18°S 140°E Leichardt River – Queensland by Degrees

AT THE POINT Surrounding the degree confluence (Google Earth image) Location: Degree Confluence 18S 140E is located in Gulf Country, in far north-west Queensland. The closest settlement is Burketown, approximately 56 km to the north-west. The confluence itself has yet to be visited, but access should be possible via private property tracks by 4WD. Landscape: Elevation at the degree confluence is approximately 25 m, and the surrounding landscape is a predominately flat plain, broken by the courses of numerous creeks, which could make the terrain muddy and boggy during the tropical summer rains. Aside from a fence or track just to the west of the point, the Google Earth image shows that there is some scattered vegetation nearby, and that the nearest creek is an arm of Lagoon Creek, just to the south. All watercourses in the area drain into the Gulf of Carpentaria via the Leichardt River (after which the degree square is named). The main geological features of the confluence are Normanton Formation (Early Cretaceous [146-100 million years ago]) sedimentaries including sandstone, siltstone, mudstone and limestone. Point Information By: Jo Grant   IN THE DEGREE SQUARE Climate: The closest representative weather station to the confluence is at the Burketown Post Office, which is 56 km north-west of the confluence, and has an elevation of 6 m. The station has been collecting data since 1886. Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year Mean max (ºC) 34.2 33.6 33.5 33.1 30.5 28.0 27.7 29.4 31.9 34.2 35.4 35.4 32.2 Mean min (ºC) 25.0 24.6 23.5 20.7 17.0 14.3 13.1 14.5 17.7 21.1 23.6 24.8 20.0 Mean rain (mm) 221.4 192.8 151.7 23.3 6.1 6.3 2.4 0.8 1.9 12.6 38.8 115.8 785.6 The highest temperature recorded was 46.0°C in January 1973, while the lowest temperature was 3.3°C in July 1941. The greatest rainfall recorded in a year was 2 026.6 mm in 1998 and the least was 187.6 mm in 1902. These and other climate statistics for Burketown can be found at: Australian Bureau of Meteorology, http://www.bom.gov.au/climate/averages/tables/cw_029004_All.shtml. Extremes of Nature: Given the area's tropical location, it is very much subject to the impact of tropical cyclones. The database maintained by the Bureau of Meteorology shows that 42 cyclones have passed within 200 km of the confluence since 1906, nine of which passed within 50 km (1939, 1952, 1956, 1959, 1964, two in 1976, 1979, and 1987). 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 the confluence, 1906 to 2006 (Bureau of Meteorology web site) Like most places in the Australian tropics, extreme heat is also a danger. Records show that the Georgetown Station experiences 86 days annually with temperatures 35°C or warmer, although very few of these reach over 40°C. 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.   REFERENCES Geoscience Australia, NATMAP Raster Geoscience Australia, Scanned 250 K Geology Maps Google Earth

Last updated 23 October 2009. For more information email admin@rgsq.org.au Return to home