15 July 2019 - Testing has shown the effluent spill risk of faecal contamination has passed.

On 16 May a private farm east of Oxford had an irrigator malfunction leaking dairy effluent water across a paddock – the overland flow eventually made its water into a small section of the irrigation and stock water race network.

A precautionary boil water advisory was recommended by Community and Public Health (CPH) as there was a low risk the spill could affect private well water quality.

Following the spill Waimakariri District Council and Waimakariri Irrigation Limited (WIL) contacted nearby residents who may have been affected to offer support and organise regular testing of their well water. Tests over  several weeks have shown results typical of a private untreated water supply.

Residents urged to regularly test private water supplies

Results showed the private wells, except one, were unlikely to have been affected by the effluent spill event. However, the testing did highlight that E.coli (indicating faecal contamination) was present after heavy rain events.

Variable water quality is not uncommon for private wells, and the results highlight the importance of residents either to boil their water, particularly after heavy rain, or install point of use treatment. Water should also be tested regularly.

Residents seeking more information on private well testing and treatment options are asked to contact Council Water Environment Advisor - Sophie Allen.

All updates to date are below.

1 July 2019

The precautionary boil water advisory for Horrellville remains in place until the all clear can be given from Community and Public Health.

Testing of potentially affected private wells has been undertaken following the effluent spill east of Oxford on May 16. Most results to date have shown nothing of concern or outside what is considered typical of a private untreated water supply.

Movement of water through the ground is slow so the boil water advisory from Community and Public Health will remain in place until the risk has passed.

Residents with questions are encouraged to call Waimakariri District Council on 0800 965 468 (0800WMKGOV).

31 May 2019

The precautionary boil water advisory for Horrellville remains in place while testing continues.

Testing of potentially affected private wells has been undertaken following the effluent spill east of Oxford on May 16. Most results to date have shown nothing of concern or outside what is considered typical of a private untreated water supply.

However, the precautionary advisory remains in place so further data can be collected to confirm current findings.

Until the advisory is lifted residents are recommended to continue boiling their water as a precaution, and infants avoid well water altogether.

Any residents who are concerned, and believe they may be affected, are encouraged to call Waimakariri District Council on 0800 965 468 (0800WMKGOV).

Background:

On 16 May a private farm east of Oxford had an irrigator malfunction leaking dairy effluent water across a paddock – the overland flow eventually made its water into the irrigation and stock water race network.

The spill was contained within two hours by Waimakariri Irrigation Limited. Environment Canterbury and Canterbury Public Health were notified. Council’s community water supplies are unaffected.

The precautionary advice was recommended by Community and Public Health as there is a low risk the spill could affect private well water quality.

Map: Horrellville - Area Recommended to Boil Well Water

23 May 2019

The precautionary boil water advisory for Horrellville remains in place while testing is undertaken to confirm if private wells across the area have been affected.

On 16 May a private farm east of Oxford had an irrigator malfunction leaking dairy effluent water across a paddock – the overland flow eventually made its water into the irrigation and stock water race network.

Map: Horrellville - Area Recommended to Boil Well Water

The spill was contained within two hours by Waimakariri Irrigation Limited. Environment Canterbury and Canterbury Public Health were notified.

Horrellville and other nearby residents are recommended to continue boiling their water as a precaution, and infants avoid well water altogether. Council’s community water supplies are unaffected.

The precautionary advice was recommended by Community and Public Health as there is a low risk the spill could affect private well water quality.

Movement of water through the ground is slow the boil water advisory remains in place until testing can show the risk has passed.

Testing underway to monitor underground water quality

All properties within the affected area have been directly contacted by either the Council or Waimakariri Irrigation Limited (WIL).

Approximately 14 properties in the following areas have been identified for testing:

• Littles and Carleton Road – near the spill site
• Horrellville – areas to the East between Poyntzs Rd, Tram Rd, Moderates Rd and the Eyre River.

Of the test results obtained to date only one has returned E. coli levels greater than would be considered typical of a private untreated water supply.

These residents have received advice from Community and Public Health. The positive test result may not be directly related to the effluent spill as variable water quality is not uncommon for private wells.

Testing of wells in the area will continue until results show the risk has passed.

Any residents who are concerned, and believe they may be affected, are encouraged to call Waimakariri District Council on 0800 965 468 (0800WMKGOV).

17 May 2019

The precautionary well water advisory for Horrellville remains in place.

Nearby residents (those between Poyntzs Rd, Tram Rd, Moderates Rd and the Eyre River) are recommended to boil their water as a precaution, and infants avoid well water altogether, as there is a slight risk it could affect private wells.

Map: Horrellville - Area Recommended to Boil Well Water

The precautionary advice has been recommended by Community and Public Health as there is a low risk the spill could affect private well owners.

The spill has been contained by Waimakariri Irrigation Limited (WIL). Environment Canterbury and Community & Public Health have been notified.

Advice for those on private wells

Waimakariri District Council have today contacted well owners in Horrellville who may be affected to organise water testing of selected bores.

The movement of water through the ground is slow (between 10 – 100m per day) and as such it’s not expected there will be any effect on private wells for a number of days.

However, underground conditions can vary and the boil water advisory remains in place until any potentially affected water has passed and testing confirms this.

The Council will continue working with landowners and undertaking testing on their behalf.

Water is available for those affected at the campervan filling point outside 82 High St, Oxford.

Any residents who are concerned, and believe they may be affected, are encouraged to call Waimakariri District Council on 0800 965 468 (0800WMKGOV).

Advice for those who use the irrigation and stock water race system

Waimakariri Irrigation Limited today began work to clean the contained spill area east of Oxford.

Vacuum trucks were brought in to remove the contained water and stock water has been reintroduced to the network.

Testing and cleaning of affected water races in the area has been undertaken.

There may be a temporary loss, or intermittent supply, of stock water for a small part of the network until flow returns to normal capacity. We expect this to be within 24 hours.

Any stock water race network users with concerns are encouraged to contact Waimakariri Irrigation Limited on 022 086 99 86.

16 May 2019

Residents on private water wells living near Horrellville are being advised to boil their water, and infants avoid well water altogether, as a precaution following an effluent spill into the irrigation and stock water race.

Council’s community water supplies are unaffected.

On 16 May a private farm east of Oxford had a centre pivot irrigator malfunction leaking dairy effluent water across a paddock – the overland flow eventually made its way into the irrigation and stock water race network.

The spill was contained within two hours by Waimakariri Irrigation Limited. Environment Canterbury and Canterbury Public Health have been notified.

Nearby residents (those between Poyntzs Rd, Tram Rd, Moderates Rd and the Eyre River) are recommended to boil their water as a precaution, and infants avoid well water altogether, until further testing can take place as there is a slight risk it could affect private wells.

It’s believed there are only a small number of properties at risk of being affected.

Affected residents are being contacted this evening and recommended they shut off their bores and use the water stored with their on-site water tanks. Water is available for those affected at the campervan filling point outside 82 High St, Oxford.

The Council operates a water race network supplying stock-water to farmers. The stock water network is an open network with low quality water intended for use by animals.

There is no specific advice for other stock water race users as the spill was contained. Some stock water users in the area may have a loss of, or intermittent supply, over the coming days due to the network being isolated.

More information will be shared when available.

Map: Horrellville - Area Recommended to Boil Well Water