Saturday, 10 December 2016

Where the heck is the Carwoola flood monitoring station?

In my previous post I commented that
  • Point D is approximately the location from which the Bureau of Meteorology (BoM) compile estimates of rainfall for their river flow/flood danger analysis in the Molonglo valley.  Trying to work out exactly where that is to be found is a work in progress.
It is pleasing to report that progress has been made and the task is complete.  Many thanks Jan for showing me the site.  There are many nuances to this as reported below.  

The site is about 650m West (ie downstream) of the low-level crossing on Briars-Sharrow Rd (and about 1200m SSW of the location provided by BoM records).  To prove that I found it, here are a couple of images of the station:
The cylinder in the foreground is the current device, which sends signals by wireless (or satellite, I'm not sure).  The green shed in the background is an older device which used to be connected by landline.

A crucial part of the operation is the pipe at the foot of the cylinder: this is full of gas which is periodically released and the pressure required to do this is used to calculate the height of water above the end of the pipe (which is, helpfully, in the river).  This process means that the cylinder, and associated devices are well above the River level and thus not going to be whupped by any sensible floods.  The need for maintenance is obvious: apart from anything else the supply of gas will need renewing.

This next image focuses on the top of the cylinder showing the rain collector on top and the solar panel which presumably keeps the transmissions happening.
The first nuance relates back to the naming of the site as Carwoola.  I suspect that it is, technically, not in Carwoola but Hoskinstown.  That's because I think the River is the boundary at this point and the North Bank is in the latter locality.

The more interesting nuances relate to where the data from the site appears in BoM "products".  The next image comes from the BoM series South Coast Rainfall and River Conditions.
I have labelled two sites in this.  
  • The Burbong site (#570012), appearing as a turquoise triangle, appears to be used to calculate flood risk and is described by BoM as the "... key gauging station of Molonglo River at Burbong (410705) ...".    At the time of writing this the River level is cited in the river level conditions map as -0.083  - presumably relative to a minor flood level.  It is also intriguing that the reference number for Burbong stated in the linked report is very different to that revealed by clicking the icon on the map.  (On thinking about this a little more, I suspect that the number in the text report refers to some item of equipment in an old device - equivalent to the shed at Carwoola - whereas the actual work is done by some device equivalent to the cylinder, with a similar identifier.  Someone just hasn't bothered updating the title of a graphic and a text reference.)
  • The Carwoola site (#570986) - greyed out - is not used to assess flood risk, but is used in a BoM product Latest River Heights for NSW South West, and gives a current level of 0.7m.  Another member of the Carwoola community has noted that if this level rises to 1.4m then water is over the low-level crossing.  However that is not an official classification.
If one switches to rainfall measurements the Carwoola site is shown as a turquoise dot while the Burbong site disappears (possibly because there was no rainfall there in the previous 24 hours and the consequent grey dot is obscured by the ACT boundary).

So it appears that one has to be very careful in using these data to understand which station is being referred to and what its purpose is.  From my perspective, I generally want to know whether Briars-Sharrow Rd is open and will thus refer to the Carwoola site.

Apart from resolving the question of where the Carwoola station is located (albeit opening several cans of worms about BoM metadata) it was nice to find some native water lilies  (Nymphoides montana) in the river near the pipe.

Thursday, 8 December 2016

Where the heck is Carwoola?

This has been catalysed by some conversations about the site of some weather observations that appear under the label of "Carwoola".  It has become apparent that there are many meanings of the term.

The locality doesn't appear on many signposts.  In fact the only one I can think of is at the Eastern end of Briars Sharrow Rd.  My suspicion is that gives the distance to the Community Hall and Fire Shed.  Those with long memories will also recall there being a shop in that vicinity, but it has now closed.  There are signs on Captains Flat Road (one near the intersection with the Kings Highway and the other near Woolcara Lane) announcing that one has entered the locality, but I see these as different to the signs showing a distance.

The best geographic description of the area is a locality adjacent to Queanbeyan.  This is defined by the Australian Burea of Statistics as the State Suburb (SS) of Carwoola.  In the (Bad Old) Days of two Councils part of the area was in the City of Queanbeyan and part in the Shire of Palerang.  Now it is, quite sensibly all in the one administration as part of Queanbeyan Palerang Regional Council.  Here is an overview of the SS Carwoola.
I have also developed what I call the Carwoola bird watching area with approximate boundaries in purple ..
 .. which includes most of Hoskinstown and Primrose Creek, as well as Carwoola.  It is largely based on the catchment area of the Stoney Creek Gazette, through which reports for the birding project are circulated.

The next map plots various spots which I have come across labelled as Carwoola.

  • Point 'A' is the location tagged as Carwoola by Google Earth.  I suspect it is the centroid of the State Suburb polygon shown above.
  • Point B is the location equivalent to a point labelled Carwoola for Meat and Livestock Australia rainfall reports.  I suspect it is someone's estimate of the centre of the locality - perhaps attached to the closest road intersection?
  • Point C is the shop/hall/fireshed location referred to above.  
  • Point D is approximately the location from which the Bureau of Meteorology compile estimates of rainfall for their river flow/flood danger analysis in the Molonglo valley.  Trying to work out exactly where that is to be found is a work in progress.
  • Point E is the location of the buildings for Carwoola Station.
  • Point F is St Thomas's Church at Carwoola.  It is interesting that the Council sign for "Carwoola"lies to the North of the Church!
As well as the above there is a Parish of Carwoola used for cadastral purposes.  (cadastre, using a cadastral survey or cadastral map, is a comprehensive register of the real estate or real property's metes-and-bounds of a country.)  Uncle Google has not thus far been able to be persuaded to deliver me an image of the boundaries of this Parish.  However I have got part of it from an 1888 map of County Murray from the National Library website.  I have added a few annotations - noting the vintage of the map, its surprising how many features were recognisable.

Monday, 5 December 2016

Queanbeyan QE 2 Park redevelopment

For thepast year our run in Queanbeyan along the river has had to take a different route as our traditional voyage through QE 2 Park was subject to the whims of the construction industry.  They more or less finished on Saturday with the redeveloped area opened by the Governor-General.  I drove past on Sunday and it seemed well replete with family funsters, which is GOOD.

This morning I went for a run past to check the possible new routes and take a few snaps.  Here is an overview of the upper level.  I didn't try sitting on the benches but they looked quite good.
 The playground is a lot larger and has a water feature (which will be good until the next drought comes).  Note that in both images there are Mums and rugrats enjoying the facility.

I presume there are plans for performances at the bottom of this amphitheatre.  Which will be fine or possibly excellent as long as it isn't garage bands at 500dB as was the case with the the thrash metal exposition at Regatta Point on Sunday.
 They have a nice BBQ area and I assume vines with grow over the pergola eventually.  It will be interesting to see if the social group which used to gather here at lunchtime will return or if they will stick to their alternate venue by the River.  (The dunies here could be a positive, the Alcohol-free zone possibly less so.)
 Nicely designed refuse bins have natural history designs on them ..
 ... but why some has stuck a species not found within 650km of Queanbeyan is a worry.
 A worry shared is a worry halved, so I have shared my views on this with the Council.

Here is a wider view from across the River.

Sunday, 4 December 2016

Here and there

Frances was desirous of going there, but as we left here some Gippsland Water Dragons were sunning themselves on rocks by the ford.  A third one, midway in size between the two featured, was also present but couldn't be fitted into the shot.

The medium sample was imaged the next day

 A close up of the biggie.
 The ultimate 'there' was the Sculpture Garden of the NGA.  It was as always a lovely place, only spoilt by the appalling noise coming from Bogan Central also known as the Spilt Milk 'Festival' being perpetrated at Regatta Point.  As we found it too loud at 1km range it must be bad for the health of the brain-dead attendees.

The mist sculpture was evident.  However I was reminded of one time a guy was doing maintenance or as he put it "Making it more like a mist sculpture rather than a poor lawn sprinkler."
 A small person - not the Small Person  - was a tad reluctant to go through the fog.
 Fiona Hall's tree fern work is doing rather well ....
 .. although we noticed that several of them seem to have adopted a more horizontal approach to growth.
 We then decided to visit the Turrell installation.
 Views of clouds were available through the hole in the roof.
With binoculars it was possible to establish that the black dot was a jewel spider!

Friday, 2 December 2016

A day of weeds (mainly)

The day started off very well.
 As we did our tour-de-block with Tammy we were struck by this swathe of Xerochrysum viscosum, which is having a brilliant year.
 I started my chores by carting a load of pine pruning up to an erosion gully.
 They were duly dumped in!
 A few years back the electricity provider knocked over a copse of  Acacia dealbata which was growing right under the lines.  Last year they finally chipped most of what they had knocked down.  his meant I could get in there this year with my brushcutter and deal with the regrowth.
 Here it is dealt with!
 There is still a bit more work to do to cart stuff away but it is an improvement.

Nearby some Blue Devils (Eryngium ovinum) were growing vigorously .
 Less pleasing were these bad St Johns Wort.
 They were transformed into better St Johns Wort by the simple process of adding them to my pile.
It was then time to break out the brickies hammer ...
 .. and go talk to some bad thistles ...
 ... which were changed into better thistles ...
 ... and eventually best thistles , joining the wort on the pile.

For the past couple of days we have been graced with the noisy and amusing presence of a clan of 12 White-winged Choughs.  Today they were very close to the house and it was obvious that some of them were fairly fresh out of the nest.
 I think this is an adult squawking at one of the juveniles. Note the demonic red eye!
 The whole clan spent much of the early evening perched on the lattice around our septic tank.
Sunset decided to compete with sunrise.

Thursday, 1 December 2016

November 2016 weather report

Here is a slightly updated version of the report published in the Gazette.  The main change is a decrease of 2mm in monthly rainfall - obviously something got duplicated in my updating.  Sorry about that.
An overall summary of the month would be that following a very wet Winter and and early Spring, and a very cool October, this month was pretty average in everything.


I regard 50mm of rain in a month as 'reasonable' and we just made it this month.  The rain fell on 8 days spread through the month, although the last week was dry.
Note that the average shown here is for the past 9 years while that in the Gazette notice is for a 32 year period.

Whiskers Creek has run through the month, although getting a bit close to 'trickle' level by the 30th.


Looking at the month in detail there have been a series of warmings (shown by the chain of red boxes) followed by a sharp drop as a front comes through. 
Average maximum temperature was very similar to last year and the long term average.  
 In much the same way that I have commented on frosts during the colder months I intend to cover the number of Heat Wave Days each month over the warmer period.  In essence a Heat Wave is a period if 3 or more consecutive days with a maximum temperature >35o
C and a minimum >10oC.  If you wish to know more its here!'
For November this year we have one heat wave last 4 days.  This is about normal.

The minimum temperature was well less than 2015, but almost exactly on average.


When I first compiled a chart of daily readings for Relative Humidity at 3pm I was quite surprised at how many days were below my "reasonable"level of 40%.  So I also downloaded the Bureau of Meteorology data for Canberra Airport.
 It is clear that the two series are very similar.  I then looked at longer term - 4 years of observations - average data which showed that the month was almost spot on the average, but somewhat less than 2015.
I believe the dryness does explain wide the wide brown land is justifying the brown element of the cliche.


Looking at the daily maximum gust ...
 ... shows a breezy first half of the month after which the wind was much less evident.

The longer term picture continues to show a pattern of a higher average wind speed than in the past.  (I cannot help but consider I have caused this by clearing the spider webs off the anemometer in April!  Friction is a terrible thing!)

However again I consider the month to be rather average!