A focus on boots-on-the-ground TWQ Hub work and engineering for improved water quality in Great Barrier Reef catchments in northern Queensland has proven popular and successful as 2017 draws to a close.

The NESP TWQ Hub’s flagship combined water quality and behavioral change project, Project 25, has been highly successful in engaging with cane farmers in its test catchment and increasing confidence in both the validity of water quality monitoring data and on-farm decision-making.

The project, which was announced at the launch of the Tropical Water Quality Hub in 2015 and continues under Research Plan version 4, uses fine-scale water quality monitoring at multiple points along the Russell-Mulgrave river system south of Cairns to produce hard data on levels of runoff of dissolved inorganic nitrogen, phosphorus and sediment. The project is demonstrably building confidence in both the process and outcome of water quality science among local cane farmers, whose practice decisions are crucial factors in Great Barrier Reef water quality.

Dr Aaron Davis from James Cook University presented progress on Project 25 at the Cairns district CANEGROWERS annual general meeting on 13 December, laying out water-quality data gathered over the 2016-17 period.

“This was really about some of this year’s ‘first flush’ data meaning it included the first big rainfall and runoff event recorded so far for this wet season,” Dr Davis said.

“What it demonstrates is that everything in this scenario is driven by rainfall, and much of what we’re interested in occurs in just that first few runoff events for the year.”

Dr Davis said there was a definite positive reception from gathered cane farmers to the presentation.

Dr Aaron Davis presenting on Project 25 to the Cairns CANEGROWERS AGM on December 13 2017.

CANEGROWERS district manager Sarah Standen agreed, saying the project was rapidly gaining attention and acceptance amongst growers in the region.

“There’s been a major change in thinking from our growers, they’ve always been wanting real data instead of modelling and this project is giving it to them. There’s been a whole change in the atmosphere around it, the interest is huge,” she said.

“When it was presented at the CANEGROWERS AGM, there were hardline blokes from the district that would be normally jumping up and down that were instead hanging on every word Aaron said.

“The growers are definitely keen to get involved, there was a negativity before but that’s gone now.”

Babinda grower Steve Destro attended the AGM and said Project 25’s focus on real data was very convincing.

“We were impressed by getting these figures at long last, we have only been shown modelling in the past – we didn’t know how accurate they were,” he said.

“It’s the first time I’ve seen data on that kind of scale and detail that includes tides and other things like that.

“I’d definitely say this will build confidence. Most growers are interested, we are always trying to do our best, always modifying what we are doing to try to help.”

In the same catchment and elsewhere, investigations into converting marginal caneland into wetlands are ongoing under Project 3.3.2, led by Dr Nathan Waltham from James Cook University.

This project evaluates the effectiveness of converting marginal cane land to wetlands.

Wetlands are a critical resource in improving and maintaining quality of water entering the Great Barrier Reef lagoon. By slowing water and hosting several vital plant species they remove some sediments and other pollutants like dissolved inorganic nitrogen.

Dr Waltham is running trial sites at Babinda, Mungalla, the Burdekin and the Burnett-Mary natural resource management region, with the Babinda site in particular showing good potential for valuable data.

The Babinda Constructed Wetland project, run by Indigenous-led Jaragun NRM, is a prime example of reclaimed cane land being converted to wetland and has been equipped with automatic cameras and other sensors by Dr Waltham.

Dennis Ah-Kee from Jaragun Natural Resource Management at the Babinda Constructed Wetland (image: Dr Nathan Waltham)

“What we’ll be looking at is how the water flows into the wetland which will help us understand the water balance in this system,” he said.

“In addition to the cameras taking photos of the wetland every 20 minutes, the sensors will be measuring water depth, flow and salinity.  We’ll be looking to develop a hydrodynamic model from there.

“Wetlands are important because they have this effect of ‘polishing’ the water, as in cleaning it out of suspended sediments and dissolved inorganic nitrogen that would otherwise go on to cause issues out on the Great Barrier Reef.”

Dennis Ah-Kee from Jaragun Natural Resource Management said that his organization was ‘very excited’ to be working with the Tropical Water Quality Hub as it meant that a rigorous scientific analysis of the Babinda Constructed Wetland could be undertaken.

“The involvement of NESP means that we’ll be able to have a scientific evaluation of the capacity of the wetland, both in terms of its total capacity and how efficient it is in removing dissolved inorganic nitrogen from the water.

“It’s a complex wetland system, so it’s not simple to get that data on it – there’s a lot of detailed measurements and mathematics that are needed.

“We’re very much looking forward to seeing the results.”


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