21°S 143°E Essex Downs – Queensland by Degrees

AT THE POINT

Degree confluence 21°S 143°E, Google Earth

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Looking northLooking east
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Location: This confluence point is located on Essex Downs station close to Twenty Mile Creek about 2.5 km west of the Richmond - Winton Road. The site is at an elevation of about 200 m ASL.

The Landscape: The area surrounding the point is generally flat with little relief and is in the drainage channels of Twenty Mile Creek which flows to Alick Creek, a tributary of the Flinders River which flows to the Gulf of Carpentaria. The point itself sits on Quaternary alluvium but is surrounded by sandstone and mudstone of Albian age (around 100 million years). The soils are clay black soils. Vegetation is dominated by Mitchell Grass; there are few trees or shrubs.

 

Point information and photos: Paul Bailey, 2009

IN THE DEGREE SQUARE

The Country: There is very little variation in elevation or relief across the square. The highest elevation is around 250 m ASL and the lowest around 150 m ASL. The bulk of the area drains to the Gulf of Carpentaria; Wockingham Creek in the south-east corner is a tributary of the Diamantina River which flows to the Lake Eyre Basin.

The great majority of the area is composed of sandstone and mudstone of Albian age (Early Cretaceous around 100 million years). The numerous drainage channels including the Flinders River and Alick Creek have flood plains of Quaternary alluvium (less than 1.6 million years).

The dominant vegetation is Mitchell Grass. Along the drainage lines are narrow bands of riparian trees such as Coolibah and River Red Gum.

 

The Climate: The climate of the area is classified as hot grassland with a winter drought. The Bureau of Meteorology climate station at Richmond Post Office provides representative statistics.

Richmond Post Office (030045) 1889 to 2009 (elevation 211 m ASL)

 

JAN

FEB

MAR

APR

MAY

JUN

JUL

AUG

SEP

OCT

NOV

DEC

YEAR

Mean max (0C)

36.9

35.7

34.9

32.7

29.1

26.1

25.9

28.5

32.3

35.8

37.6

38.1

32.8

Mean min (0C)

23.0

22.5

20.7

17.0

13.1

9.8

8.5

10.1

13.9

18.0

20.9

22.4

16.7

Mean rain (mm)

122.6

104.3

60.2

22.3

15.2

15.4

9.4

4.2

6.2

16.2

30.1

69.9

475.7

The highest temperature ever recorded in Richmond was 46.0oC in January 1973 while the lowest temperature was -2.5oC in July 1925. Rainfalls also vary greatly. The highest total of 1160.2 mm was recorded in 1891 and the lowest total of 108.1 mm in 1952.

Extremes of Nature: The cyclone database maintained by the Bureau of Meteorology shows 12 active or former cyclones have tracked within 200 km of the confluence point since 1906. Of these, only one passed within 50 km of the point: TC Althea in December 1971. Each of these storms brought heavy rain falls that produced flooding in both local and regional catchments.

 

cyc

Cyclone tracks within 200 km of point 1906 to 2006 (Bureau of Meteorology web site)

 

The area receives between 20 and 25 thunder days on average each year. The more severe thunderstorms can produce destructive winds, intense rainfall that may cause localised flash flooding, and lightning strikes may spark bushfires if there is sufficient fuel for it to spread.

There have been 13 major flood peaks in the Flinders River recorded at Richmond since 1942. The flood of record occurred in 1955 when a peak of 11.43 m was reached on the Richmond gauge, almost 5 m over the Richmond Bridge. Floods in this square tend to spread over a wide area and have relatively low velocities.

Drought and heatwave are the most serious hazards. Droughts can have a long-lasting economic impact and cause great losses in the cattle industry. Heatwaves, on the other hand, kill more people than all other hazards combined. Richmond experiences on average 142 days over 35oC and 27 days over 40oC each year.

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

The Indigenous Story: The land within the square is the traditional country of two major groups - the Wunumara people to the west and the Yirindali to the east. The northern edge falls within the Mbara country.

MORE INFORMATION WELCOME

European Exploration and Settlement: The area was first visited by William Landsborough in 1862 and the first European settlers followed into the area in 1863. By 1870 Richmond was a police post and the town was surveyed in 1882. By 1909 the rail link to Julia Creek was opened and in 1931 the first complete Kronosaurus fossil was discovered.

MORE INFORMATION WELCOME

Today: The total population of the degree square at the 2011 national Census was 828. The steady decline in population over the past decade from 1996 to 2006, that was probably a result of a prolonged drought and its impact on the cattle industry, appears to have been reversed.

MEASURE

1996

2001

2006

2011

Total population

889

815

682

828

Total males

496

407

380

437

Total females

393

408

302

391

Under 5 years

85

67

52

55

65 years and over

93

84

80

105

Indigenous

83

32

45

45

The majority of the population live in Richmond which had a population of 517 at the 2011 census. Richmond has a good range of basic services and retail outlets. The Richmond area is rich in fossils and the Richmond Marine Fossil Museum, Kronosaurus Korner, is a popular tourist stop. The replica of the Richmond Pliosaur, a 5 m long marine reptile, is a key attraction.

 

Richmond (Google Earth image)

There is around 1600 km of public roads within the square including the Flinders Highway that links Townsville and Mt Isa. Most roads are natural surface. The main rail link between Townsville and Mt Isa also passes through the square.

The bulk of the square falls within the Richmond Shire. In the south-east corner there are small sections of the Flinders and Winton Shires. There are no national parks within the square.

Site Summary:

Location

Essex Downs station close to Twenty Mile Creek

Access

By road on the Richmond-Winton Road then 2.5 km on station road

Nearest settlement

Richmond is 33km north-east of the point

Terrain

Flat to low undulations

Catchment

Flinders River part of the lake Eyre basin

Geology & soils

Quaternary alluvium over sandstone and mudstone

Vegetation

Grassland

Land use

Cattle grazing

Climate

Hot grassland with a winter drought

Population in degree square

682 at the 2006 census, most live in Richmond

Infrastructure

1600 km of public roads including Flinders Highway , main rail link from Townsville to Mt Isa

National Parks

No national parks in the degree square

Compilers: Ken Granger 2010

Edited by: Hayley Freemantle

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