I hereby give notice that an ordinary meeting of the Franklin Local Board will be held on:




Meeting Room:



Tuesday, 26 February 2019


Local Board Chambers
Pukekohe Service Centre
82 Manukau Road


Franklin Local Board










Angela Fulljames


Deputy Chairperson

Andrew Baker



Malcolm Bell



Alan Cole



Brendon Crompton



Sharlene Druyven



Amanda Hopkins



Murray Kay



Niko Kloeten



(Quorum 5 members)




Denise  Gunn

Democracy Advisor - Franklin


25 February 2019


Contact Telephone: (09) 237 1310

Email: denise.gunn@aucklandcouncil.govt.nz

Website: www.aucklandcouncil.govt.nz




Franklin Local Board

26 February 2019



ITEM   TABLE OF CONTENTS                                                                                        PAGE


24        Sunkist Bay Seawall - Remedial Work Options                                                         5 



Franklin Local Board

26 February 2019



Sunkist Bay Seawall - Remedial Work Options

File No.: CP2019/00859




Te take mō te pūrongo

Purpose of the report

1.       To seek approval from the Franklin Local Board for the recommended replacement solution for the eastern seawall at Sunkist Bay, Beachlands.

Whakarāpopototanga matua

Executive summary

2.       In the January 2018 storms, wave action caused erosion of part of the reserve above the seawall at the eastern end of Sunkist Bay.

3.       In response to storm damage seawall, staff prioritised the seawall for renewal and commenced investigation on how best to address the issue. Investigation was funded from the January 2018 regional storm damage budget.

4.       Staff retained Tonkin and Taylor to assess the site and recommended best option for minimising future erosion, protecting existing assets and maintaining safe use of the beach for the community. Staff also requested that a grouted rock seawall was considered as part of this assessment at the request of the Franklin Local Board.

5.       Tonkin and Taylor report (attachment A) clearly recommends that the existing seawall (a tipped rock seawall) is inadequate in terms of coastal protection and outlines the effects of two replacement options.

6.       This report recommends that the existing tipped rock be replaced with a new rock armour revetment seawall and seeks approval from the board to proceed with this option as a renewal project.


Ngā tūtohunga


That the Franklin Local Board:

a)      note the addition of Sunkist Bay tipped rock seawall renewal to the 2018/2019 Community Facilities renewal programme.

b)      endorse the remediation solution, which is to replace the existing tipped rock seawall with an armoured rock revetment seawall.




7.         Beachlands is a fast-growing suburb of Auckland, and the beach at Sunkist Bay, including the boat ramp, boat club, coastal walkway and park at the eastern end is well used by locals and visitors to the area.

8.         The Franklin Local Board developed a Sunkist Bay Concept Plan (Attachment B) in 2017/2018 to inform future development of the reserve including renewals. Within this concept plan, improvements to the seawall in terms of beach access and visual amenity were highlighted, and retention of the carpark endorsed.

9.         The western end of Sunkist Bay is protected by a grouted rock seawall constructed in 1997 by Manukau City Council along the toe of the cliff that is the natural alignment of the coastline.

10.       At the eastern end of Sunkist Bay is reclaimed reserve and approximately 200 metres of tipped rock was constructed by Manukau City Council in 1972 to protect the reclamation.  The reclaimed low-lying area has been developed to contain a carpark, ramp and reserve area.

11.       Sunkist Bay is exposed to major storm-generated northerly and north easterly storm surges, and wind generated waves that form in the Tamaki Strait. Waves that reached higher than the seawall (wave overtopping) in the January 2018 storms resulted in scour and erosion of the unprotected ground above the low crest of the existing tipped rock structure.  The storm damage triggered the need for the coastal protection to be renewed.

12.       Tonkin and Taylor Limited were engaged to assess coastal erosion damage to the structure and adjacent reserve, and to provide detailed design information to effect replacement of the tipped rock protection.  This investigation was funded from the January 2018 Storm Damage budget. 

13.       The investigation report also provides information on the relative benefits and disadvantages of rock armour revetment, and at the request of the Franklin Local Board (on behalf of the local community) also considers a grouted rock seawall alternative.

Tātaritanga me ngā tohutohu

Analysis and advice

14.     Repair to the existing tipped rock seawall is not a viable option due to the absence of any geotextile and under layer material, the low crest and over-steepened profile of the existing slope, and poor connectivity for access to the foreshore via existing steps. The placement of additional rock material over the existing tipped rock would not prevent migration of fines through the existing rocks and ongoing settlement and undermining of the structure would still occur, and it is recommended that the existing tipped rock be completely rebuilt.         

15.     Two replacement options have been considered for the renewal of the existing tipped rock seawall that armours the coastal edge of the reclaimed reserve at the eastern end of Sunkist Bay.  Comparison of the rock armour revetment option with the grouted rock seawall option is provided in the summary table below.


Armoured Rock Revetment

Grouted Rock Seawall




Beach character and visual

Similar to existing rock character, with improved visual appearance as engineered armour rock revetment is constructed from interlocking rocks at a uniform slope.

Change in visual character at eastern end of beach, but similar to existing western seawall. Likely to require hand rail/balustrade due to height above beach which may impede views from the reserve.




Beach levels

The slope, permeability and surface roughness of stacked interlocking rock dissipates wave energy and reduces wave reflection.  Scouring of beach (loss of sand) is less likely.

Solid seawalls have higher incidence of wave energy reflection.  Grouted rock seawall would create more turbulence, particularly from wave reflection in the eastern corner Scouring of beach (loss of sand) likely.



Beach access (from road to sand)

Similar for either option – steps can be incorporated into both types of structure




Beach access (alongshore)

Similar footprint to existing structure, no extension over foreshore and no change in beach width.

Potential increase in beach width if alignment of new seawall is pulled landward and rock removed from foreshore.




Effects on beach sand (and founding depth)

More dissipative structures have less wave reflection, which means less potential for beach lowering along toe of structure. Shallower founding possible.

Deeper founding is required to account for wave reflection and potential scour effects that can lower beach sand levels along the toe of the structure.




Planning implications

Repair of existing lawful reclamation either a Permitted Activity i.e. can proceed without a resource consenting process or Restricted Discretionary activity.

New hard protection structure discretionary activity. New Resource consent required, delaying remediation and adding cost to project delivery.




Adaptive management potential

Easier to reuse materials for future variations of protection.

Expensive to adapt for future sea level rise.




Wave overtopping

More dissipative structure due to slope, permeability and surface roughness so more wave energy is absorbed and there is less wave overtopping.

Less dissipative structure due to solid face and generally steeper slope that reflects more wave energy and has generally higher wave overtopping rates.




Design life

Similar, 50 years








Indicative Cost (Physical Works Only)

$3,000 per lin. m

$8,000 per lin. m


16.       Replacement with a rock armour revetment option is recommended to remediate the storm damage and scour above the existing tipped rock.  The proposed rock armour revetment option will;

i.    dissipate more wave energy, be less reflective and have lower wave overtopping rates than the alternative grouted rock wall option. Minimising the risk of beach/sand loss.

ii.    be more readily adapted for future sea level rise.

iii.   enable improved public access with steps through the rock armour revetment to provide safe connection to the foreshore from the reserve. 

iv.  accommodate improved public access and amenity landward of the revetment crest should the local board chose to invest in this enhancement in the future.

v.   be able to progress as repair to the existing lawful reclamation meaning that remediation can commence with minimal delay and risk to further erosion and public safety is minimised.

Ngā whakaaweawe me ngā tirohanga a te rōpū Kaunihera

Council group impacts and views

17.       This recommendation has been informed with input from the following council departments: Engineering Technical Services; Community Services; Community Facilities, and Regulatory Services.

Ngā whakaaweawe ā-rohe me ngā tirohanga a te poari ā-rohe

Local impacts and local board views

18.       The remediation of the tipped rock seawall at Sunkist Bay is of high interest to the local community.  Community feedback on the Sunkist Bay concept plan (Attachment B) highlighted the importance of safe public access to the foreshore and along the reserve, and a community desire to enhance connectivity with beach area.  The visual character of Sunkist Bay is also recognised as an important aspect of the amenity of the area.

19.       The strength of community feeling is further demonstrated through a petition received by Council on 12 December 2018 (Resolution number FR/2017/213) that requested funding allocated to be “firstly invested in the building of a permanent seawall along the eroding boulder edge foreshore in Sunkist Bay.”  (Refer to Attachment C)

20.       The Tonkin and Taylor options report was workshopped with the Franklin Local Board on 4 September 2018. Some members of the board reiterated the community interest in an alternative grouted seawall option. The board also expressed interest in opportunities to enhance recreational and visual amenity values as part of the project.

Tauākī whakaaweawe Māori

Māori impact statement

21.       The coastal environment of Sunkist Bay is of interest to a number of mana whenua groups.  The appropriate mana whenua groups will be consulted in relation to the proposed remediation option should the board approve the addition of the project to the Franklin Local Board work programme.

Ngā ritenga ā-pūtea

Financial implications

22.       The indicative cost estimate for the rock armour revetment is $970,000, which includes  professional services, physical works for coastal erosion protection, internal charges and contingency.

23.       The cost estimate includes consenting; however does not include any unforeseen consent conditions that may have to be met before being granted.  Should this risk materialise, a funding variation will need to be sought from within the renewal programme budget.

24.       The estimate does not include additional features to enhance public access along the reserve, landscape design features or delineation of parking and vehicle access on the adjacent reserve.  Should the board wish to broaden the scope of the project to engage specialist landscape designers to provide options for enhanced public access and visual amenity in Sunkist Bay reserve, additional funding would be required.

25.       The allocation for this project from within renewals programme is as below:


2018/2019 – Coastal Renewals




2019/2020 – Coastal Renewals


$870,000 (provision will be allocated to the board in the 2019/2020 Annual Plan to fund the balance).


26.       Additional Discretionary Works – Walkway improvements and/or landscape design features is out of scope for this project. These may be funded using LDI Capex or alternative sources of funding.

Ngā raru tūpono me ngā whakamaurutanga

Risks and mitigations

27.       Temporary safety fencing has been erected above the scoured reserve edge to mitigate potential risks to pedestrians from existing damage and to avoid vehicles parking close to the top of the bank and worsening damage from existing erosion; however this temporary solution does not eliminate risk.

28.       If no works are undertaken there is a risk that, in the event of any future storm events, there may be additional wave overtopping induced scour of reserve and damage to the carpark area at Sunkist Bay.

29.       If the Franklin Local Board does not approve the recommended option and instructs staff to proceed with a grouted seawall option the following risks have been identified:

i.          Increased wave overtopping rates experienced for the grouted rock seawall because it     is more reflective and less dissipative than rock armour revetment.

ii.          Increased time and cost associated with consent application for grouted rock seawall,       and risk that consent application may be declined.

iii.         Unforeseen consent conditions could impact on scope and budget, and may trigger          future budget variation.

iv.        The rock armour revetment structure is more adaptable to future management options     to address wave overtopping and sea level rise than a grouted rock seawall that would           be more expensive to adapt in the future.

Ngā koringa ā-muri

Next steps

29.     Following a decision by the Franklin Local Board on the staff recommendation to replace the tipped rock seawall with a armoured rock revetment seawall, the next steps will be:

1.    Tonkin + Taylor Ltd to commence stakeholder consultation, and proceed with detailed design and tender documents. 

2.    Tender release on a competitive basis

3.    Tender negotiation and award

4.    Physical works

5.    Practical completion and handover.

30.     The Franklin Local Board may wish to extend the project to include development of additional landscaping features above the rock armour revetment to enhance public access along the reserve, any parks amenity structures or delineation of parking and vehicle access on the adjacent reserve.  In this instance, the board would need to request a report seeking additional funding to engage specialist landscape designers to provide options for enhanced public access and visual amenity in Sunkist Bay reserve.


Ngā tāpirihanga






Remedial Works, Sunkist Bay - Tonkin + Taylor Ltd Report dated August 2018



Sunkist Bay Concept Plan December 2017



Sunkist Bay Petition



Ngā kaihaina



Rodrigo Pizarro - Senior Property Manager


Rod Sheridan - General Manager Community Facilities

Nina Siers - Relationship Manager


Franklin Local Board

26 February 2019













































Franklin Local Board

26 February 2019



Franklin Local Board

26 February 2019



Franklin Local Board

26 February 2019




Franklin Local Board

26 February 2019



Franklin Local Board

26 February 2019



Franklin Local Board

26 February 2019



Franklin Local Board

26 February 2019




Franklin Local Board

26 February 2019



Franklin Local Board

26 February 2019



Franklin Local Board

26 February 2019



Franklin Local Board

26 February 2019