Land and Water Link

September 2002

Combating Catchment Erosion Erosion in the Burdekin Catchment Queensland can now be tackled at key hotspots, thanks to information released jointly by Meat and Livestock Australia (MLA), CSIRO, the National Land and Water Resources Audit and the Queensland Department of Primary Industries. 'Mapping an entire catchment is a difficult task', says CSIRO scientist, Dr Ian Prosser, 'especially when the catchment covers over 130,000 square kilometres, much of it undocumented.' The solution was to collect all the available regional information about the catchment and then combine it with Geographical Information System (GIS) maps to develop a predictive model. A team of researchers took two months to compile the regional data needed to develop a comprehensive model of the Burdekin Catchment. The next step was to apply a computer modelling program called SedNet (Sediment Network) to predict sediment movement. SedNet has also enabled scientists to develop historical models of the catchment, its current state and future scenarios based on different management strategies. According to Dr Prosser, 'Existing information about the catchment included stream gauging data from 22 places, information from soil loss studies, aerial photographs and information from the literature. Gully erosion data was collected from almost 100 sample sites. We combined this with GIS maps showing the structure of the landscape, its topography, soil types, geology, land use, roads, river networks and gully networks, and then analysed the information using the SedNet program to assess the movement of sediment and nutrients'. The results indicate that the Burdekin Catchment is delivering almost four times the amount of soil to streams and rivers than it did at the turn of the century. This is due to grazing pressure disturbing the ground cover, combined with heavy tropical rainfall. Producers and land managers have long recognised that erosion is a problem threatening the district's $100 million beef industry and have been tackling erosion on a number of fronts over the past ten years. Working to assist them, CSIRO Sustainable Ecosystem's Ecograze Project has studied grazing pressure and developed a number of strategies to rehabilitate and retain sustainable ground cover in order to address soil degradation. The measures include conservative stocking rates, rotational wet season pasture spelling, appropriate use of fire, fencing riparian areas, man-made stock water points, fighting woody weeds and intensive land and grazing management. A brochure recently released by CSIRO and Meat and Livestock Australia, Patterns of Erosion and Sediment Transport in the Burdekin River Catchment (PDF, 1.5 MB), has been distributed to all graziers in the catchment. The brochure outlines the latest findings using SedNet and describes erosion hotspots in the Burdekin Catchment and how best they can be managed.

Targeting of the erosion hotspots shows where resources can be directed for maximum benefit. The good news for Burdekin land managers is that 95% of sediment comes from 13% of the catchment. By land managers joining forces, planning and directing resources to strategically tackle erosion problems, the catchment has a fighting chance of remediation and long term, sustainable production. Working together, landholders, government agencies and land managers are developing strategies to deliver resources that will enable regional communities to look after their own catchments. In November 2002, the Council of Australian Governments endorsed the National Action Plan for Salinity and Water Quality (NAP), providing seven years of funding, totalling $162 million for Queensland, for sustainable land management at the regional level. In the Burdekin Catchment, NAP foundation funding has underpinned the establishment of a regional body called the Burdekin Dry Tropics Group (BDTG), with representatives from community groups, local councils and scientists. The BDTG will develop an accredited and integrated natural resource management plan as well as an overall strategy including set targets and an investment strategy. Once the investment strategy is endorsed by state and federal governments, the Board can implement the plans. 'This is an excellent mechanism for devolving responsibility to regions', explains Dr Christian Roth, Acting Regional Coordinator for CSIRO's Healthy Country Flagship Program. 'This process will empower the regions, enabling them to take issues into their own hands. Centralised government does not have the resources to undertake all the action required to make production sustainable in the Burdekin. This way, landholders, communities and managers can understand what needs to be done and can take responsibility for making the necessary changes'.

For further information

Contact

Dr Christian Roth
Ph: 07 4753 8569

Mr Bob Shepherd
DPI Charters Towers
Ph: 07 4754 6100