Many drops make a flood...

Once again the river is up and as usual the Google searches have begun. That being the case, I thought I'd better get some photos up of the latest flood event - such as it is. Over Friday night and into Saturday, in the vicinity of 70mm of rain fell in the upper reaches of the Barwon catchment. In other circumstances this may not have had much of an impact, but after a wet winter and with the ground already saturated, any rain was going to raise the river height.
And rise it did. Rickett's Marsh on the upper Barwon quickly reached moderate flood level, the Batesford gauge on the Moorabool peaked at the minor flood level and by Sunday night the usual sections of the path around Barwon through Geelong were going under.

Barwon through Geelong, 5:30pm Sunday, 19th August, 2012

Barwon through Geelong, 9am Monday, 20th August, 2012

Matters continued to develop overnight. The Rickett's Marsh gauge fell but Geelong continued to rise and is currently (8:30pm Monday) at a peak around the minor flood level.
As usual when the river floods, I didn't have time today to do more than whip around the same old inner-suburban locations, so below are a few shots from various points:

Old Breakwater Bridge, 9am Monday

Hmmm...perhaps they'll wash away and solve the problem..., 1pm Monday

Looking at Queen's Park from Windmill Reserve, 1:30pm

Bunyip Pool or Whirlpool?

Rock detail at the Bunyip Pool

Next time I will hopefully make it further afield.

I did also attempt to upload a video or two of the water flow to give some idea of the volume and the noise, however Blogger didn't want to oblige. Another aspect it can't convey is the smell of a flood. At the Bunyip Pool where the water is aerated, the smell of muddy water is quite marked. When the water recedes, I know from experience that the paths will all smell of mud...but that is something for next week...



Whether the weather

Every time I run round the river when it is windy, I could swear that I seem to be running into a head wind, no matter what direction I am running. This perception probably isn't helped by the fact that I often start my run in a westerly direction and the prevailing wind around here is yes, westerly.

Rain storm moving across Geelong, viewed from Tait's Point

Yesterday was no different. I hit the river at Landy Field and headed upriver, beating into a solid westerly. By the time I was on my way back, I could swear I was still running into the same head wind and not for the first time, it occurred to me to wonder what impact the weather has on the river and - conversely - what effect the river and its surrounding geographical features might have on the weather.
In previous blog posts I've mentioned the impact of day to day wind patterns on the wildlife which lives along it banks - fish and birds seem quite sensitive to wind levels. In geological terms, wind caused the build up of sand dunes at the mouth of the Barwon, helping to shape the estuary as we see it today.
However, the most obvious element of the weather to affect any river is rain - its lack or abundance determining water levels along the length of the watercourse. The Barwon River is no different in this respect, with the river and its associated ecosystem relying on regular flood cycles to maintain a healthy balance along its length.

Barwon at Geelong in flood, 16th January, 2011

Not surprisingly, rainfall levels vary from the headwaters in the Otways to the river mouth at Barwon Heads. Through Geelong, the average annual rainfall is 552.7mm, however the main ridge of the Otway Ranges averages almost four times this amount at 2000mm per annum. This occurs as a result of what is called a rain shadow which is caused by the Otways themselves. In short, warm, moist air flowing in from the west hits the mountains and is forced upwards, cooling and condensing as it rises. Any remaining cool, dry air flows over the mountains and descends to the plains below which are sheltered from the rain on the other side of the range. The rain shadow cast by the Otways extends as far as Geelong and Werribee, making this the driest area in the state, with an average rainfall only about 55mm higher than - for example - Barcaldine in outback Queensland and 16mm lower than Roma.
Little wonder then that, most of Geelong's water supply comes from catchments in the Otways, namely the West Barwon Dam which also plays a significant role in mitigating the effects of flooding on the lower reaches of the Barwon. It does not however, prevent it entirely as we saw earlier this year when moderate flooding was recorded.

Baum's Weir in flood, 16th January, 2011

Flooding occurs through Geelong after about 150mm of rain on a dry catchment or 75mm on a wet catchment over a 1-3 day period. Typical weather patterns which produce this kind of rainfall are either a slow moving low pressure system over Victoria and southern New south Wales, a low pressure trough moving down from the northern states - such as in the case of a cyclone as occurred in January - or persistent winter rainfall.

The three highest flood levels recorded through Geelong were in 1880 (4.59m), 1952 (5.47) and 1995 (5.23m). By comparison, the flood this January (reaching around 4m through Geelong) was not outstanding. Despite this, there was still quite a mess to be cleaned up and it is easy to see the impact the the force of a flooded river can have on the landscape.
Another factor which has a significant impact on river health is temperature, which along with rainfall can affect water levels through increased water storage use and through evaporation. This, along with issues of pollution can lead to increased salinity in the river system which in turn puts stress on the plants and animals which rely on the river. Likewise, a change in the water temperature of the river in combination with low water levels and high nutrient content can - and in summer often does - lead to an outbreak of blue-green algae. This is toxic to humans and animals, causing skin irritation, nausea and asthma/allergy symptoms.

Of course,wind is also an important aspect of weather conditions, however, I must say that despite a significant on-line search, I can find little information about wind patterns and the Barwon, unless it is to discuss short-term forecasts. I would imagine that at the very least, the shadow of the Otways would provide protection from wind for some surrounding areas or that at some points, the natural geography of the river would influence local wind movements. But I can find no on-line mention of such effects.

Queen's Park from Windmill Reserve

One final weather phenomenon which I have experienced around the river but so far had not until now photographed - although others have - is fog. The fog which forms in river valleys is generally of the type called radiation fog. It forms at night in clear weather with little wind. After the sun sets, radiant heat is lost from the Earth's surface and forms a layer of moist air close to ground level. Humidity rises and fog is formed. This fog can be quite dense and can hang around for quite some time. I live on higher ground above the river, so I can sometimes leave home on a bright, sunny morning, descend into the river valley and find myself in another world filled with damp, cool air. This was the case during a trip to Fyansford earlier in the year when it took a good several hours for the fog to clear to reveal the sun which I knew was just overhead.
I imagine that the natural depth of the river valley, the moist environment and the slightly cooler temperature closer to the water all play a part in preventing the dissipation of fog which occurs on higher ground - another example of the river influencing local weather patterns.

Bricks and Mortar

Trying to connect the topic of this post to the Barwon River is drawing a rather long bow, however I though it interesting enough to include anyway. So here goes:
A recent geocache hunt took me to Limeburners' Point where the remains of five lime kilns can still be seen so of course I snapped a few photos and did some research.

Remains of lime burning kiln at Limeburners' Point, East
Geelong

One of the earliest and most important industries to develop in the Geelong region was the production of lime which was in high demand by the building trade where it was used in the production of mortar, cement, plaster and stucco amongst other things. Lime production on the site is believed to date back to 1838 and the earliest days of European settlement in the region when limestone was quarried nearby and burnt in kilns on the western side of the point. Seashells were also collected and used in production. This site was no doubt chosen for the availability of limestone which was found in the cliffs, in the limestone gravel of the beach and in the shells which collected there. 
The limestone in the cliff face which is believed to be between 65 and 3 million years old was covered by a layer of clay, deposited in a later period. Other limestone deposits in the region are believed to have formed around 20 - 35 million years ago during the Oligocene-Miocene periods, when changing sea levels lead deposits of shells to form along shorelines which no longer exist. I wasn't able to discover how the deposit at Limeburners' Point relates geologically to these other deposits at places like Waurn Ponds, Fyansford and Batesford.
During the peak of operations at Limeburners' Point, the kilns operated day and night, burning timber which was hauled in on drays. Alternating layers of timber and limestone were fed into a funnel-like chimney at the top of the kilns which were stone and brick structures built into the cliff face. The contents were burnt, then the lime rendered by this process was collected from the chamber at the bottom of the chimney, bagged and carted away.

Remains of a bluestone quarry on the Barwon River

Initially owned by Messrs Taylor and Bourchier, the kilns were purchased in 1852 by George Cakebread from Caleb Joshua Jenner. Sources appear to differ on when the surviving kilns were built, however it would seem that these kilns date only to the 1860s or 70s. There are also the remains of a powder magazine at the site which dates back to 1854.
So important to the early building industry of the region was Cakebread's lime (the only other source of lime at that time was Point Nepean Peninsula) that it was shipped all over the Western District. I would imagine therefore that many of the significant homesteads of the region were built from rock quarried from basalt deposits along the Barwon and held together with mortar made using lime from the shores of Corio Bay.
One such example is Sladen House, Newtown which was built in 1849 with basalt taken from Melville's Quarry on the river at the bottom end of Noble Street. The first to do so.

Sladen House

Quite a number of quarries operated in this area: on West Fyans Street either side of Shannon Avenue, at Windmill Reserve overlooking Queen's Park and also near the end of Camden Road. All tapped into the deposits of basalt along the Barwon Valley, providing stone for local churches such as the Wesleyan Church in Noble Street, houses and even the Geelong-Queenscliff railway line.
Another example perhaps is the privately owned Barwon Bank in Riversdale Road, Newtown which was constructed between 1853 and 1856 from - I assume local - basalt, trimmed with freestone from the Barrabool Hills. Likewise, Barwon Park Mansion at Winchelsea is also built from basalt.
In addition to these buildings, Barwon Grange, Kardinia House and St. Albans Homestead along the banks of the Barwon are all brick, or stone and brick, structures built between 1850 and 1875 which presumably used Cakebread's lime.
Despite this overwhelming need for lime, pressure from tourist interests at nearby Eastern Beach soon saw the lime burning process forced to move to the eastern side of Limeburners' Point where these remaining kilns are situated. Production was not affected by the move and reached a peak in the 1870s, however nothing lasts forever and by 1875, another lime-burning operation located on the opposite side of Corio Bay at Duckponds (near Lara) was producing a superior quality lime. By the 1880s only one of the kilns at Limeburners' Point remained in operation and profits had dropped ten-fold.

Barwon Bank

The new producers had set up their kilns on the shores of the small lagoon into which Hovell's Creek empties. Somewhat confusingly, this is now known as Limeburners' Bay. At that time however, the entrance to the lagoon was known as  Limeburners' Point, with the site which is known by that name today, instead called Galena Point.
It is also worth mentioning that Duckponds and Limeburner's Point weren't the only source of Limestone in the region. The deposit near Waurn Ponds - an extension of which reaches to the Barwon where it forms the Belmont Escarpment - is still being quarried to make cement by Blue Circle Southern Cement Ltd. The stone is also used for monument-making purposes by various stonemasons in the region.
Historically, it seems that quarrying took place at Waurn Ponds as early as the 1840s, however it was probably only used for building purposes at this time. It was not until the 1880s when production at Limeburner's Point was in decline that kilns were built at Waurn Ponds and lime production began.
A little later, in 1890, the cement works at Fyansford commenced operation. The lime to supply these works was quarried about 5.6km away at Batesford from the Miocene era deposit which was found there in 1888. The rock was crushed on site and then transferred to the works at Fyansford first by a ropeworks and then by rail. With the opening of a new quarry in 1931, stone was loaded straight onto trucks and then taken to the works by rail for crushing. This open cut quarry is still in use today, despite the closure of the cement works.
Further research has just shown me that there was almost a very direct link between lime production in Geelong and the Barwon River. In the early 20th century the Fyansford Cement Works needed to get their product to the rail lines which would take it to Melbourne. Before the route from North Geelong to Herne Hill was eventually chosen, two other options were put forward. One was a railway line running from South Geelong through Newtown and Chilwell and then along what would become Deviation Road, whilst the other involved a siding running from South Geelong Station to the Barwon River and a wharf at Yarra Street. A second wharf upstream at Fyansford would be serviced by an aerial ropeway from the cement works. This plan however was overlooked in favour of the branch line from North Geelong.