Adroit Environmental Water Monitoring in the Pūniu River

Working with Pūniu River Care, a marae-led initiative to clean up waterways in South Waikato, and energy company, Mercury, Adroit has installed an environmental monitoring solution to provide real-time data on the health of The Pūniu River and makes it available to iwi, stakeholders, scientists and interested members of the public. Adroit’s role is an initial part of what is a significant legacy project for the region. The Pūniu River is one of the longest secondary tributaries in Aotearoa, running 83 kilometres from the heart of the Pureora Forest to the Waipa River and then on to the Waikato River. The Pūniu River holds a cultural significance to local marae, hapū and iwi, taking its name from the Patupaiarehe (a Māori mythical being of human form) who travelled down the river from the Pureora Forest to Pirongia. Once clear with a gravelly bottom, it is now brown with a muddy silt bed, caused in part by erosion of riverbanks releasing over 10,000 tonnes of sediment that discharges into the Waipā River from the Pūniu River every year. However, the Pūniu River has passionate supporters such as Shannon Te Huia (Ngāti Paretekawa, Ngāti Maniapoto), founder of Pūniu River Care who now leads the efforts to restore the Pūniu.

What has already been achieved in the catchment is impressive. Since it was launched in 2015, Pūniu River Care has planted more than 2 million trees within the Waipā, King Country and Waikato regions and completed more than 60 kilometres of fencing. It now employs 47 people, and its Te Awamutu nursery can produce more than 700,000 plants a year for restoration projects. While that sounds significant, it is still definitely work-in-progress, with estimates suggesting it could take up to 80 years with 80 million trees required to remediate the area – just within the Pūniu River catchment. Te Huia is well aware of the challenge ahead. “Essentially, intensive land use has caused an impact on our river. So, it’s about how we work with the people that own the land, to try and get the river back to how it was – because a lot of our people want the same thing for their kids and for their grandkids because they used to swim in the river when they were little, so they’re equally as invested,” he says.

Sensor Solutions

In August 2022, Adroit was engaged by Pūniu River Care and Mercury to design and install an environmental monitoring solution into the Pūniu to monitor key metrics and upload that data to the cloud in real-time, 24/7. The Adroit solution includes a full suite of sensors, comprising an In-Situ sensor monitoring water PH, dissolved oxygen, conductivity and temperature, plus an s:scan sensor measuring nitrates, suspended solids and turbidity. Data from the sensors is uploaded to the Adroit Platform via the Spark Cat-M1 network where it is made available to all stakeholders and interested members of the public. The solution was funded by Mercury’s partnership with Waikato Tainui. Te Huia says the Adroit solution is an important part of the river restoration puzzle.

In terms of catchment management, I think we need quite a lot more sensors. Hopefully with the amount of stations that Mercury’s funding it’ll all start getting some traction, and it’ll start being accepted as the best practice for managing the catchment,” he says. Te Huia believes that fixed sensors are just the beginning and can see the potential for other applications for the technology. He advocates the use of satellite technology to identify which tributaries are bringing in the most contaminants, and then work from there. “You’d probably have permanent stations at some of those tributaries. And then, if you are finding that there are issues, you’d probably have some temporary or mobile ones you could move to that site to help you understand what’s causing it,” he says. “And then, if you’re doing some remediation, you could have mobile ones there to understand how your remediation is benefiting.” Te Huia says after 8 years working with the Pūniu River he’s excited to see the new technology become available. “I think it’s exciting because we need to do things differently in terms of water quality. We need to get ahead of the curve. “We want to think this is the worst it’s ever going to be, and it’s going to get better from now on,” he says.

Don Scarlet: Key Relationships Manager for Mercury is also excited by the potential of the real-time sensors in the Pūniu and the Waikato and expects to see their use expand exponentially in the near future. He describes the Waikato as “New Zealand’s hardest working river” facing the impacts of tourism, industry, sewage, farming, forestry, quarries “and a lot more than that”, with significant hydro and geothermal electricity production also happening in the region. Scarlet says that Mercury’s belief is that the Waikato either is or has the capability to be the world’s best-managed catchment. That ambition led the company to Adroit, seeking best-in-breed real-time monitoring solutions for the catchments.

Mercury originally worked with another sensor provider but found that Adroit had the right solution for the project. “Adroit was able to provide a service that was much fitter for purpose,” Scarlet says. “We’ve now got seven Adroit sensors in the region. And we’re trying to catalyse a movement in this space,” he says.

At present, the regional council has approximately 78 sites across the catchment that are monitored with grab samples once a month. Scarlet says that those techniques, while very precise, don’t provide the immediacy that digital real-time monitoring can provide, and he’d like to see many more Adroit sensors used in the region. “An important benefit of moving from grab sampling to real-time monitoring is being able to see changes in the river and its important indicators 24/7. “I think another thing we’re going to see is the results of farmers undertaking catchment restoration, especially the places where farmers are working together to undertake ‘whole catchment restorations’. I think we’ll be able to track the cumulative effects of that across catchments much more effectively with real-time water quality monitoring, than grab samples will,” Scarlet says. Adroit has recently engaged Hill Laboratories to undertake expert independent validation of water sensor equipment. Scarlet says this validation is essential to gaining the confidence of stakeholders to commit to running real-time monitoring alongside or replacing grab sampling in some areas. Another criteria that is very important to Mercury, is that water quality information should be available to anybody. Scarlet says it is exciting to consider a future where the entire Waikato River could be viewed from anywhere in the world so that stakeholders could get essential information about its health and its life force.