Eurobodalla
Indicator: Surface Water Quality
Results for this indicator are also available for [an error occurred while processing this directive]
What the results tell us for Eurobodalla
Eurobodalla is located within the Southern Rivers Catchment Management Authority area. The Shire has a diverse network of surface drainage leading to the main river systems, such as Clyde, Moruya and Tuross. Water from these river systems sustain much of Eurobodalla’s irrigated agriculture, dairy and food processing industries, as well as providing for domestic supply through extraction.
This assessment of surface water quality in the Eurobodalla is based primarily on the results for three key determinants of surface water quality (electrical conductivity, total phosphorus and turbidity) at two sites in the Eurobodalla Shire area. The two sites reported are situated at the Deua River at Wamban in the Moruya River and on the Tuross River at Eurobodalla. Both of these sites are located in the upper source water areas that are utilised for drawing the Eurobodalla’s water supply and are beyond the reach of normal tidal influence, close to water supply inlet pumps.
Trends in surface water quality
Eurobodalla surface water quality monitoring sites are:
- Deua River at Wamban (site number 217002)
- Tuross River at Eurobodalla (site number 218008).
| Parameter* and location | Median values | Default trigger values ** | ||
|---|---|---|---|---|
| 1997–2000 | 2000–04 | 2004-08 | ||
| Deua River at Wamban (217002) | ||||
| Electrical conductivity (µS/cm) | 114 | 118 | 117 | 350 |
| Total phosphorus (µg/L) | 8 | 8 | 7 | 20 |
| Turbidity (NTU) | 1 | 2 | 2 | 25 |
| Tuross River at Eurobodalla (218008) | ||||
| Electrical conductivity (µS/cm) | 90 | 102 | 95 | 350 |
| Total phosphorus (µg/L) | 10 | 11 | 12 | 20 |
| Turbidity (NTU) | 2 | 2 | 2 | 25 |
* µS/cm = microsiemens per centimetre; µg/L = microgram per litre; NTU = nephelometric turbidity unit; ** For information on default trigger values, see About the Data
Source: NSW Provisional River Data, 2008
Deua River at Wamban
The median value for electrical conductivity, turbidity and total phosphorus at Wamban were all below the default trigger value for the current reporting period (Table 1). This trend has been consistent with the previous two reporting periods between 1997 to 2000 and 2000 to 2004, with no major change in the water quality over the three reporting periods.
Tuross River at Eurobodalla
At Eurobodalla the median value for electrical conductivity decreased slightly over the currently reporting period. This value, like the median values for total phosphorus and turbidity were below the default trigger values. The total phosphorus and turbidity median values have stayed relatively constant over the three reporting periods.
Other studies
Eurobodalla Shire Council also routinely conducts the Eurobodalla Estuary Monitoring Program which monitors water quality in lower river estuarine areas which are subject to tidal influences, particularly sites adjacent or near to sewage treatment plants, sewage outfalls and oyster farming activities.
This monitoring program includes monthly water quality monitoring at 54 sites in Eurobodalla, comprising of:
- six estuaries/lakes with a total of 38 sites per month, seven sites on Clyde River, three sites on Tomaga River, five sites on the Moruya River, four sites on Coila Lake, seven sites on the Tuross River and 12 sites on Wagonga inlet.
- 11 beach sites are also monitored during the swimming season – from the October Long Weekend to around Easter
- Monitoring on five rivers, weirs and dams that are sources for water supply
Eurobodalla Shire Council previously also participated in the South East Water Quality Monitoring Project with Bega Valley Shire Council. This program was completed in 2004/5, with the Report available on Council’s website. The South East Water Quality Monitoring Project was a Natural Heritage Trust project partnership developed between the various stakeholders and funded by Waterwatch Australia via the Natural Heritage Trust. Two of the major objectives of the program were to; establish what is known about local water quality; and assess the adequacy of existing monitoring programs of the South East. The South East Water Quality Monitoring Project has informed all of the surface water quality monitoring currently undertaken by Eurobodalla Shire Council.
Eurobodalla Shire Council also monitors five locations as part of the NSW Department of Environment and Climate Change sewerage treatment plant licence conditions. These locations include sites at Wimbie Headland and Long Nose Point, where Council is licensed to discharge treated wastewater to the ocean outfalls. Council also monitors the three other sites, where the treated effluent is discharged into Ryans Creek in Moruya and sand exfiltration at Bingie and Kianga Point.
About the data
Data for the monitoring sites covered in this report were from the NSW Department of Water and Energy (DWE) http://www.dwe.nsw.gov.au/
Data is routinely reported at http://nratlas.nsw.gov.au. DWE is responsible for quality control and on-going maintenance of the data collected in its databases.
Monitoring as part of the New South Wales Department of Environment and Climate Change (DECC) licensing requirements for sewerage treatment plants is undertaken at beaches where Council has ocean outfalls approved for the discharge of treated wastewater. This information is reported annually to DECC.
Interpreting the data
Default environmental value
The Water Quality and River Flow Interim Environmental Objectives (EPA 1999) for NSW, which are still current, indicate that protection of aquatic ecosystems is the default environmental value for most water bodies in catchments associated with Eurobodalla Shire. Although individual Councils are free to assign additional or different values through local processes and based on site-specific information, so far no Councils in the Australian Capital Region have done so.
Default trigger values
The default trigger values used in this report were those values set out in ANZECC and ARMCANZ (2001). The values applicable to the Australian Capital Region are those for ‘south-east Australia for slightly disturbed ecosystems’ (ANZECC and ARMCANZ 2001). The default trigger values for different water quality parameters for the protection of aquatic ecosystems are based on the type of water body in question. Compared to most other environmental objectives, the protection of aquatic ecosystems is one that requires more stringent water quality guidelines.
The median value (i.e. middle value of a data series) for each monitoring site in the Shire over the reporting period was compared with the default trigger value from the guideline values suggested in ANZECC and ARMCANZ (2001). This approach was recommended when no environmental values were set, water quality objectives were not determined, local reference sites were unavailable and local site-specific information could not be sourced. This broad reporting approach cannot be used to assess 'compliance'; it is merely a warning system to alert natural resource managers.
The data was firstly sourced from the NSW Natural Resource Atlas, if the relevant data wasn’t available from this resource, the information supplied from the NSW Department of Water and Energy (DEW) was used. The data from the NSW Natural Resource Atlas generally provided daily data on stream flow and electrical conductivity, amongst others. Whereas the data supplied by the DEW had periodic samples of the data, however did include values for the turbidity and total phosphorus.
Electrical conductivity is a measure of the ability of water to conduct an electric current. This is considered an appropriate indicator of salinity, as it is proportional to the concentration of total dissolved salts in water.
Phosphorus is considered as a key indicator of eutrophication in Australian freshwaters because it is typically a limiting nutrient for primary production under natural conditions (Cullen 1986; Donnelly et al. 1992). Total phosphorus is analysed as it represents an aggregation of all fractions of phosphorus reaching the water column from various processes and it represents the potential maximum concentration of phosphorus available for biological uptake (NSW EPA 2000).
Australia has naturally turbid waters, owing to deeply weathered soils rich in clay-sized particles. These particles are readily transported to streams during storms. Because of their colloidal nature they remain suspended in the water column, resulting in high turbidity (Cullen 1986). In addition to natural causes, the turbidity of many waters has increased as a result of human-induced erosion through practices such as land clearing (agriculture and forestry), urbanisation, extractive industries and river regulation (Walker 1985). Turbidity is a measure of light scattering and absorptive properties of water, which are roughly proportional to the type and concentration of suspended matter. It is therefore commonly used as an indicator of the amount of suspended matter in the water column, although quantitative relationships between the two are difficult to define, because various types of suspended material have different light-scattering properties.
Additional data
Other potential sources of water quality monitoring data include the Community Access to Natural Resources Information (CANRI) website and the Waterwatch program.
References
Australian and New Zealand Water Environment and Conservation Council (ANZECC) (1992) Australian Water Quality Guidelines for Fresh and Marine Waters, Prepared for the National Water Quality Management Strategy
ANZECC and Agricultural and Resource Management Council of Australia and New Zealand (ARMCANZ) (2001) Australian Water Quality Guidelines for Fresh and Marine Waters, Prepared for the National Water Quality Management Strategy
Australian Government (2008), Australian Natural Resources Atlas, viewed at http://www.anra.gov.au/index.html on 7 October 2008
Cullen, P. 1986, ‘Managing nutrients in aquatic ecosystems: the eutrophication problem’, in Deckker P. and Williams W.D. (eds) Limnology in Australia, CSIRO, Melbourne, pp.539–554.
Donnelly, T.H., Caitcheon, G.G. and Wasson, R.J. 1992, ‘Algal blooms in inland Australian water systems: sourcing nutrients and turbidity’, in CSIRO Division of Water Resources Divisional Report 92/4, CSIRO, Canberra, pp.74–81
Haines, P, Wainwright, M and Wilson, J (2005) Interpretation of water Quality Monitoring Program Results, report prepared for Eurobodalla and Bega Valley Shire Councils by WBM Oceanics Australian, Newcastle.
MDBC, 2008, Sustainable Rivers Audit – A report on the Ecological Health of rivers in the Murray-Darling Basin, 2004-2007, Murray Darling Basin Commission, SRA Report 1, June 2008. Viewed at http://www.mdbc.gov.au/SRA on 10 October 2008.
NSW EPA (2000) NSW 2000 State of the Environment Report – Waters Chapter
NSW NRA (2008), New South Wales Natural Resource Atlas: NSW Provisional River Data, viewed at http://nratlas.nsw.gov.au on 7 October 2008
Walker, K.F. 1985, ‘A review of the ecological effects of river regulation in Australia’, Hydrobiologia vol.125, pp.111–129
Waterwatch NSE (2006), Waterwatch NSW, view at http://www.waterwatch.nsw.gov.au/index.html on 7 October 2008
