A nice easy Earth Cache for beginners with a high T rating for some added fun!
**You will be required to swim or Paddle ( we recommend Paddle) to complete this EC. Please don’t’ take any unnecessary risks and use safety gear at all times. Never swim alone. Never enter floodwaters.
Murrumbidgee River, a major tributary of the Murray River within the Murray–Darling basin and the second longest river in Australia. It descends 1,500 metres (4,900 ft) as it flows 900 kilometres (559 mi) in a west-northwesterly direction from the foot of Peppercorn Hill in the Fiery Range of the Snowy Mountains towards its confluence with the Murray River near Boundary Bend. 88 creeks and rivers flow into the Murrumbidgee River.
The word Murrumbidgee means "big water" in the Wiradjuri language, one of the local Aboriginal languages.
The mainstream of the river system flows for 900 kilometres (560 mi). The river's headwaters arise from the wet heath and bog at the foot of Peppercorn Hill situated along Long Plain which is within the Fiery Range of the Snowy Mountains; and about 50 kilometres (31 mi) north of Kiandra. From its headwaters it flows to its confluence with the Murray River. The river flows for 66 kilometres (41 mi) through the Australian Capital Territory near Canberra, picking up the important tributaries of the Gudgenby, Queanbeyan, Molonglo and Cotter Rivers. The Murrumbidgee drains much of southern New South Wales and all of the Australian Capital Territory, and is an important source of irrigation water for the Riverina farming area.
The reaches of the Murrumbidgee in the Australian Capital Territory are affected by the complete elimination of large spring snow melt flows and a reduction of average annual flows of almost 50%, due to Tantangara Dam. Tantangara Dam was completed in 1960 on the headwaters of Murrumbidgee River and diverts approximately 99% of the river's flow at that point into Lake Eucumbene. This has extremely serious effects on native fish populations and other native aquatic life and has led to serious siltation, stream contraction, fish habitat loss and other problems. The Murrumbidgee where it enters the ACT is effectively half the river it used to be.
A study suggests a section of the upper river's channels are relatively new in geological terms, dating from the early Miocene (the Miocene era being from 23 to 5 million years ago). It is suggested that the Upper Murrumbidgee is an anabranch of the Tumut River (that once continued north along Mutta Mutta Creek) when geological uplift near Adaminaby diverted its flow. From Gundagai onwards the rivers flow within its ancestral channel.
A confluence is the meeting of two or more bodies of water. Also known as a conflux, it refers either to the point where a tributary joins a larger river, called the main stem, or where two streams meet to become the source of a river of a new name.
We regrettably didn’t take coordinates for the best track leading into the junction, finding your way there can be half the fun? We can tell you that leading off the Murray Valley Highway approximately 5 kilometres upstream of Boundary Bend and only 50 kilometres south of Robinvale is a small sign posted track that takes you to the junction of two great Australian Rivers: the Murray and the Murrumbidgee.The track itself is about 5km long and in dry weather is 2WD accessible.
To log this Earth Cache we require you to swim or paddle out and look at the area, consider the information given and perhaps if you need to do some research of your own, then message us with the following answers to the best of your ability;
1. Where the two rivers meet in front of you, there is a distinctness between them in size and colour, what is it and what do you think causes this?
2. Looking at either of the banks, what Geology do you see, and how did it get there?
3. Position yourself or your vessel in the confluence, can you feel the current, describe what you feel and the direction you are taken, are you surprised at all by your observations?
4. Moving away from the confluence upstream and into the main flow of the Murrumbidgee is there any difference? Why/Why not?
5. Moving away from the confluence upstream and into the main flow of the Murray is there any difference? Why/Why not?
6. Moving downstream after the confluence into the main stem (the Murray) is there any difference? Why/Why not?
7. A photo of your team or GPS near GZ. (Optional)
You are welcome to log your answers straight away to keep your TB's and Stats in order but please message us with your answers within 24 hours. Cachers who do not fulfil the Earth Cache requirement will have their logs deleted.
Source: Wikipedia, Peter Phillips (photo credit)