MCWWS Extension Project Open Day 04 April 2015


  • The Mangawhai Community Wastewater Scheme (MCWWS) Extension Project held an Open Day on 04 April 2015. The Advisory Panel has now presented their recommendations report to Council, the Panel's report is available click here
  • A Community Advisory Panel has been engaged by Kaipara District Council to make recommendations on the extension of the MCWWS. Community Advisory Panel members are as follows:
D’Arcy Quinn (Chair of Panel)   
Belinda Vernon 
Dr Gordon Hosking
Darryl Reardon
Dr Ian Greenwood
Peter Wethey
  • The storyboards displayed today are intended to be informative and to present options for your consideration.   
Mangawhai Community Wastewater Scheme Community Advisory Panel's Recommendations Report.
The panel presented their recommendations report to Council on 28 July 2015. The panel's report is available click here
 Information can also be found on the Kaipara District Council website:


Purpose of the Advisory Panel

To provide a vehicle through which Council can receive a considered preferred option from community input and advice on a range of technical, policy and funding issues related to the future development of the MCWWS, especially in regard to the reticulation network and disposal capacity.  (Terms of Reference)

About the Advisory Panel


D'Arcy Quinn (Chair)

D'Arcy D’Arcy Quinn and wife Heather are now into their sixth year as Mangawhai residents having moved from Eastbourne, Wellington.  D’Arcy has held several Chief Executive and senior management positions both in New Zealand and internationally.  He is currently a Chartered Member of the Institute of Directors, holding several directorships on private companies.
Belinda Vernon  
Belinda-Vernon Belinda Vernon has been a ratepayer in Mangawhai since 1990.  A past member of the MRRA she served on the Committee in the 1990s and in 2010 and 2011.  She is a consultant in accounting and shipping, director of GNS Science, member of Maritime New Zealand, Chair of the Auckland Philharmonia Foundation and a former Member of Parliament.
Dr Gordon Hosking  
Dr-Gordon-Hosking Gordon Hosking is a Forest Health Ecologist and is currently the Operations Manager for the Tindall Foundation’s Living Legends Project.  He is the Chair of the Mangawhai Tracks Charitable Trust and a Trustee of Project Crimson.  Gordon is passionate about the conservation and sustainable use of our native forests and is a dedicated mountain biker. 
Darryl Reardon  
Daryll-Reardon Darryl Reardon has been a Mangawhai resident and ratepayer for six years.  He is the current owner of Mangawhai Fishing and Tackle.  Darryl is an ex-Chairman of the Auckland/Waikato Fish and Game Council and been a serving Councillor for over 30 years.  He has worked in management roles for 35 years of which 20 years was spent within his own businesses.
Dr Ian Greenwood  
Dr-Ian-Greenwood Dr Ian Greenwood PhD (Eng), FIPENZ (Civil), CPEng (NZ) is an international specialist in the field of infrastructure asset management (AM) and performance‑based contracting.  Ian is a former Director of AM for the University of Otago, former Chairman of the Business New Zealand Transport Infrastructure Group and was an industry appointment to the Government Task Force on road maintenance.  He was the recipient of the Award for Excellence in Asset Management at the 2009 International Public Works Conference and is both a Fellow of the Institute of Professional Engineers of New Zealand and a Chartered Professional Engineer.
Peter Wethey  
Peter-Weatherly Peter Wethey has extensive experience in both the pulp and paper and meat processing industries and more recently has owned his own business.  He has a background of industrial chemistry and has managed resource consent applications for industrial wastewater discharges.  He has owned a property at Mangawhai Heads since 2001 and moved there permanently in 2013.

Revisiting the original objectives of the Scheme

The 2003 Statement of Proposal document outlines the problems that existed with water quality in the Harbour area with a note that:
 The harbour and groundwater is polluted and has been since at least 1976 when the first surveys indicated unacceptable levels of human waste and other pollution sources…Survey results have consistently demonstrated faecal coliform and enterococci levels to be significantly above accepted guidelines…Public health and safety issues from swimming/playing within the estuary environs.’

Concluding with a statement that:

           ‘Doing nothing is no longer a viable option for Mangawhai.’

The 2003 Statement of Proposal further noted that:

           ‘The prime objective of the project is to improve the water quality in the estuary.  This will be achieved by eliminating flows from septic tanks and other systems from entering the groundwater and the estuary.’
The original objective along with the desired social outcome of  ‘improving the well‑being of the estuary to allow the Mangawhai community and those other residents and tourists to the area to fully enjoy the environment that makes Mangawhai what it is’ are equally valid today in guiding future decisions.



Some Key Facts and Figures about the Scheme

  • The Scheme currently has nearly 1,800 connections (February 2015), of which around 20% require the use of a grinder pump to connect into the system.
  • A further 500 properties (around 50 have dwellings on them, the remainder are vacant) are adjacent to the existing lines and could be readily connected (termed ‘connectable’ properties).
  • A further 500 properties (just over 300 with dwellings, remainder vacant) will be made ‘connectable’ as the reticulation network is extended as proposed (refer storyboard #7).  This number of properties would increase as large land plots are subdivided during development.
  • The average volume of water treated is about 300m3 per day, with a peak daily volume of approximately 1,000m3 per day over the Christmas/New Year period (by comparison an Olympic‑sized swimming pool holds 2,500m3).
  • Each week a truckload (up to 6 tonnes) of ‘dry solids’ is extracted at the treatment plant and disposed of safely, leaving a nutrient‑rich but otherwise clean water supply to be disposed of.
  • The amount paid by the first 1,216 connections to the Scheme was less than half of the actual cost to connect.  Even with a central government subsidy at the time, Council undercharged.
  • The treatment plant is operating at about 50% capacity however the disposal system (irrigation area) for the treated waste is currently nearing its capacity.
  • To maximise use of the treatment plant, disposal capacity needs to be increased.  Doing nothing means the treatment plant will continue to be under-utilised; this is a key issue to be addressed.

The Infrastructure Components of the Scheme



Raw (untreated) waste is collected from properties within the catchment area.  Componentry includes property connections, grinder pumps, pump stations and pipes.  Connection to the Scheme can be via a gravity‑fed ‘private drain’ or a pressurised grinder pump connection.

Treatment Plant (at Thelma Road South)


Mangawhai Wastewater Treatment Plant

The plant produces a relatively high quality tertiary treated effluent albeit nutrient-rich with nitrogen and phosphorus.  The effluent e-coli are typically less than 1 MPN/100mg.

Treatment Disposal

The treatment plant separates the untreated waste into dry solids (which are disposed of in the Purewa Landfill just south of Whangarei) and clean (but nutrient‑rich) water.  The water is pumped inland to the Council-owned leased, dry stock grazed, Lincoln Downs Farm at Hakaru and used as irrigation.

Capacity and Reliability of the Scheme

The 2013 Office of the Auditor-General Inquiry into the Mangawhai Community Wastewater Scheme concluded, ‘The sewerage system that has been built is functioning well and has appropriate capacity for growth’.  (Summary 6.2)


  • Peak flows into the treatment plant are around the 1,000m3 per day range, while the peak capacity of the plant is estimated to be in the order of 1,750m3 per day under the current operating model.  Normal plant operating capacity is 1,680m3.
  • 25 hectares of the 200 hectare Lincoln Downs farm is currently used for irrigation; there is potential to use 60-65 hectares only for irrigation.  At projected growth rates more land (than the Lincoln Downs farm) will be required by 2024 – 2035.


Mangawhai Community Wastewater Scheme Status Map


Note: 18 projects are proposed to include the future ‘connectables’ over the next 5 years.

Maintenance, what was intended?


The 2007 EcoCare Project Information Booklet outlined:

  • That Council would provide one grinder pump per property
  • That property owners would pay for maintenance where misuse occurs
  • That property owners were responsible for future grinder pump replacement (15 years)
  • That property owners would pay for the power consumed by their grinder pump
  • That property owners were responsible for decommissioning their septic tanks
  • That property owners would pay for grinder pumps for properties within recent subdivisions (2009/2010).

What actually happened?

  • Council provided both individual and shared grinder pumps
  • Council pays the power for shared grinder pumps
  • Property owners pay the power for individual grinder pumps
  • Council fixes faults for all grinder pumps
  • Council replaces grinder pumps when required
  • Council paid for some grinder pumps for properties within recent subdivisions (2009/2010)
  • Approximately 20% of connections required a grinder pump (versus 80% gravity)
  • Property owners are responsible for decommissioning their septic tanks.

Options going forward

  • Council pays the power for shared grinder pumps; or
  • Property owners pay the power for individual grinder pumps;
  • Council fixes faults for shared grinders; or
  • Property owners fix faults for individual grinders.


Property owners are responsible for decommissioning their septic tanks.


Communal Schemes

There are ten subdivisions, three camp ground/parks and one school within the Mangawhai Drainage District that have private/communal schemes.  These schemes use a network of pipes and an effluent field.  They are not connected to the public scheme.

They have a condition registered on the Title of each property that requires connection once the public wastewater service is available.  The condition reads:

Use of the communal effluent disposal system within the subdivision is permitted only until such time as connection to the Mangawhai Community Wastewater Scheme (MCWWS) project is available.  At that time all properties will be required to connect to the MCWWS project and must comply with all of the Council’s requirements relating to such connection, including the payment of any Development Contribution, connection fee or any other charge.

The subdivisions locations are:

  • Back Bay – Molesworth Drive
  • Butler Subdivisions – Molesworth Drive/Sailrock Drive
  • The Heads Subdivision – Wintle Street
  • Moir Point Park – Estuary Drive
  • Moir Point Park – Estuary Drive/Devon Street
  • Ocean Links – Greenview Drive
  • Ewing and Yuretich – Moir Street
  • Woodglen Subdivision – Ti Tree Place
  • Point Utility – Grove Road

The camp ground/parks are:

  • Mangawhai Park – Moir Street
  • Mangawhai Beach Hideaway Park – Estuary Drive
  • Moirs Point Christian Centre – Estuary Drive/Devon Street

The School is:

  • Mangawhai Beach School – Insley Street


Connections Policy


Requirement to Connect

Reasons to favour increasing the number of connections include:

  • The original objectives of the Scheme (storyboard #3)


  • To meet the demand for growth in Mangawhai

Property Groups with connection potential
A Existing connectable properties with an existing dwelling (49[1])
B Existing connectable properties without a dwelling (443)
C Future connectable properties with an existing dwelling (325)
D Future connectable properties without a dwelling (182)
E New properties created by subdivision or development (Estimate 1,548)
  [1] All rating unit data is at 18 February 2015

Property Group Option 1 – Connection optional Option 2 – Connection mandatory
A   By 2019 or on development or building consent if prior
B   At time of development or building consent
C   Within 5 years of reticulation network extension or on development or building consent if prior
D   At time of development or building consent
E   At time of development or building consent

Connections Policy

Connection Process




***Connections Policy

Private Connection Costs and Funding – who should pay for private connections?

  • Option 1 - Full cost – Requires property owners to carry out and bear all of the on‑site costs of private connection.
Potential exceptions to Option 1 could be:
  • Group B properties, those that are already connectable but without a dwelling, have the grinder pump (where applicable) funded by the Council[1];
  • Group C properties, with a dwelling but not yet connectable, where the building was constructed before calendar year 2009, have the grinder pump (where applicable) funded by the Council[2].
  • Option 2 - Partial assistance – Require property owners to fund limited private connection costs for gravity system private drains (including decommissioning where required) with Council bearing the additional costs of grinder pumps in pressure wastewater systems with recovery through a uniform targeted rate, operating rate or through the Development Contribution.
  • Option 3 - Full up-front Council funding - Council to carry out and bear all private connection costs with recovery through a uniform targeted rate, operating rate or through the Development Contribution.

[1] Intended to encourage connection as development/building takes place.

[2] There was an expectation prior to 2009 that the network would be extended to existing properties with dwellings and that the costs of private connection would be met by Council as part of the costs of the MCWWS.


See ‘Glossary’ storyboard #20

See ‘Indicative Costs to Individuals’ storyboard #18


Connections Policy

Operation and Maintenance of Private Connections – who should be responsible?

Situation Types
Situation X
Single dwelling private drain directly between the dwelling and the public drain; or
Situation Y Multiple dwelling common private drain serving a number of dwellings/premises and connecting the public drain; or
Situation Z Cross property private or common private drain, with the drain crossing other properties to reach the public drain.

Option 1 – Full private responsibility - Property owner/s to provide, own, operate and maintain private drains
Potential refinement to Option 1 could be:
  • in simple single dwelling gravity Situation X and in multiple dwelling gravity Situation Y;
  • for electricity costs only in Situation X single dwellings on pressure systems with their own grinder pumps.  This will apply to all property groups A, B, C, D and E (Other options will apply to the maintenance and replacement costs in this Situation X – See below);

Option 2 – Council provision and private responsibility – Council provides private drains – property owner/s operate and maintain private drains.

Option 3 – Private provision and Council responsibility - Property owner/s provide private drains – Council takes over and declares these as public drains under Section 462 of the Act, and operates and maintains them.
Potential refinement to Option 3 could be:
  • for property groups D and E in Situation X single dwellings on pressure systems.  The preferred option in Part 2 is for these property groups to fund their own private connection costs in full (including grinder pumps).  However, the pumps would be taken over by the Council and become its responsibility to maintain.
  • for all property groups A to E in Situation Z where gravity system private or common drains cross other properties.  The intention in Part 2 is that all private connection gravity systems will be privately provided.  However, where these cross other properties, the intention in Option 3 is that Council takes responsibility for these systems, declares them as public drains and maintains them on an ongoing basis.

Operation and Maintenance of Private Connections (continued)

Option 4 – Full Council responsibility - Council to provide, own, operate and maintain private drains and declares these as public drains under Section 462 of the Act.
Potential refinement to Option 4 could be:
  • is favoured in any situation involving a pressure system, with the exception the owners of property groups D and E in Situation X single dwelling pressure systems, will provide the private connection.  The Council will then take full responsibility for the maintenance of all pressure systems in Mangawhai including replacement of property group D and E grinder pumps when this becomes necessary.


Note: Electricity costs:
  • Full private responsibility for costs in Situation X
  • Council responsibility in Situations Y and Z

Connection and Maintenance Examples
(Illustrative examples only – subject to confirmation and not exhaustive)

Listed are scenarios relating to possible private and public cost arrangements


Future Disposal Options Considered

The Advisory Panel looked at a range of disposal options including discharge to the Estuary and Hakaru River.  These options were discarded based on low social acceptability, negative impact on these water systems plus, albeit low, a risk of pollution.  The following options were selected for further consideration and evaluation:

Option 1 (Default)

  • Continued irrigation to Lincoln Downs, increasing to match growth in connections
  • More intensive land use to increase demand for water

Option 2

  • Ocean outfall using current discharge standards
  • Decommission and sell Lincoln Downs Farm
  • Resource Consent will need to be obtained
  • Assumed farm resale value $2.5 million
  • Approximate cost relative to Option 1 (Default)
o      Capital expenditure – higher
o      Annual operating cost – lower

Option 3

  • Outfall to Estuary on outgoing tide with higher quality discharge standards
  • Decommission and sell Lincoln Downs Farm
  • Will need higher than current discharge standards
  • Resource Consent will need to be obtained
  • Assumed farm resale value $2.5 million
  • Approximate costs relative to Option 1 (Default)
o      Capital expenditure – lower

o      Annual operating cost – lower

Option 4

  • Irrigation to the Mangawhai Golf Course
  • Modification of the wetlands on the golf course and potential irrigation of fairways
  • Decommission and sell Lincoln Downs Farm
  • Approximate costs relative to Option 1 (Default)
o      Capital expenditure – lower

o      Annual operating cost – lower

Key Financial and Funding Assumptions

  • All existing houses will be connected within 5 years of reticulation network extension.
  • New dwellings to increase by 68 per annum.

Disposal Options
  • Two of the four options were chosen to give a “least” cost ($1.5 - $2 million net) and a “most” cost ($5 - $6 million) option for illustrative purposes.
  • Work completed over two years with sale of farm in the following year.
  • The cost of the options are ‘high level’ preliminary estimates and will be refined via feasibilities studies.
Reticulation Network Extension
  • The network will be extended.
  • 18 projects to be undertaken over 2015 to 2018 to extend the existing reticulation network.
  • Estimated cost to be $3.0 - $3.5 million.

Distribution of Debt – which group of ratepayers bears the cost?

  • Original $58 million debt attributed to existing communities (connected and connectable - $13.4 million and district‑wide $18.4 million) and future communities (development $26.2 million) in accordance with the current KDC Long Term Plan.


  • Other assumptions as per KDC’s Consultation Document 2015/2025.

Indicative Costs to Individuals

Based on preliminary financial estimates, indicative costs could be an initial Development Contribution or Targeted Rate PLUS privately funded connection costs as set out in the table below and annual operating costs as they come on-stream. 

(NB: only one payment option would apply for the Development Contribution or Targeted Rate)



Have your say

Question 1      Requirement to connect –
‘Should connection be optional or mandatory?’


Question 2      Private connection costs and funding –
‘Do you favour Option 1, 2 or 3?’


Question 3      Operation and maintenance of private connections –
‘Do you favour Option 1, 2, 3 or 4?’


Question 4      Future Disposal options –
‘Do you favour Option 1, 2, 3 or 4?’




Below are some commonly used Council terms:

Annual Operating Charge - the charge to operate and maintain the Scheme on a day to day basis.

Capital Contribution - a property’s financial contribution towards the cost to build the Scheme.

Common Drain/line - a line that crosses through and services up to 5 properties.

Connectable - a property that is within 30 metres of the public wastewater line.

Connected - a property that is physically connected to the Scheme.

Connection - the physical connecting of a building to the wastewater service.

Catchment Area/Drainage District - a defined area used for rating purposes.

Decommission - the removal or filling in of a septic tank or the disestablishment of an effluent field.

Development Contribution - A revenue contribution from property developers to cover the cost of servicing growth resulting from development activity.

Dwelling - Any building, part of a building or group of buildings used or intended to be used principally for residential purposes and occupied or intended to be occupied by not more than one household and includes a minor household unit, a utility building or any unit of commercial accommodation.

Existing Network - the area where the wastewater service is currently available.

Gravity System - Made up of 100-150mm diameter sized pipes that use gravity to transport wastewater.  Gravity systems have connection points or stubs at the property boundary.

Grinder Pump - a pump that macerates solids within a flow.

KDC - Kaipara District Council.

MPN – (most probable number) of the e-coli count.

Original Area of Works - consists of approximately 1,200 properties mainly within the older Mangawhai urban area.

Pressure System - Made up of 40-50mm diameter sized pipes with pumps that push wastewater through the system.  Pressure systems require boundary kits and infusion welding to cut into the line.

Private Drain/line - where the line or drain enters private property begins at the property boundary and enters into the building.

Public Drain/line - the line within a road or reserve area.

Reticulation - the technical components that make up the wastewater scheme – (lines or drains, grinder pumps, boundary kits, connection points or stubs, pump stations and treatment plant.

Subsidised Targeted Rate - those that received a central government subsidy and who Council connected.

Targeted Rate - A rate that is charged only to members of particular communities or groups of ratepayers that benefit from the activity being funded by the rate.

Vacant - a section with no building.
[1] Unless full Development Contribution paid.

[2] Not all properties will require a grinder pump and sharing facilities will reduce the ‘per unit’ cost.


Online requests 

Kaipara District Council
0800 727 059 (24 Hours)
Phone: +64 9 439 7059


Office hours: 8 am to 4.30 pm Monday to Friday

Address: 42 Hokianga Road, Dargaville 0310
Address: Unit 6, The Hub, 6 Molesworth Drive, Mangawhai 0505

Mail: Private Bag 1001, Dargaville 0340


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