Yer noticed that, I honestly cannot recall seeing that on my entire time in these forums, well more-so the Murray Catchment. Great to see indeed and hopefully the strengthening La Nina does more good.

TS

Winter 2010, Upstream Onkaparinga 18th July 2010, 1.27 pm

Winter 2010, Downstream Onkaparinga 18th July 2010, 1.27 pm

…1.7 mm in the 24 hours to 4:55 pm.

Another 4.4 mm over 2 days, and it is more apparent that the water level is receding at locations down stream. It was raining at about 12:30 this afternoon, but I managed to get what might be the best photo of the local river to date, looking downstream 150-200 metres upstream from the previous two photos.

Streamflow Onkaparinga River, Winter 2010, 20th July, approx. 12.40 pm

Also, further upstream from the above location, the water appears to be at about the level of the minimum water level (see photo below), or even a bit higher, as no dark soil is visible along the edges of the riverbed. That’s probably a half metre rise in the water level, mostly resulting from the 19 mm we received to 9 am on the 14th, but with some coming after (about 55.7 mm in 9 days to 11 am on the 17th of July).

Streamflow Onkaparinga River Further Upstream, Winter 2010, 20th July, approx. 12.35 pm

I said minimum water level above because the photo below gives an idea of what streamflow for the Onkaparinga can be like.

Streamflow September 2005

...and that's not even close to magnitude of flow in 1992.

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Update:

Onkaparinga River 24th July 2010

Temperature is currently 12 C in the early afternoon (around 2 pm).

Nothing much to report in recent times. Here are a couple of photos further downstream (probably over half a kilometre from the last photos).

Upstream Onkaparinga River 20th July 2010, 2.40 pm

Downstream Onkaparinga River 20th July 2010, 2.40 pm

Also of interest earlier in July was the passing of what looked like severe mammatus clouds stretching from horizon to horizon, northeast to south west. This was followed by a system of severe winds (I don’t have footage of these as it was very early morning, but it’s enough to say they were strong enough that some very large trees were swaying in them, gusts I would guess up to 100 km/h). We received about 11 mm overnight from that system, but it didn’t really contribute much at all (to streamflow).

Mammatus Approaching 9th July 2010, approx. 6 pm

Mammatus Leaving 9th July 2010, approx. 6 pm

The quality of the last two images was not great because of the time of day, and I’m not exactly an expert in photography.

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Update:

Onkaparinga River 28th July 2010

Taken a little over 5 hours before it started raining:

Downstream Onkaparinga River, 28th July, 5.42 pm

The water level has not fallen much since the 24th (less than 0.5 m). Seems to mean water retention is good for what we have received so far this winter (124 mm). I also noticed an ant nest had been built 2-3 m above the main area of water flow. Might point to the height of peak flow in coming weeks (in other words, possibly no major flooding this year). Can’t be more certain about the timing of peak flow yet, however indications suggest the date may be in mid-to-late August.

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Update:

Onkaparinga River 29th July 2010

10.7 mm to 8:55 am since 11 pm last night, and drizzle with the occasional light-to-moderate shower – 1.8 mm to 2:30 pm. It’s been a very murky sky for most of the day with overcast conditions. The drizzle has often been so fine it’s just drifted to the ground. Temperature was 10 C at 11:26 am.

I would be guessing, but I think unless we get falls in excess of 10-15 mm in the next 24 hours, we’re not going to see significant changes in streamflow (will probably wait until then next strong system before taking more observations). The current rate of rainfall (which is near constant drizzle) is probably not enough to have any noticeable impact.

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Update:

When comparing this:

Onkaparinga River Downstream 28th July 2010, 5.39 pm

With this:

Onkaparinga River Downstream 29th July 2010, 3.16 pm

There is a noticeable change in the level of water, and the streamflow response after firstly the 10.7 mm to 8:55 am and then around 2 mm or more in the afternoon. This seems to indicate the retention of water in the system is sufficient to increase flows by 5-10 cm – 12.5 mm rain gives 5-10 cm change.

Directly related to streamflow observations, but on the most major river system in Australia:
I have an official historical table and graphs of Monthly Murray Darling Dam Inflows for Hume & Dartmouth Dams from 1892 to current 2010(Courtesy MBD Commission), on my new upgraded, updated, modernised web site under articles section for anyone who may be interested at
http://www.holtonweather.com

Onkaparinga River 30th July 2010

Further upstream towards Charleston and Springhead (where the source of the Onkaparinga is) there is likely to have been more rainfall in the past 2 days than there has been at Woodside – the water level was even higher at 12:30 pm than it was a 3:16 pm yesterday (29th), and the change in the streamflow response is noticeable. I do not think the 2.8 mm yesterday is what caused the water level to rise – it seems far more likely this occurred because flow increased many kilometres upstream.

The water content of the soil is pretty clear given that after a little over half an inch up to yesterday, water was still soaking into the paddocks. The forecast for showers over the coming days seems to be promising; we’ve already had a few light, sharp showers today, though they haven’t been sustained yet. The streamflow response is unlikely to change much until they do become sustained.

Onkaparinga River 1st August 2010

First, a correction: 81.4 mm for June, 95.7 mm for July, and about 14.3 to start August. We have just had a moderate shower pass through the area (12 pm). It is now sunny. At around 12:10 am last night, a severe thunderstorm on a squall line (the second of 2) passed through the region. This brought with it very heavy rain/hail for a few minutes, and heavy rainfall over a period of 5-10 minutes. There was small hail, close and frequent thunder and lightning, and I suspect we got caught in a microburst. Taking photos of the river this morning, after a further 13 mm overnight, most probably coming from the thunderstorm, it was clear the peak flow had passed. The river was swollen at 9 am (and could not be crossed), and the peak water mark was visible a further half to one metre up the riverbank. It is very wet underfoot and some rain has not soaked into the soil.

Streamflow Onkaparinga River, 9.01 am 1st August 2010
Streamflow Onkaparinga River, 9.02 am 1st August 2010
Streamflow Onkaparinga River, 9.03 am 1st August 2010 – High Water Mark

In the 24 hours to 9 am we’ve had about 27 mm, with another 3.1 to midday.

Hi BD,

Just at a glance it looks very interesting with the historical inflow records . I would assume that to reconstruct these kinds of records you would need some sort of precipitation and evapotranspiration input data from further upstream from where the inflow records were taken!?

Hi Cosmic

These are simply the natural inflow data to the Hume and Dartmouth Dams(by deleting any unnatural sources ie piping from Snowy, etc).
They were compliled by MBD commission for me at my request. I asked for the monthly natural inflow data to the hume and dartmouth dams, and that is what they supplied me months later(So I am not fully certain what they delete out of the original inflows).
I use the data to formulate my dam inflow forecasting models for a certain large irrigation authority, but thought that others might like the raw data for studies, so I asked them if I could put the data on my website, to which they agreed, as long as it was available to all.
Cheers BD

Ok .

Onkaparinga River 6 pm 4th August 2010

Roughly 70 mm in less than 7 days has the river resembling a raging torrent, yet still below minor flood level. The photo below is taken rather hastily in an attempt to capture the remaining flow late in the evening (probably well past peak flow for the weather system). The flow level in the photograph is probably at least a metre below the peak flow reached during the day.

Streamflow Onkaparinga River, 4th August 2010, 5.55 pm

...After 22.5 mm in less than 24 hrs .

Hopefully this works :):

Video 1 Streamflow Onkaparinga River, 14th August 2010, 1.47 pm – Peak Flow 1

Peak Flow 2 was early in the morning the following day.

This is how wet it was underfoot earlier yesterday:

Rain at 10.45 am, 14th August 2010

N.B.: Peak Flow 2 was higher than Peak Flow 1 .

Previously:

Onkaparinga River 4.50 pm 6th August 2010

23.3 mm since 3:20 pm on the 3rd of August plus another 15.5 since the beginning of the month gives 38.8 total for the month. The most significant falls occurred on the 1st and 3rd. Flows are moderate and well above levels on the 30th of July, but not higher than on the morning of the 1st, at 9 am.

Onkaparinga River 4.30 pm 7th August 2010

Streamflow has increased slightly over the last 24 hours; only 0.1 mm in that time.

Onkaparinga River 17th August 2010 – Possibly Peak Winter Flow

Since roughly 4 am on the 15th, flows have steadied and are now falling.
The volume of water measured travelling down the river at A5031001: Onkaparinga R US Dissipater (http://e-nrims.dwlbc.sa.gov.au/swa/) was about 5026 ML/day at 9 am, the peak, while at Woodside Weir (http://www.bom.gov.au/fwo/IDS60247/IDS60247.523714.plt.shtml)the water level peaked at 4:02 am at 1.16 metres. This was still below minor flood level.

We’ve had another 5.7 mm in the last 2 days, bringing the total for the month to 97.6 mm, and the total for June to August to 274.7 mm.

Currently:

Observations and Update 20th of August 2010

Since 12:45 pm on the 14th of August we’ve received 50.8 mm to 5:15 pm today. At 1:23 pm to the 16th, streamflow peaked at Woodside Weir at 0.34 metres, and again at 10:23 pm on the 19th at 0.46 metres. While the river is still running moderately, flows have generally steadied and recent rains suggest flows are simply being maintained and increased slightly. Over the last three days we have averaged 9.2 mm per day.

Total rainfall for August to date is 122.3 mm, with 299.4 mm for winter. This is within 50 mm of the June to August average. Several periods of 24-48 hour falls have exceeded 10 mm. The highest fall of 22 mm was record in the 22 hours to 10 am on the 17th of June.

Edit: I just noticed Woodside Weir flows have hit 1 metre.

The Onkaparinga River at Johnston Rd (Oakbank) on the 20th at 11:09 pm reach minor flood level.

The Namoi River is flowing high enough for me to see the water from my window. It has been doing it for days. I am reflecting on how rare this sight has become.
Keepit Dam is filling up now, despite the determination of the authorities to empty it out. They have had it steady at 26% for years, despite 2007 and 2008 having rainfall well above average. I was beginning to think that demand would permanently exceed supply. Now Keepit Dam is up to 51%. It will take a little while to use that up.
The smaller upper storage, Split Rock Dam, which filled completely in winter 1998, but was rapidly used up, and has been steady at 2.6% for as long as I can remember, has more than doubled in volume to 5.9%. That could be used in the twinkling of an eye.

There should be a warning out. or at least a watch - the river passed minor flood level at 3:48 pm!

It's probably not safe to go down within 5 metres of it atm! There is a huge volume of water flowing downstream at a rapid rate. The river has risen 2-3 metres since last night.

Yer I cant understand why there isnt really.... with 10-20mm+ expected again in next 24 hrs, surely further rises would be expected...
Ch 10 just showed footage of paddocks already under water from the burst Lenswood Creek.

They should issue a flood warning, it's absolutely pi''ing outside!

Streamflow Onkaparinga River, 25th August 2010, 5.32 pm

Streamflow Onkaparinga River, 25th August 2010, 5.33 pm