Christchurch City Council

Supplementary Agenda NO. 2

 

 

Notice of Meeting:

An ordinary meeting of the Christchurch City Council will be held on:

 

Date:                                     Thursday 25 October 2018

Time:                                    9.30am

Venue:                                 Council Chambers, Civic Offices,
53 Hereford Street, Christchurch

 

 

Membership

Chairperson

Deputy Chairperson

Members

Mayor Lianne Dalziel

Deputy Mayor Andrew Turner

Councillor Vicki Buck

Councillor Jimmy Chen

Councillor Phil Clearwater

Councillor Pauline Cotter

Councillor Mike Davidson

Councillor David East

Councillor Anne Galloway

Councillor Jamie Gough

Councillor Yani Johanson

Councillor Aaron Keown

Councillor Glenn Livingstone

Councillor Raf Manji

Councillor Tim Scandrett

Councillor Deon Swiggs

Councillor Sara Templeton

 

 

23 October 2018

 

 

 

Principal Advisor

Dr Karleen Edwards

Chief Executive

Tel: 941 8554

 

Jo Daly

Council Secretary

941 8581

jo.daly@ccc.govt.nz

www.ccc.govt.nz

Note:  The reports contained within this agenda are for consideration and should not be construed as Council policy unless and until adopted.  If you require further information relating to any reports, please contact the person named on the report.
Watch Council meetings live on the web:
http://councillive.ccc.govt.nz/live-stream

 


Council

25 October 2018

 

 


Council

25 October 2018

 

TABLE OF CONTENTS

 

32.     Resolution to Include Supplementary Reports...................................................................... 4

35.     Water supply improvement update and summer conservation.......................................... 5  


Council

25 October 2018

 

 

32 Resolution to Include Supplementary Reports

1.       Background

1.1          Approval is sought to submit the following reports to the Council meeting on 25 October 2018:

35.   Water supply improvement update and summer conservation

1.2          The reason, in terms of section 46A(7) of the Local Government Official Information and Meetings Act 1987, why the reports were not included on the main agenda is that they were not available at the time the agenda was prepared.

1.3          It is appropriate that the Council receive the reports at the current meeting.

2.       Recommendation

2.1          That the reports be received and considered at the Council meeting on 25 October 2018.

35.   Water supply improvement update and summer conservation

 

 


Council

25 October 2018

 

 

35.    Water supply improvement update and summer conservation

Reference:

18/1060868

Presenter(s):

Helen Beaumont – Programme Manager Water Supply Improvement

 

 

1.   Purpose and Origin of Report

Purpose of Report

1.1       The purpose of this report is for the Council to note the progress on the well head remediation works and to endorse the proposed water conservation campaign over the summer period.

Origin of Report

1.2       This report is being provided to update Council on progress with respect to the Council resolution on 25 January 2018 approving the installation of temporary chlorination for up to 12 months within the Christchurch City Water and Brooklands/Kainga water supplies and the Council resolutions CNCL/2018/00073 on 26 April 2018:

That the Council:

1.         Reinforces the Council’s previous resolution that states: “Requests staff continue best endeavours to complete this additional work within the 12 month timeframe”.

2.         Resolves that the preferred approach to improving well head security is to raise well heads above ground wherever practicable, affordable and timely and requests staff to examine the options of installing UV treatment, including leasing and/or purchasing, as an alternative to wellhead improvements on a pump station by pump station basis where finance, timing and/or long term advantages have been considered.

3.         Approves staff to proceed with the delivery of works required to improve wellheads or install UV treatment when the solution is obvious due to its economic timing and practicality.

4.         Resolves to implement temporary chlorination in Wainui until its well is made secure.

5.         Requests staff identify funding sources to undertake the well head security improvements when the preferred approach and programme has been confirmed.

6.         Requests staff to bring back to a May ITE Committee or Council meeting, a report outlining progress to date and a draft programme of improvements proposed which takes into account the optimum solutions, timing, funding and interdependencies of the water network and future proofing.

7.         Request staff look at all other options to regain secure status or equivalent including renewal, remediating and/or the possibility of abandoning a wellhead.

2.   Significance

2.1       The decision in this report is of low significance in relation to the Christchurch City Council’s Significance and Engagement Policy.

2.1.1   The level of significance was determined by considering the regular nature of summer water restrictions across the district.

2.1.2   The community engagement and consultation outlined in this report reflect the assessment.


 

 

3.   Staff Recommendations 

That the Council:

1.         Receive the information in the water supply improvement update report noting that:

a.         Works are proposed for the summer months to maintain the momentum of the well head remediation programme

b.         Temporary secure status will be sought for a number of below ground well heads.

2.         Endorse the water conservation campaign for the summer period to enable well head remediation works to continue noting that:

a.         The campaign will include a general water conservation message with targeted communications in those areas where remedial works are being carried out on wells

b.         Council’s parks and gardens will conserve water where it does not interfere with operational requirements, such as providing suitable playing surfaces for summer sports.

c.         Staff will monitor consumption and, if necessary, introduce level 3 water restrictions, restricting watering to hand held hoses between 9pm and 7am on alternate days.

 

 

4.   Key Points

4.1       This report supports the Council's Long Term Plan (2018 - 2028):

4.2       The water supply network is being managed to maximise production from pump stations without chlorination treatment. The chlorine is being removed, where remedial works have been completed, and the dose is being reduced at a number of pump stations.

4.3       Thirty of the Council’s 140 operating water supply wells have been signed-off as secure following the completion of remedial works.

4.4       Further works have been programmed over the next few months with 13 wells to be remediated over the summer period.

4.5       A targeted water conservation campaign is proposed for the summer months, to ensure that the water supply network can provide adequate water, while these 13 wells are taken out of service.

4.6       The 12 month timeline for temporary chlorination remains a challenging target given the number of wells that require remediation works.

4.7       Further improvements to the security of our potable water supply, through upgrades to the water supply infrastructure and the opportunity to implement a ‘smart water network’, are being explored and will inform the next Long Term Plan.

 

5.   Context/Background

5.1       The Christchurch water supply network has 140 operating wells and 53 pump stations. In January 2018 the Council decided to temporarily chlorinate the water supply while work was done to improve the security of our wells. Only four of these pump stations were considered to be secure and did not require disinfection treatment under the current Drinking Water Standards for New Zealand. Together these four pump stations provide at least 5% of the water for the city (based on the flow data for the 2017 calendar year).

5.2       The water supply improvement programme is seeking to return Christchurch’s water supply to secure status which would allow the removal of the temporary chlorination. Prioritising work to ensure that the drinking water supply is safe and secure was addressed in the Council’s Long Term Plan 2018-2028. Capital expenditure of $25 million has been brought forward into the first three years of the Long Term Plan to fund this programme.

Reducing the chlorine dose

5.3       A reduction in the chlorine dose, from 1 part per million (ppm) to at least 0.5 ppm, has been agreed with the Drinking Water Assessor where we have at least two minutes’ contact time before the first consumer on the network.

5.4       The chlorine dose has been lowered at fifteen pump stations across the city:

·    Auburn, Avonhead and Crosbie in the North West supply zone

·    Hills, Kerrs, Montreal, Sydenham and Worcester in the Central supply zone

·    St Johns in the Central/Ferrymead supply zone

·    Picton in the Riccarton supply zone

·    Tanner in the Rocky Point supply zone

·    Aston in the Central/Rawhiti supply zone

·    Marshlands in the Parklands supply zone

·    Sockburn and Wilmers in the West supply zone.

5.5       The water supply network is being managed to maximise the delivery from secure wells and pump stations without disinfection treatment. Six pump stations have the majority of bores have above ground well heads and these bores can provide sufficient water to the network at times of low water demand, that is, during the winter months.

5.6       Minor remedial works have been carried out to the above ground well heads at these six pump stations to enable the well heads to be signed off as secure. The works included installing and/or raising air valves (above the 100 year flood), sealing around cables, sealing any cracks and/or installing new concrete plinths around the well head.

5.7       A procedure has been agreed with the Drinking Water Assessor to isolate the below ground well heads at each pump station which has allowed chlorination to cease at times of low demand. The pump stations are:

·    Burnside (ceased 28 July) and Farrington (ceased 28 July and reinstated 8 October), Grampian (ceased 10 August) and Thompsons (ceased 28 August) in the North West zone

·    Hills (ceased 10 August) and Lake Terrace (ceased 10 August) in the Central zone.

5.8       The recent reinstatement of chlorine at the Farrington pump station was due to the need to carry out works on wells at Burnside at a time of increasing demand across our network.

5.9       Progress on removing and reducing the level of chlorine in the water supply network since the roll-out of temporary chlorination in May 2018 is summarised in the chart at Attachment A.

Alternative disinfection

5.10    While Christchurch’s source water has typically been assessed as sufficiently old to comply with the Drinking Water Standards for New Zealand criterion 1 for bore water security – that the bore water must not be directly affected by surface or climatic influences – there is a risk that some wells drawing on the shallowest aquifer (Aquifer 1 / the Riccarton Gravels) may no longer meet this criterion.

5.11    We have 17 operating wells across the city that draw on Aquifer 1. Recent results for age testing are inconclusive for some of these wells and further sampling, and modelling of the groundwater, is being undertaken. This work is due to be completed by August 2019.

5.12    If a well does not comply with criterion 1 then the water must be treated. The alternative treatment options allowed under the Drinking Water Standards have been considered and ultraviolet light disinfection has been selected as the most appropriate for the Christchurch supply.

5.13    The detailed design work for ultraviolet light disinfection has been completed for Main Pumps, which supplies approximately 5% of the city’s water, in the Central supply zone. Construction is proposed for 2019 with commissioning to be completed by June 2019.

5.14    Further work is underway to assess the technical feasibility and cost effectiveness of UV treatment at a number of other pump stations.

Well head remediation works

5.15    At the beginning of the dedicated water supply improvement programme seven wells had been signed off as secure. As at 10 October 2018, 30 wells at 16 pump stations have been signed off as secure – these wells provide approximately 21% of the water for the city. The progress of the programme of works for well head remediation is summarised in the chart at Attachment B.

5.16    The table below lists the wells that have been signed off as secure and notes the total number of wells at each of the pump stations.

Pump Station &

Supply Zone

Well heads

Secure / Total

Blighs - Central

1 / 2

Hills - Central

2 / 3

Trafalgar - Central

1 / 3

St Johns - Central/Ferrymead

1 / 3

Woolston - Central/Ferrymead

1 / 3

Tanner - Rocky

1 / 2

Estuary - Central/Rawhiti

2 / 2

Keyes - Central/Rawhiti

3 / 3

Lake Terrace - Central/Rawhiti

2 / 3

Burnside - North West

5 / 6

Crosbie - North West

1 / 3

Farrington - North West

4 / 5

Gardiners - North West

2 / 2

Grampian - North West

1 / 3

Thompsons - North West

1 / 2

Prestons - Parklands

2 / 4

 


 

5.17    The design work is complete and construction is timetabled or underway for a further 12 wells at 7 pump stations – these wells provide at least 4% of the water for the city.

Pump Station &

Supply Zone

Wells

Planned Remedial Works

Estimated Completion

Kainga - Brookland/Kainga

1

Raise below ground well head

Nov 2018

Hills - Central

1

Raise below ground well head

Nov 2018

Burnside - North West

1

Raise below ground well head

Nov 2018

Farrington - North West

1

Raise below ground well head

Dec 2018

Grampian - North West

2

Raise below ground well head; connect new well

Nov 2018

Jeffreys - North West

4

Make above ground well heads secure, raise 1 below ground well head, replace suction tank

Mar 2020

Wrights - North West

2

Raise below ground well head

To be confirmed

 

5.18    The physical works to raise a below ground well head generally include placing a full grout seal around the well casing; standard head works with a two way air vent, double bellows and double check valves; electrical upgrades, sensors and a flow meter; and an impermeable apron/plinth.

5.19    The design work is complete and the tenders are in the market (for construction works over the summer period) for a further 13 wells at 5 pump stations – these wells provide approximately 11% of the city’s water supply.

Pump Station &

Supply Zone

Wells

Planned Remedial Works

Proposed Completion

Brooklands - Brookland/Kainga

1

Raise below ground well head

Feb 2019

Lake Terrace - Central/Rawhiti

1

Raise below ground well head

Feb 2019

Trafalgar - Central

2

Raise below ground well heads

May 2019

Dunbars - West

4

Raise below ground well heads

Feb 2019

Denton - West

5

Raise below ground well heads

Feb 2019

 

5.20    Design work is underway or has been completed for a further 52 wells. Three further tender packages for remediation work to raise well heads are planned for release over the next three months – for 9 wells in late October (to be completed by June 2019), 18 wells in November and 13 wells in December 2018. The construction work would be carried out in 2019. Further work packages will be released into the market early in 2019.

5.21    As indicated in the 25 August 2018 report to Council the indicative timelines to bring all of our water supply wells up to best practice, that is with above ground well heads, would not enable us to complete the works and recommend the removal of chlorine from the whole network within the 12 month temporary chlorination timeframe.


 

Secure status for below ground well heads as an interim solution

5.22    Further investigation of the option of remediating of below ground well heads, without raising above ground, has identified 46 wells across 25 pump stations where improving the security is technically feasible at a reasonable cost. These are all wells that tap into deep flowing artesian aquifers where the artesian head provides a hydraulic barrier to potential contamination at the surface.

5.23    We are engaging with the Drinking Water Assessor on an approach to sign these wells off as achieving secure status on the understanding that the well heads will be raised above ground within the next two years. The wells will be considered to meet the requirements of the Drinking Water Standards Bore Water Security Criterion 2 subject to remedial works and additional mitigation measures (including more stringent inspection, maintenance and monitoring procedures) to be documented in a site specific Water Safety Plan.

5.24    St Johns pump station in Woolston has been assessed as a pilot for this approach. The engineering works will be itemised and costed over the next few weeks.

Financial implications

5.25    The estimated costs for the remediation works depend on the approach taken to each well:

5.25.1       The average cost of improving the security of above ground well heads is around $1,000.

5.25.2       The estimated cost of physical works improve the security of a below ground well head is $10,000 to $50,000 depending on the extent of the upgrade works.

5.25.3       The cost of the physical works to raise a below ground well head is $150,000 to $350,000 depending on the site and depth to the aquifer. This work includes a full grout seal around the well casing; standard head works with a two way air vent, double bellows and double check valves; electrical upgrades, sensors and a flow meter; and an impermeable apron/plinth.

5.25.4       The cost of the physical works to drill and develop a new well is $700,000 to $1,300,000 depending on the site and the depth to the aquifer.

5.26    Additional costs may be incurred if new plant, or upgrades to existing infrastructure, is required at the associated pump station.

5.27    The capital expenditure on the well head improvement programme to 15 October 2018 is $3.1 million with a forecast expenditure to the end of June 2019 of $15.9 million.

Water conservation campaign

5.28    Summer water demand in Christchurch is approximately double that of winter as illustrated in Attachment C. The need to have almost all of the pump stations in service over the summer months effectively precludes any major well head remediation works or drilling of new wells, for approximately five months of the year, unless water conservation measures are effective in reducing the demand on our potable water supply.

5.29    A random-dial telephone survey has been undertaken to assess the level of acceptance in the community for implementing stringent water restrictions over the summer months to allow crucial wellheads work to be done and bring an end to chlorination sooner.

5.30    Efforts were made to ensure the survey was representative of the Christchurch population. Both landline and mobile numbers were used to ensure respondents of all ages and background were included with soft quotas for age, gender, ward and ethnicity.


 

5.31    This survey has provided the following insights:

·    Respondents have indicated they are willing to work together with the Council to return to unchlorinated water as soon as possible. 71% of respondents consider it a high priority.

·    Motivated by wanting to return to an unchlorinated water supply as quickly as possible, 64% of respondents agree to significantly reduce their water usage over the summer months. 78% of respondents were in favour of moderate water restrictions (Level 2 or 3).

·    Residents consider it important to be able to water their lawns and gardens in summer. However, 57% were in favour of Level 3 water restrictions, allowing residents to water their lawn and garden using a hand held hose on alternate days.

·    Most people (72%) were interested in receiving timely information about the water capacity and utilisation levels.

5.32    Overall, the responses gathered from the community indicate a willingness to compromise on water usage provided that the Council takes the lead and sets a good example to encourage economical water usage in the community.

5.33    The Executive Leadership Team have endorsed water conservation at Council facilities, especially with respect to irrigation of our parks and gardens. Some of our facilities have their own bores, separate to the potable water supply for the city, and using these does not affect our network.  Some parks and gardens have particularly sensitive plant collections and/or operational requirements (such as providing for suitable playing surfaces for summer sports or supporting new plantings) that may mean some irrigation during the day is necessary.

5.34    A water conservation campaign would begin in October to encourage people to conserve water. The early evening is the peak time for water consumption and it is this period that would be specifically targeted. We also need the total daily demand to be lower so that the reservoirs do not run dry. 

5.35    Reducing water usage over summer means we can continue work towards removing chlorine from our network. This is because:

·    High water use means we need to rely on all wells in our system to ensure we can keep up with demand.

·    This means that we can’t shut any wells down to continue with our process of converting well heads from below ground to above ground.

·    This will slow our programme down and push out the timeframe that we need to chlorinate.

5.36    If consumption is not significantly reduced we will be introducing Level 3 water restrictions for Christchurch city. This would mean hand held watering for gardens, between 9pm and 7am, on alternate days only.

5.37    The campaign will be staged over a period of months from October-March.

·   Stage one: Alerting residents that water conservation will be required from the beginning of November. This means the messages will be fresh in people’s minds when peak demand/pressure begins in December/January.

·   Stage two: target communication in geographical areas where work is happening with messaging on reducing consumption.

·   Stage three: if demand continues to increase we will introduce water restrictions. Noting that if demand is too high we would have we have to stop our programmed work on the wells.

5.38    Key water saving tips will be recommended:

·    Avoid watering in strong winds

·    If you are washing your car, use a commercial facility (where they recycle the water), or wash it on the lawn

·    Keep paddling pools covered and recycle the water back in to your garden

·    Keep showers to 3 minutes – or 5 minutes at most

·    Wait for a full load before you use the washing machine or dishwasher

Looking to the future for potable water supply

5.39    A draft Integrated Water Strategy (draft IWS) was developed in 2017 following engagement with stakeholders. Progress on bringing this draft to Council has been held up while staff have been working through the application for the Comprehensive Stormwater Network Discharge Consent with papatipu runanga. Agreement has now been reached on this consent application and the draft IWS will be considered by Te Hononga and then come to come to Council for approval later this year. The draft IWS would go out for public consultation before being adopted by Council.

5.40    The proposed vision of the draft IWS, ‘Te wai ora o Tane – Water for Life; Valuing water and water services for people and the environment’, recognises the importance of water to the life of the community of Ōtautahi / Christchurch and the significant cultural values associated with water.

5.41    The draft IWS contains four goals and 13 objectives to achieve the Vision. The four goals are as follows:

·    Goal 1: The multiple uses of water are valued by all for the benefit of all

·    Goal 2: Water quality and ecosystems are protected and enhanced

·    Goal 3: The effects of flooding, climate change and sea level rise are understood, and the community is assisted to adapt to them

·    Goal 4: Water is managed in a sustainable and integrated way in line with the principle of kaitiakitanga.

5.42    The  objectives relevant to potable water supply are:

·    Objective 1: increase awareness and engagement with the community and mana whenua regarding the multiple uses and values of water

·    Objective 2: ensure efficient use of three waters infrastructure and ensure resilience of the networks over the long term through timely asset renewal

·    Objective 11: advance source protection of groundwater recharge areas and surface water supply sources for all drinking water supplies

·    Objective 12: understand the vulnerability, transit times and extent of confining layers of the Christchurch aquifers as well as the link to surface water quantity and quality

·    Objective 13: manage drinking water supplies to meet reasonable demands over the long term and ensure efficiency of water use.

5.43    The Integrated Water Strategy will replace three existing strategies – the Water Supply Strategy 2009-2039, the Surface Water Strategy 2009-2039 and the Wastewater Strategy 2013 – and will be supported by a number of implementation plans.


 

5.44    A Water Supply Strategic Plan is being drafted to address:

5.44.1 An overview of the water supply – this must meet the requirements of the Land and Water Regional Plan

Description of the supply

Water demand assessment

Water conservation and efficiency

Alternative water sources

Drought management plan

5.44.2 The six guiding principles for safe drinking water – as set out in the Australian Drinking Water Guidelines and recommended in the Report of the Havelock North Drinking Water Inquiry: Stage 2.

A high standard of care must be embraced

Protection of source water is of paramount importance

Maintain multiple barriers against contamination

Change precedes contamination

Suppliers must own the safety of drinking water

Apply a preventative risk management approach

5.44.3 Public health risk assessment – link to the Water Safety Plans

5.44.4 Improvements to the distribution network – link to asset management plans

Reconfiguring the water supply zones

Development of a ‘smart water network’

Real time water quality information

A smarter water network

5.45    New technologies and the Internet of Things present an opportunity to improve the understanding, management and operation of infrastructure and ‘smart water networks’ are being developed around the world.

5.46    The Council’s water supply network is operated using and mix of manual and automated controls through a SCADA (supervisory control and data acquisition) system that gathers data from the network and controls the response of the pump stations to ensure a continuous water pressure 24 hours a day. The total length of the main and submain pipe network in Christchurch city is approximately 3,300 kilometres.

5.47    A ‘smart network’ trial has been running for the past two years in the Riccarton and North West supply zones. Twenty six additional sensors have been deployed to monitor pressure transients (variations in pressure or water-hammer) and acoustic noise (indicating leaks) within the network. These provide an early warning of breaks (before they become catastrophic failures), indicate the location and the scale of a leak, and provide monitoring information to optimise network operations (better management of pressure to reduce the frequency of pipe burst). In conjunction with asset condition data the ‘smart network’ analytics can also identify pipes under stress and those with a high likelihood of leakage and/or failure which in turn informs the priorities in the asset management plans.


 

5.48    The ‘smart network’ approach could be extended to include smart meters for customers and real time water quality information (parameters such as pH, conductivity and turbidity) through an expanded array of sensors placed at critical points in our network. A change in water quality can provide an early warning of a contamination event and prompt a response to isolate that part of the network, warn potentially affected consumers and send out repair crews.

5.49    The time taken to detect bacteria in the network is one of the reasons given for residual disinfection in the water distribution network. A trial of a rapid assay on-line instrument to detect indicator bacteria in the distribution network is planned for later this year. The coliform analyser can provide a rapid screen within 1 to 2 hours and a count of coliform bacteria within 6 to 12 hours, compared to 24 hours for traditional laboratory techniques. The results are sent through automatically and an alarm can be triggered to prompt a rapid response.

5.50    As set out in the Water Supply Asset Management Plan the water supply zones for the city are proposed to be reconfigured into smaller management zones in order to achieve:

·    Improved emergency response capability

·    Improved resilience and protection of vulnerable assets (and extend asset life)

·    Delivery of optimal supply pressures to reduce burst frequency and support demand management

·    Defer or avoid the need for an additional water source for Christchurch through leakage reduction

·    Create a more efficient and sustainable network through improved energy efficiency.

5.51    The city would be supplied from 14 primary zones, each with their own sources of water and back-up generators to maintain supply in the event of power failure. The Rawhiti water supply zone is the first of the new zones to be implemented and the inclusion of ‘smart network’ technology would complement this rezoning programme.

5.52    Staff will continue to explore the options for developing a smarter network and opportunities to trial new technologies to support improvements to the management and security of our water supply infrastructure. The results of the research and the trials will be incorporated into the Water Supply Strategic Plan and the Water Supply Asset Management Plan, and inform the next Long Term Plan.

 

 

Attachments

No.

Title

Page

a

Temporary Chlorination by Pumpstation

16

b

Status of Wells

17

c

Christchurch Water Consumption

18

 


 

 

Confirmation of Statutory Compliance

Compliance with Statutory Decision-making Requirements (ss 76 - 81 Local Government Act 2002).

(a) This report contains:

(i)  sufficient information about all reasonably practicable options identified and assessed in terms of their advantages and disadvantages; and

(ii) adequate consideration of the views and preferences of affected and interested persons bearing in mind any proposed or previous community engagement.

(b) The information reflects the level of significance of the matters covered by the report, as determined in accordance with the Council's significance and engagement policy.

 

Signatories

Author

Helen Beaumont - Programme Manager - Water Supply

Approved By

David Adamson - General Manager City Services

Karleen Edwards - Chief Executive

  


Council

25 October 2018

 

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Council

25 October 2018

 

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Council

25 October 2018

 

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