Lake Macdonald water for thought

BY ALEX PURCELL

COOROY’S Lake Macdon- ald Dam is one of 12 dams that supply drinking water to South East Queensland.

The dam, officially known as Six Mile Creek Dam, is part of the SEQ Water Grid – a connected network of source water assets, bulk water pipelines and water treatment plants.

A Seqwater spokesperson said the grid allows them to move treated drinking water around the region. “The SEQ Water Grid connects 12 dams: Wivenhoe, Somerset, North Pine, Hinze, Baroon Pocket, Leslie Harrison, Ewen Maddock, Cooloolabin, Sideling Creek, Lake

Macdonald, Little Nerang and Wappa; 32 conventional water treatment plants; three advanced water treatment plants; one desalination plant; 28 bulk water reservoirs; 22 pump stations; and bulk supply pipelines that stretch more than 600 kilometres.

“It enables us to move treated drinking water around the region in either direction when needed, from the Sunshine Coast to Greater Brisbane, to Redlands and south to the Gold Coast.”

The Seqwater spokesperson said this is especially important when patchy rainfall leaves some areas with full dams and other parts of the region with lower dam levels.

“This provides Seqwater with some flexibility to help manage water supply challenges arising from variable rainfall patterns, drought, climate change and population growth.

“While we always encourage everyone to do their part to use water wisely, urban water restrictions are not considered until the combined capacity of the 12 water grid dams falls below 50 per cent.

“As at 21 February 2023, the SEQ Water Grid storage capacity is 79 per cent and the capacity of Lake Macdonald is at 87 per cent.”

In the past five years, the

SEQ Water Grid storage capacity has only dropped as low as 54 per cent and Lake Macdonald Dam as low as 74 per cent.

“Water supply is constantly monitored through a combination of manual checks and gauge readings and automatic gauge instrumentation, and where needed, we adapt our operation of the water grid accounting for storage levels, consumption and other factors.”

Seqwater also monitors and manages topped-up dams, offering dam release notifications to those living or staying near dams like Lake Macdonald.

When Lake Macdonald, an ungated dam, reaches 100 per cent capacity as it did in February 2022, water flows over the spillway and safely out of the dam.

“The dam release notification service, combined with alerts from the Bureau of Meteorology and council-led local disaster management groups, are important resources for people living, working or holidaying near or downstream of a dam.

“Our public safety app provides up-to-date safety alerts, information on water supply levels and recreation notices for the authority’s 26 dams.

“Subscribers can receive notifications for their chosen dams and opt-in for updates by email, text message or recorded message to landline telephone about when Seqwater dam releases are occurring and when ungated dams are spilling or have stopped spilling.”

Lake Macdonald was built in 1965 and the dam was raised in 1980 to increase its storage capacity. A project to further upgrade the dam was scheduled to begin in 2021 but was put on hold to be reassessed after information emerged during the procurement stage that project costs would be significantly higher than the approved $127 million budget.