25°S 139°E Eyre Creek – Queensland by Degrees

AT THE POINT

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Degree confluence 25° S 139° E, Google Earth

n

Looking north

e

Looking east

s

Looking south

w

Looking west

 

Location: The site is in western Queensland, in the heart of Channel Country, and on the eastern edge of the Simpson Desert. The confluence point is unmarked, and located in a corridor between two SSE-NNW trending dunes, approximately 1.8 km apart. An ephemeral lake lies just to the north of the confluence. Access is via the Eyre Developmental Road and dirt tracks that come within a kilometre of the point. The remaining distance was traversed by 4WD across country. The nearest settlement is Bedourie, which is approximately 85km to the north-east. The site was visited by a party of RGSQ members travelling in four 4WD vehicles from Brisbane in May, 2008.

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Setting up camp near the degree confluence

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Landscape: The view from the confluence shows a flat terrain, with an elevation of approximately 80m. The ground surface is covered primarily with tussocks of grass, stones and rocks, and some bare soil. Scattered bushes and low trees are visible on the dunes to the east and west. Geological features of the area include undifferentiated Cainozoic gravel, and pebbles of silicifed rock (i.e. gibbers).

The outlying dunes of the Simpson Desert near the confluence are smaller than those in the centre, with their average distance apart being approximately 2km, and their average height given as 8 m.

There is no coordinated drainage pattern at the confluence, but the wider area is part of the Eyre Basin. Eyre Creek, which gives its name to the degree square, is the closest significant watercourse and is less than 20km north-west of the point. A great many waterholes and salt lakes are found in the surrounding country, and while typically dry, can become swampy after heavy rains.

Point Photo Credits: Paul Feeney

Point Information Prepared By: Jo Grant

 

IN THE DEGREE SQUARE

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Google Image: linear dunes adjacent to Degree Confluence 25S 139E

Climate: The closest representative weather station is at the Bedourie Police Station, which is 85 km north-east of the degree confluence, and has an elevation of 91 m. The station has been collecting data since 1932.

 

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Year

Mean max
(ºC)

38.8

38.1

36.2

32.5

26.8

22.6

23.3

25.5

30.8

34.1

36.3

38.4

32.0

Mean min
(ºC)

25.1

24.6

21.7

17.4

11.7

8.2

7.6

9.1

14.4

17.9

20.9

23.5

16.8

Mean rain
(mm)

33.4

35.3

17.6

10.1

11.6

10.0

10.3

7.2

6.3

14.1

16.2

16.2

187.7

The highest temperature recorded was 47.0°C in January 2004, and the lowest was 1.6°C in July 2004. The greatest rainfall recorded in a year was 485.1 mm in 2000, and the least was 33.4 mm in 2002. These and other climate statistics for Bedourie can be found at: Australian Bureau of Meteorology, http://www.bom.gov.au/climate/averages/tables/cw_038000_All.shtml

Extremes of Nature: The area experiences extreme heat for much of the year, with Bedourie having an average of 139 days annually that have maximum temperatures equal to or over 35°C. The hottest months are December to February, all of which experience on average over 20 days with temperatures equal to or over 35°C. With an extremely low average rainfall and only 21 days a year with any rain, the area is also among the driest in Australia.

Since 1906 there have been no cyclones to pass within 50 km of the degree confluence, but 3 have passed within 200 km (1918, 1955, 1976) despite its inland location. Cyclone information for this area and all of Australia can be found at the Australian Bureau of Meteorology website, http://www.bom.gov.au/cgi-bin/silo/cyclones.cgi.

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Cyclone tracks within 200 km of the confluence, 1906 to 2006 (Bureau of Meteorology web site)

Extreme heat and drought are also serious issues. Records show that Bedourie experiences 139 days annually with temperatures over 35°C, 49 of which typically reach 40°C or warmer. Such extreme temperatures can cause heat stroke and death if appropriate measures are not taken such as avoiding strenuous physical effort, keeping as cool as possible and drinking lots of water. Heat waves kill more people in Australia than all other natural hazards combined. In addition, with very little rainfall and only 21 days a year on average with any rain, the area is also among the driest in Australia.

Today:

The population of the degree square at the 2011 national Census was probably less than 50.

MEASURE

1996

2001

2006

2011

Total population

20

129

125

<50

Total males

12

78

73

?

Total females

8

51

52

?

Under 5 years

3

6

12

?

65 years and over

3

4

5

?

Indigenous

3

52

35

?

The apparent fluctuation in population over the past 15 years is more likely due to changes in census boundaries than to actual population changes.

 

Information: Ken Granger

Edited by:  Hayley Freemantle

REFERENCES

Geoscience Australia, NATMAP Raster

Geoscience Australia, Scanned 250 K Geology Maps