26 June, 2014

A watershed moment

As this blog has progressed over the last three years, its scope has grown to include the two major tributaries of the Barwon - the Leigh/Yarrowee and Moorabool Rivers - as well as the smaller creeks which also drain into each of the three rivers. Then, a while back I was asked what area was included in the watershed of the Barwon.
Good question! I knew in general terms that it would include the three rivers and any creeks and streams which flowed into them, but just how far did that extend? So I thought I'd have a bit of a look an see what maps and diagrams were available that would provide a visual image.
On the Australian National Library's website I soon found several historical maps which outlined the area including the following map published in the 1950s:

Map of the Barwon watershed. Image produced by the Victorian State
Rivers and Water Supply Commission, 1954 and held by the State Library
of Victoria (Click to enlarge)
As expected, the extremities of the watershed to the headwaters of the three rivers and the Barwon river mouth at Barwon Heads. The most southerly extent of the catchment lies to the south of the township of Forrest in the Otway Ranges, with the peaks of that mountain range providing a dividing line between the Upper Barwon and the Victorian coastline. In the north, the watershed extends from Ballarat where the Yarrowee River rises in the city, to a point north of Ballan in the Wombat Sate Forest where the east and west branches of the Moorabool River begin their journey to the sea.
For administrative purposes, the Barwon catchment area falls within the boundaries Corangamite Catchment Management Authority (CCMA). The Corangamite Catchment is responsible for some 13,340 square kilometres from Ballarat to Geelong and the Bellarine Peninsula and along the coast to the town of Peterborough which lies about 50km east of Warrnambool. It is one of ten such authorities which cover Victoria.
Map of the Victorian catchment management authorities taken from the
Department of Environment and Primary Industries website
For provision of services such as drinking water and sewerage, the Barwon and its tributaries - as far as I can tell - fall under the jurisdiction of two water authorities. The majority of catchment area is contained within the area serviced by Barwon Water which includes an area of about 8,100 square kilometres from Apollo Bay in the west to Meredith and Cressy in the north and to Little River and the Bellarine Peninsula in the north and east. This map on the Barwon Water website shows the extent of the area of supply. Those parts which do not fall under the auspices of Barwon Water are the upper reaches of the Moorabool and Yarrowee/Leigh Rivers which lie in the area controlled by Central Highlands Water servicing an area of 9,275 square kilometres.
But this still doesn't exactly answer the question: what is the combined catchment area of the three rivers - Barwon, Moorabool and Leigh/Yarrowee?
Another 1950s depiction of the Barwon watershed, titled Catchments
of Barwon River and inland Basins, created by the Victorian State Rivers
and Water Supply Commission and held by the Victorian State Library
(click to enlarge)
According to Wikipedia, the watershed of the Barwon and its tributaries makes up about 8,590 square kilometres, however I have not been able to independently verify this and suspect it may refer to the full extent of Barwon Water which includes catchment regions which are not part of the Barwon system. According to various other websites, the Moorabool River accounts for 2,300 square kilometres, the Yarrowee/Leigh River for around 890 square kilometres, however it seems very hard to find a clear answer for the Barwon itself.
The City of Great Geelong website indicates that the Barwon's catchment extends to 3,700 square kilometres. Given the area covered I believe this refers only to water flowing directly into the Barwon however the wording is ambiguous. Assuming that my interpretation is correct, then the combined catchment area of the three rivers is in the region of 7,790 square kilometres or more than three quarters of a million hectares - but less than the 8,590 square kilometres suggested by Wikipedia.
So, in short, I'm not precisely sure, however if anyone can provide a figure, I would be pleased to add it to this post.
NOTE: subsequent to publishing this post, the CCMA inform me that "Corangamite CMA's GIS (Geographic Information System) figure is 495,480 ha for the entire basin including Upper Barwon, Barwon, Murdeduke, Leigh, Moorabool" which converts to the much smaller figure of 4,955 square kilometres for the Barwon watershed plus the Murdeduke Basin.

22 June, 2014

Branching out - scratching the surface

In my last post I looked at a gold mine along the banks of Woodbourne Creek near Bamganie, however this was not the only gold prospecting which went on along the creek. A little further upstream of the mine, along a small spring-fed creek which runs into Woodbourne Creek there is clear evidence of surface working.
A gully leading to the creek showing signs of digging
A number of small gullies show signs of excavation (and subsequent erosion) and the remains of structures used in the extraction of gold can also be seen. The first thing to note however, are a number of shallow dips in the landscape adjacent to the little creek where prospectors have removed surface soil to a depth of only a few feet, looking for those tell-tale signs which would indicate the presence of gold.
A small hollow (centre and below the skyline) indicates test digging
If none were found, they would move on, trying their luck in another spot. Other signs of activity can be seen in some of the gullies where the remains of walls are evident, built as part of the digging process.

A worked gully with the remains of a wall just visible in the middle distance
Remains of a cement wall
Remains of wall
Another obvious construction is the remains of a shallow water channel which presumably ran from further up the creek, diverting water off to the various gullies being worked.
Water channel running beside the gullies
Another less obvious sign of the mining process was pointed out by our guide. Walking up a gully we arrived at a large, levelled off area which was circular and slightly raised with a hole in the centre. After explaining the that tailings from the local mining activities had been used in later years to form road base, he then suggested that this was not the case here and I could see what he meant.
The hole in the centre of the mound
Remains of a puddling machine
These surely were the remains of a puddling machine used to crush the rock which was brought up from the gullies below. The circular area would have formed the base whilst the central hole would have contained the shaft around which the wheel turned. There was no obvious depression in which the wheel which crushed the rock would have turned, but perhaps that had been filled in.
An excellent example of a puddling machine still in operation today is that at Sovereign Hill, however the general workings can be seen in this illustration from 1855 by Samuel Thomas Gill:
1855 depiction of a puddling machine by ST Gill, image held by the National
Library of Australia
The machine was used to break up lumps of clay and gravel, before it was transferred for washing to remove the gold from the soil. This could be done using a hand-operated cradle, by panning or by running the crushed dirt through a sluice which could be a small box similar to a cradle or a larger structure running down a creek or gully. I do not know which of the various processes were used at this site but perhaps the presence of the channel leading across the top of the gullies suggests sluicing was employed. This was certainly the most efficient means of washing the dirt, but was reliant upon a good supply of water.
What I do know is that the workings along Woodbourne and Cargerie Creeks were never rich fields like nearby Steiglitz and the work there was probably hard and often unrewarding. These were small alluvial claims worked by hand and using small machinery, not the deep leads and heavy equipment of Steiglitz.

21 June, 2014

Branching out - mining on Woodbourne Creek

Recently I had the chance to examine a little more of the goldmining history of the Bamganie/Woodbourne Creek region with a trip to see a mine not too dissimilar to that at Mt Doran which I wrote about previously. Mining in this area dates back to the 1870s, with gold discoveries first at Bamganie in 1874 and then along Woodbourne and Cargerie Creeks in the following year as I have discussed in a previous post. Over the following decades, well into the 20th century, miners came to try their hand at striking gold in the area, working both on the surface (the subject of a my next post) and below ground.
This mine was not only interesting for the tunnel which, like the other mine, ran back into a hillside, but also for the vestiges of the mining process which could be seen scattered around the site. The first object pointed out was a metal boiler lying partway up the slope.
Discarded boiler
Lower down the slope, below both the boiler and the mine, there was also evidence that the creek had been dammed to provide water for various mining processes, whilst up the slope was a brick structure which our guide pointed out was constructed from Hoffman bricks.
Brick structure above the mine entrance

Hoffman brick
The Hoffman Brickworks was a Brunswick-based company established in 1870, which used various innovative brickmaking techniques over the years before finally closing its doors in 2005. These artefacts suggest that the site must have shown some potential and been backed by investors.
The interior of this mine was in many ways similar to that I viewed at Mount Doran and described in this post. It had timber support structures and according to our guide, showed evidence of some engineering skill in its construction.

Tunnel near the entrance

Tunnel with timber supports
To my inexperienced eye however, the composition of the rocks and soil seemed somewhat different and the presence of fine tree roots dangling through from the roof in this mine was also a point of difference.
Tree roots hanging from the roof of the tunnel
Commonly, gold-bearing quartz is found in the presence of iron ore. This was certainly the case across the goldfields of the Moorabool and Leigh Rivers. At the foot of Bungal Dam, not far from the mine I investigated near Mt Doran, commercial quantities of iron were mined during the late 1870s and early 1880s.
Likewise, the land around Bamganie and Woodbourne Creek contains iron. Geological survey maps from the 1860s show areas between Cargerie and Woodbourne Creeks where the soil is composed of  "ferruginous conglomerate containing [an] abundance of rounded quartz pebbles" and "thick beds of ironstone cement & quartz gravel the later containing rounded quartz boulders...where these occur payable gold has been obtained". The maps also indicate that "gold has been found in many places along Reid's [Woodbourne] Creek and in some spots payable". Unlike the gold, the iron ore was presumably not deemed payable however it was clearly present as evidenced by the rusted colour of some of the quartz.
Quartz showing rust stains caused by the presence of iron

A quartz vein showing staining
In addition to the tell-tale rust stains which would alert miners to the presence of iron and the potential for gold, another indicator was the appearance of a black line running through the rock. Such a line can also indicate the presence of iron and therefore gold. I am told that this is a result of the oxidation which can occur where soils of different mineral types come in contact and my research suggests that the black colouration may be haematite, a type of iron oxide.
Black oxide running along the rock face
An example of this was clearly present here (as can be seen in a number of the above pictures) where the line would have dictated the direction of excavation.
At the mouth of another nearby shaft, marks in the rock left by the miners' picks can still be seen as they explored what may have been another promising lead.

Pick marks still visible on the rock surface
A little further away still, the signs of surface prospecting are clearly evident also, but that will be discussed in my next post.

17 June, 2014

Branching out - Cargerie Creek

Recently I had an opportunity to walk the course of a part of the Barwon River catchment which I had not seen before: Cargerie Creek. This little creek rises outside of Elaine and runs down through local farmland to confluence with the Leigh River on private land almost 3km south west of the Meredith-Mount Mercer Road.

Cargerie Creek
For the first few kilometres, the watercourse is shallow, however it soon becomes quite steep and rocky.
Cargerie Creek looking south from below the Mt Mercer-Meredith Road
Cargerie Creek, further south
This history of this little creek is similar to that of much of the district. Prior to European settlement, the creek flowed through the lands of the Wathaurong people who lived, hunted and gathered their food along its banks. This is attested to in the Journal and proceedings of the Royal Society of New South Wales (1877-1884) where the presence of indigenous cooking mounds (described in some detail) were noted along the banks of Cargerie and Woodbourne Creeks. Whether any indication of their existence still remains, I do not know.
The arrival of European settlers in the area saw Cargerie Creek incorporated into the large squatting runs which were taken up in the area. I have not been able to determine exact boundaries however the creek itself may well have formed the dividing line between the more northerly run of George F. Read Jnr known as Cargerie and the more southerly Woodbourne No. 2 Run held initially by the Wilson brothers and then by William James Reid.
The track leading down to the confluence of Cargerie Creek and the Leigh River
In the wake of the squatters, selectors moved into the district during the 1870s. It was at this time that much of the land along the west bank of Cargerie Creek was purchased by the Nolan family whose descendants remain on the property to the present day but whose initial purchase appears to have been a small block of land on the banks of the creek several decades earlier in 1839. East of the creek, things were a little slower to get moving, with that land (including the property I grew up on) not selected until the last few decades of the 19th century.
The lower end of Cargerie Creek is similar to the Leigh and Moorabool Rivers in that it runs through a deep channel which I assume would cause the water level to rise quickly in times of flood which is certainly the case for the Leigh a little further downstream.

Looking up the Leigh River near the confluence with Cargerie Creek
Looking down the Leigh River just above the confluence with Cargerie Creek
Below the confluence of creek and river, the channel remains steep and rocky whilst the land around is relatively flat.

The Leigh below Cargerie Creek
Walking beside the river, there are expansive views across the surrounding farmland and the occasional sign of the earlier days of European settlement.

Abandoned hut on the Leigh River below Cargerie Creek
Below the creek, the Leigh meanders first south and then south east to meet Wilsons/Woodbourne Creek several kilometres downstream. Our walk on this occasion, took us almost 3km past Cargerie Creek along the Leigh to a little ford which lead us to the property of our guide for the day (Marg Cooper) on the opposite side of the river.

Ford on the Leigh River

Looking upstream from the ford

Downstream of the ford
Whilst the ford marked the extent of our walk, the conjunction with Wilsons Creek is  further 10km downstream following the watercourse or a distance of less than 7km via the direct route, but that walk will have to wait for another day.