Dr Jacqueline Rowarth: Water and climate reports - ‘tis the season

For water, the most important holiday report is Can I swim here? by Our Land and Water. Photo / Nicki Harper

OPINION

Water and climate reports are plentiful at the moment, which is timely given the coming holiday season, but it always pays to swim between the flags and read between the lines, writes Dr Jacqueline Rowarth.

In the flurry of reports being released before Christmas, it might be hard to miss the important facts.

Reports are released for different reasons, from shock to information. Some are, in my view, alarmist, and some are vital.

Water and climate have featured which is timely given the coming holiday season.

For water, the most important holiday report is Can I swim here?

The website is updated regularly and frequently. For swimming, the important factors are Escherichia coli contamination (bugs) and sediment (visibility).

The website states that swimming is not advised for two to three days after heavy or prolonged rain.

In addition: “Avoid swimming near potential sources of contamination such as flocks of birds, stormwater or wastewater outlets. Check for hazards (e.g., rips or strong river currents, underwater objects, steep drop-offs, or stinging jellyfish at beaches). Know your limits, and never swim alone. If in doubt, stay out.”

Good advice.

Rain washes faecal matter from banks into the water and soil from bare ground and steep areas into waterways.

The likelihood of illness is increased if contaminated water is swallowed, which is why the website also warns about flocks of birds and wastewater outlets.

Increased sediment (soil) following rain reduces visibility and hides underwater obstructions. This is why jumping or diving into cloudy water is stupid – you can’t see what might be there, and you can’t see the currents.

Advice for beaches is always - Swim Between the Flags. Again, you can’t see the currents.

E. coli also featured in media coverage of a late November report from Our Land and Water on the reduction in contaminant loads required to achieve New Zealand’s national bottom line for water quality standards.

Media reports sounded the alarm without pointing out that the E. coli in the modelling study involved monthly measurement over a five-year period.

“Monthly” includes winter and high rain.

Swimming is generally in warmer months (and should avoid high rain).

The Our Land and Water report was produced to help regional councils target the areas of concern. It did not identify sources of E. coli but noted that three-quarters of all land in Aotearoa is contributing more E. coli to water than is allowed.

Pastoral agriculture occupies almost 50 per cent of land in New Zealand, with dairying on 1.7 million ha (6.3 per cent of the total of 26.8 million hectares of New Zealand).

Agriculture is clearly not the only contributor to E. coli.

Dr Jacqueline Rowarth.

The report authors stated that they were not challenging the set bottom lines but were indicating where action is most needed to meet them.

Before being elected, National’s water policy indicated the intent to give flexibility to regional councils on managing water resources.

The concept was stated as “Financial sustainability will enable the long-term investment in infrastructure that will deliver the quality drinking water, cleaner rivers and swimmable beaches that New Zealanders want and expect”.

Despite this assurance of “Cleaner rivers and swimmable beaches”, concerned people are already creating alarm that standards will deteriorate.

Further alarm has, in my opinion, been created by the Greenpeace report and new website on nitrate in drinking water.

Regular restatement from scientists that nitrate in drinking water does not cause colorectal cancer (Bowel Cancer New Zealand says “Nitrates in drinking water are highly unlikely to increase the risk of bowel cancer in New Zealand, according to the current weight of evidence”) has in my view bounced off cloth ears.

Similarly, nitrate in drinking water is not linked to pre-term babies (the University of Otago 2016 report recommended interventions to reduce smoking and intimate partner violence, improving access to family planning to reduce the number of closely spaced pregnancies, and providing support to socially disadvantaged women).

There is an ethnicity link in the research from overseas that has been ignored. Also ignored have been the reports of high nitrate in groundwater on the Canterbury Plains since the 1940s when measurements started (data from 1960 onwards presented here, long before dairying became a feature on the Plains).

Another report, this time from COP28, that New Zealand has signed the agreement on food system transformation appears to have been misunderstood as well.

Listen to Jamie Mackay interview Dr Jacqueline Rowarth on The Country below:

The COP28 agreement focuses on food security and nutrition while maximising the climate and environmental benefits associated with agriculture and food systems.

New Zealand produces essential amino acids for almost 1 per cent of the global population for less than 0.04 per cent of global greenhouse gases through dairy production alone and is in a good position to be able to help other countries achieve similar efficiencies – where the soil and climate allow.

Suggestions that New Zealand should immediately change its production systems overlook our starting point of low-impact production from high-quality soils.

Not mentioned but of future importance was the COP28 statement about water management in “agriculture and food systems at all levels”.

This is certainly something that could do with attention and water storage to allow improved management is on the new Government’s agenda.

In reading any report, the first step should be to identify its purpose and then consider the results and limitations as applied to that purpose.

And before heading to the water, always check the LAWA.org.nz website.

• Dr Jacqueline Rowarth, Adjunct Professor Lincoln University, is a director of DairyNZ, Ravensdown and Deer Industry NZ. The thoughts and analyses presented here are her own. JSRowarth@gmail.com