Cattle station helps keep sediment off Reef

December 11, 2018

Major earthwork projects on a Far North cattle station are stopping erosion and preventing hundreds of truckloads worth of fine sediment from flowing to the Great Barrier Reef.

Engineers have designed a 100m-long rock chute to divert water from an eroded gully between the Herbert River catchment and a large dam system as one of the projects in a $3 million initiative to reduce sediment loads on the Reef.

The work is happening on Woodleigh Cattle Station near Mt Garnet, through the Australian Government’s Reef Trust IV program.

Terrain NRM’s Jen Mackenzie said 5500 tonnes of rocks were being used to create the chute, linking Charcoal Creek with a dam complex that covers almost 2000 hectares, and isolating a badly-eroded gully system that gained 70m last wet season.

The earthworks are one of up to 10 major gully remediation projects planned for the Herbert catchment as part of the $3 million Herbert Gully and Grazing Program.  Other works include repairs to old tailings dam complexes from alluvial tin mining ventures on grazing land in the Herbert catchment.

Ms Mackenzie said grazing practice changes were just as important.

“This project includes fencing, the creation of new off-stream watering points for cattle, revegetation projects and weed management,’’ she said.  “And we’ve had a great roll-up at workshops for graziers. We’ll be holding more next year.”

Woodleigh Station’s Kate Waddell said it was important to leave the land in a healthy state for future generations.  The property has been in the family for more than a century.

“Over the last 10 to 15 years we’ve started things like wet season spelling – where we fallow paddocks – and we’ve stopped burning,’’ she said.  “We’ve noticed a big improvement in our grasses and soil biology, including the water-holding capacity of our soils.

“This project is the next step. We are putting in 13km of new fences to split paddocks for better wet-season spelling, we have off-stream watering points going in and there’ll be revegetation work at the earthworks sites.

“Even with good grass cover and light stocking rates, some of our soil types erode easily during heavy rainfall so there has been quite a bit of erosion over the years.

“It’s important to keep our soil on the property – it’s our lifeblood.”

Sediment is one of the major materials affecting the health of the Great Barrier Reef.  Fine sediment and soils affects the growth rate and survival of corals, seagrasses and other plants, and in turn affect other sea life relying on these plants.

Terrain NRM’s Jen Mackenzie said the Herbert River Gully and Grazing Program would run for five years in partnership with landholders, and sites like Woodleigh Station would become models for future projects across the Great Barrier Reef catchment.

FAST FACTS – ROCK CHUTE

Length – 100m

Rocks – 5,500 tonnes (plus 450 tonnes of gravel)

Fish passage – a series of 6 pools rising 2.3m

Gully that’s being isolated – 600m long (after moving 70m in 2017-18 wet season)

Sediment prevented from entering Great Barrier Reef – 1200 tonnes per year