As a result of recent heavy rains experienced in Ballarat Lake Wendouree is now overfull.

The circular brick ‘heritage’ bi-wall outlet has been controlling the outflow of water from the Lake for the past 130 years, however it was not designed to enable the water level to be ‘actively controlled’.

With inflows exceeding the outflow from the existing outlet, the water level of the Lake has remained high, despite all supplementary supplies of stormwater and treated water having been switched off.  The overfull condition has caused some lake water to spill onto adjacent public areas and the capacity of the existing single outlet has meant that the Lake has remained overfull for prolonged periods.

City of Ballarat has commenced works to install an additional outlet drainage system for the lake that will allow some manual control of the flow of water from Lake Wendouree.

City of Ballarat Director Growth and Development Eric Braslis said that by installing an additional outlet pipe with an adjustable valve the controlled release of water now will be possible.

“The new outlet will allow the Lake to continue to hold back peak stormwater flows during heavy rain events and for Council to release the water over subsequent days once storm surges have passed.

“This control of water flow will be beneficial to the health of the river system and will aide in reducing erosion and flooding issues in the Yarrowee, Leigh, Barwon River system.”

The new outlet is being installed adjacent to the existing one and will be operational by early next week. It will then commence releasing water flows into the stormwater drain system which flows through to the Yarrowee River system.

The water level will be reduced to the Lake’s full weir height. It may be reduced by a further 100-200 mm if there is a prospect of further high intensity rainfall. This reduction will have no impact on the use of the Lake by aquatic users. The lake is intended to be managed with fluctuations of up to 300mm without impact on its use or aesthetic appeal.

Dredging of the rowing course is on schedule despite the issues that an overfull lake presented, being migration of sediments from retention areas and water above safe operating level for an excavator. The works are scheduled to be complete by May/June.

The new outlet will have a fish proof screen fitted to ensure the trout that are stocked in the Lake are not lost with the flowing water.