Graziers Gain Insight Into Gullies
AUSTRALIA - New research that gives scientists an insight into erosion in river catchments will assist land rehabilitation programmes to tackle sedimentation and improve the quality of water flowing out of grazing lands.Agri-Science Queensland Charters Towers-based principal extension officer Bob Shepherd has studied gully erosion along the Upper Burdekin River frontage by combining new technology with more traditional methods.
As part of his research, Mr Shepherd selected an area of extensive gullying near the confluence of the Burdekin and Clarke Rivers. He then studied aerial photos and satellite imagery of the gully network, which gave a visual history of the area from 1951 to 2009.
By measuring the area affected, Mr Shepherd calculated that the gullies had expanded by 22 per cent in 58 years.
Not satisfied with this time frame, Mr Shepherd strengthened his research by scouring historical documentation from some of the region’s first explorers.
The diary of Ludwig Leichhardt, published in 1847, mentions gullies in the same specific area in 1845. This is significant because it predates the introduction of domestic livestock by at least 16 years.
"This research suggests that in some areas gully formation occurs due to geomorphological reasons - such as changes in river behaviour and water movement," he said.
"Graziers in the Burdekin are committed to improving land condition, but it is important to discern between naturally occurring erosion and erosion caused by poor grazing land management - or areas where there is a combination of the two.
"By using technology such as long term satellite imagery, and going even further back through historical archives, we can more strategically identify priority areas for remediation work by landholders.
"This will ultimately improve grazing land by reducing erosion and sedimentation, and improve the quality of water for downstream users."
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