Works to reduce the height of Warren Dam’s spillway are now complete, as part of SA Water’s efforts to ensure the dam continues to safely operate during major rainfall events.
More than 100m3 of concrete was removed from the spillway crest during the past two months to lower it by around 1.9m and create a 20m-wide slot to enable water from the reservoir to be released downstream.
Water has now begun flowing down Warren’s modified spillway for the first time after the reservoir reached around 65 per cent of its original capacity, which will be captured by nearby South Para Reservoir.
A detailed engineering review of Warren Dam – as part of the utility’s long-term upgrade program – found recent changes in the condition of the dam, which could impact its stability if it was at full capacity during major rainfall events.
SA Water Senior Manager of Infrastructure Planning and Strategy, Dr Daniel Hoefel, said the utility’s interim measures have improved the dam’s stability during major rainfall events.
“After learning of the change in Warren Dam’s condition, we’ve acted swiftly to ensure the dam continues to operate safely during major rainfall events, and I’m pleased to share with the local community that both of our interim measures have now been implemented,” Dr Hoefel said.
“Importantly, these are defined as rainfall events higher than a ‘one in one hundred year’ event.
“While lowering the reservoir’s water level was an immediate action we could take, reducing the height of the spillway required thorough planning before we mobilised our crews to undertake the work.
“This measure was achieved by removing a large section of the spillway crest to enable water to be safely released downstream at the reservoir’s reduced operating level of around 65 per cent of its capacity.
“Our crews operated specialist machinery to safely remove concrete from the spillway, while a temporary pumping system on the reservoir diverted water downstream until our work was completed.
“Importantly, these two proactive measures are an interim step to ensure Warren Dam continues to operate safely as we progress our investigations into long-term solutions.
“This work will also consider how we can incrementally improve the dam’s safety through staged upgrades, to help balance water security for the region.
“At this stage, we expect to share the outcomes of this investigation with the community early next year.”
Featured image: Gary Unwin/shutterstock.com
