The Rangitaiki River may be flowing crystal clear, but the regional council says this is due to the lack of rain rather than lockdown restrictions.
People living alongside the river have noticed the "significantly improved" water clarity since the country went into lockdown and are sceptical of the Bay of Plenty Regional Council's claim that is due to low levels of rain.
Heyden Johnston said he had been living at Thornton for the past 40 years and had never seen the river this clear before.
"The change in the river has been quite dramatic and it has impacted the aquatic life also, we had a kahawai school work up inside the harbour," he said.
"Most people who frequent Thornton will agree that when you can see the bottom of the river at high tide things have changed dramatically, especially when often you can’t see the bottom at low tide.
"It is such a great thing to see these positive changes in our awa; we now need to find out how we can keep it this way. We have lived with a polluted river for so long that we don’t even realise how good the water quality can be."
Mr Johnston said he had spoken to several locals about it and they all agreed this was the clearest the water had been.
He said he was sceptical about it being caused by a lack of rainfall. If that were true, this year would have needed to be the driest on record.
He is unsure why the water quality has improved during lockdown as many essential activities are still taking place alongside the river but speculates it may be the lack of forestry.
"If it is the lack of forestry, this is up to the regional council to assess and report to the public," Mr Johnston said.
"Let's call Bay of Plenty Regional Council to task. They are paid by us to maintain our environment. When we see a definitive change in water quality during such an unprecedented event as the lockdown, then all of us must act and ensure we aim to maintain water quality as it is today,” he said.
“We should not revert to past practices for what are likely to be financial gains for few, to the detriment of the environment and the wider community."
Information on Land, Air, Water Aotearoa shows that the Rangitaiki River has high levels of nitrogen and phosphorus. When compared to the national average it is in the bottom 25 percent.
The biggest source of nitrogen in New Zealand's waterways is urine from farm animals while phosphorus comes from farm fertiliser.
The Rangitaiki River also performed in the bottom 50 percent of rivers for turbidity. This is a measure of the cloudiness of water and high turbidity can be caused by heavy rainfall, disturbance of the riverbed or bank by heavy machinery or through direct discharges.
The awa was in the top 25 percent for E coli.
Regional council science manager Rob Donald said his team was really pleased that people were enjoying the clarity of the Rangitaiki River and that there was more fish life visible further upstream.
He said water quality monitoring was suspended under level four, so it was not possible to provide data on any specific change under lockdown.
However, some water monitoring had picked back up under level three and he said that might provide data in the future if there had been any substantial improvements.
"However, from my experience, it seems more likely that it is the lower rainfall over the past several months that has contributed to the clarity that the member of the public has noticed," he said.
"Certainly many of the industries that operate alongside or on the river continued throughout the lockdown, farms are still operating, the dam is still generating and most other industries - primarily the dairy factory - have continued operations as essential industries.
"However, less rain means less run-off from all industries and from urban and rural areas. That includes less run-off from forestry areas as well."
Mr Donald said water monitoring was a broad measure across a number of indicators including bacteria, clarity, nitrogen and phosphorus. Most of these factors wouldn’t be visible to the public.
"Water quality and making sure that our freshwater is healthy now and for future generations is a core part of Toi Moana’s work in the community," Mr Donald said.
"What happens on land affects our waterways so our work provides funding, advice and regional coordination to help improve the way land, water and biodiversity habitat is cared for in our local catchments.
"We invest more than $30 million each year on work with local people to improve and protect the water in local rivers, lakes, streams and aquifers."