Report on Compliance with the Drinking-Water Standards for New Zealand 2005 (Revised 2008) and Duties Under Health Act 1956
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Report on Compliance with the Drinking-water Standards for New Zealand 2005 (revised 2008) and duties under Health Act 1956 For Period: 1 July 2017 to 30 June 2018 Drinking Water Supplies: Hurunui District Council Supplies (with population >100) Water Supplier: Hurunui District Council South Island Drinking Water Assessment Unit (Christchurch) P.O Box 1475, Christchurch 8140 Report Identifier HurunuiDistrictCouncil_DWSNZ2005/08Compliance_081018_v1 Terminology Non-Compliance = Areas where the drinking water supply does not comply with the Drinking Water Standards for New Zealand 2005 (revised 2008) (DWSNZ). Special note: Blythe and Peaks supplies are not included in this report as supplies serving populations of less than 100 were not assessed during the Ministry of Health’s Annual Survey process. Treatment Plants Bacterial compliance is under section 4 of the DWSNZ Protozoal compliance is under section 5 of the DWSNZ Cyanotoxin compliance is under section 7 of the DWSNZ Chemical compliance is under section 8 of the DWSNZ Radiological compliance is under section 9 of the DWSNZ Treatment Plant: Bacterial compliance Summary of E.coli sampling results Plant name Number of Number of Number of Compliance samples samples transgressions required collected Amuri Rural 104 106 0 Compliant Ashley Rural 104 106 0 Compliant Balmoral 52 52 1 Non-compliant Broomfield 12 12 0 Compliant (Racecourse Rd) Bakers Ford (Hawarden- 104 106 1 Compliant Waikari) Cheviot 104 106 0 Compliant Culverden 12 12 0 Compliant Hanmer 104 106 0 Compliant Hurunui #1 Rural 104 106 0 Compliant (Motunau/Greta/Scargill) Kaiwara 52 52 0 Compliant Kowai 241 24 0 Compliant (Amberley/Amberley Beach) Leithfield Beach 12 12 0 Compliant Lower Waitohi 52 52 0 Compliant Parnassus 52 52 0 Compliant Waitohi Upper 104 108 0 Compliant Waiau Home Stream 52 52 0 Compliant (Waiau Rural) Waiau Township 52 106 0 Compliant Waipara 52 57 0 Compliant 1. Kowai TP requires 24 E.coli samples (12 from State Highway 1 Bore and 12 samples from Kowai Bore) Report Identifier: HurunuiDistrictCouncil_DWSNZ2005/08Compliance_081018_v1 Scope 1 Appendix 1 Compliance Report for Network supplies DWSNZ 2005 Version 1: 1 September 2014 Page 2 of 13 Summary of compliance with sampling / analytical / remedial / operational requirements All plants were assessed for compliance against Bacterial Compliance Criteria 1 (E.coli monitoring only), with the exception of Waiau Township, which was assessed against Section 10. 17 of the 18 treatment plants that were in operation during the compliance period (and that serve a population of greater than 100) met all the requirements to comply with Criteria 1. This amounts to a similar level of achievement of bacterial compliance to the previous year, when 19 of 20 treatment plants complied (during the previous year, supplies serving fewer than 100 people were included in the report. This year Peaks and Blythe have been excluded from the assessment). The overall rate of transgression is the same as last year. This year there were 2 transgressions from 1227 samples (transgression rate of 0.2%). In 2016-17 there were 3 transgressions from 1424 samples (transgression rate of 0.2%). This has sustained the improvement from 2015-16 when there were 14 transgressions from 1619 samples (transgression rate of 0.8%). Balmoral was the one plant that did not comply with the Bacterial Compliance Criteria. The non- compliance was due to the E.coli transgression that occurred. It is good to see that appropriate corrective action was taken in response to the transgression. One plant (Bakers Ford) had an E.coli transgression yet was still able to comply given the number of samples that had been taken. The DWSNZ has allowable exceedances e.g. 1 E.coli transgression from 77 samples will still comply (Ref:DWSNZ Table A1.4). The requirement for E.coli samples to be analysed by a Ministry of Health recognised laboratory was met for all treatment plants. Treatment Plant : Protozoa compliance Plant Name Protozoal Risk Category Log Credit Required Leithfield Beach (Lucas Ave N/A – Full Groundwater Security N/A Bore) Culverden N/A - Full Groundwater Security N/A Amberley (Kowai) (including N/A – All sources Full Groundwater N/A Kowai Bore, Lucas Ave Bore, Security SH1 Bore) Racecourse Rd (Broomfield) N/A – Full Groundwater Security N/A (Racecourse Rd bore) Amuri, Ashley Rural, Bakers Surface Water or groundwater with 3 Ford, Cheviot, Hanmer, surface influence – with <0.75 mean Hurunui#1, Kaiwara, oocysts per 10 litres (in 24 samples) Waitohi Upper Waipara Groundwater, unconfined aquifer 10- 3 30m deep, satisfies groundwater security criteria 2 Report Identifier: HurunuiDistrictCouncil_DWSNZ2005/08Compliance_081018_v1 Scope 1 Appendix 1 Compliance Report for Network supplies DWSNZ 2005 Version 1: 1 September 2014 Page 3 of 13 Balmoral, Lower Waitohi, Surface Water or groundwater with 4 Parnassus, Waiau Rural, surface influence – with catchment risk assessment to confirm DWSNZ Table 5.1a category Waiau Town Participating Small Supply – 4 ‘Unprotected catchment’ under DWSNZ Table 10.1 Summary of Compliance with Risk Categorisation process HDC submitted results of protozoa raw water testing for the majority of supplies, in accordance with the programme outlined in Section 5.2.1.2, in addition to catchment risk assessment reports during the compliance period (refer letters from the Drinking Water Assessor (DWA) to Brett Beer dated 31.7.2017 and 16.10.2017). The DWA is aware that HDC were in the process of completing further raw water protozoa testing during the compliance period, so some treatment plants log credit assignations based solely on the catchment risk assessment may change for the compliance period 2018-19. Summary of Treatment Processes and associated Log Credits Plant name Treatment Potential Summary of Compliance with all Log credit Process1 Log Turbidity results other requirements achieved Credit of criterion2 Available Leithfield Full N/A N/A Yes Yes Beach Groundwater Security Culverden Full N/A N/A Yes Yes Groundwater Security Amberley Full N/A N/A Yes Yes (Kowai) Groundwater Security: (SH1 and Lucas Ave) Interim Security: (Kowai) Racecourse Full N/A N/A Yes Yes Rd Groundwater (Broomfield) Security Waiau Town Membrane 4 N/A3 Complied with the Yes Filtration requirements of DWSNZ, Section 10 All other None of the plants have treatment in place No 0 plants (see comments regarding Hanmer Springs) that meet the protozoa removal/inactivation requirements of the DWSNZ 1 Treatment Process meeting DWSNZ definition of available combination of treatment technology 2 Further detail provided below under log credit assessment Report Identifier: HurunuiDistrictCouncil_DWSNZ2005/08Compliance_081018_v1 Scope 1 Appendix 1 Compliance Report for Network supplies DWSNZ 2005 Version 1: 1 September 2014 Page 4 of 13 3 Waiau Township treatment plant does have continuous, online turbidity measurement, but there are no turbidity related compliance criteria in Section 10 of the DWSNZ. The treatment process was ‘monitored and operated in accordance with the manufacturer’s instructions’ as per the requirement in Section 10.3.1. Summary of Log Credit Assessment Hanmer Springs treatment plant has rapid sand filtration and a validated U.V unit in place that is potentially capable of complying with the protozoa requirements of the DWNSZ. However, protozoa compliance cannot be achieved until such time as HDC are able to present compliance monitoring data to demonstrate compliance with all aspects of Section 5.16 of the DWSNZ. Waiau Township meets the criteria for assessment as a ‘participating small supply’ under Section 10 of the DWSNZ. It has an approved and implemented water safety plan. It has appropriate treatment (with membrane filtration followed by chlorination). The membrane filtration plant that was fully operational during the compliance monitoring period. This membrane plant (followed by chlorination) achieves ‘Bacterial and 4-log protozoal treatment’ as per DWSNZ Table 10.1. The treatment process was ‘monitored and operated in accordance with the manufacturer’s instructions’ as per the requirement in Section 10.3.1. Aspects of the plant operation were checked during an onsite visit to the plant by the DWA in November 2017. Leithfield Beach, Broomfield, Amberley/Amberley Beach and Culverden are all supplied water via treatment plants that are fed by groundwater with full security status and therefore comply with the protozoa compliance criteria. All other HDC treatment plants don’t have treatment in place capable of complying with the protozoa removal/inactivation requirements of the DWSNZ. Log Credit Total (Total of all Treatment Processes) Achieved: Kowai (Amberley) - Protozoa compliant Culverden - Protozoa compliant Leithfield Beach - Protozoa compliant Racecourse Rd (Broomfield) - Protozoa compliant Waiau Town - 4 Log = Protozoa compliant All other HDC plants - Protozoa non-compliant Treatment Plant : Cyanotoxin Compliance Hurunui District Council do not currently have cyanobacteria management protocols in place for any supplies that are abstracting (either directly or via a hydraulic link) from surface waters. A number of HDC supplies abstract water from shallow bores or infiltration galleries that are known to be hydraulically linked to rivers that from time to time experience toxic algal blooms(e.g. Hurunui, Ashley, Waitohi and Waiau Rivers). The DWA considers the following source waters to be at risk from bloom development in surface water: Amuri / Rotherham (Mouse Point Wells – G00649) –