Environmental issues

Water

Wyong Shire Council

Ocean beaches: Frazer, Birdie, Budgewoi, Lakes, Hargraves, Jenny Dixon, Cabbage Tree Bay, Lighthouse, Gravelly, Soldiers, North Entrance, The Entrance, Blue Bay, Toowoon Bay, Shelly, Blue Lagoon, Bateau Bay. River sites: Wyong River, Ourimbah Creek, Tumbi Umbi Creek.
Coastal lakes: Summerland Point, Gwandalan, Chain Valley Bay, Elizabeth Bay, San Remo, Toukley Aquatic, Canton Beach, The Entrance Channel, Long Jetty. For details see 08472Wyong.pdf, 656 KB.

Local government area description

Wyong Shire Council is located 100 kilometres north of Sydney and covers an area of 827 square kilometres. The Shire extends from Gwandalan in the north to Ourimbah in the south and has a population of approximately 135 900, growing at the rate of 3.9 per cent each year. There is a considerable expansion in planned urban development within the shire.

The council area encompasses numerous ocean beaches, the southern extent of Lake Macquarie, Tuggerah Lakes and the Wyong River.

Wyong Shire is characterised by towns and villages separated by extensive areas of natural vegetation, with the three most predominant land uses being urban development, agriculture and forestry. (Wyong Shire Council 2002).

Program outline

A total of 29 swimming locations were monitored by Wyong Shire Council, including 17 ocean beaches, nine lake sites and three river sites in the Tuggerah Lakes catchment. For details see 08472Wyong.pdf, 656 KB.

Faecal coliform and enterococci samples were collected from all locations over all seven months of the 2007–2008 summer swimming season to assess compliance with NHMRC (1990) swimming water quality guidelines. The required five samples were not collected at Birdie Beach during April 2008 so compliance was unable to be assessed for that month. At sites with only four samples collected in month, the closest sample in time from an adjacent month was ‘borrowed’ to provide the five samples necessary for the compliance calculation.

Monitoring in the Wyong Council area was also conducted in the 2006–2007, 2005–2006, 2004–2005, 2003–2004 and 2002–2003 summer seasons and results have been reported in the State of the Beaches reports for these years (DEC 2004a, 2004b, 2006a and 2006b, DECC 2007).

Wyong Council has erected warning signs at Tumbi Umbi Creek, Ourimbah Creek and a number of other estuarine swimming locations with histories of poor water quality.

Rainfall

Rainfall data presented in the timeseries plots were obtained from the Bureau of Meteorology’s gauge at Wyong Bowling Club. Where data were missing in the record, data from the Bureau of Meteorology’s gauge at Gosford (Narara Research Station) were used.

Ocean beaches

Guideline compliance

A high level of compliance with NHMRC (1990) swimming water quality guidelines was recorded at the 17 ocean beaches (Figure 9). All beaches were suitable for swimming in all months of the 2007–2008 summer swimming season.

A very high level of compliance with swimming water quality guidelines has also been reported at the ocean beaches in previous years (DEC 2004b, 2004b, 2006a and 2006b, DECC 2007). For details see 08472Wyong.pdf, 656 KB.

Response to rainfall

Bacterial levels at all beaches were generally low throughout the monitoring period. Although slightly elevated levels of bacteria were measured at most of the ocean beaches on one or two occasions, monitoring did not reveal evidence of sewage contamination (as indicated by faecal coliform and enterococci levels greater than 1000 cfu/100 mL) in either dry or wet weather conditions.

Similar results were obtained during the 2002–2003, 2003–2004, 2004–2005, 2005–2006 and 2006–2007 summer swimming seasons (DEC 2004b, 2004c, 2006a and 2006b, DECC 2007).

Lake Macquarie

Guideline compliance

The three swimming locations monitored in Lake Macquarie were Summerland Point, Gwandalan and Chain Valley Bay. All three sites passed the NHMRC (1990) swimming water quality guidelines in all seven months of the 2007–2008 summer swimming season (Figure 9). For details see 08472Wyong.pdf, 656 KB.

Figure 9: Summary of compliance with NHMRC (1990) microbiological guidelines for swimming at Wyong Shire Council swimming sites over the 2007–2008 summer season

Graph -

Response to rainfall

Levels of faecal coliforms and enterococci at Summerland Point, Chain Valley Bay and Gwandalan were generally low throughout the summer season and displayed no clear response to rainfall.

Results from previous monitoring indicate that swimming in Lake Macquarie should be avoided during and after rainfall (DEC 2004b).

Lake Munmorah

Guideline compliance

Elizabeth Bay, located in the southeast corner of Lake Munmorah, complied with the NHMRC (1990) swimming water quality guidelines in six of the seven months of the 2007–2008 summer swimming season. The site failed in April 2008 owing to elevated levels of enterococci. This is an improvement from the previous summer season when the site failed the guidelines in November 2006, December 2006 and January 2007 owing to elevated levels of faecal coliforms (DEC 2007). For details see 08472Wyong.pdf, 656 KB.

Response to rainfall

Levels of bacteria were generally low throughout the monitoring period, showing little response to rainfall. However, some elevated results were recorded in April following heavy rain.

Results from previous monitoring indicate that high levels of bacteria may be measured at the site in response to heavy rainfall (DEC 2004b).

Lake Budgewoi

Guideline compliance

The two swimming locations monitored in Lake Budgewoi were San Remo in the north and Toukley Aquatic in the south. For details see 08472Wyong.pdf, 656 KB.

Toukley Aquatic complied with NHMRC (1990) swimming water quality guidelines in all seven months of the 2007–2008 summer swimming season (Figure 9).

San Remo complied with NHMRC (1990) swimming water quality guidelines in five of the seven months of the 2007–2008 summer swimming season (Figure 7). The site failed the guidelines in February and April 2008 owing to elevated levels of enterococci.

Response to rainfall

Bacterial levels at Toukley Aquatic showed little response to rainfall, with elevated levels only recorded occasionally in response to heavy rain. Slightly elevated levels of enterococci were recorded throughout the 2007–2008 summer swimming season at San Remo, with no clear response to rainfall.

Tuggerah Lake

Guideline compliance

The three swimming locations monitored in Tuggerah Lake were Canton Beach in the north, Long Jetty in the south, and The Entrance Channel. For details see 08472Wyong.pdf, 656 KB.

Long Jetty and The Entrance Channel complied with the NHMRC (1990) swimming water quality guidelines in all seven months of the 2007–2008 summer swimming season (Figure 9). High compliance was also recorded at Canton Beach which complied six of the seven months. The site failed the guidelines in April 2008 owing to elevated levels of enterococci.

Response to rainfall

Slightly elevated levels of bacteria were recorded occasionally at all three locations in Tuggerah Lake in response to rainfall during the 2007–2008 summer swimming season.

Previous monitoring has revealed elevated bacterial levels in response to rainfall at these sites (DEC 2004b and 2004c).

Tuggerah Lakes catchment

Guideline compliance

The three sites monitored in the Tuggerah Lakes catchment were Wyong River, Ourimbah Creek and Tumbi Umbi Creek. For details see 08472Wyong.pdf, 656 KB.

Very low levels of compliance with the NHMRC (1990) swimming water quality guidelines were recorded at all three locations. Ourimbah Creek and Wyong River failed the guidelines in five of the seven months of the 2007–2008 summer swimming season, and Tumbi Umbi Creek failed the guidelines in all seven months (Figure 9).

Response to rainfall

Because of the ongoing high levels of bacteria measured at these sites, swimming should be avoided at these sites at all times.

Further Investigations

As part of Wyong Shire Council Management Plan a review of data collected from Tuggerah Lake was undertaken. Council tested for evidence of correlation between historic rainfall and bacteria levels. In addition, Council carried out faecal sterol analysis of ten sites to determine potential sources of faecal contamination. These results will drive a modified Beachwatch program for the 2008–2009 season in accordance with the NHMRC (2008) guidelines.

Micro-catchment rainfall data were compared for correlation with faecal coliform and enterococci levels. A few marginal correlations were found across some sites. Current field sampling has demonstrated significant variation across samples at each site. Council is currently testing whether an increase sample size for each site will demonstrate significant correlations against rainfall and enterococci levels.

For the faecal sterol analysis, none of the 120 samples was found to have correlation between enterococci levels and human and/or herbivore sterols. Although numerous samples had elevated enterococci levels, only five samples returned positive results for contamination from a herbivorous source. Only one sample returned positive results for aged human sterols. Potential other sources of elevated enterococci levels include water fowl and dogs, for which faecal sterol ratio methodology is inconclusive.

For further details contact Wyong Shire Council’s Regulation and Compliance Section on (02) 4350 5555.


 

Page last updated: 24 June 2013