Satellite image from Environmental GraffitiThis is an image taken from space of the Great Sandy Desert.
Drainage is limited to short ephemeral creeks and rivers, which only flow after heavy rainfalls. The bioregion comprises two ancient inactive river basins that are divided by a low watershed. The watershed is a lateritic surface that forms the Anketell Range in the west and Southwest Tableland in the east. North of the watershed Sturt Creek (now only visible from satellite imagery) once flowed across the desert to Mandora on the 80 Mile Beach. The southern basin contains Percival Lakes which represent a river system from the past (Beard, 1990). Calcrete and evaporite outcrops are associated with palaeodrainage systems that traverse the desert.
The headwaters of the Rudall and Cotton Rivers are in the northern limits of the bioregion in Western Australia. The Rudall River is a significant wetland/ecological refuge, which contains major permanent waterholes and soaks. The Rudall River flows approximately 120km into Lake Dora (30, 000ha) in the Western Australian sector of the bioregion.
In the northwest of the bioregion is Dragon Tree Soak, a 5ha swamp regarded as a relict of the riverine vegetation found along the palaeo-river in the wetter climates of the early to mid Holocene. The soak is a fresh water spring that supplies freshwater to the marsh and peatland.
Lake Amadeus is a massive saline lake in the Northern Territory, which has no significant surface inflow. The main inflow of water is via groundwater seepage.
The headwaters of the Rudall and Cotton Rivers are in the northern limits of the bioregion in Western Australia. The Rudall River is a significant wetland/ecological refuge, which contains major permanent waterholes and soaks. The Rudall River flows approximately 120km into Lake Dora (30, 000ha) in the Western Australian sector of the bioregion.
In the northwest of the bioregion is Dragon Tree Soak, a 5ha swamp regarded as a relict of the riverine vegetation found along the palaeo-river in the wetter climates of the early to mid Holocene. The soak is a fresh water spring that supplies freshwater to the marsh and peatland.
Lake Amadeus is a massive saline lake in the Northern Territory, which has no significant surface inflow. The main inflow of water is via groundwater seepage.
Are we looking at a window into the future showing us all what will become of the southern half of the Murray Darling Basin?
It is now a minute past midnight and it looks as if we have missed the chance to save the Murray Darling.
1 comment:
Good post. I have been reading Peter Andrews' book "Back from the brink" and that made me realise that there is a lot more to rescuing our river systems and our landscape than just releasing extra water. I have to admit, when I see the occasional images of broad acre farming on television, with those massive irrigation channels and endless fields with no tree in sight, it makes me shiver. In my view, that is not efficient farming, it is agricultural vandalism, and the river is paying the price.
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