Lake Macquarie and Tuggerah Lakes
Water Quality and River Flow Objectives
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At a Glance |
This section gives the Water Quality Objectives (WQOs) and the River Flow Objectives (RFOs) for the for the Lake Macquarie and Tuggerah Lakes catchments, which should 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.
Mainly forested areas
Streams in mainly forested areas are often valued for their conservation or recreational values. They often have relatively natural flows and water quality. Many are in national parks or state forests.
Map: The objectives apply to streams running through areas coloured green on the map (state forests, national parks, any nature reserves); and through other forested areas, if any are defined locally (private land or Crown land).
Water Quality Objectives
Protection of:
River Flow Objectives
Supporting information
- In national parks and state forests, the emphasis is on aquatic ecosystem protection and recreational uses. In some cases, these streams have agricultural land uses along the upstream sections (see 'Uncontrolled streams', below). In these cases, management of upstream impacts will be needed to achieve or maintain the high water quality levels and close-to-natural flow patterns expected in forested areas, particularly for drinking water and RFO Maintain natural flow variability.
- In extensive private forests, livestock and homestead water supplies may be desired uses, in which case they should be included as objectives.
- In upper catchment forested areas, the flow regime will be substantially natural and should be protected. The above RFOs are precautionary, and recommended to protect these flow regimes.
- Lower in the catchment, forested areas may have a flow regime highly altered by upstream uses. These areas should be a priority for remedial action, given that the land surrounding the waterways will have substantial natural values.
Waterways affected by urban development
Streams within urban areas are often substantially modified and carry poor quality stormwater. Many local communities are keen to see such streams returned to more natural conditions.
Map: These areas are shown in orange on the map.
Water Quality Objectives
Protection of:
River Flow Objectives
Supporting information
- This category includes Cockle Creek and small streams flowing through urban areas around the lakes.
- Streams in these areas are relatively small, highly altered, channelised and with high pollutant levels. Flows have been modified by increased runoff due to hard-surfacing of the urban area. Affected creeks and wetlands will flood to higher levels and may be wetter than natural.
- In some urban waterways aquatic ecosystems are considerably modified. A return to pristine aquatic ecosystems in these areas is unlikely and impractical, however, water quality conditions for existing ecosystems can be improved greatly for the benefit of local species and broader catchment health. Data from other local aquatic ecosystems of similar type, in areas that are not urbanised, may provide achievable criteria for these modified aquatic ecosystems.
- The environmental value of primary contact recreation for some specific locations within urban areas may be desired, given community demand and evaluation of water quality for feasibility. This will require action to protect identified sites from the effects of upstream uses.
- There are identified wetlands and floodplain ecosystems within urban areas around Lake Macquarie and Tuggerah Lakes.
Uncontrolled streams
This covers waterways that are not in the other categories. Their flow patterns are largely natural but may have been altered to a limited degree.
Map: These streams are shown as blue lines on the map.
Water Quality Objectives
Protection of:
River Flow Objectives
Supporting information
- Most rivers in the catchment fall into this category. Water quality is worst in Jilliby Jilliby and Ourimbah creeks and may not support the objectives listed above.
- Mine subsidence and acid mine drainage have the potential to affect water quality (lower pH) and reduce flows.
- Ourimbah Creek supplies drinking water. Special zones for protection of water quality may need to be designated upstream of drinking water supply offtakes.
- Levels of licensed extraction are high in places, and riparian use (irrigation, stock and domestic) may reduce water levels at times of little or no flow. The priority RFOs are to protect the rivers at times of low flow.
- The rural areas of these catchments contain important and protected wetland and floodplain ecosystems.
- This is an area of high groundwater use for domestic needs, livestock watering, the citrus industry, market gardens, poultry farming and water bottling. Protecting groundwater levels will maintain base flows in the headwaters of streams and groundwater-dependent ecosystems.
- Ourimbah Creek has weirs that impede fish passage.
- Boating was not specifically requested during the community consultation; however, if the water quality is good enough for swimming, it is also safe for boating.
Controlled rivers with increased flows
In these rivers the flow is supplemented by water diverted from an adjoining catchment for town water or hydro-electric purposes. These releases alter the river flow pattern and may affect water quality. In the case of town water supplies, high water quality is needed.
Map: These streams are shown as brown lines on the map.
Water Quality Objectives
Protection of:
River Flow Objectives
Supporting information
- This category includes a section of the Wyong River.
- Wyong River receives inter-valley transfers of water for drinking water supply when natural flow levels are insufficient for water supply purposes. These transfers originate from Mangrove Creek Dam in the Hawkesbury-Nepean catchment and can affect Wyong River's flow regime and water quality. In particular, when transfers are made, the Wyong River is wetter and has more rapid changes in river height than natural.
- Levels of licensed extraction are also high and riparian use (irrigation, stock and domestic) may reduce water levels at times of little or no flow.
- The Wyong alluvials soils provide groundwater suitable for potable water supply.
- Wyong River has weirs that impede fish passage.
Estuaries
Being dominated by saline conditions, estuaries have hydraulic and water quality characteristics, and potential problems, that are often very different from those of freshwater systems.
Map: Estuaries are coloured purple on the map.
Water Quality Objectives
Protection of:
River Flow Objectives
Supporting information
- This category includes the whole of the saline parts of Lake Macquarie and the Tuggerah Lakes.
- There is no commercial shellfish production from these lakes.
- Industries around the lakes can affect water quality by their thermal impacts and by introducing heavy metals into the lakes.
- Maintaining natural variability in the inputs of freshwater to the lakes is important for ecosystem health in these estuaries.
- Dredging can have major impacts, affecting both erosion and sedimentation processes and water quality. Apart from its impacts on turbidity, nutrients and oxygen levels, dredging can disturb and liberate heavy metals from the sediments to the water.
- Parts of the lower estuarine reaches are underlain by potential acid sulfate soils, which should not be disturbed. Dredging and disturbance of bottom sediments (i.e. those below water level) can also have major impacts in these areas.
- Plans to increase circulation in Tuggerah Lakes require stringent environmental assessment
This page was published 1 May 2006
About the Objectives
