20 May, 2015

Lake Murdeduke

In my previous post, I looked at the history of the Murdeduke Estate, which in part lay on the banks of the Barwon River. To the west, the estate also encompassed the eastern shore of Lake Murdeduke and for this reason - amongst others - I thought it worth looking at the history of the lake itself.
Today, Lake Murdeduke is a RAMSAR listed wetland, home to a variety of birds and other fauna. Whilst I did not see a single bird in the time I was at the lake, I did see a pair of Australian Shelducks and a Nankeen Kestrel in a field not too far away as I was leaving. Of course, many of the birds which frequent the lake are migratory.
The lake is made naturally saline by the release of minerals from the decay of volcanic rock in the region. It is fed by Mia Mia Creek which rises in the high ground south west of Mt Mercer and flows south to the top of the lake. When full, Lake Murdeduke covers around 4,200 acres, however it is many years since the lake has reached capacity.
The boat ramp highlights how far the shoreline has receded. In the background
Mt Gellibrand can be seen to the left and the broader rise of Mt Hesse to the right
In addition, years of reduced rainfall have lead to the lake being classified as hypersaline, that is, having a salt content up to 10 times higher than sea water. In general, it has no outflow (meaning it is classed as endorheic), however during periods of exceptionally high rainfall such as occurred during the 1950s and 1990s, water from the lake can make its way east to the nearby Barwon River.
The receding waters of Lake Murdeduke with the cone of the extinct
Mt Gellibrand volcano rising in the background
Lake Murdeduke evolved from a combination of factors millions of years in the making and whether they realised it or not, the various families to occupy Murdeduke Estate over the decades were reaping the rewards of these geological quirks. In geological terms however, this is a relatively new region. Volcanic activity during the Pliocene Epoch as recently as 2 million years ago, saw the original course of Mia Mia Creek blocked by a flow of basalt. This natural damming resulted in the formation of Lake Murdeduke in a depression in the basalt. Over the following millennia winds blowing in from the west, breaking down the volcanic rocks deposited soil against the eastern bank of the lake, forming a "lunette lake".
The formation of lunettes is a particularly southern Australian phenomenon which occurs when westerly winds sweeping across the countryside, cause curved dunes to form on the eastern banks of a lake. Typically, the western or windward side is steep whilst the eastern or leeward side has a more gentle slope. This is true of Lake Murdeduke which lies on high ground at the edge of the basalt flow, above the flat plains which stretch away to the Barwon below.
Steep windward bank of the lake
Longer, undulating, leeward side of the lake's east bank
All of these factors combine to make this particular area of land some of the most fertile in the region. The breakdown of volcanic rock from these recent lava flows has resulted in rich, well-drained soil situated on higher ground, which takes the form of stony rises. This makes for good winter pasture which does not become waterlogged and at the same time, the rocks can provide protection for stock. The older, lower-lying plains which are also found on the estate are more useful in summer weather, having deep soil deposits which hold water during the hot months better than the porous volcanic soil of the stony rises which become dry.
Grey clay soil deposited on the floor of the lake
It was features such as these which first attracted land-hungry squatters to the region in the late 1830s and which then continued to make Murdeduke and the other estates which stretch across Victoria's western districts so successful down the decades, however the fertile land was exploited by humans long before the arrival of European settlers.
For 40,000 years the indigenous people of the region fished and hunted along the shores of Lake Murdeduke. Several different species of ducks as well as migratory wading birds were caught and a variety of edible plants were also gathered by the people of the four Gulidjan clans. Their land extended west to the shores of Lake Corangamite, south to the Otways and east to the Barwon River and the lands of the Wathaurong, with a portion extending in a northerly direction to a point west of Meredith. The Gulidjan were a semi-nomadic people with a matrilineal clan structure, each belonging to either the Gabadj (Black Cockatoo) or Guragidj (White Cockatoo) moiety. Among the many artifacts found along the lake shores are stone tools and blades which suggest a trading system with neighbouring tribes, with whom they also intermarried.
The lands of the Gulidjan people
The arrival of white settlers however, brought conflict as the Gulidjan were forced from their lands and their traditional food sources were taken away. There were deaths on both sides, the best known being the disappearance of the explorers Joseph Gellibrand and George Hesse in 1837. Their remains were never located, but it is suggested that members of the Gulidjan people were responsible. This resulted in Gulidjan deaths at the hands of the white settlers. With conflict also came retaliatory raids. The Gulidjan reacted to the loss of their lands by driving off stock whilst the settlers broke up indigenous camps and took their tools. The Gulidjan were also hit hard by European diseases such as the flu, chickenpox and smallpox which greatly reduced their numbers.
In 1839 an attempt to provide for the remaining members of the surrounding indigenous clans resulted in the establishment of the Buntingdale Wesleyan Mission Station by the Reverend Tuckfield to the north west of Deans Marsh, however the venture was not a great success and the license was forfeit in 1851.
Today, the lake is surrounded by private property - including Murdeduke Estate, however public access is available via Blocks Lane off the Shelford Road from Winchelsea where the above pictures were taken.

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