machine reaches Shaft E, it will be moved back to Shaft C to start tunnelling towards Shaft B.
  3. The contractor has delayed the construction of Shafts A and B due to the unforeseen ground conditions. The micro-tunnel boring machine can only start tunnelling from Shaft C towards Shaft B once Shaft B is excavated to the required depth.
  4. Further details of the project delay are included in the confidential agenda report.


Local board views and implications

  1. While the Papakura Local Board was not consulted on the procurement process, the local board provided input into the design of the project through a workshop held in June 2014. Overall, the local board provided positive feedback on the project. The local board will be notified of the revised project timeframe, as soon as it has been confirmed by the contractor.

Māori impact statement

  1. Stormwater works which impact on water quality and the mauri of waterways are of significant interest to mana whenua in their role as kaitiaki of Auckland’s natural environments. In recognition of this, mana whenua have been consulted on the design and delivery of this project.
  2. This consultation included an initial engagement and invitation to a site walkover for the 13 iwi who have an interest in this rohe for all three major stormwater projects in the Takanini area. This engagement was carried out in February and March 2014. Representatives from Ngāti Tamaoho and Te Ākitai Waiohua participated in the walkover.
  3. In July 2014, feedback from iwi was sought specifically on the Artillery Drive stormwater tunnel project. A workshop and site visits were held which representatives from Ngāti Tamaoho, Te Ākitai Waiohua and Ngāi Tai ki Tāmaki attended. Apologies were received from Ngāti Maru.
  4. Staff have integrated the feedback into the design of the project. Ngati Tamaoho, Te Akitai Waiohua and Ngai Tai ki Tamaki all confirmed that no Cultural Impact Assessment was required.
  5. Mana whenua will be advised of the project delay, as soon as the revised timeframe is confirmed.


  1. There are no implementation issues arising from this report. Any implementation issues relating to the contract variation have been noted in report titled “Confidential: Artillery Drive Stormwater Tunnel Project Variation”.



No. Title Page
A Artillery Drive tunnel and shaft alignment map 23





Nothing to be alarmed about but one to watch. Hopefully Councillor Newman will be keeping the Papakura Local Board and the Papakura community informed where he can without breaking confidentiality.


Part of McLennan Park. The background of the photo is where the wetland is planned to take the water from the proposed channel further east
Part of McLennan Park. The background of the photo is where the wetland is planned to take the water from the proposed channel further east