Murrumbidgee River and Lake George
Water Quality and River Flow Objectives

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This section gives the Water Quality Objectives (WQOs) and the River Flow Objectives (RFOs) for the Murrumbidgee River and Lake George catchments, which will be used to develop plans and actions affecting water quality and river health. Only the priority RFOs are listed in this section, but the remaining objectives still need to be considered when developing flow management plans or dealing with particular local river conditions.

The following section provides a catchment-wide perspective in terms of the interim environmental objectives as they apply to the general waterway categories listed. The more detailed work already underway on the management of specific river reaches and localised catchment areas must be recognised.

A broader catchment overview of the links and interactions between upstream and downstream subcatchments is also necessary, and locally agreed objectives will need to remain consistent with the statewide interim objectives outlined below.

Previous work has also defined four regions of the catchment with broadly different characteristics. These are marked on the maps as:

  1. upper Murrumbidgee
  2. mid Murrumbidgee
  3. irrigation areas
  4. lower Murrumbidgee.
  5. Lake George catchment

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Town water supply subcatchments

The streams in town water supply subcatchments typically feed into a town's water supply storage. In many cases, the catchment may be declared as specially protected to minimise land use effects on water quality.

Map: This category applies to streams running through areas coloured light blue on the map.

Top of PageWater Quality Objectives

Protection of:

Aquatic ecosystems
Visual amenity
Drinking water-Disinfection only
Drinking water-Clarification and disinfection
Drinking water-Groundwater

Top of PageRiver Flow Objectives

Protect pools in dry times
Protect natural low flows
Manage groundwater for ecosystems
Minimise effects of weirs and other structures

Supporting information

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Mainly forested areas

Streams in these areas are valued for conservation or recreation. Streams that drain catchments covered mainly by mature forest or woodland are likely to have relatively natural flows and water quality.

Map: This category applies to uncontrolled streams running through areas coloured green on the map (state forests, national parks and nature reserves); and to streams in other forested areas or areas with locally defined high conservation value.

Top of PageWater Quality Objectives

Protection of:

Aquatic ecosystems
Visual amenity
Secondary contact recreation
Primary contact recreation
Drinking water at point of supply-Disinfection only
Drinking water at point of supply-Clarification and disinfection
Drinking water at point of supply-Groundwater
Aquatic foods (cooked)

Top of PageRiver Flow Objectives

In many of the streams within upland forests, all RFOs are being achieved. Priority action may be required to achieve one or more of the following objectives in uncontrolled streams through other areas of forest or natural vegetation:

Protect pools in dry times
Protect natural low flows
Protect important rises in water levels
Maintain wetland and floodplain inundation
Mimic natural drying in temporary waterways
Maintain natural flow variability
Manage groundwater for ecosystems
Minimise effects of weirs and other structures

Supporting information

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Waterways affected by urban development

Waterways within urban areas are prone to substantial modification and may carry poor-quality stormwater. Local communities are often keen to see these waterways returned to more natural conditions.

Map: These areas are shown in orange or as orange dots on the map.

Top of PageWater Quality Objectives

Protection of:

Aquatic ecosystems
Visual amenity
Secondary contact recreation, as a short-term objective, within 5 years
Primary contact recreation: assess opportunities to achieve as a longer-term objective, 10 years or more

Top of PageRiver Flow Objectives

Protect pools in dry times
Protect natural low flows
Maintain natural rates of change in water levels
Minimise effects of weirs and other structures

Supporting information

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Waterways affected by irrigation drainage

This applies to natural and semi-natural waterways whose flows are now dominated for substantial periods by irrigation drainage. Flow and water quality are therefore largely unnatural.

Map: These waterways are shown as green lines on the map.

Top of PageWater Quality Objectives

Protection of:

Aquatic ecosystems
Visual amenity
Livestock water supply
Irrigation water supply
Homestead water supply

Top of PageRiver Flow Objectives

Maintain wetland and floodplain inundation
Mimic natural drying in temporary waterways
Maintain natural flow variability
Manage groundwater for ecosystems
Minimise effects of weirs and other structures

Supporting information

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Uncontrolled streams and the Lake George catchment

This category applies to all streams, wetlands and natural lakes that are not in the other categories. The flow patterns of these streams are largely natural. It also includes Lake George and all waters feeding into the lake.

Map: Uncontrolled streams are marked as blue lines on a pale yellow background on the map. The Lake George catchment adjoins the upper Murrumbidgee catchment and is marked by a number 5 on the map.

Top of PageWater Quality Objectives

Protection of:

Aquatic ecosystems
Visual amenity
Secondary contact recreation
Primary contact recreation
Livestock water supply
Irrigation water supply
Homestead water supply
Drinking water at point of supply-Disinfection only
Drinking water at point of supply-Clarification and disinfection
Drinking water at point of supply-Groundwater
Aquatic foods (cooked)

Top of PageRiver Flow Objectives

For all streams:

Protect pools in dry times
Protect natural low flows
Minimise effects of weirs and other structures

For streams with relatively high extraction rates:

Mimic natural drying in temporary waterways
Maintain natural flow variability

For groundwater areas that sometimes feed water into streams, or are naturally shallow enough to supply trees, or have rising watertables:

Manage groundwater for ecosystems

For all wetlands, lakes, high-flow channels, remnant floodplain vegetation and adjoining lands and watercourses:

Protect pools in dry times
Protect natural low flows
Protect important rises in water levels
Maintain wetland and floodplain inundation
Mimic natural drying in temporary waterways
Manage groundwater for ecosystems
Minimise effects of weirs and other structures

Supporting information

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Streams affected by Snowy Scheme

These streams either contribute to or receive flow from the Snowy Mountains Hydro-electric Scheme. The Snowy Water Inquiry was commissioned in 1998 to assess river management of the Snowy Mountains Hydro-Electric Scheme and recommend environmental flow options for rivers affected by the Scheme. The Inquiry's terms of reference required analysis of the environmental, social and economic effects of various options for future management, prior to making recommendations to the NSW and Victorian Governments. The final report of the Inquiry was submitted on 23 October 1998. In August 2000, the NSW and Victorian Governments reached an agreement for environmental releases for the Snowy River below Jindabyne Dam which will increase flows from 1% to 22% of natural flows downstream of Jindabyne Dam within 10 years. Releases were also agreed for other rivers affected by the Scheme, including the upper Murrumbidgee River, the upper Snowy River (above Jindabyne Dam), the Goodradigbee River and the Geehi River.

Map: This category applies to streams in the areas coloured pink on the map.

Top of PageWater Quality Objectives

Protection of:

Aquatic ecosystems
Visual amenity
Secondary contact recreation
Primary contact recreation
Irrigation water supply
Homestead water supply
Drinking water at point of supply-Disinfection only
Drinking water at point of supply-Clarification and disinfection
Drinking water at point of supply-Groundwater
Aquatic foods (cooked)

Top of PageRiver Flow Objectives

All eleven inland RFOs should be considered in flow planning and management. However, the overall framework for the amounts of flow diverted to or from streams affected by the Snowy Scheme has been agreed by the NSW, Victorian and Commonwealth governments and is regulated by the Snowy Water Licence under the NSW Snowy Hydro Corpratisation Act 1998.

Supporting information

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Major regulated rivers

These are rivers from which large volumes of water are diverted for irrigation by large dams. Flows during the irrigation season are supplemented by release of water stored from high flows, resulting in unnaturally high water levels in summer. These flows lack natural patterns of variability and sometimes change rapidly. River flow is substantially reduced during non- or low-irrigation seasons. At any time of year in periods which would normally have high or very high flow, flows may be substantially reduced by the trapping of water in a large dam.

Map: These rivers are shown as yellow lines on the map.

Top of PageWater Quality Objectives:

Protection of:

Aquatic ecosystems
Visual amenity
Secondary contact recreation
Primary contact recreation
Livestock water supply
Irrigation water supply
Homestead water supply
Drinking water at point of supply-Disinfection only
Drinking water at point of supply-Clarification and disinfection
Drinking water at point of supply-Groundwater
Aquatic foods (cooked)

Top of PageRiver Flow Objectives

No RFOs were recommended in 1999 as flow rules had been developed by the former river management committee. In 2004, a Water Sharing Plan (WSP) commenced for the Murrumbidgee Regulated River.

Supporting information

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Controlled river with reduced flows (Murrumbidgee below Maude Weir)

The section of the Murrumbidgee below Maude is defined as a regulated stream, but it is not used to supply much water for irrigation. Its flow is substantially less than natural for much of the time in most years as a result of the storage and diversions for irrigation upstream. The remaining flows tend to lack natural patterns of variability.

Map: This river section is marked in red on the map.

Top of PageWater Quality Objectives

Protection of:

Aquatic ecosystems
Visual amenity
Secondary contact recreation
Primary contact recreation
Livestock water supply
Irrigation water supply
Homestead water supply
Drinking water at point of supply-Disinfection only
Drinking water at point of supply-Clarification and disinfection
Drinking water at point of supply-Groundwater
Aquatic foods (cooked)

Top of PageRiver Flow Objectives

No RFOs were recommended for this river in 1999 as flow rules had been developed by the former river management committee.

In 2004, a Water Sharing Plan (WSP) commenced for the Regulated Murrumbidgee. It includes environmental water provisions that affect this section of the river. A separate WSP for the Lowbidgee district (off the main regulated river) will be developed in due course.

Top of PageSupporting information

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Controlled river with reduced flows (Queanbeyan River below Googong Dam)

Part of the Queanbeyan River is affected by diversions from the Googong Dam to Queanbeyan and Canberra. Some high flows and most low to moderate flows are substantially reduced below the dam for most of the year. Some water is released down the river for environmental purposes.

Map: This stretch of river is marked in red on the map.

Top of PageWater Quality Objectives

Protection of:

Aquatic ecosystems
Visual amenity
Secondary contact recreation
Primary contact recreation
Livestock water supply
Homestead water supply

Top of PageRiver Flow Objectives

Protect pools in dry times
Protect natural low flows
Protect important rises in water levels
Maintain natural flow variability
Maintain natural rates of change in water levels
Minimise effects of weirs and other structures
Minimise effects of dams on water quality
Make water available for unforeseen events

Top of PageSupporting information

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Controlled rivers with altered flows (regulated creeks)

Yanco and Colombo creeks receive controlled flows from the Murrumbidgee River. They have been declared as regulated streams. Provision of a continuous flow for irrigation and other purposes results in moderately high flows in summer and autumn when flows would naturally be brief or low. In other seasons flows may sometimes be less or more than would naturally occur. The variability of flows has been altered.

Map: These creeks are shown as brown lines on the map.

Top of PageWater Quality Objectives

Protection of:

Aquatic ecosystems
Visual amenity
Secondary contact recreation
Primary contact recreation
Livestock water supply
Irrigation water supply
Homestead water supply
Aquatic foods (cooked)

Top of PageRiver Flow Objectives

Protect natural low flows
Protect important rises in water levels
Maintain wetland and floodplain inundation
Mimic natural drying in temporary waterways
Maintain natural flow variability
Maintain natural rates of change in water levels
Manage groundwater for ecosystems
Minimise effects of weirs and other structures

Supporting information

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Artificial channels

This category applies to entirely artificial watercourses built to supply water for irrigation or other purposes.

Map: Artificial channels are not shown on the map.

Top of PageWater Quality Objectives

Protection of:

Aquatic ecosystems
Visual amenity

Top of PageRiver Flow Objectives

No RFOs are recommended for artificial channels.

Supporting information

This page was published 1 May 2006