The goal of the Herbert Gully and Grazing Program is to reduce fine sediment loads flowing to the Great Barrier Reef lagoon by tackling erosion and helping landholders to change grazing practices.
This is a five-year project, funded through the Australian Government's Reef Trust Phase IV program and delivered by Terrain NRM in partnership with landholders from the Atherton Tablelands to Ingham.
The Herbert Gully and Grazing Program includes earthworks to reshape gullies, fencing to keep stock away from stream banks, the creation of off-stream watering points for stock, revegetation and weed management projects.
Just as importantly, it includes a range of workshops for graziers right across the Wet Tropics region on natural grazing practices, soil health and its link to pasture management.
Why it's important
Sediment is one of the major pollutants affecting the health of the Great Barrier Reef.
When fine sediment is suspended in water on the reef it blocks the sunlight from reaching algae that photosynthesise sunlight to gives coral its vibrant colours. The algae is dependent on sunlight for its survival.
In addition to coral, sea grasses also need sunlight to survive. Sediment can kill or damage sea grass beds, which also has a knock-on effect on mammals and fish that feed on them.
The three catchments responsible for the majority of fine sediment reaching the Great Barrier Reef are the Burdekin, Herbert and Fitzroy.
What causes sediment to reach the reef
Erosion of subsoil contributes approximately 90 per cent of the fine sediment load flowing to the Reef.
Most of this comes from gully and stream channels. Gully erosion contributes at least 40% and stream erosion about 30%. The rest comes from subsoil from rilling on hillslopes.
Gully erosion became a problem after the introduction of livestock grazing and other catchment disturbances between 1850 and 1900.
Gully erosion became extensive along drainage lines and in floodplain sediments adjacent to some large river channels, while stream banks exposed to grazing and degradation of vegetation have been eroding at accelerated rates.
Another issue identified in the Herbert is leaking tailings dams from old mines. These contain super fine crushed rock, a waste by-product of mining. The integrity of some tailings dams has been compromised, resulting in materials discharging into the Herbert when it rains.
Who to contact
If you are a grazier in the Upper or Lower Herbert and you would like to find out more about this project, please contact Jen Mackenzie on 0438 206343 or email firstname.lastname@example.org.