2016 – Spillway gates, CFD analysis, Uplift forces, Hydrodynamic forces, Flow Modification, Gate Locking Mechanism.

Chris Kuenne

Paradise Dam is located on the Burnett River 20 km northwest of the town of Biggenden in Queensland. It is a gravity dam with a height of 37 metres and a total capacity of 300,000 ML. It was primarily constructed to service local agriculture.

The dam features a complex outlet works contained within a tightly constrained footprint. It provides for irrigation releases, fish passage and power generation. Additionally, the outlet is required to pass very high environmental flows of up to 270 m3/s.
The dam was subjected to major flooding in 2013 resulting in significant damage to the mechanical equipment associated with the outlet works, and severe scour downstream of the spillway.

Since construction, the operating range for the environmental outlet has been restricted. A rough operating zone has been identified through which the gates are quickly moved through. It is believed to be caused by the dynamics of the gates and the upstream conduit arrangement. Failure of the downstream stainless steel liner associated with the conduit has also occurred. The environmental outlet lacks the ability to be isolated from the storage, complicating the maintenance / modification of the gates. At the time of design, it was agreed by the alliance partners that major maintenance of the gate would be planned for when the reservoir was low, being below the intake bellmouth.

The irrigation release valves suffer from high vibration levels during operation. Component failure and severe corrosion have also been experienced.
This paper details:
Operational and maintenance experiences and restrictions since commencing operation including the impact of flooding;
Investigation and testing of environmental gate dynamics and the impact of these on the intake tower;
Failure of the environmental conduit liner, investigation and proposed rectification;
Proposed method to enable servicing of environmental gates without the use of a bulkhead and without draining the storage;
Proposed enhancements to irrigation valves to reduce vibration and extend service life.

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