The upgrades to Sideling Creek Dam, as part of our Dam Improvement Program, will involve strengthening the main embankment of the dam and the concrete spillway, and then restoring the dam’s capacity to the original full supply level. Upgrading the dam is the most cost-effective way to improve dam safety, while maintaining the dam’s flood mitigation benefits and keeping the lake open to recreation.

The work will involve strengthening the main dam embankment (pictured below) by constructing a sand filter layer across the downstream face of the embankment held in place by a layer of engineered fill. The lower part of the dam in the original creek bed will be strengthened by the construction of a rock-fill berm to support the embankment. We expect the upgrade will take about 12 months to complete, subject to weather conditions and other unforeseen delays.

This phase of the project also involves safety and environmental assessments so that we can include any special requirements for construction in the design. A traffic management assessment has already been completed for Sideling Creek Dam to consider the impacts of construction on the local road network. We have recently been completing Cultural Heritage and Environmental assessments at the site in preparation for construction.

We have also been speaking with the Department of Energy and Water Supply, the Department of Agriculture and Fisheries and the Department of Natural Resources and Mines regarding our plans to improve the area downstream of the spillway.

A new dissipator in the form of an excavated pool will be constructed at the end of the concrete spillway to manage erosion and improve fish migration downstream. We will also be making improvements to the creek channel downstream.

Currently, there is potential for fish to become stranded below the concrete spillway after flood events in waterholes that can be found in the creek bed. The dissipator will be excavated in the existing rock to break up the energy from flood flows and will help fish travel downstream. We will also be providing safe access for rescuing any stranded fish if required. Design plans (below) for the dissipater are being finalised to provide the best solution for ongoing operation.

As part of the dissipator improvements some of the excavated material will be used to stabilise the downstream creek banks which will help to minimise erosion.

Last year, we announced we would be opening Lake Samsonvale to the public for paddlecraft for the first time, as well as revising the current shared recreation arrangement on Lake Kurwongbah to allow public rowing, paddling and club skiing on the lake, seven days a week. We are currently planning to introduce these changes at both lakes. We will continue to talk to key stakeholders throughout the planning process. Keep an eye on our website for updates.