Christmas Bells

Christmas Bells
Christmas Bells - Blandfordia nobilis

Wednesday, January 30, 2013

Carrington Falls running properly again

The people of Robertson are very pleased to see the rivers and creeks running again, and to hear the Frogs croaking and the Crickets and birds singing their little hearts out.

Further to my post about Carrington Falls being nearly bone dry (and that was just last week), I decided to check it today.

You will not be surprised to know I got 177mm of rain, (or 6.97 inches) of rain over the last 3 days. Most fell on Sunday afternoon and evening. But I had other things to do on Monday and Tuesday - besides it was raining intermittently anyway - so I wanted to get the full extent of the "rainfall event".

Carrington Falls Wednesday 30 Jan
Flowing as it normally does.
Last week, I showed the rock bar- all but dry.
Below is the same view today.

This is the "Old Ford"
It was used by the local Timber cutters
as their crossing point,
before the Bridge was built.
Contrast with the "dry rock bar" image linked above.

The level of flow in the river was obviously higher on Monday, as a friend of min, Kellie, posted a short video on Facebook today of the Kangaroo River at the Bridge, filmed on Monday afternoon.
You can view this if you have a Facebook account.

Either way, this is not a "High" levels of flow, by any measure. That fact can be attributed to how dry the region has been over the last 6 months, and hence, the amount of water the soil and rock beds can absorb. I have observed previously, that we got about 12 inches of rain in June 2007, followed by a further 6 inches (from memory),  and it was the smaller, subsequent rainfall event which triggered a flood in the Nepean River. Point is, the first lot of good rain filled the minute gaps in the soil and rocks, and only then would our local soil conditions produce enough "run-off" to cause a flood.
That is not the case everywhere in Australia - as we can see this last week.
I know, for example that much smaller "rainfall events" around Canberra and Queanbeyan can produce flash floods. But their soils are mostly old decomposed granite - not the porous basalt soils of Robertson.

1 comment:

Flabmeister said...


We ended up with 92mm over the weekend of which 55mm fell in 30 minutes on Saturday evening! As what is laughlingly called soil here had been baking at 39-49C for 4 weeks it was even more brick-like than usual and as a result rejected the rain completely. So flash floods were the outcome.

I spent a fair bit of Sunday excavating our culvert. One set of friends were recovering their drive from the middle of the road while another was shifting the tan bark from his front garden to his back garden (where it had been on Saturday lunchtime).

After 3 days with no rain the flow in our Creek is back to low, hopefully as a result of the water that has gone into the soil staying there!