Changing times for New Zealand’s water supply
Calibre’s Water & Environment Sector Lead, Chris Wrathall explores the impact of the Havelock North water contamination outbreak.
Humans have been treating their drinking water using boiling and filtering techniques for thousands of years, but it was the advent of modern treatment systems that helped to rid many countries of diseases such as cholera.
The result is that, as a society, we tend to take the health of our drinking water for granted. But the truth is, in some instances, drinking water suppliers are struggling to provide high quality water that is safe to drink.
When water treatment goes wrong
Water treatment and supply may not be one of the sexiest fields of engineering, but everyone depends on the water they drink being safe; it is crucial to public health to get it right.
Get it wrong, and the results can be tragic, as the town of Havelock North in New Zealand’s North Island, discovered to its detriment. In August 2016, when an outbreak of gastroenteritis affected 5,500 of the town's 14,000 residents, unsafe drinking water and was linked to 45 hospitalisations, three deaths and several lives that will never be the same again due to renal damage.
The outbreak was traced to contamination of the drinking water supplied by two bores on the outskirts of Havelock North. The result was that serious questions were raised about the safety and security of New Zealand's drinking water and the Central Government established an inquiry into the outbreak.
Stage One of the inquiry sought to understand what happened, and the cause of the outbreak found amongst other things, the likely cause of the contamination was the bacteria campylobacter (from sheep faeces) entered the water supply as a result of runoff from nearby paddocks.
Stage Two of the inquiry, addressed lessons learned and, based on those learnings made recommendations to reduce the likelihood of such an outbreak occurring again.
Key Recommendations from Inquiry
The Stage Two report includes 19 urgent and early recommendations as well as a number of further recommendations to prevent recurrences.
The recommendations are wide-ranging and, should they be adopted by Central Government (which the industry awaits with baited breath), will see considerable changes in the way water is provided in New Zealand. Some would say about time.
For me, however, there are three recommendations that are a high priority in terms of ensuring people are supplied with safe drinking water:
1) The establishment of a dedicated drinking water regulator.
The Inquiry highlighted the large number of organisations currently involved in the delivery of water in New Zealand. These include district councils, regional councils, district health boards and the Ministry of Health. Indeed, New Zealand has the second highest number of Central Government agencies involved in the provision and regulation of water in the OECD. This has the potential to confuse and complicate roles and responsibilities, and accountability.
Having a single, independent organisation, whose sole focus is ensuring the supply of safe drinking water would simplify the industry considerably. It would also provide other benefits, including far greater levels of compliance with drinking water standards, as has been the case in other countries.
Having an independent body ‘in charge’ of water supplies in New Zealand also de-politicises the issue. In my view, the decision whether money is best spent on an upgrade to a library or ensuring the water to a small rural community is safe should not be in the hands of councillors.
2) Abolishing the concept of a ‘secure bore’ status.
The drinking water standards (New Zealand Drinking Water Standards) include a section on secure bores; drinking water provided from a secure bore requires no treatment and less monitoring than, say, a shallow bore or surface water, such as a river.
The reasoning is that the water from a deep water source is not affected by surface or climate influences; this is satisfied by establishing the water is of sufficient ‘age’, determined by testing. The other criteria are that the bore head must be sealed at its surface and that monitoring of the water demonstrates an absence of positive E.coli results.
A number of water suppliers with secure bores monitor their water more than required, however, as it takes 24 hours to obtain the result of the bacterial (E.Coli) indicator test, one might say the horse has already bolted.
What the Havelock North inquiry has learned through the thorough investigation of the nature of the groundwater source at Havelock North and its hydrogeology, is that groundwater has the potential to be contaminated via other bores or wells. It was found at Havelock North that the groundwater from which the council bores drew, had a number of other previously unknown bores drawing from the same aquifer.
Though not identified as the cause of the contamination event, the potential of unknown bores to be a source of risk exists.
3) Mandate Universal Treatment including a residual disinfectant in the reticulation.
It would be fair to say that this recommendation is one I initially had trouble with. Does clean, green New Zealand really have to dose a residual disinfectant (aka chlorination) into every water supply? Has it really come down to this – the ambulance at the bottom of the cliff?
And having lived in Christchurch for over a decade, where everyone is so proud of the fact the water isn’t chlorinated (‘the best water in the country’ they say), is this necessary?
After a bit of thought, and leaving emotions aside, I came to the conclusion that, yes, it is necessary. Once water has left a treatment plant there are many ways it can become contaminated. Be it from cross-contamination when repairing a watermain, to a backflow event by a water user or a number of other factors.
Of course, chlorination won’t kill all pathogens in a supply, but having it in place does reduce the risk of another event such as Havelock North.
For now, we await the government’s response to the Stage Two recommendations.
If I was an Engineering Manager with a local council, l would firstly want to have up-to-date water safety plans in place for all water supplies in my city or district. I would also make sure I had an idea of what would be required to upgrade these plants to meet drinking water standards if required. I’d also be talking to my CEO, Councillors and the community – and seeking some external advice.
About Chris Wrathall
Chris is a Chartered Engineer and Environmentalist and is sector lead for Calibre’s Water & Environment teams across Australia and New Zealand. Chris spent his early career in the water industry in the UK and India, before returning to New Zealand where he has held senior roles with contractors and consultants. In addition to his sector role, Chris is the executive responsible for Calibre New Zealand’s South Island operations.