Snowy River
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 Snowy River
Snowy River Shire Council is located in both the Murrumbidgee and Southern Rivers Catchment Management Authorities. The Shire's rivers and creeks form part of the catchments of Murrumbidgee and Snowy Rivers. Water from these river systems also sustains much of Snowy River’s irrigated agriculture.
This assessment is based primarily on the results for three key determinants of surface water quality: electrical conductivity, total phosphorus and turbidity levels, at one monitoring site in the Snowy River Shire. Other physio-chemical parameters for two sites are also reported, including dissolved oxygen, pH, temperature and total suspended solids.
The site is in the Murrumbidgee River catchment at Yaouk Bridge on the Murrumbidgee River. The Yaouk Bridge site was also reported as a part of the Cooma-Monaro surface water quality indicator chapter.
There is another water quality monitoring site for Snowy River Shire at Bolaro on the Murrumbidgee River, however no water quality data was reported during the current reporting period.
Trends in surface water quality
There is one monitoring site within the Snowy River Shire on the Murrumbidgee River at Yaouk Bridge (site number 41010336).
| Parameter* and location | Median values | Default trigger values ** | ||
|---|---|---|---|---|
| 1997–2000 | 2000–04 | 2004-08 | ||
| Murrumbidgee River at Yaouk Bridge (41010336) | ||||
| Dissolved oxygen (mg/L) | 9 | 10 | 10 | |
| Dissolved oxygen saturation (%) | 101 | 94 | 99 | Between 90-110 |
| Electrical conductivity (µS/cm) | 25 | 21 | 18 | 350 |
| pH | 7.6 | 7.2 | 7.3 | Between 6.5 - 7.5 |
| Temperature (degrees C) | - | - | 12 | |
| Total phosphorus (µg/L) | 8 | 8 | 8 | 20 |
| Total suspended solids (mg/L) | 1 | 1 | 2 | |
| Turbidity (NTU) | 6 | 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
Murrumbidgee River at Yaouk Bridge
The median values for the physio-chemical parameters at the Yaouk Bridge were all within the default trigger limits, indicating that Snowy River Shire maintained good surface water quality over the current reporting period. The Shire has not exceeded any water quality limits since the 1997-2000 report, when the median value for pH slightly exceeded the upper limit.
Other studies
There are no Waterwatch monitoring sites in Snowy River Shire . However the response of environmental flows released to the Snowy River below Jindabyne Dam are assessed. The environmental flows are staged, and a long term goal of up to 28% of Mean Annual Natural Flow released to the river is in place. The releases into the Snowy River are dependent on water savings in the Murray-Darling Basin. It is reported that currently, only a small increase in base flow has occurred and the physical, chemical and biological condition of the river is still being assessed by monitoring and/or modeling of river discharge, the physical structure and composition of the river, water quality, algae, vegetation, aquatic insects and fish (NSW DNR, 2008).
The first stage of the environmental flows to the Snowy River were released from the Mowamba River in August 2002. Monitoring began in 2000 and continued during the release of the first and subsequent environmental flows. The results of the monitoring and modelling are generating new information about the Snowy River (NSW DNR, 2008).
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.
Interpreting the data
Default environmental value
The Water Quality and River Flow Interim Environmental Objectives for NSW (EPA 1999), which are still current, indicate that protection of aquatic ecosystems is the default environmental value for most water bodies in catchments associated with Snowy River Shire. Although individual Councils are free to assign additional or different value 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; Donelly 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. http://www.anra.gov.au/index.html.
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.
MDBC,(2008) Sustainable Rivers Audit – A report on the Ecological Health of rivers in the Murray-Darling Basin,2004-2007,Murray Darling Basin Commission. http://www.mdbc.gov.au/SRA.
NSW DNR (2008) Water for the Environment: Monitoring the response to Environmental Flows in the Snowy River.New South Wales Department of Natural Resources. http://www.naturalresources.nsw.gov.au/water/water_environment_snowy_project.shtml.
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. http://nratlas.nsw.gov.au.
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. http://www.waterwatch.nsw.gov.au/index.html.
