Late season rain sets up southern Grampians wetlands for another good year

It’s shaping up to be another “half-decent” year for wetlands around the southern tip of the Grampians.

Despite a very dry autumn and winter, spring rains arrived to get the catchment running. The Wannon River has been flowing south of Lynchs Crossing Rd since mid-August but really only started to pick up in the Brady Swamp system in September. Last Friday it was flowing in at around 230 ML/day which is more than anytime last year. Downstream from Brady Swamp it’s flowing under Wannon River Road at 86 ML/day, which tells us that Brady Swamp is overflowing, activating the natural Wannon River outlet which has been restored since we completely backfilled the artificial drainage outlet in 2015.

Below are a few images I have taken during a recent visit around the southern Grampians sites to give you a sense of current conditions.

The eastern channel of the Wannon River at Lynchs Crossing (flowing at 140 ML/D)
Wannon River downstream of Brady Swamp – Wannon River Rd (flowing at 86 ML/D)
Brady Swamp, showing Gooseneck Swamp and wetlands on the Walker Swamp Restoration Reserve in the background

Both of NGT’s local reserves at Walker and Green Swamp are receiving inflows but still have a little way to go, with neither yet to spill. We’ll be watching another decent rain band coming through over the next week with great interest!

Green Swamp approximately three quarters full

Over the range, the Victoria Valley has received high September rainfall. The headwaters of this system are full meaning that any additional rainfall is going to translate directly into runoff toward Bryan Swamp and the Wannon River. For those of you who joined us for restoration works at Barrahed, you’ll be pleased to know that the spillway is performing well. The levels are perfect and I even heard the seasons first ‘growler’ (aka Growling Grass Frog / Southern Bell Frog) calling!

Mirranatwa wetland at the top of Victoria Valley
Attenuated spill from Mirranatwa wetland
Lachlan Farrington