Walker's Lake Bird Survey

Wednesday 20th Feb 2019 saw several members from St Arnaud Field Nats and Avon Plains Banyena Landcare Group leave the boat ramp for a round-the-Lake bird survey. Beautiful clear, sunny and cool weather kept any pesky insects at bay and we spent 2 1/2 hrs watching birds and listing them for Birdlife Australia's online Bird Atlas. Walker's Lake, north-west of St Arnaud, one of the waterbodies in the highly significant Avon Plains Lakes system.

30 species were seen, mostly waterbirds or landbirds that are associated with wetter environments such as Magpie-larks. For first part of our walk, through Black Box Woodland to the western end of the lunette, we were accompanied by a small family of Black-fronted Dotterels, moving like little clockwork toys along the insect-laden edges of the water. Moving with the BF Dots, but staying in front of the pack was a pair of Red-kneed Dotterels. You can see the red knees in this on-the- move long telephoto shot by Prue McAllister (APBLG).

Up onto the lunette( a huge sandbank, formed over thousands of years from pelleted clay blown from the lake bed during dry,cold spells) and the bird assembly changed- Welcome Swallows and White-plumed Honeyeaters foraged busily above or in the massive Redgums, Galahs and Long-billed Corellas defended their nesting areas; the Redgums are full of hollows, indicating their great age (150 year of growth before hollows begin to form). From our vantage point we spied a raft of Australasian Darters, diving and fishing in the shallow waters, almost like a choreographed water ballet- all up, then one after the other, down again! It was hard to count how many there were. Male Darter in breeding array Photo A Hughes StAFNC

Several smallish rafts of ducks were seen a good distance away- photos later revealed Pacific Black Ducks, Grey Teal, one lonely Hardhead, the pretty little Pink-eared Ducks and wonder of wonders, a group of 4 Australasian Shovelers, a protected species during the duck shooting season, and not unlike the Pinkies in profile( strange bills) but larger and with more distinguishing marks- white patch and dark rump. This group included 3 males and one female and the very long shot was taken again, by Prue McAllister.

Coming around to the inlet area, we were escorted along the shoreline by a Sacred Kingfisher, nervous of our presence but reluctant to leave us to our own devices for some reason. Photo by Anne Hughes StAFNC

Moving along the southern shore, through the Redgums and Black Box, we spotted 4 White-breasted Woodswallows using the fenceposts as perches.

They were not interested in posing for the cameras but the photos were good enough for identification purposes. White-breasted Woodswallows are seen at the Lake mostly during Summer.

This pair behaved like juveniles, waiting for parents to return with a meal.

Food was certainly on our minds as we completed the 3km walk and headed for our morning tea- the usual relaxed and enjoyable end to our outings at the lake.

THE CHAIN OF PONDS

I deduce that before Victoria was grazed and mined our waterways were very different. Early surveys seem to affirm this: maps of the plains and broad valleys often include the italic notation ‘chain of ponds’. Doubtless, dense or very mature riparian vegetation lined their banks.

In my youth I roamed the reaches and cut-off bends of the straightened-out, de-snagged Latrobe River, cleared from time to time of their numerous stands of silver wattle, and eventually I read Peter Andrews’ thoughts on Australian flood plain management. (Basically he says: Hold water as long as you can, where it falls!)

Then, perusing Google Earth some years ago, I noticed unusual features along Middle Creek - 10 km SW of St Arnaud. As you moved upstream the raw gullies, so characteristic of northern Victoria, gave way to – yes!!! – a chain of ponds. On-ground examination later with the landowner confirmed my assumptions.

I could see that, once hoofed animals such as sheep and cattle displaced the gentler indigenous grazers, the newcomers, tracking in and out to drink, broke down the intervening earthen barriers between the pools, over which runoff had for millennia more or less gently trickled. Continuous gullies soon opened up.

Here is part of what I saw, thanks to Google.

Note the creek is still fairly intact where the cover is better - obviously there’s been less grazing here of late - but to the east where the land is hammered even today, the creek is a gutter. All the way more or less to the Avoca!

Here are several other images of Middle Creek from above:

That led to work on our 95 hectares at Adams Road, where there are now 100 waterholes (we call them gilgai), mainly small water bodies - cf the original 10 ‘traditional’ farm dams – that we are slowly ‘decriminalising’! In other words, converting them to wetlands. See below:

John Douglas of Stuart Mill constructed these ponds on our land around 1983. There are 19 altogether over some 150 metres down a slope.

Adams Road – 2016 – 11 ponds in a row, thanks to Aaron Watts. We no longer leave banks on the downstream side. Since we seeded the bare areas a few totem-poles have germinated. We readily transplant sedges from existing dams.

Here’s my recent (experimental) painting on the subject:

Here is a new ‘chain of ponds’ on a Bendigo property, S of Whipstick Forest

So, what next?

A modest gully runs SW-NE through our block of box-ironbark country below near Stuart Mill. In parallel is a non-eroded grassy drainage line. I want to try to restore the former to a chain of ponds.

This means, I think, getting an excavator to reshape the bed of the eroded gully into a series of terraces, rather than the present constant fall, and filling the channel with as much natural debris – especially branches and heads of tree – as possible.

It might also mean an inconspicuous series of upslope riplines. And maybe judiciously thinning 5-10 percent of the vegetation within say 40 metres of the creekline - across the slope, not up- or downhill – to ‘roughen the catchment’, as a friend once put it.

Thinking broadly, the pre-European waterways of our state would have been full of large- and medium-sized debris.

During the heaviest floods, such as we had in 2010-11, this debris would have been swirled around like an auger, and the resulting silt continually flushed out, thereby keeping the holes deep, and rich in habitat and organic matter, as in food, or riparian wildlife. Remember, some holes along the Murray were apparently 40 metres deep.

Erosion control Project

My 121 Ha property, “The Granites” at Carapooee, consists of a granite outcrop with sloping granitic sand terraces at the foot. There is about 7 km of erosion gullies on the property, which represents a serious loss of habitat, resulting in a significant sediment load in the Carapooee Creek and ultimately the Avoca River.

The sandy soil of the terraces has very little clay to bind it and so erodes readily. There is an underlying soft sandstone layer which is eroded slowly by the process of falling water.

The photo below shows typical erosion.

The Project

The Kara Kara Conservation Management Network secured a grant for some erosion control work on this property. The grant paid for 60 tonnes of rock, gravel/sand mix, filter cloth and seeds for regeneration.

Half of these materials have been used to control the erosion in a 400 m section of one gully, where about ten leaky weirs have been placed using the rocks across the eroding sections and a further five areas of undercut have been stabilised.

The objective of the work is to

• stop the spread of drops from propagating upstream

• stop widening of the gully floor

• stop further undercutting

• Slow the water speed in the bottom of the gully

The slope of the steep sections and drops were jack hammered until the slope was about one in five. Filter cloth was laid across the gully floor and covered with the sand/gravel mixture. Rocks were the placed over the filter cloth to form a water race and leaky weir to slow the water flow and collect sediment.

This has effectively stopped all erosion in the bottom of the gully. Any further erosion of the sides of the gully results in reducing the slope of the wall. Eventually the walls will become revegetated. The sediment from this erosion is collected by the leaky weirs and does not leave the erosion area.

Other leaky weirs were placed across the gully floor to slow down the water flow.

A typical undercut is shown below. By placing a rock wall beside the undercut, eroding water flow is kept away from the undercut. The undercut will eventually collapse, but will not widen further.

The work requires at least annual inspections and minor repairs. As the sediment builds up at each wall, additional rock will be added to raise the height.

Natural Healing of some gullies

Some of the gullies have self-healed just by removal of stock (in 1995) and reducing rabbit numbers. The slope of the sides of these gullies has become less steep and grasses (mainly weeds) and trees are regenerating there, thus stopping further erosion.

The photo below illustrates this effect.