Preventing erosion in the Herbert

Soil health is the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans. Healthy soils are the basis for healthy food production and help maintain a diverse community of soil organisms.  

Graziers and growers in the Herbert have been supported to build sustainable agricultural systems through increased understanding of soil health and its link to pasture management and erosion prevention. As a result, grazing management changes are reducing erosion and fine sediment loads in the Herbert River catchment and on the Great Barrier Reef. 

The $3.4 million Upper Herbert Water Quality Program was funded through the partnership between the Australian Government's Reef Trust and the Great Barrier Reef Foundation. Terrain NRM led the program's delivery, achieving a reduction in fine sediment losses through landscape restoration and improved grazing land management practices.  

Landscape restoration projects included the remediation of a gully network west of Ravenshoe and the rehabilitation of a section of streambank on the Herbert River. 

A 40-metre rock chute was built on Woodleigh Cattle Station with an accompanying 500 metres of bund walls. These structures are stopping the spread of a gully complex several hundred metres long. 

Contracted environmental engineering firm Neilly Group's Jen Mackenzie said, “This is an area with historical erosion that’s several hundred metres from a creek and getting worse over time,’’ she said. “The chute was built in the worst of a series of gully heads. When it rains, the bund walls now channel all the water into the chute, and on into a pre-existing channel to the creek.” 

The rock chute is the first engineered structure in a project that is heavily focused on grazing management practice changes. Woodleigh Cattle Station’s Kate Waddell says the combination is working well on her family’s property. 

“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 is important to keep our soil on the property – it is our lifeblood,” she said. 

A flood damaged streambank was rehabilitated on Terry Sheahan's Abergowrie cane farm, about 35km north-west of Ingham. Pile-fields were installed on several hundred metres of the Herbert Riverbanks. Pile fields are multiple rows of piles, driven up to seven metres into the earth. They are designed to slow down water and build up sediment, to protect and repair damaged riverbanks while revegetation occurs. 

“We have had floods over the years but there was one six years ago that cut through the paddocks, taking a corner piece of land and everything on it. With the silt dump as well, we lost about 20 acres of cane. We have been trying to build everything up again since,” said Terry.  

The teams at Neilly Group and Terrain NRM are confident the pile field will solve erosion problems, “Major erosion sites need more than vegetation initially. In coming years, we expect vegetation to establish in and around the timber piles and in time, as these piles break down, the vegetation will act as the long-term erosion control measure. Revegetation work at the site was completed at the end of the 2022 wet season," said Jen Mackenzie. 

The series of workshops and in-paddock sessions delivered with grazing families over the course of the program has provided new learnings and a better understanding of rangelands and grazing management practices. Strong relationships have been developed and the networks built through the process have provided opportunities to bounce ideas off other like-minded graziers.  

Support was provided by grazing management specialist Dick Richardson, an internationally recognised leader in the practice of natural grazing to improve soil health and increase biodiversity and animal production. 

Dick Richardson said, “From a grazier’s perspective a healthy soil is one that, when it gets a little rain, provides that to plants, gives you beautiful greenery and good nutrition for your animals and a good growing phase for them. It can hold more moisture for a longer period of time." 

“The way we move our animals through the landscape is key to creating change in the landscape. Making the decision to run stock in an environmentally positive way is a business decision that is definitely worth your while,” he said.

Graziers are now dividing larger paddocks into smaller paddocks and grazing some intensely and spelling (excluding cattle) others for up to a year as part of a cycle to improve pasture. This approach to grazing land management creates tighter plant spacing which enables moisture to be retained in the soil, reduces run-off, and improves soil health.  

To reduce erosion from hillslopes, grazing land management practice changes were enabled through new infrastructure implemented across over 56,000 hectares of grazing land. 

Grazier Brett Blennerhassett said, “We have split paddocks, some into five. I can see big improvements from the rotational grazing we have done. The pasture has got thicker and thicker over time. As it gets thicker and more vibrant, your soil is getting healthier.” 

Landholders Margie Atkinson and Greg Jenkins say it is never too late for fresh ideas. They currently graze 4,000 head of beef cattle on 29,000 hectares of land. She said a Grazing Naturally workshop with Dick Richardson had been a catalyst for change. Their long-term aim is to create better ground cover and more diverse and nutritious pastures.  

A 70 km fencing project is making 62 paddocks out of the property’s 28 paddocks for a switch from set stocking to rotational grazing in smaller paddocks for shorter, more intense periods. Extra water points are also being added for cattle to help manage grazing pressure. 

Terrain NRM’s Duncan Buckle said graziers from 29 properties that collectively manage more than 320,000 hectares in the Herbert catchment have taken on board new ideas through the series of workshops on grazing practice change, soil health and rehydrating the landscape. 

“We work with graziers to improve the health of grassland ecosystems, of cattle and production. Fine-tuning grazing management practices is a big part of the program. Making the land more resilient is the key to reducing erosion in this catchment, which is one of the five highest contributors of fine sediment to the Great Barrier Reef,” he said.

The Herbert is the largest catchment in the Wet Tropics region and the river spans 288km from the Atherton Tablelands to the coast at Ingham. In the long-term, landscape restoration and grazing land management changes made through the program will improve soil health, land condition and water quality resulting in less sediment leaving grazing properties and entering the Herbert River.  

To date, the Upper Herbert Water Quality Program has achieved a reduction of nearly 4 kilo tonnes of fine sediment load per year, the equivalent of 200 dump truck loads, from entering local waterways and the Great Barrier Reef lagoon.