Taylors, Wartook key for Green

“Last time Green Lake saw significant inflow was in 2016 and then a smaller volume in 2017. On both occasions Taylors Lake and Lake Wartook were full” – Kym Wilson

More rain across the Wimmera catchment and more water flowing into Taylors Lake and Lake Wartook hold the key to recreation impoundment Green Lake’s chances of filling this spring.

A full Taylors, which with Green is part of the Boga Lakes system southeast of Horsham, and Wartook, providing Horsham supply from the Grampians, would open the door for a diversion.

Gwmwater storage manager Kym Wilson said under water-sharing rules, the only other way to guarantee water for Green Lake would be a water-entitlement holder considering itself in a position to make an allocation offer.

“Last time Green Lake saw significant inflow was in 2016 and then a smaller volume in 2017. On both occasions Taylors Lake and Lake Wartook were full,” he said.

“As part of the ongoing monitoring process and analysis of storage levels, we’re closely watching the levels of Taylors and Wartook, which will ultimately determine any decisions regarding Green Lake.”

If an entitlement holder decides it has water available for distribution into Green Lake based on levels in the overall system, Horsham Rural City Council has allocated $30,000 for its purchase.

Water-entitlement holders and stakeholders include Gwmwater, Coliban Water, Wannon Water, Victorian Environmental Water Holder, Commonwealth Environmental Water Office, Victorian Department of Environment, Land, Water and Planning and Wimmera, North Central, Glenelg-hopkins and Mallee catchment management authorities.

Last week’s storage-level figures showed Taylors Lake sitting at 69 percent full and Lake Wartook at 72 percent.

“Both are still increasing slowly, but without a lot of rain in the past fortnight the rate is decreasing. We’re waiting for more rain to keeping it running,” Mr Wilson said.

“With the filling of those lakes comes increasing opportunity. We’re still in August and there are still opportunities to see inflows for that to happen. It is all dependent on where and when the rain falls.”

Mr Wilson said Green Lake, no longer part of the storage-supply system but with a capacity for opportunistic supply, would need 2500 megalitres of water to get it up to a level appropriate for recreational boating.

“It’s worth noting that with that amount of water we could fill all 10 other lakes that receive recreation water through pipeline allocation across the region,” he said.

While Green Lake might soon be in a position to receive a water diversion, Lake Toolondo, south of Horsham, has less chance.

Toolondo, another secondary storage and part of a recreation and wildlife wetland, needs a Rocklands volume to reach a trigger level to be eligible for supply.

Rocklands, also bound by water-sharing rules to provide environmental supply to the Glenelg River, was last week 26,000 megalitres short of the trigger level for Toolondo.

As has happened in the past, the only way Toolondo Reservoir could receive water under current circumstances and operation procedures would again be via an agreed sharing allocation from an entitlement holder.

Water naturally running down the Wimmera River after rain in the catchment is flowing independently of the system, providing supply for the environment and weir pools at Horsham, Dimboola and Jeparit.

Under bulk-entitlement arrangements, Gwmwater must provide portions of passing flows to Wimmera and Glenelg rivers. But the level of natural flows caused by consistent rain have been high enough to allow for the capture of more water for storage and release at a later date.

Flows in the Wimmera River have made their way to Lake Hindmarsh in the northern Wimmera.