If the information is collected consistently and diligently, it could help show when the efforts of farmers to protect the environment have an impact, he says.
Dr Storey says volunteers can contribute by conducting monitoring beyond what regional councils and researchers can achieve on their own. However, support from professionals was crucial.
"Streams are a bit like blood vessels - councils monitor the arteries and big veins but the capillaries need monitoring as well."
Dr Storey and his team found the reliability of volunteer data was strongest when it came to measuring water temperature, electrical conductivity, visual water clarity and the cover of thick periphyton growths.
It was less strong, although still useful, for indicators of stream ecological health and E.coli indicator bacteria, for example.
Taking E.coli measurements and identifying invertebrates were regarded as more difficult but Dr Storey says many volunteers relished the challenge and the results were in line with council monitoring at near identical sites and times.
The volunteers monitored for nitrates but there was a hiccup with that aspect of the study as it wasn't noticed until some rogue results started coming in that one of the chemicals supplied to the groups had expired.
But Dr Storey says the SHMAK-based kits used (see below), "could definitely be used to track [nitrates] data [indicating] major pollution, medium pollution, very clean water, and so on.
"But I wouldn't push the data any further; I wouldn't go down to two decimal places or anything like that."
The nine community groups involved in the research project were monitoring waterways in a mix of urban, peri-urban and one or two rural areas.
It could be argued because the volunteers knew they were part of a study, they would be on their toes to be non-biased and extra careful.
Dr Storey told NFR he wouldn't want to guess at people's motives "but certainly they had to be quite motivated to be part of the study, so I guess we got the best groups just because they self-selected in that way".
Chris Allen says while some farmers test water in streams, there is no hard data available on how many might be doing so.
"Certainly there are a lot of farmers who test drinking water to their houses that comes out of shallow wells. Dairy farmers also have to do testing for wash-down of their sheds as part of their supply agreements."
Canterbury farmer and Feds member Ian McKenzie is part of an umbrella group that helps monitor waterways in the Hinds district.
There had been disputes over whether the results of monitoring of test bores by Environment Canterbury could be relied on but when the farmers did their own testing, in a framework overseen by Dairy NZ and ECANZ water quality scientists, "the results were in line with what ECANZ were saying", Chris says.
"The farmers' attitude then was 'right, what do we need to do to sort this out'.
"Knowledge in these water discussions is king, and you've got to have good, reliable information," Chris says.
"If you've gathered some of that information yourself, and you know you've done it the right way, it can help back up the bigger part of the story, and lead you to the correct problem statement, rather than scrapping over whether the regional council got it right."
In an area like the Waikato, for example, rural property owners are facing significant restrictions on their businesses.
"Do you rely solely on the council monitoring, or do you as a collective or four or five farms along a tributary do some monitoring yourself, sharing the cost?
"They might prove that some of the stuff being talked about shouldn't apply to their waterway, or indeed that there is a problem they need to fess up to."
Chris says it's an issue that a lot of the regional council testing of water quality is at swimming sites "but in a lot of cases that's not representative of all the river".
