NSW – Copeton Dam Safety Upgrade Project
Author: Nava Jeyachandran.
Copeton Dam is located on the Gwydir River in northern NSW and supplies water for town water supply as well as irrigators. Copeton Dam was upgraded to ensure the dam complies with the Australian National Committee on Large Dams (ANCOLD) and NSW Dams Safety Committee (NSW DSC) standards for extreme floods.
The Copeton Dam Stage 1 safety upgrade involved construction of a four-bay, 250-metre-wide, fuse plug (FP) spillway to reduce the risk and impact of extreme floods on downstream communities; relocation of elements of the Copeton Waters State Park (CWSP) to make way for the new FP; construction of a temporary public access road to allow public access to CWSP and nearby towns and demolition and re-establishment of the Copeton Dam Road as a fusible permanent road.
The project was completed in March 2013, five months ahead of schedule, 23% under budget, with no lost time injuries and excellent quality and environmental outcomes. During construction the dam’s water level rose from 50% to 100% of capacity (17.8 metres of water). An engineered cofferdam was built prior to excavating the spillway channel to ensure continued protection of downstream communities and the construction activities. Over 1.2 million cubic metres of predominantly granite rock was removed to construct the FP spillway by blasting within close proximity to the operational (CWSP) park. The innovation of a fusible permanent road downstream of the new spillway in lieu of a bridge provided significant cost savings and improved environment outcomes to the project. The regional community enjoyed an injection of circa $20 million into the regional economy.
The project is the finalist for the 2013 Engineers Australia Excellence Awards for project management.