Bega Valley
Indicator: Drinking Water Quality
Results for this indicator are also available for [an error occurred while processing this directive]
What the results tell us for Bega Valley
The quality of drinking water supply in the Bega Valley Shire Council is uniformly high. Microbiological contamination is negligible, indicating a high standard of water treatment, as the water is drawn from very diverse sources. Iron occurs in some sources at concentrations that may be detectable to taste, but have no negative health implications.
Quality of the water supplied
Data are available for Bega River, Bemboka River, Brogo River, Couria Creek, Illawambra Creek, Kiah, Tantawangalo Creek, Wyndham Reservoir and Yellow Pinch Dam water supply systems. These systems collectively supply water to about 11,500 properties across 21 towns or communities in the Shire, the largest system being the coastal area around Merimbula. The coastal towns of Bermagui, Eden, Merimbula and Tathra increase their population three-fold in summer, with holiday visitors.
Thirty to forty water quality parameters were measured on a weekly, fortnightly and monthly basis during the reporting period, including Total Coliforms and E. coli. No comment has been made on Total Coliforms, as this parameter does not reflect health risk. In fluoridated supplies, this concentration was measured daily. Herbicides and pesticides were not measured. The microbiological indicators were measured at different intervals depending on the population connected to the supply and possibility of contamination. Bega, Tantawanglo and Yellow Pinch Dam supplies were most frequently evaluated, with some 400 to 600 samples taken over the 4-year period. Other supplies such as Bemboka River and Wyndham (Myrtle Creek) were sampled about 100 times between 2004 and 2008 with microbiological counts on each sample, whereas inorganic constituents were measured less often and only 8 times in the Wyndham supply.
Bega Water Supply system
Supply drawn from Bega Borefield adjacent the Bega River and sporting fields - Supplies Bega, Tathra, Kalaru, Mogareeka, Tarranganda and North Bega
This system supplies 6,700 people. It is disinfected by chlorine and fluoridated. A total of 400 water samples were tested during the reporting period. The quality of water supplied over the four years was uniformly excellent, with no samples showing any E. coli present. Inorganic constituents were well below the Guideline Values, apart from one slightly higher iron concentration, of no health significance. Consistently excellent water quality.
Bemboka River
This system drawn from the Bemboka River supplies 300 people. It is disinfected by chlorine. A total of 102 samples were assessed for E.coli, with none detected.
Eight samples were assessed for inorganic constituents, the only component exceeding the Guideline Values was iron, which was consistently slightly higher than the Guideline. The Guideline Value for iron is 0.3mg/L, whereas the mean iron concentration in the samples was 0.33. In this case the Guideline Value is based on aesthetic considerations, as 0.3 mg/L is the approximate threshold for taste. There is no health implication from this iron concentration. This was a uniformly good quality supply.
Brogo River. Supplies Bermagui and Quaama.
This system supplies 3,270 people. It is disinfected by chlorine. A total of 248 samples were assessed for E. coli, with none detected during the reporting period.
Eight samples were assessed for inorganic constituents, with the only components exceeding the Guideline Values being iron and colour. Iron was consistently higher than the Guideline. The mean concentration in the samples tested was 0.5mg/L, with the highest at 0.94. While this has no health implications, it is likely to be detected by people drinking the water, and can affect the colour. A consistently good water quality.
Couria Creek. Supplies Beauty Point, Wallaga Lake, Akolele and Wallaga Lake Village (Akolele and Wallaga Lake Village are both located in Eurobodalla Shire but Bega Valley Shire Council is the Water Supply Authority for both villages).
This system supplies 4,155 people. It is disinfected by chlorine. A total of 195 water samples were assessed for E. coli, and only one sample showed a single organism in 100mL of water. This is a negligible level of contamination.
Eight samples were assessed for inorganic components. Iron was consistently higher than the Guideline Value, with a mean concentration in the samples tested of 0.43 mg/L and a peak concentration of 0.87mg/L. This has no health implications. Aluminium and colour slightly exceeded the Guideline on one occasion each, again with no health implications. A consistently good water quality
Illawambra Creek. Supplies Cobargo.
This system supplies 400 people. It is disinfected by chlorine. A total of 101 water samples were assessed for E. coli, and no samples showed any organisms in 100mL of water.
Eight samples were assessed for inorganic components. Iron was consistently higher than the Guideline Value, with a mean concentration in the samples tested of 0.47 mg/L and a peak concentration of 0.84mg/L. This has no health implications. Two samples exceeded the guideline value for colour, probably as a result of the iron content. Lead slightly exceeded the Guideline Value in one sample, which is of no health significance. A consistently good water quality
Kiah water supply system. Source Kiah Bore, Ben Boyd dam. Supplies Eden.
This system supplies 5,500 people. It is disinfected by chlorine. A total of 194 water samples were assessed for E. coli, and none were detected.
Forty-five samples were assessed for inorganic components. Iron slightly exceeded the Guideline Value in one sample, and no other component exceeded the Guideline Values. A consistently excellent water quality.
Tantawanglo Creek. Supplies Candelo and Wolumla
This supplies 710 people. It is disinfected by UV light. A total of 97 water samples were assessed for E. coli, and three were reported to contain the organisms. These samples had 1 organism in 100mL water on 12/7/05, three organisms on 31/10/05 and 4 on 4/1/06. Each was a single occurrence, and no samples contained the organisms since January 2006. There are no on-going health implications from these results.
Fifty two samples were assessed for inorganic components. Colour exceeded the Guideline Value in one sample, and in another pH was above the Guidelines at 9.2.No other component exceeded the Guideline Values. A consistently good water quality.
Wyndham (Myrtle Creek) system. Supplies Wyndham.
This supplies 200 people and is a privately owned and operated system. It is disinfected by UV light. A total of 105 water samples were assessed for E. coli, and one was reported to contain a single organism in 100mL of water. This is a negligible level of contamination. Eight samples were assessed for inorganic components. Colour and iron exceeded the Guideline Value in four samples. The mean level of iron was 0.33 (Guideline Value 0.3 mg/L) and the peak value 0.7mg/L, this has no health implications. No other component exceeded the Guideline Values. A consistently good water quality.
Yellow Pinch Dam / Tantawangalo Creek system. Supplies Merimbula, Tura Beach, Pambula Beach, Pambula and South Pambula. This supply serves the largest population in the Shire.
This supply provides drinking water for 13,000 people. It is disinfected by chlorine. A total of 516 water samples were assessed for E. coli, none were reported to contain the organisms.
Forty five samples were assessed for inorganic components. None exceeded the Guideline Values. A consistently excellent water quality.
About the Data
Drinking water quality is monitored as part of the NSW drinking water monitoring programme, and detailed results can be accessed through the website http://www3.health.nsw.gov.au/waterqual/samples/register.cfm.
This report on drinking water quality for 2004-2008 is prepared from examination of this data, to illustrate the quality aspects of the water supplied for domestic consumption in the Shire. The Shire uses both public and private water supplies, but is also the Water Supply Authority for the Wyndham supply (an incorporated private supply) and as such samples and monitors the public health quality of this supply. All the water supplies in the Shire including the privately operated Wydham supply are recorded on the Department of Health database and are utilised in this report.
Interpreting the data
In 2004 the National Health and Medical Research Council introduced the Australian Drinking Water Guidelines, which provide the basis for quality assessment. These Guidelines have not included Total Coliforms as a measure of water quality for health purposes, as the organisms are widely present in soil and untreated water and grow in water pipes, and do not reflect the content of pathogenic organisms. Monitoring for Escherichia coli is, by contrast, particularly informative, since this organism occurs in large numbers in faeces and hence is an effective indicator of faecal contamination. It is killed by standard drinking water treatment and therefore should not occur in domestic supplies. The drinking water Guideline Value is zero organisms per 100ml sample and any detected organisms present in the water therefore exceed the guideline, and should result in an increase in the disinfection of the supply.
This remedial action should be taken until the E. coli count returns to zero.
While there are many other pathogens present in faecal contamination of water, monitoring of E. coli has been shown to be an effective and straightforward method for public health protection and maintenance. Where the data from a water supply for this period show E .coli present, it has been commented upon for each water supply reported.
Concentrations of inorganic components of water supplies do not have such a sharp impact on health as faecal contamination. The Guideline Values reflect safe concentrations for lifetime exposure, and minor exceedences, which briefly occur, are of negligible risk to public health. Inorganic constituents become a risk to public health when they consistently exceed the Guideline Values, with the risk increasing with the concentration in the supply. Where these have occurred, they are commented upon in the appropriate section of the report. Unless there is accidental contamination of the supply, it is unlikely that any substantial variations in concentration of inorganic components will occur throughout any year. Continuing concentrations that significantly exceed the Guideline Values require investigation and rectification.
The information assessed in this report is available on the NSW Health water database, and uses the current National Health and Medical Research Council Drinking Water guidelines as the reference for the analytical comparisons. The results included in this report are from 1st January 2005 to the time of writing, mid-November 2008.
References
NSW Department of Health Drinking Water Database 2008 http://www3.health.nsw.gov.au/waterqual/samples/register.cfm.
NH&MRC and NRMMC 2004. Australian Drinking Water Guidelines. National Water Quality Management Strategy. http://www.nhmrc.gov.au/publications/synopses/eh19syn.htm
