Water Quality and Nutrient Management

The major water quality issue in the Hopkins River Basin is high salinity. Due to this, surface supplies are supplemented by groundwater and surface water imports. Low dissolved oxygen and medium nutrient levels are also a concern in the Basin. Water quality with respect to dissolved oxygen is generally moderate in the upper half of Mt Emu Creek and in Brucknell Creek. Available data for nutrient levels indicate that the nutrient status is low in the Hopkins River and medium in Brucknell Creek and the Merri River. As a result, the suitability of the water for aquatic life is affected. Turbidity levels are fairly low in the Basin’s major streams, indicating good quality, however, during winter, levels are often elevated in certain areas.

Surface water quality in the Portland Coast Basin is good with respect to catchment condition and suitability for aquatic life but high salinity is a major issue. Surface water quality with respect to salinity is poor in the major streams, with the exception of the Surry River, where salinity is slightly lower. This precludes use of surface water for extensive domestic supply. The high salinities in the base flow of the streams are an indication of elevated groundwater salinity and minor dry land salting.

In the Glenelg River Basin, high salinity is a problem in the major streams, as are high levels of colour. Therefore, it is generally unsuitable for domestic supply. Water quality in the Wannon River at Dunkeld is locally poor due to moderate levels of nutrients and associated stimulation of productivity. Salinities in the main river systems generally increase downstream and are especially high in the tributaries of the Glenelg and Wannon Rivers. Catchment condition is otherwise good and the water is generally suitable for aquatic life. With respect to dissolved oxygen levels, water quality in the Basin is generally moderate with the exception of the Wannon River at Dunkeld – where concentrations are particularly low.

(DWR, 1989)

Dry seasonal conditions throughout the entire region during 1998-99 resulted in sharp increases in salinity levels in many district lakes and wetlands. Limited or no runoff into many lakes and wetlands last winter has exacerbated the increases. For example, the normal seasonal fluctuation for Lake Linlithgow is 10 000 EC in winter and spring, rising to 16 000 EC in late autumn. During 1999, the lowest salinity levels recorded were 25 000 EC and peaked at 50 000 EC (seawater) in autumn (GHCMA, 1999). These dry seasonal conditions continued during 1999-00, resulting in many wetlands drying completely and sharp increases in EC levels resulting (to 45 000 EC at Lake Linlithgow prior drying in February 2000). Increased salinity levels were also recorded for Lake Bolac and Lake Burrumbeet during 1999-00. As a result the Glenelg-Hopkins Catchment Management Authority (external link) has funded 95 water quality projects in the region throughout 1999-00 (GHCMA, 2000a).

Nutrient Management:

From 1928 to 2000, algal blooms have been reported at 16 sites in the Glenelg-Hopkins Catchment Management Region at differing frequencies.

Recorded algal blooms at waterbodies and waterways in the Glenelg-Hopkins Catchment Management Region:

Drainage Basin	Location	Algae	Comments
Glenelg	Dunkeld	Anabaena Oscillatoria	CuSO4 dosing CuSO4 dosing
	Merino Basin	Phormidium	monitored
	Rocklands Reservoir	Botryococcus	monitored
Hopkins	Alexander Lake	Anabaena and Microcystis
	Caramut Reservior	Chroococcus	monitored
	Caramut Water Supply	Ulothrix and Euglena	monitored
	Deep Lake	Microcystis	Warning signs
	Green Hill Lake, Ararat	Microcystis	Drinking, recreation facilities banned
	Hopkins River, Boonerah	Unicellular green	monitored
	Lake Burrumbeet	Microcystis and Oscillatoria	Closed to recreation
	Lake Cartcarrong	Anabaena
	Lake Gellie	Oscillatoria	Warning signs
	Lake Gillear	Anabaena	Warning signs
	Lake Terrinallum	Oscillatoria	Warning signs
	Mt Ewen Reservoir	Anabaena	CuSO4
	Tank Hill Reservoir	Struastrum	CuSO4
Portland	Aringa Reservoir	Anabaena	Closed to recreation

Source: GHCMA (2000b)

In March 1995 the State Government of Victoria released the Nutrient Management Strategy for Victorian Inland Waters (DCNR, 1995). This Strategy recognised the link between high nutrient levels in water bodies and the increasing occurrence of algal blooms. Blue-green algal (BGA) blooms are potentially toxic and threaten both human use of water and the ecological biodiversity of aquatic life. The strategy suggested a planning process to assess regional problems and encourage local communities to develop and implement nutrient management plans specific to local nutrient problems. The Glenelg-Hopkins Nutrient Management Plan (GHNMP) (external link) aims to provide a strategic framework for nutrient management projects. Nutrient management works have been prioritised to ensure that they provide maximum net economic, environmental and social benefits.

Reports that also set the basis for a regional based Nutrient Management Plan are the National Water Quality Management Strategy (NWQMS) and the State Environmental Protection Policy - Waters of Victoria (SEPP-WoV). The SEPP’s goal is to attain and maintain levels of water quality that are sufficient to protect the beneficial used of the surface waters of the policy area. Water Quality targets relate to marine, estuarine and freshwater areas together with the beneficial use to which the waters are used.

For information about Catchment Nutrient Management Plans, contact the Glenelg-Hopkins Catchment Management Authority. (external link)

Related Links

Landcare Notes

Has your dam got a blue-green algae problem?

EPA Victoria website (external link)

The Health of Streams in the Glenelg Catchment (external link)
This report, in association with DSE, is the latest in the River Health Bulletin Series and reports the results of biological monitoring in the Glenelg catchment.

Other Information

Algal Blooms


References:

Department of Conservation and Natural Resources (DCNR). Victorian Blue-Green Algae Project Team, (1995), Nutrient Management Strategy for Victorian Inland Waters. DCNR, Melbourne.

Department of Water Resources (1989). A Water Resource Handbook, Melbourne.

Glenelg-Hopkins Catchment Management Authority (2000b). Glenelg-Hopkins Nutrient Management Plan Draft; A framework for reducing the incidence of blue-green algal blooms in regional waters.


Other useful references include:

Dixon P., Wagg C., Armitharajah M. (1998). Aspects of Environmental Conditions in the Glenelg-Hopkins Catchment Management Region with particular reference to Salinity and Nutrients, (the former) NRE, East Melbourne.

Read Sturgess and Associates (1999). Benefits and Costs for Reducing Frequency of Algal Blooms in the Glenelg-Hopkins CMA Region. Glenelg-Hopkins CMA, Hamilton.

Sherwood, J., Magilton and Rouse, A. (1998). The Glenelg River; Nutrients and Estuarine Hydrodynamics. (the former) NRE, East Melbourne.

Schreiber S., Wagg C., Metzeling L., Perris S. (1989). Assessing stream Health in the Glenelg Catchment using macroinvertebrates. (the former) NRE, EPA, NLP, Victoria.

Sinklair Knight Mertz (1998). Baseflow and Nutrient Conditions in Groundwater in the Glenelg-Hopkins CMA Region. (the former) NRE Victoria.

Turoczy, N. (1998). A preliminary assessment of the nutrient status of selected farm dams in the Glenelg River Catchment, Deakin University, (the former) NRE, Victoria.

Vinall, G., Kew, P. (1999). Identifying Nutrient Hot-Spots in selected Subcatchments in the Glenelg-Hopkins and Portland Coast. Glenelg-Hopkins CMA, Hamilton.

Wagg C. (1999). Development of CMSS model for the Glenelg CMA region. (the former) NRE, East Melbourne.

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