A beautiful sunny morning to farewell Mannum, the most picturesque town I have seen and the very best caravan park right on the mighty Murray River.    We have had a lovely laid-back couple of days here and loved it!

We head north west for the Barossa Valley, following the incredible Adelaide water supply pipe, ducking and diving under roads and winding its way up the hills looking like a mini Great Wall of China winding over the mountains.   It is quite an amazing sight.

As we wound our way up through the hills we came across another phenomena.   Message rocks I call them but I suppose it is graffiti in the real sense of the word.   For several kilometres, rocks were written on, all along the roadside and further up into the hills.   Quite an amazing sight and no doubt one or two people did it, then hundreds more followed.   Not unlike the stone cairns on the Great Ocean Road.  

We needed to get fuel but, for the first time, we didn't appear to be anywhere near a service station.   The closest one was about 20km away and in a slightly different direction;  we had heaps of fuel to get there but not to get to our destination of Tununda.   So off we go to a middle-of-nowhere service station in Williamstown.   I had read about this place!   It has the Barossa Reservoir dam on its doorstep, with an amazing attribute hidden in its strangely curved concrete walls.   I was pretty excited by this as I didn't think we would go close to this place.

So after the fuel stop off we went to the Whispering Wall!   A concrete damn which was built by more than 400 workers, living in tents in the rough, on the banks of the South Para river.   It took 3 years – started in the 19th century and finished in the 20th in 1902.   This is an 'arch' dam; the first in South Australia and, at the time, the highest in Australia.   Pretty amazing engineering for those days.

This is the thing!   Being an arch dam with a hard concrete curved surface, it has incredible acoustics.   A person (Bill) can stand at one end of the dam, by the wall, and talk in a whisper (or normal tones) to another person (me) standing at the other end of the wall.  

I was doubting this would work actually.   What with Bill never hearing anything I say and him mumbling!   Haha.   Anyway I can confirm it is true and Bill enunciated beautifully on this occasion and he actually heard what I said too!    Truly a wonder – on all counts J   It is as clear as if you are standing right next to one another.

Folklore or not, the story goes that during the build some of the workers were complaining about their boss and the working conditions (much like today I reckon) and the boss, who was ostensibly out of earshot at the other end of the dam, heard every single word very clearly.   They consequently all lost their jobs and presumably, from that time on knowing the capabilities of the dam wall, everyone on site would have been most guarded in all their conversation!   Love a good story!

Some pretty big machinery, which helped build other close-by dams in the 30’s, was on display which was pretty interesting, however the most interesting thing I saw was a wooden water pipe!   It was made in the same way as a barrel, with timber lengths, then bound tight with wire wrapping its entire circumference.    There must have been a few coopers employed to make these en masse.

And so on to the Barossa Valley.