The Department of Commerce has been engaged on behalf of the Carrathool Shire Council to prepare a Review of Environmental Factors (REF) for the proposal to upgrade the Eastern Levee Bank in Hillston. The REF has been prepared to identify potential environmental impacts arising from the proposal to meet the requirements under the Environmental Planning and Assessment Act 1979. Hillston is located approximately 680 km west of Sydney and is situated adjacent to the Lachlan River. Hillston has been affected by a number of floods with the most significant recorded floods being in 1956 and 1990. A series of levee banks currently exist around the town. The eastern levee banks were built on the eastern side of the town during the 1990 flood to protect the town from overbank flows and flood runners emanating from Gum Swamp. The re-alignment and improvement of the eastern levee has been identified as a priority structural measure in the Floodplain Risk Management Plan to protect the town of Hillston from flooding from Gum Swamp.

A number of environmental impacts associated with construction of the project have been identified and include the potential for sedimentation and erosion, elevated dust, noise, traffic and impacts to flora and fauna through vegetation clearing. Two Aboriginal Scarred Trees have also been identified within the vicinity of the works area. The impacts from the construction of the project have been assessed as not being significant, provided identified mitigation measures are implemented. The soils in Hillston have been assessed through geotechnical investigations, as being very stable and suitable for the construction of the levee. Due to the current drought and the stable nature of the soils, the levee will be allowed to naturally revegetate. The area would be compacted and stabilised and regularly inspected to ensure erosion does not occur. An operational maintenance plan would be developed to address the ongoing maintenance requirements for the levee including requirements for regular inspections to ensure erosion does not occur.

The upgraded levee is not expected to substantially alter the flow of floodwaters compared to the current arrangement. The upgraded eastern levee will provide effective and long-term flood protection for the residents, properties and infrastructure in the town of Hillston. Based on the findings of this REF it is concluded that provided the mitigation measures identified are implemented, the proposal would not result in any significant adverse environmental impacts.