High hopes for spring flows
The Wimmera River is primed to continue flowing deep into spring if weather in the upper catchment follows traditional patterns.
Several natural flows are gradually heading down the river to Jeparit, the largest pulse peaking at 1000 megalitres, or 1000 million litres, a day.
Other pulses generated from winter run-off range between 100 and 800 megalitres a day.
An onset of dryer weather finishing off the season has meant flows have started tailing off but catchment monitors remain hopeful spring rain will provide a trigger for more water in the next couple of months.
Wimmera Catchment Management Authority chief executive David Brennan said sporadic rain in the region had led to a variability in flow regimes.
“The largest of pulses should just about be at Jeparit – it normally takes about three weeks to get there – and this on-and-off rain pattern has been providing surges leading to what appears as a meandering flow,” he said.
“What is good about what’s happening in the river is that, historically, our large inflow months are September and October. This means the river is well positioned leading into the high-yielding months.
“Fingers crossed it keeps on raining and provides a circumstance where the river continues to run under its own steam well into the warmer months.”
Mr Brennan said despite healthy flows making their way from the river’s source in the Pyrenees to the ‘always thirsty’ lower catchment, expectations were that it would
have little impact on Lake Hindmarsh, the first of terminal lakes at the end of the system.
He said the catchment had started from an ‘extremely’ dry base and had taken considerable rain to become saturated.
“We’d be happy if we could get a trickle into the mouth of Lake Hindmarsh but what’s happening at the moment will be of little consequence in regard to putting water into the lake,” he said.
“But the good news is that right along the river, this water is providing a refreshing boost to aquatic life. It will do everything from triggering a boom in macro-invertebrates such as insects and crustaceans to help out anglers with a better summer catch than they might previously have had.
“It’s a win for the environment as well as communities that rely on the river for its socio-economic benefits. We’ll wait and see whether it continues – it will great if it does.”
Wimmera headworks storage levels last week showed the system was sitting at 42.71 percent full, down from 51.95 percent for the same time last year.
The region’s primary pipeline supply impoundment Lake Bellfield at Halls Gap was 75 percent full, and key transfer lake Taylors Lake, south-east of Horsham, at 60 percent.
Figures also showed Lake Fyans near Stawell at 78 percent, nearby Lake Lonsdale at 37, Grampians lakes Wartook and Moora Moora at 58 and 71 respectively, Rocklands at 32, Toolondo at 28, Mt Cole Reservoir at 65 and Green Lake near Horsham at 65.
Gwmwater officials will update reservoir figures today.