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Piha Lagoon Pollution – Addressing the problem

Opening the Piha Stream/Lagoon to the sea.

The case for Requiring or NOT Requiring Resource Consent

 Background

  1. The Piha Lagoon at the seaward end of the Piha Stream has been recognised for many years as being potential health hazard due to pollution.
  2. Auckland Council and the legacy Waitakere City Council have commissioned a number of reports addressing the pollution issue as far back as the late 1980’s.
  3. The last report commissioned by Auckland Council from Tonkin & Taylor Consultants(1) in February 2015, states in section 7, Summary and Recommendations, “A combination of focussing on reducing point source pollution and periodic excavation provide the most comprehensive approach to reducing contaminant levels within Piha Lagoon.”
  4. The report severely over estimates the quantities of sand that would need to be moved and also the frequency. The Tonkin & Taylor estimates quite correctly look at the worst-case scenario.  The report estimates are repeated in a subsequent Auckland Council Internal Memo(2) and thereby negate the conclusion reached in section 6, Consenting requirements, “Once detailed proposals have been developed, it will be necessary to review and reconfirm consent requirements.”  However, the Piha R&R Assn. approach takes advantage of the natural sand movement to minimise the volume of sand that must be moved and the frequency required to effect the desired outcome.

 The Solution

  1. Reducing the point source pollution: The two Councils, Auckland and Waitakere City, have undertaken works to combine the waste water effluent from the Piha Campground, Piha Bowling Club, Piha Community Library, Piha RSA, Piha Surf Lifesaving Club and two public toilet facilities into a large treatment system that discharges the treated waste water into an area known as “Trees for Babies” on the western bank of the Piha Lagoon.

Auckland Council also initiated inspections of private waste water systems immediately adjoining the Piha Stream and are addressing more than 30 systems found to be below standard.

Revised AUP(Auckland Unitary Plan) requirements for on-site waste water systems inspection have also been put in place by Council and implementation has been commenced.

  1. Periodic excavation: This is the key component and it is essential to keeping the lagoon breathing by providing a natural, healthy, estuarian habitat with regular intake of seawater and exhausting of stagnant water.

Repeated requests of Auckland Council to undertake this work have been met by refusals based on the inflated estimates for sand movement contained in the Tonkin and Taylor report(1)                  also refer AC Memo(2). ( Also refer Background, item d) above.)

 Actions Taken

  1. In April/May 2020 the pollution and potential flood level of the Piha Lagoon reached a point where local residents were alarmed and posting in social media for action. Based on the Auckland Council Regional Plan: Coastal(3), Section 16, Disturbance of Foreshore and Seabed, Other than Dredging; Permitted Activities, 11.5.1c Piha R&R undertook to clear a channel through the accumulated sand at the Piha Stream mouth to the ocean.
  2. On 17 May, 2020 Piha R&R notified Auckland Council that based on the above, they were going to undertake a clearing of the Piha Stream mouth.
  3. The work was undertaken by a local contractor with a 0.5 m3 bucket excavator and moved approximately 100 m3 of sand to the north of the stream.
  4. The sand disturbance was remedied by the natural action of waves and tide within two or three tide cycles.
  5. The water level in the lagoon was significantly reduced and the visually obvious pollution dissipated within two days.
  6. Subsequent testing(3&4) showed that the ecoli levels had reduces significantly below the levels recommended by Auckland Council for safe swimming and the water clarity noticeably improved.

 

Current Situation

  1. Piha R&R Assn. received advice from Auckland Council that the Auckland Council Regional Plan: Coastal had been superseded by the AUP.
  2. Review of the AUP (Revised 2016) shows that the rules and intent of the Auckland Council Regional Plan: Coastal are embodied and that they are maintained in the current AUP, Chapter F2 Costal – General Coastal Marine Zone. 5 Disturbance of the foreshore and seabed.(6)
  3. Auckland Council have defined the work undertaken as “River Mouth Dredging” and determined that under that definition a Resource Consent is required for the work.(7)
  4. It seems clear from reading of the Auckland Council Regional Plan: Coastal, and the AUP that the intent is that Dredging refers to major works where significant quantities of material are dredged and removed to another site.
  5. The AUP(revised 2016), Section 4 is the only place found where Dredging is defined(8). The definition no longer appears in the AUP, but removal of the definition does not change it’s meaning or applicability.
  6. The definition refers to “removing the Excavating material from the bed of the CMA and removing the excavated material from the site.”(8)  Piha R&R did not disturb the “bed” of the Coastal Marine Area or remove excavated material from the site.
  7. AUP Chapter F2 Costal – General Coastal Marine Zone. 5.3 Policies, provides for the type of works undertaken.  F2.5.3 (2)(d) Refers to allowing this type of work for Health and Safety reasons.(6)
  8. AUP F.2.19.4 Activity Table (A32) clearly shows this type of work as a Permitted Activity in all activity status areas.(9)

 

Future Options for Resolving Piha Stream and Lagoon Pollution

  • No Resource Consent: Auckland Council could review it’s counterproductive and restrictive decision to define the work as “Dredging.”  This would allow for the opening of the stream mouth to allow the flushing of the lagoon by seawater two to four times per year, over the summer months, when or if the flushing is not occurring naturally.

To minimise disturbance to the foreshore, the works must be undertaken in conjunction with appropriate local tidal and weather conditions.  Therefore, utilisation of a local contractor who              can act at short notice is critical to the success of this work.

The work can be completed with minimum disturbance to the foreshore at a cost of less than $1,500 per occurrence.  Maximum annual cost is expected to be less than $5,000.

  • Apply for Resource Consent: Auckland Council can insist on requiring a Resource Consent for the works. As this is Council property, they should be making the application if required.

However, Auckland Council have signalled that they require Piha R&R Assn. to make application for the Resource Consent.

The application fee has been proposed as $7,000 and we have received indications of cost for preparing an application of between $15,000 and $25,000.  There would still be the cost for                     actually undertaking the work.

The Waitakere Ranges Local Board is the technically the land owner and therefore should be making the consent application, but would also normally have a role in approving the                                application.

 

Ken Cowan

President

Piha Ratepayers and Residents Assn. Inc.

January 19, 2021

 

References (Attached):

  • Tonkin and Taylor; Piha Lagoon Flushing and Enhancement Options, February 2015
  • Auckland Council Internal Memo, 20 March, 2015.
  • Auckland Council Regional Plan: Coastal
  • Piha Stream Channel Report(Carrie) 2020-07-02
  • Piha Stream Channel Report(Carrie) 2020-09-03
  • AUP. Marine Coastal Permitted 2020-10-17
  • Piha Stream Compliance Reply(2) 2020-06-30
  • AUP 2016 Definition 2020-10-17
  • AUP Table F2.19.4 Activity 2020-10-12