Works begin this week on the reinstatement of the Dunkeld Arboretum dam, damaged in the 2016 floods.
The flood event caused significant water to flow over the wall outside of the spillway footprint. The spillway and discharge channel were significantly damaged, causing erosion and narrowing of the wall structure.
The State Government of Victoria made a budget allocation in the 2018/19 budget to reduce the risk rating on a number of regional dams, and the Dunkeld Arboretum Dam was part of this funding initiative. Inspection by Southern Rural Water found the dam to be in an unsatisfactory condition with some serious issues identified, most notably relating to failure from piping, stability and lack of flood capacity.
Following engineering design work completed by consultant SMEC, contractor LincRoads have been engaged to repair the wall and spillway to pre-flood condition. This includes adhering to current engineering standards for large dams, in order to reduce the risk associated with stability and potential dam failure, improving safety for Dunkeld residents.
The project is being delivered in partnership with Department of Environment, Land, Water and Planning (DELWP) through National Disaster Relief Funding Arrangements. Funding of $1million has been released by DELWP to complete the project, with Council to contribute the remaining approximately $400,000.
Major construction activities at the site include:
• de-watering of the dam;
• construction of a new spillway;
• re-strengthening of upstream embankment;
• removal of the trees along the upstream embankment,
• removal of the existing jetty; and
• relocation of the existing pump infrastructure on the reservoir embankment.
The project is due for completion by the end of April 2020, subject to weather conditions.