AT THE POINT
Location: This confluence point is located 2.35 km to the south west of the Warrego Highway and lies in the riparian zone of the Condamine River which is 100 metres from the point and is the major drainage catchment of the area. Following heavy rain it was not possible to drive to the point however in normal circumstances it would be possible to drive within 400 metres. Accuracy using GPS was within +/- 2 metres. The nearest settlement is the village of Macalister some 9.4 km to the south east of the point which lies within the Dalby Regional Council area.
GPS at the point
The Landscape: The area is quite flat with some low rises and forms part of the Western Downs. The elevation of the area is around 300 metres. It is a black soil area and movement off made roads is very difficult after as little as 20-30 mm of rain. The underlying geology is channel and flood plain alluvium of Quaternary age (less the 1.6 million years).
Flooded track leading towards the degree point.
Most of the vegetation in the riparian zone is comprised of eucalypts and acacias. There was some growth of woody weeds in small previously cleared areas near the river. Birdlife consists of parrots, magpies, crows and kookaburras while grey kangaroos and wallabies are also in the area.
Point information and photos: Keith Hall and Ray Kelly 2008
IN THE DEGREE SQUARE
The Country: The country within the degree square ranges in elevation from 800 m ASL in the Bunya Mountains section of the Great Dividing Range in the east to around 250 m ASL where the Condamine River exits the square in the west. Topography is generally flat to undulating. Much of the square is alluvial sediment of Quaternary age in the floodplain of the Condamine River and its tributaries. To the south west of the Condamine are sand plains of Cainozoic age (less than 65 million years). The Great Dividing Range within the square is made up of areas of basalt of Oligocene age (around 34 million years), sandstone of Early Jurassic age (205 to 184 million years) and gneiss of Late Carboniferous age (354 to 325 million years).
The land within the square is used for intensive summer and winter cropping and has been cleared of native vegetation for many years. This use for crops is universal north of the Condamine River however to the south of the river there are areas set over to cattle raising where the land is not as suitable for cultivation.
The area is part of the Surat Basin which contains extensive coal deposits. The major coal mine in this area is at Wilkie Creek about 6.5 km south west of the confluence point.
Climate: The climate of the area is classified as being subtropical with a moderately dry winter. The closest weather station is at the Dalby Airport, which is 32 km south-east of the confluence and has an elevation of 344 m. This station has been in operation since 1992, however, the former station at the Dalby Post Office had accumulated 98 years of records before it closed in 1992.
The highest temperature recorded was 41.7°C in January 1994, and the lowest was -6.2°C in August 2003. The greatest rainfall recorded in a year was 847.0 mm in 1996, and the lowest was 421.0 mm in 2006. These and other climate statistics for Dalby can be found at: Australian Bureau of Meteorology, http://www.bom.gov.au/climate/averages/tables/cw_041522_All.shtml.
Extremes of Nature: The area is subject to the impact of cyclones. In the 101 years from 1906-7 to 2006-7 there were 18 cyclones that passed to within 200 km of the confluence point. Of these, only one cyclone (TC Wanda of January 1975) passed within 50 km. Each cyclone brings potentially destructive winds and torrential rains. 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 that passed within 200 km of the point since 1906 (Bureau of Meteorology web site)
Major floods occur regularly in the Condamine River, on average every 2 years. The worst flooding occurred in 1942, 1950, 1956, 1975, 1976, 1983 (twice), 1988 and 1996. Of these the 1942 flood is the flood of record, measuring 14.25 m on the Condamine gauge. Any flood over 10.7 m on that gauge will put water into the town and threaten houses. Major floods generally only occur in the first half of the year although records indicate that they may also occur in late spring.
The area experiences, on average, around 20 thunder days each year. Severe thunderstorms can bring destructive winds, intense rainfall that can produce flash flooding and lightning. Some thunderstorms may trigger tornadoes with extremely destructive winds across a narrow band. Storms in the dry winter period can spark bushfires if there is sufficient fuel to promote spread.
Bushfires can pose a very significant threat to property and agricultural land. In the late autumn and early summer bushfires can be especially dangerous given that fuels such as grass and forest litter is well cured and strong dry westerly to north-westerly winds are common.
The area can experience extreme heat throughout some of the year, with a 98 year average of 24 days on which temperatures are hotter than 35°C and one day over 40°C a year recorded at Dalby. The hottest months are December to February. 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.
The area can also experience chilly conditions, having a 98 year average of 30 days annually with minimum temperatures equal to or less than 2°C and 14 days at or below zero.
The National Earthquake Database maintained by Geoscience Australia contains nine earthquake epicentres within the degree square. None of these events had magnitudes in excess of ML 1.8. These events tend to follow the western slope of the Great Dividing Range. Such a small quakes were probably not even felt in the area. No damage was reported from this event.
Dalby, on Myall Creek, also has a record of severe flooding. Myall Creek has records of floods dating back to 1908 with 9 major flood events having occurred since this time, the highest being the February 1981 flood which rose to a height of 4.50m on the flood gauge located in Patrick Street. This resulted in some 700 homes and 140 businesses being inundated by floodwaters and some 25,000 ha of agricultural lands suffering moderate to severe flood damage.
The Indigenous Story: This area was part of the country supporting the Barunggam language group.
Explorer Ludwig Leichhardt encountered the Barunggam on his first expedition in 1844, and again in 1846 when his party camped at Charley's Creek (named in honour of Leichhardt's aboriginal guide Charley Fisher). He described them as tall, strong, healthy and helpful. With the arrival of the first settlers, their helpfulness turned to violent resistance, resulting in death and destruction from both sides. In 1912, those who had avoided slaughter by the Native Mounted Police and the settlers were forced to live at the Aboriginal settlement at Taroom, thereby removing them from their homeland forever.
European Exploration and Settlement: The first European explorers to enter this area were with botanist Allan Cunningham in 1827 and by 1841 pioneering settlements had been established at Myall Creek (present day Dalby), Jondaryan and Jimbour. Ludwig Leichhardt used Richard Scougall's station at Jimbour as his base before setting off on his epic expedition to Port Essington (near present day Darwin) in 1844.
Chinchilla Station was taken up in 1848 and a 'homestead' built by 1850. A succession of good seasons in the 1850s and early 1860s led other landholders to take up properties adjoining the Chinchilla Station, but severe droughts, notably in 1866 and 1868, took their toll.
Dalby, originally known as The Crossing or Myall Creek, was gazetted as a municipality in 1851, however the council was not established until 1862. The rail link from Toowoomba to Dalby was opened in 1868 and was subsequently extended west as far as Chinchilla by 1876. Chinchilla became established as a shanty town by 1877 at the rail crossing of Charley's Creek.
In 1910 Prickly Pear (Opuntia stricta) was declared a pest and all attempts at control such as injecting the plants with arsenic, proved ineffective. As a result the Queensland Government offered 100,000 acres (40,469 ha) reward to the first person to eradicate Prickly Pear. Initially 3,000 eggs of the moth Cactoblastus cactorum were imported from Argentina by the Commonwealth Prickly Pear Board under Allan Parkhurst Dodd and, from a population of 527 females, a total of 100,605 eggs were hatched. Half these eggs were sent to the Chinchilla Prickly Pear Experimental Station and half were kept in Brisbane. The moth was spectacularly productive. The second generation yielded 2,539,506 eggs. At the height of the operation Chinchilla was sending out as many as 14 million Cactoblastis eggs a day.
Prickly pear infestation near Dalby in the 1920s
In 1926 the Cactoblastis moth was released to attack Prickly Pear and by 1933 most of the land was cleared of the pest. Vast areas of land that had been taken out of production by the pest were returned to productivity. No wonder the locals decided to dedicate a hall to this small insect. Located 10 km east of Chinchilla on the Warrego Highway is the Boonargo Cactoblastis Hall which was built by the local farmers in 1936 and dedicated to the redoubtable insect which had managed to eat its way through the jungles of Prickly Pear. It was seen as the true saviour of rural Australia and thus it is entirely reasonable that a hall should have been dedicated to its memory. A monument to the Cactoblastus was erected in Dalby by Queensland Women's Historical Association in 1965. This is believed to be the only monument to an insect in Australia.
MORE INFORMATION WELCOME
The total population of the degree square at the 2011 national Census was 24,576. The growth since 2006 is probably linked to the development of the power and gas industries within the square.
Of this total 9874 were living in Dalby; Chinchilla had 4780, up from 3598 in 2006; and Jandowae had 746. The rest of the population was spread across the rural areas and in small villages such as Warra, Jimbour, Kaimkillenbun and Macalister.
Dalby is the major commercial and administrative centre within the square. It has a wide range of retail, wholesale and service facilities including schools, hospital and court house. It is a significant transport hub with both rail and road transport services. It also has an all weather airstrip.
Dalby (Google Earth image)
Chinchilla has become the base for the construction and operation of the nearby Kogan Creek Power Station which opened in 2007. The town has a good range of commercial and other services.
Chinchilla (Google Earth image)
The Kogan Creek power station is the largest single coal fired generating unit in Australia with an output of 750 megawatts. It draws its coal from the neighbouring Kogan Creek mine.
Kogan Creek power station (Google Earth image)
The Wilkie Creek coal mine is also a major industrial activity in the square. It produces 2.35 million tonnes of low sulphur coal a year from an open cut operation.
Wilkie Creek coal mine (Google Earth image)
All major roads in the area are sealed, and minor roads are generally of good repair. This is "black soil" country however and lesser roads may become unusable after rain. The western rail line passes through the square and a spur line between Dalby and the Surat area services the coal and agricultural industries.
Typical dirt roads along the Condamine (Keith Hall, 2008)
Most of the square is within the Dalby Regional Council area, though the name is likely to be changed to Western Downs Regional Council following a plebiscite of rate payers in 2008. A small section of South Burnett Regional Council is in the north east corner. Lake Broadwater is the only conservation park in the square though a small sliver of the Bunya Mountains National Parks is located on the north west boundary of the square.
MORE INFORMATION WELCOME
Compilers: Keith Hall, and Ray Kelly, with additional material by Ken Granger, 2009
Images: Ray Kelly and Keith Hall
Edited by: Hayley Freemantle
References: various web sites including EPA, local governments, tourist industry and Bureau of Meteorology.