Rare River Murray sight as Lock Three drained dry for maintenance

More than eight million litres of water has been drained from the River Murray’s historic Lock Three, as part of important maintenance work to improve operations at the 100-year-old site.

Stationed at Overland Corner in the Riverland, the refurbishments being undertaken by SA Water on behalf of the Murray-Darling Basin Authority include replacing the lock chamber’s water control valves, re-sealing the four large hydraulic chamber gates and re-concreting sections of the lock floor.

This work is expected to be completed by mid-2025, with vessels temporarily unable to navigate through the lock chamber until the project is complete and the lock is rewatered.

SA Water’s Senior Manager of River Murray Operations Garry Fyfe said the maintenance will positively benefit the site’s operation into the future.

“For the past century, Lock Three has played a vital role in the daily lives of hundreds of houseboats, kayaks, dinghies and other vessels travelling up and down the River Murray each year,” Garry said.

“While the lock chamber continues to operate as normal, we have identified minor refurbishments that will improve how we operate it, and speed-up the lockage process for river users passing through.

“This includes refurbishing and replacing sections of timber and rubber sealing on the lock’s four 18-tonne hydraulic gates, along with replacing all 12 of the internal control valves used to raise and lower water levels in the lock chamber for boats traversing from one side of the lock to the other.”

To allow construction crews safe access to the site, Mr Fyfe said two cofferdams have been strategically constructed at either end of the lock chamber to prevent water flowing in, before it was gradually de-watered in early May.

“The lock chamber itself is more than 100-metres long, and to see such a large piece of infrastructure completely drained is a sight you don’t see that often!” Garry said.

“Following the completion of these vital works in the coming months, we will start to gradually re-fill the chamber with its normal water capacity before reopening the lock back to business as usual.

“This is a sizeable task, and it is a credit to our team who have spent the best part of a year carefully planning this vital work to align with optimal river flows and timing the site’s closure during the quieter winter months where river traffic is at its lowest.”

Constructed in 1925 and this year celebrating 100 years of service, Lock Three was the second to become operational in the South Australian stretch of the River Murray.

On behalf of the Murray-Darling Basin Authority, SA Water manages Locks One to Six in South Australia as well as Lock Seven at Rufus River and Lock Eight at Wangumma in New South Wales, and Lock Nine at Kulnine in Victoria. The utility also operates barrages at Goolwa, Mundoo, Boundary Creek, Ewe Island and Tauwitchere.

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