22°S 150°E Broadsound – Queensland by Degrees

AT THE POINT

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Confluence point location (Google Earth image)

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Location: This confluence point is located at sea 11 km north-east of the tip of Long Island. The point has not been visited. It lies within the Rockhampton Regional Council area.

The Landscape: In the waters of Broad Sound.

Point information and photos: Ken Granger and Google Earth, 2009

IN THE DEGREE SQUARE

The Country: The land within the degree square falls into three broad landscape types: the continental islands; the low-lying coastal area; and the low hills of the interior. The continental islands are the tops of hills left isolated after the sea rose at the end of the last ice age between 35,000 and 6000 years ago. They are mostly less than 100 m in elevation though the highest points in the square are Southport Hill on Long Island and the 145 m ASL summit of Marble Island in the Duke Islands. The geology of these islands is very mixed and ranges in age and composition from Devonian age (410 to 354 million years) gneiss and rhyolite to Late Carboniferous age (325 to 298 million years) mudstone.

The coastline of Broad Sound is low-lying and marked by wide mud banks of Quaternary age (less than 1.6 million years) that are exposed at low tide and backed by extensive areas of mangrove forest. The head of Broad Sound experiences the greatest tide range on the east coast of Australia - around 9 m - so the extent of mud and sand along the coast can vary greatly. There are several mangrove-lined estuaries that break the coastline. These include the Herbert and St Lawrence Creeks and Styx River.

Like the islands off the coast, the low hills of the area are of mixed geological age including Devonian schist and rhyolite and Late Carboniferous mudstone and sandstone. The hills are low and rounded and the vegetation cover is a mixture of grassland and low eucalypt forest or woodland.

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Land use in the area includes cattle grazing on private land; the Defence Force Shoalwater Bay Training Area occupies a section in the south-east corner. This area is used periodically to stage large scale military exercises.

The Climate: The climate in the area is classified as sub tropical with a dry winter. The closest weather representative station to the confluence is at the St Lawrence Post Office, which is 62 km to the south-west, and has an elevation of 18 m. The station has been collecting data since 1870.

 

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Year

Mean max
(ºC)

31.7

31.4

30.9

29.3

26.8

24.3

23.8

25.0

27.0

28.9

30.5

31.5

28.4

Mean min
(ºC)

22.5

22.4

21.1

18.4

15.1

12.2

10.8

11.7

14.3

17.7

20.2

21.7

17.3

Mean rain
(mm)

206.4

197.2

131.6

59.8

47.8

49.6

31.7

22.9

26.4

45.3

71.8

122.0

1 012.5

The highest temperature recorded was 44.0°C in January 1994, and the lowest was 2.2°C in July 1963. The greatest rainfall recorded in a year was 1 976.1 mm in 1956, and the least was 197.7 mm in 1902.

These and other climate statistics for St Lawrence can be found at: Australian Bureau of Meteorology, http://www.bom.gov.au/climate/averages/tables/cw_033065_All.shtml.

Extremes of Nature: The point lies within one of the more active cyclone areas on the Queensland coast. The database maintained by the Bureau of Meteorology shows 49 cyclones have passed within 200 km of the point in the 101 years from 1906-7 to 2006-7. Of these nine passed within 50 km of the point. They were: an unnamed cyclone in January 1939; an unnamed cyclone of February 1942, an unnamed cyclone in January 1946; an unnamed cyclone in February 1947; an unnamed cyclone in March 1950; an unnamed cyclone in March 1955; TC David in January 1976; TC Elinor in February 1983; TC Pierre in February 1985. These cyclones would have produced very high seas that would have caused damage to the coastal areas and reefs within the square. They also bring destructive winds and intense rainfall that can produce wide-spread flooding. 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 that passed within 200 km of the confluence point 1906-2006 (BoM web site)

Numerous cyclones have had a destructive impact on the area. The earliest on record was in January 1874 when a furious gale along the northern coast which destroyed much property at St Lawrence. A new wharf disappeared, the Post Office and miles of telegraph lines were blown down and several stores were wholly or partially destroyed. Trees for miles around were uprooted. The schooner Countess of Belmore was badly damaged. The sparsely populated nature of the area however greatly reduced the potential damage.

The area experiences around 20 thunder days each year. Such storms can bring intense rainfall leading to flash flooding. They can also bring strong winds and lightning strikes. Lightning can start bushfires if there is sufficient fuel to sustain a fire.

The area can experience extreme heat throughout some of the year, with St Lawrence having an average of 5 days annually with maximum temperatures equal to or over 35°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.

The National Earthquake Database maintained by Geoscience Australia contains no earthquakes within the degree square.

The Indigenous Story: The land within the degree square, including the islands, is the traditional country of the Guwinmal people.

MORE INFORMATION WELCOME

European Exploration and Settlement: The first European navigator to sail along the coast in this square was James Cook in HMS Endeavour in 1770. Cooked named various features including Broad Sound. The next navigator was Matthew Flinders in HMS Investigator in 1802. Flinders also named features in the area including the Percy Islands.

The location of St Lawrence mid-way between Rockhampton and Mackay and with the potential port sites in the Broad Sound led to its development as a port for the export of cattle from the hinterland. A large meatworks was established about eight kilometres from the town in 1893. It continued to operate until 1919 by which time rail links to the major centres made it and the port redundant.

MORE INFORMATION WELCOME

Today:

The total population of the degree square at the 2011 national Census was 396.

MEASURE

1996

2001

2006

2011

Total population

436

281

268

396

Total males

254

160

154

230

Total females

182

121

114

166

Under 5 years

24

9

14

7

65 years and over

63

50

65

105

Indigenous

12

12

0

4

The population of St Lawrence was probably around 125 at the 2011 census. This population can fluctuate depending on the season. Professional fishermen and tourists can increase the population during the winter season.

The area has around 625 km of public roads. The main northern rail line also passes through the area.

The area is divided between two local governments: Rockhampton Regional Council in the east and Isaac regional Council in the west. There are six national parks and conservation parks in the area: Broad Sound Island National Park, Charon Point Conservation Park, Newport Conservation Park, Northumberland Islands National Park, Percy Isles National Park and Shoalwater Bay Conservation Park.

Site Summary:

Location

In Broad Sound about 11 km north-east of the tip of Long Island

Access

Point was not visited

Nearest town

St Lawrence is 62 km south-west of the point

Terrain

At sea

Climate

Sub tropical with dry winter

Population

268 at the 2006 census

Infrastructure

625 km of public roads and the main northern rail line

National Parks

Six parks in the square

  

Compiler: Ken Granger, 2009

Edited by: Hayley Freemantle

REFERENCES

various web sites including EPA, local governments, tourist industry and Bureau of Meteorology.