Friday, 7 December 2007

Crossing the Murray again


Apologies to regular readers for 'missing' the blog yesterday!

On the subject of readers, the patterns on the Clustr map in the sidebar are becoming very interesting. At the moment you can almost see Mark's route in the Clustr map - clearly the majority of readers are located in a swathe along this line. Did you know that if you click on the Clustr map, it opens up into something much more detailed like the map below...... Your red dot will be there! Perhaps it's the geographer in me but I find this fascinating - imagining the people and environments in which this blog is being read and hoping that the word of Mark's amazing race is spreading. Unsurprisingly, there are not many red dots in South America and Africa though I did notice a new one in Libya popping up the other day. Mark clearly also has a good following in polar bear country in Churchill on Hudson Bay in the north of Canada. However, just look at the paucity of red dots in Australia. Shame on you Oz! Mark has gone more than half way round the world and has almost completed a crossing of your country. He has met loads of your countrymen along the way but I am only seeing 8 red dots! So, if you are one of those dots, tell your friends, spread the word and, if you have any contacts, let the media know! It is not every day that someone cycles all the way from Europe to Australia.

Back on the road, I am playing 'catch up'. I turned on my computer this morning to find that Mark is now in another state, having crossed from Victoria into New South Wales...
The boundary between the two states follows the River Murray which Mark last saw shortly after leaving Adelaide and is described in this posting. Although much of the Google imagery in the vicinity of Mark's inland route to Brisbane is very low resolution, the Murray river section is excellent and gives us the chance to 'revisit' some features last described when Mark was crossing the Ganges plain in the posting called 'River Ramblings'.
Above is a section of the river (which is flowing bottom right to top left in the image) just to the east of the point where Mark crossed and here on the right a photo of the river in this section. The two settlements in the view below are Cobram on the left and Barooga on the right and you can see how they are situated above the flood plain of the river. If you look closely, you can see evidence of the fact that the river has changed its course over the centuries....
These meanders are very dynamic and traces of their former courses are etched out in the forest. In places, where there has been a recent change, the meander cut offs remain as ox bow lakes. What is particularly interesting here is the fact that you can date the changes. the state boundary was presumeably established around the middle of the 19th century and clearly followed the river. But what if the course of the river subsequently changes? The image above shows an old meander loop which was already cut off at the time the boundary was drawn whereas in this one .....
the boundary was drawn before the river cut through the neck of the meander. In time as the old meander silts up, the boundary will be detached from the current course of the river.
Another 10 km or so to the east of this spot is Lake Mulwala .........











....where the boundary seems most odd until you realise that this lake was not always there. It represents a flooded portion of the Murray River behind a dam built back in 1939 to provide irrigation water for the district. It is a shallow lake, as the image below shows, with the tops of the trees which once lined the banks of the river still visible above the waters of the lake.

3 comments:

kiso said...

Mrs V,

In defence of potential Australian readers, Mark's trip has received very little publicity here. I'm only here because my brother chanced upon your blog yesterday. I stayed up last night reading up on the trip so far. It's a few decades since I studied Geography, but I've enjoyed your insights into the landscapes and the lives of the people who live along Mark's route.

As it happens I'm in Dubbo, NSW - Mark should ride through here sometime tomorrow! On the Newell Highway, just before he reaches town, he may hear some unexpected animal sounds as he rides past Western Plains Zoo!

Mrs V said...

Hi Kiso

Your reaction is exactly what I was hoping for! It would be good if you could now help to spread the word.

Glad you have found the blog interesting.

Lee said...

I think the large number of visitors shown for Churchill in Canada is because this is the geographical centre of the country and any visitor from Canada whose precise location cannot be ascertained will be shown as coming from there.