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ASIAN PACIFIC FRIEND |
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Torrens River
Map of River
Table of Basic Data
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Name: Torrens River at Mt Pleasant (Upper Catchment of Torrens River AW504512) |
Serial No.: Australia-5 |
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Location: South Australia |
S 34o 40’ ~ 34o 50’ |
E 139o 00’ ~ 139o 05’ |
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Area: 25.9 km2 |
Length of main stream: 8 km |
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Origin: Mt Pleasant-Partalunga |
Highest point: Mt Pleasant 543 m |
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Outlet: Gulf St Vincent |
Lowest point: sub-catchment outlet~420m Av elevation 463m |
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Main geological features: Cambrian with Quaternary formation along main river channel. |
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Main tributaries: None |
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Main lakes: None |
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Main reservoirs: None |
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Mean annual precipitation: 621 mm (1895-1997) (see isohyetal map) |
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Mean annual runoff: 85.1mm (1974~1998) at sub-catchment outlet |
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Population: < 500 |
Main cities: Township of Mt Pleasant |
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Land use: Grazing , Vineyards and Natural vegetation |
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1. General Description
The Torrens River at Mt Pleasant has a catchment area of 25.9 km2 and is located at the head waters of the Torrens Catchment in South Australia to the east of Adelaide. Flowing in basically a south westerly direction in this catchment, the length of the Torrens River to the Gauging Station is approximately 8 km. The total Torrens River Catchment area is approximately 508 km2, 80% of which lies in the Adelaide Hills. The climate of the catchment is typically temperate with high maximum daily temperatures and evaporation in summer. Rainfall tends to occur in winter and spring (from May to October) with the majority of the rainfall in the winter months. The topography is dominated by the high summit peneplain which provides a landscape of low relief. The upper river slope, east of Gumeracha, has an average gradient of 0.6%.
The average catchment elevation is approximately 463 m. Overall the soils of the catchment can be considered to be moderately permeable consisting of coarse sandy material overlying weathered rock. Grazing comprises the major land use in the catchment with some vineyards in the northern part of the catchment and native vegetation existing in the south western part of the catchment. The township of Mount Pleasant is situated in the south western part of the catchment adjacent to the River Torrens. Approximately 7% of the catchment is irrigated and due to the low rainfall, irrigation application rates tend to be higher than elsewhere in the catchment. The majority of water for irrigation comes from captured surface water due to the high salinity levels in ground water. Within the Mt Pleasant catchment there are 117 dams.
Issues within the Mt Pleasant catchment include dryland salinity, water quality, riparian zone health, lack of native vegetation, dam building and water use.
2. Geographical Information
2.1 Geological Map
2.2 Land Use Map
The land use within this catchment is principally grazing with some areas of intensive agriculture such as vineyards.
2.3 Characteristics of River and Main Tributaries
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No. |
Name of river |
Length [km] |
Highest peak [m] |
Cities population (1994) |
Land use [%] (1998) |
|
1 |
Torrens River (Main river) |
8 25.9 |
543 m 420 m |
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Natural Vegetation (1.2%), Forest (0.4%), Urban (1.5%), Intensive Rural (2.9%) Grazing (94%) |
2.4 Longitudinal Profile
3. Climatological Information
3.1 Mean Annual Precipitation Map and Observation Stations
3.2 List of Meteorological Observation Stations
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StationNo. |
Station |
Elevation [m] |
Location |
Observation period |
Mean annual precipitation [mm] |
Mean annual evaporation |
Observation items 1) |
|
023801 |
Lenswood Research Centre |
452 |
S 34o 57' |
1968 - 1998 |
1041 |
1280 |
P, E, T, DS, TB, DP |
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023737 |
Mt Pleasant |
430 |
S 34o 46' 48'' |
1895 - 1994 |
621 |
P |
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AW504512 |
Mt Pleasant GS |
420 |
S 34o 47 |
1989-1999 |
512 |
TBP |
1) P: Precipitation (daily read raingauge 203 mm), TBP:
Tipping bucket pluviograph, E: Evaporation (Class A Pan - 120
cm).
DS: Duration of Sunshine (hrs),
DP: Dew Point
3.3 Monthly Climate Data
|
Observation |
Observation |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
Annual |
Period for the mean |
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Temperature [oC] Max. |
Lenswood |
25.2 |
25.7 |
22.8 |
18.9 |
14.9 |
12.0 |
11.4 |
12.4 |
14.5 |
17.7 |
20.6 |
23.2 |
18.3 |
1967-1996 |
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Temperature [oC] Min. |
Lenswood |
12.9 |
13.5 |
12.3 |
10.7 |
8.6 |
6.7 |
6.0 |
6.3 |
7.1 |
8.5 |
10.0 |
11.6 |
9.5 |
1967-1996 |
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Precipitation |
Lenswood |
35.1 |
27.6 |
43.2 |
78.7 |
112.5 |
134.1 |
165.6 |
151.4 |
117.9 |
82.4 |
46.5 |
46.4 |
1041.4 |
1967-1996 |
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Raindays [No.] |
Lenswood |
7.3 |
5.8 |
8.8 |
12.9 |
16.6 |
17.7 |
19.6 |
20.1 |
16.5 |
14.0 |
10.6 |
9.0 |
158.9 |
1967-1996 |
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Evaporation [mm] (Pan) 1 |
Lenswood |
196.2 |
168 |
136.4 |
81 |
49.6 |
33 |
33 |
49.6 |
72 |
114.7 |
141 |
176.7 |
1251 |
1967-1996 |
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Duration of sunshine [hr] |
Lenswood |
9.8 |
9.4 |
7.8 |
6.3 |
4.7 |
3.9 |
4.1 |
5.2 |
6.1 |
7.6 |
8.7 |
9.2 |
6.9 |
1967-1996 |
1) Class A Pan (120 cm)
Note Lenswood is in an adjacent catchment
3.4 Long Term Variation of Annual Precipitation
4. Hydrological Information
4.1 Map of Streamflow Observation Stations
See Climatological Map
4.2 List of Hydrological Observation Stations
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Station No. |
Station |
Location |
Catchment area (A) [km2] |
Observation period |
Observation items (frequency) |
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504512 |
Torrens River at Mt Pleasant |
S 34º 48' E 139º 03' |
25.9 |
1973 - 1997 |
Continuous height record , Rainfall |
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Station No. |
[m3/s] |
Q max 2) [m3/s] |
[m3/s] |
[m3/s] |
[m3/s/km2] |
Q max / A [m3/s/km2] |
Period of statistics |
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504512 |
0.076 |
67.64 |
0.279 |
0.002 |
0.003 |
2.6 |
1973 ~ 1998 |
1)
1) Mean annual discharge
2) Maximum discharge
3) Mean annual maximum discharge.
4) Mean annual minimum discharge
4.3 Long-term Variation of Monthly Discharge
4.4 Annual Pattern of Discharge
Annual Plot of flows 1992
Flow Duration Plot ( m3/sec)
4.5 Unique Hydrological Features
The runoff from the Torrens River is highly seasonal, being concentrated in the winter spring seasons (June October). During the summer season, the Torrens River ceases to flow. This catchment even though it is at the upper boundary of the catchment has a lower rainfall than the majority of the catchment below it.
4.6 Annual Maximum and Minimum Discharges
Torrens River at Mt Pleasant [25.9 km2]
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Year |
Maximum 1) |
Minimum 2) |
Year |
Maximum 1) |
Minimum 2) |
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Date |
[m3/s] |
Month |
[m3/s] |
Date |
[m3/s] |
Month |
[m3/s] |
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1973 |
1/9 |
19.99 |
5, 12 |
0.0 |
1987 |
15/7 |
9.212 |
many |
0.0 |
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1974 |
4/10 |
25.25 |
1, 3 |
0.0 |
1988 |
6/7 |
15.3 |
many |
0.0 |
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1975 |
23/10 |
21.12 |
1-5, 12 |
0.0 |
1989 |
31/7 |
12.34 |
many |
0.0 |
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1976 |
17/10 |
0.095 |
many |
0.0 |
1990 |
15/8 |
4.356 |
many |
0.0 |
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1977 |
15/1 |
0.24 |
many |
0.0 |
1991 |
18/9 |
9.01 |
many |
0.0 |
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1978 |
5/7 |
9.279 |
many |
0.0 |
1992 |
30/8 |
67.64 |
many |
0.0 |
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1979 |
12/10 |
8.365 |
1-7, 12 |
0.0 |
1993 |
19/9 |
1.494 |
many |
0.0 |
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1980 |
12/10 |
4.929 |
1-4, 12 |
0.0 |
1994 |
24/6 |
0.410 |
many |
0.0 |
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1981 |
14/8 |
24.36 |
1-5,11,12 |
0.0 |
1995 |
22/7 |
34.54 |
many |
0.0 |
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1982 |
15/6 |
0.036 |
many |
0.0 |
1996 |
30/9 |
20.64 |
many |
0.0 |
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1983 |
8/9 |
22.84 |
many |
0.0 |
1997 |
31/10 |
0.596 |
many |
0.0 |
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1984 |
24/8 |
6.833 |
many |
0.0 |
1998 |
28/7 |
3.184 |
many |
0.0 |
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1985 |
13/9 |
2.059 |
many |
0.0 |
0.0 |
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1986 |
12/9 |
4.074 |
many |
0.0 |
0.0 |
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1), 2) Instantaneous observation by recording chart
Flood Frequency Distribution
4.7 Hyetographs and Hydrographs of Major Floods
5. Water Resources
5.1 General Description
More than any other factor the scarcity of water resources has limited the development in South Australia. Approximately 83% of the State receives less than 250mm annual rainfall. Only 3.3 percent of the state receives an annual rainfall of over 500mm. On an overall basis, there are limited water resources in South Australia. It is estimated that major ground and surface water resources have the potential to provide approximately 3500GL/y of which 3000GL/y is termed fresh and marginal water (water 0-1500mg/L TDS) (E&WS, 1989). The scarcity of water resources has made it necessary to develop water that would be considered to be marginal elsewhere and to pump water over long distances. South Australia is very dependent on the River Murray which originates outside the state. In an average season this river supplies over 50% of South Australia’s urban water consumption and in a dry year this can be as high as 90%.The largest factor affecting the present and possibly future water supplies is water quality and significant catchment management programs have been implemented to halt degradation and improve the quality of runoff. In the Mount Lofty Ranges the quality of runoff water entering local reservoirs is being addressed. In the selection of the site of the city of Adelaide an adequate water supply was sought. This was achieved using the Torrens and Onkaparinga Rivers.
5.2 Map of Water Resource Systems
5.3 List of Major Water Resources Facilities
The water resource facilities listed here are those that are in the catchment below Mt Pleasant and are used for water supply for Adelaide. The Torrens System comprises three reservoirs and the Mannum-Adelaide Pipeline. A fourth storage, Thorndon Park, which is the State’s oldest Reservoir was taken out of service in 1978. Hope Valley Reservoir is fed by an aqueduct from the Gorge Weir which has an upstream catchment area of 343 km2. Kangaroo Creek Dam is a rock fill Dam . Its capacity was reduced in 1984 by spillway modifications that were part of the River Torrens Flood Mitigation Program. A proportion of the water in these reservoirs is from the River Murray, released into the Torrens River from the Mannum-Adelaide Pipeline at a number of points along its route.
Major Reservoirs
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Name of river |
Name of dam (reservoir) |
Catchment area [km2] |
Gross capacity |
Purpose 1) |
Year of completion |
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Hope Valley Dam |
Off stream Storage |
3.47 |
W |
1872 |
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Torrens River |
Kangaroo Creek Dam |
280 |
24.4 |
W |
1969 |
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Thorndon Park |
Off Stream Storage |
.64 |
R |
1860 |
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Millbrook Reservoir |
Off stream storage |
16.5 |
W |
1918 |
1) W: Municipal water supply
6. Socio-cultural Characteristics
The climate of the Mt Lofty Ranges was conducive to being populated by early settlers. It had the highest annual rainfall area within the state. Settlement of other country regions was confined to places that had small streams, soaks or springs augmented by small earthen dams and wells. South Australia’s development has been characterised by the development of pipelines from the River Murray. The River Murray provides a source of water for domestic, industry and agricultural pursuits along its banks. It is also the main source of water for Adelaide and many towns far distant from the river including Whyalla, Woomera and Keith. Serious consideration for augmenting Adelaide’s water supply includes utilising local run off, rainwater tanks, urban stormwater runoff in conjunction with aquifer storage and recovery, and treated effluent.
7. References, Databooks and Bibliography
- Bureau of Meteorology (1988) Climatic Atlas of Australia, AGPS, Canberra, April 1988, 70 pp
- Department of Environment Heritage and Aboriginal Affairs (1999) Sth Central Regional Network- Water Resources Project (unpublished Report)
- Department of Primary Industries and Energy (1987) 1985 Review of Australia’s Water Resources and Water Use, Volumes 1 and 2, AGPS, Canberra, November 1997, 114 pp
- Department of Resources and Energy, (1983) Water 2000: Consultants Report No. 7, Water Quality Issues, AGPS, Canberra, 1983, 310 pp
- Department of Resources and Energy, (1983) Water 2000: Consultants Report No. 9, In-stream and Environmental Issues, AGPS, Canberra, 1983, 374 pp
- Department of Resources and Energy, (1983) Water 2000: Consultants Report No. 12, Water Demand and Availability with reference to Particular Regions, AGPS, Canberra, 1983, 321 pp.
- Engineering and Water Supply Department (1988) Development of South Australia’s Water Resources, Information Bulletin No.11, April.
- Engineering and Water Supply Department (1989) Water South Australia, Managing the Resource into the next Century, 23pp.
- Engineering and Water Supply Department (1992) Adelaide’s Water Supply Summary of the System, Information Bulletin No.7, August.
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