A recycled water program by the Fraser Coast Regional Council is maximising the reuse of treated effluent in the Fraser Coast region by irrigating native hardwood plantations with recycled water.
Based 250 kilometres north of Brisbane, Fraser Coast Regional Council now has several hardwood plantations irrigated by effluent water, which now diverts 2.5 billion litres of effluent wastewater into Fraser Coast Regional Council-managed agroforestry every year.
Most importantly, when the treated wastewater is diverted into the plantations, it is redirected away from nearby oceans, protecting the surrounding sea from 95 tonnes of nutrients and 21 tonnes of suspended solids being released each year.
With around 500 hectares under drip irrigation, the scheme is now the largest local government-owned plantation for recycled water reuse in Australia. The Fraser Coast Regional Council has also created a valuable community asset that is projected to produce over 100,000 cubic meters of harvest volume.
NTHA Senior Trainer Doug Mackenzie recently visited the uniquely grown plantations and met with two Fraser Coast Regional Council workers who look after the native hardwood plantations while completing their Certificate III in Forest Operations through NTHA Training (RTO Code: 5343).
Initially, Doug thought he was simply going to visit Steven Lapthorn and Brett Walsh to assess their practical skills and progress their training, but he found that the workers were also water reuse officers.
“The setup of the Australian hardwood plantations are absolutely stunning with rows and rows of beautifully kept trees. The council have quite a few blocks of forestry around Hervey Bay and Maryborough that are irrigated with partially treated sewerage water.”
“Not only do the workers undertake all the weed control along with the slashing and the thinning of the plantations, but they also conduct a lot of water and soil sampling. This is to make sure the activity remains sustainable,” Doug said.
When it comes to filtering the effluent water, the trees do most of the filtering naturally. This means that the workers simply need to limit the amount of water use within the plantations so there is no surface water running off into the waterways.
“This is such an incredibly interesting set-up and is very unusual from my perspective. Firstly, I have never come across irrigated native hardwood timber, and secondly, while using this method of managing non-potable water, I have heard of effluent solids being a viable fertiliser source,” Doug said.
The wastewater irrigation system is not only an environmentally friendly option for the native hardwood plantations but could potentially be a viable solution to global timber shortages.
“Depending on the species, it can take anywhere from 50 or 60 years to 120 years to have a usable log from a native hardwood plantation, which is huge when you consider workers are planting trees now for their grandchildren to harvest.”
“This is why the Hervey Bay plantation is so interesting because there is potential to rotate these hardwoods at 25 to 30 years, which is mind-blowing. This is because they are so well looked after, the weeds are controlled and they have a constant water supply,” he said.
The plantations also remove greenhouse gas (carbon dioxide) from the atmosphere, which is estimated to be up to five hundred tonnes of carbon dioxide per hectare by the time the plantation is harvested after 26 years.
Just some of the native hardwood timber species planted in the Fraser Coast Council plantations include:
Casuarina, Clone #1, Corymbia Hybrid, Dunns White Gum, Flooded Gum, Forest Red Gum, Grey Box, Grey Gum, Grey Iron Bark, Gympie Messmate, Hybrid Flooded Gum x River Red Gum, Lemon Scented Gum, Mixed Species, Rainforest, Red Mahogany, Spotted Gum, Swamp Mahogany, Tallowwood and Turpentine.
Initially transferred to several storage lagoons within the Fraser Coast Regional Council, today, the recycled water is used to irrigate not only hardwood plantations but also privately owned farms, pastures, golf courses, and turf farms within the area.
