AT THE POINT
Location: Degree Confluence 25°S 143°E is in the heart of Channel Country in central Queensland, and is located on the very edge of the Thompson River, after which the degree square is named. The closest settlement is Jundah, approximately 20 km to the north-east. While the confluence itself is unmarked, a GPS was used to find the exact location (accurate to within a few metres), on the property 'Glen Valley'. Access to the point is via property tracks, except for the last 300 m which were travelled on foot. The site was visited in the mid afternoon by a party of RGSQ members travelling in four 4WD vehicles from Brisbane in June 2009.
Landscape: Elevation at the degree confluence was 133 m, and the view shows predominantly flat plains in between the channels of the Thompson River. Surface material sandy soil, and some grass, and other vegetation include scrubs and trees (height to 5 m). Some cattle of the 'Glen Valley' property were seen at or near the point, as were kangaroos, black cockatoos, herons, wedge-tailed eagles, and brolgas.
The confluence is in the middle of a plain which is characterised by Cainozoic Quaternary alluvium such as grey and red soil, silt, sand and gravel. The Thompson River is the major site of drainage for the area, which flows south to eventually join Cooper Creek. Numerous water holes are also found along the course of the Thompson River nearby.
Point Photos By: Paul Feeney, Mary Comer
Point Information By: Paul Feeney, Jo Grant, Mary Nowill
IN THE DEGREE SQUARE
Climate: The closest representative weather station is at the Windorah Post Office, which is located south-east of the confluence, and has an elevation of 126 m. The station has been collecting data since 1887.
The highest temperature recorded was 47.1°C in December 1990, and the lowest was -1.8°C in July 1977. The greatest rainfall recorded in a year was 990.1 mm in 2000, and the least was 66.8 mm in 2002. These and other climate statistics for Windorah can be found at on the Australian Bureau of Meteorology website, http://www.bom.gov.au/climate/averages/tables/cw_038024_All.shtml
Extremes of Nature: The area is subject to the impact of some cyclones. The database maintained by the Bureau of Meteorology shows that since 1906 only 5 cyclones have tracked within 200 km of the confluence, two of which have passed within 50 km (TC Bronwyn in January 1972, and TC David in 1976). These cyclones bring with them potentially destructive winds and intense rainfall. 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.
Cyclone tracks within 200 km of point 1906 to 2006 (Bureau of Meteorology web site)
Extreme heat and drought are also serious issues. Records show that Windorah experiences 124 days annually with temperatures over 35°C, 36 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 relatively little rainfall and only 36 days a year on average with any rain, the area is also among the driest in Australia.
The total population of the degree square at the 2011 national Census was probably less than 50 (see population notes for square 25-142).
More information to come.
Edited by: Hayley Freemantle
Geoscience Australia, NATMAP Raster
Geoscience Australia, Scanned 250 K Geology Maps