2009 Post 2007 Flood Salvinia on Wollombi Brook Report


Report on the spread of Alligator Weed after the 2007 flood event. Includes methodologies for treating new infestations

1 Category

Extensive and intense flooding in the Hunter region during the June 2007 storm events caused substantial damage to thousands of properties and affected major infrastructure. Estimates of property loss and economic damage was in excess of 1 billion dollars, over 5,000 properties were evacuated in the Maitland and Singleton areas and over 100,000 residents were affected by blackouts in the Hunter region. The storm and flooding that occurred also impacted on environmentally sensitive and agricultural areas, particularly properties along the Hunter River, Hexham Swamp and surrounding environs, and Lake Macquarie Foreshore and its major creek systems. Widespread flooding also affected much of the Port Stephens and Maitland Council areas which consist of a series of interconnecting wetlands and flood prone land.

From a weed management perspective, there were very serious concerns that the nature and extent of the flooding had potential to contribute to the further spread of Alligator Weed (Alteranthera philoxeroides) and other serious aquatic weeds onto adjoining land and downstream into major river systems, tributaries, wetlands and water bodies. Alligator Weed is identified as a core infestation on a national level having a high capacity and potential for new infestations to spread further inland and further expansion of existing primary infestations.

This important regional project has achieved the identification, mapping and effective control of new, regionally significant Alligator weed infestations established as a result of the June 2007 floods that affected the Hunter and Central Coast region. It has identified that natural flooding events has indeed caused further spread of Alligator Weed infestations into new areas. The outcomes of the project have provided a framework to target priority infestations and to ensure they are contained, and in many instances eradicated, to prevent the establishment of new primary Alligator Weed infestations in the future.

The HCCREMS team project managed the initiative with financial and technical support from the Department of Primary Industries and the Hunter-Central Rivers Catchment Management Authority.

There has been enormous success realised through the co-operative efforts of all participating councils. The provision of local knowledge and technical expertise by all participants assisted with effective on-ground management strategies never previously achieved on a regional scale.

This is demonstrated by the fact that approximately 121 hectares of on ground control works have been delivered under the project, while the original target established was 19.2 hectares. In light of the outcomes and findings that have been realised, it is anticipated that this project will provide the foundation upon which successful future collaborative projects of this nature can also proceed and build upon.

Date: 2009