Water quality

Friends of Sturt Gorge

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Water quality...

The Engineering and Water Supply Department has been monitoring water quality in the Sturt River since the early 1970s. The data collected are being used to evaluate the effects of the Heathfield Sewage Treatment Works which discharges into the Sturt River system.

Data collected monthly during 1972-73 and from 1978 onwards indicate that the water quality in the vicinity of Sturt Gorge is generally poor but is extremely variable, depending largely on rate of flow sources or runoff. Water quality parameters can vary widely in a few hours with the passing of a single flood peak, and will vary considerably from year to year, reflecting annual variation in precipitation patterns.

Generally speaking, most of the water quality criteria monitored, reach their highest values during summer when slow flow rate and high evaporation rate concentrate the solution. Short-term increase in nutrient load may also occeur at peak flooding.

Water QuaIity, Engineering and Water Supply Department:
Sturt River Survey — Location 7 ( Darlington )

Parameter measured	1972	1979	1981
pH	-	7.0-8.5	7.6 - 9.2
T.D.S. mg/l	520 - 2030	98 - 2100	213 - 1900
Total nitrogen mg/i	0.2 - 2.6	0.53 - 2.48	0.74 - 3.13
Total phosphorus mg/l	0.03 - 0.45	0.032 - 0.49	0.098 - 0.920
Dissolved 02 mg/l	-	1.6 - 11.8	5.2 - 11.5
E.coli / 100 ml	-	16 - 23 000	210 - 20 000
Faecal Strep./100 ml	-	56 - 21 000	80 - 28 000

The Engineering and Water Supply Department suggests that the nitrogen and phosphorous concentrations recorded in the Sturt River at Location 7 (Darlington) are generally sufficiently high enough to allow significant algal and macrophyte growth to occur, and this is borne out by visual observations. Particularly during spring and early summer, extensive growths of filamentous green alga occur (in strands up to 20 metres long) where suitable attachment sites occur.

The most significant single source of nutrients at Location 7 was probably the Coromandel Valley Sewage Treatment Works effluent discharge which, until recently, occurred some 7 kilometres upstream. In May 1983, this effluent discharge ceased and all sewage is now pumped to the Christies Beach Treatment Works. Most other sources are probably of a diffuse nature, coming from all over the catchment. It is likely that any attempt to restrict flow or create permanent pools would result in enhanced algal and macrophytio growths.

The level of LE.coli and faecal Streptococci recorded are extremely variable and are periodically quite high. However, on the basis of the values recorded, the South Australian Health Commission does not consider that these are grounds tar discouraging the use of the river for tadpoling and paddling.

From the data collected, the discharge of effluent from the Neathfield Sewage Treatment Works has had little impact on the quality of water in the Sturt River system. However, as the population connected to the treatment works increases, this impact will also increase. Continued monitoring by the Engineering and Water Supply department of water quality in this region will allow the extent of this impact to be assessed.

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Send mail to the web master with questions or comments about this web site. Last modified: July 21, 2002

Send mail to the web master with questions or comments about this web site.
Last modified: July 21, 2002