Hunter River
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 Hunter River catchment, (excluding the Williams River, which has
already been the subject of a Healthy Rivers Commission inquiry), which should be used in developing plans and actions affecting 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.
Town water supply subcatchments
The streams in town water subcatchments or groundwater aquifers typically feed into
a town's water supply storage. In many cases, the catchment may be declared as specially
protected to minimise the land-use impacts on water quality.
Map: The objectives apply to streams and major
aquifers in areas coloured light blue on the map.
Water Quality Objectives
Protection of:
River Flow Objectives
Supporting information
- In this catchment, this category includes the Tomago sandbeds.
- Prioritise issues and management actions using reports such as the Aquifer Risk
Assessment Report (DLWC 1998a), and implement the NSW Groundwater Policy (DLWC 1997a,
1998b).
- To ensure long-term achievement of these WQOs, existing land-management programs aimed
at maintaining or improving water quality should continue and be reviewed. These include
efforts to reduce the amount of pollutants (such as nutrients, salts, persistent chemicals
and heavy metals) that reach the groundwater aquifers from surface land-uses. This also
includes ensuring that the rate of removal of water does not exceed recharge, otherwise
saline water may be drawn in from the coast or estuary.
- Raw water sourced from the Tomago sandbeds will need to be of high enough quality for
available treatment to be effective. If water quality is still inadequate after treatment,
the treatment may need to be upgraded.
- Not all parts of large river systems can be protected from human activity that degrades
drinking water quality. See 'Uncontrolled streams' and other river categories, below, for
objectives that apply to surface and groundwater drinking water offtakes in the catchment.
- The water supply for Newcastle is supplied mainly from the Williams River. Seaham
Weirpool is the major offtake point for Newcastle's water supply. Water is stored in
Grahamstown Reservoir, which falls into this waterway category. A Healthy Rivers
Commission Inquiry in 1996 developed objectives and priority actions for the Williams
River.
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. Others are generally in the upper parts of the
catchment.
Map: The objectives apply to streams running
through areas coloured green on the map (state forests, national parks and 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 some cases, streams in mainly forested areas will have agricultural land uses along
the upstream section of the river (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 forested upper catchment areas, drinking water (with treatment) may be a desired
environmental objective and requires very good water quality, particularly with respect to
turbidity and pathogens (disease-causing organisms). In extensive private forests,
livestock and homestead water supplies may be desired uses, in which case they should be
included as local objectives.
- In upper catchment forested areas, the flow regime will be substantially natural and
should be protected. The RFOs recommended are precautionary 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.
- The extensive areas of natural forest not in state forests or national parks should be
identified so that their contribution to water quality can be recognised.
Waterways affected by urban development
Waterways within urban areas that are often substantially modified and generally
carry poor quality stormwater. Many local communities are keen to see these waterways
returned to more natural conditions.
Map: These areas are shown in orange or orange
dots on the map.
Water Quality Objectives
Protection of:
River Flow Objectives
Supporting information
- This category includes the Hunter River and minor creeks within Newcastle and other
urban centres, including Cessnock, Maitland, Murrurundi, Muswellbrook, Raymond Terrace, Scone and
Singleton.
- Flows in these waterways have been modified by increased runoff due to hard surfacing in
the urban area. The 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.
- RFO Maintain wetland and floodplain
inundation is included as a precautionary measure, to protect wetlands from
drainage in developing urban areas.
Uncontrolled streams
Uncontrolled streams and waterbodies are those that are not in estuaries or the
other categories. Their flow patterns may have been altered in some way through land-use
change and extraction. Many of these streams flow into the regulated river sections, and
so changes to their flow regime will affect downstream flows.
Map: These streams are shown as blue lines on the
map.
Water Quality Objectives
Protection of:
River Flow Objectives
Supporting information
- Most streams in the catchment fall into this category. Available water quality data
indicate that the water quality in these streams is often inadequate to support most of
the desired environmental values, particularly for healthy aquatic ecosystems, for
swimming and drinking, and for irrigation of moderately salt-tolerant crops. This is
partly because of high phosphorus levels in the north-west, due to basalt geology, and
high background salinity levels in the Bylong, Growee, Wollar, Wybong and Dart Rivers, and
minor tributaries of the regulated section of the Hunter River.
- Drinking water is taken from several ground and surface offtake points to supply towns
throughout the uncontrolled parts of the catchment-including Murrurundi (Pages River) and
Merriwa (Merriwa River). Special zones for protection of water quality may need to be
designated upstream of drinking water supply offtakes or around groundwater sources.
- Low flows are mostly through the sandy river beds, and small flow events ('freshes') are
depleted if excessive amounts of water are withdrawn during low flows. If there are no
groundwater-dependent ecosystems in a particular stream, then restrictions on access to
water from these sandy beds could be relaxed.
- On-farm storages, either off-river or in drainage lines, could reduce the impact of
protecting water for the environment at times of little or no flow. However, these have
considerable potential to affect flows in the river. There need to be catchment-yield
assessments to determine the potential impact of on-farm storages on flows. RFO Protect
important rises in water levels is particularly relevant in the Pokolbin area (near
Cessnock), due to the large and increasing numbers of farm dams.
- RFO Maintain wetland and floodplain
inundation may be applied, particularly to streams in the lower Hunter, as many of
these streams interact with wetland systems.
- Changes to the flow regime in uncontrolled streams may affect flows in downstream
regulated sections.
- Boating (secondary contact recreation) was not specifically requested during the
community consultation; however, if the water quality is good enough for swimming, it is
also safe for boating.
Major regulated rivers
These rivers have large dams supplying irrigation, town and industrial water for substantial distances downstream. Flows are typically supplemented from dams, resulting in fairly stable and persistent flows when water is released for extractive use. River flow, such as small natural rises, can be reduced at other times, particularly during periods of high demand for water by industrial users. Flows in these regulated sections can also be substantially affected by use of water in the unregulated river sections upstream.
Map: These rivers are shown as yellow lines on the map.
Water Quality Objectives
Protection of:
River Flow Objectives
No RFOs were recommended in 1999, because environmental flow rules
had already been recommended by the former Hunter River Management Committee (RMC).
In 2004, a Water Sharing Plan (WSP) for the regulated river commenced. The WSP incorporated recommendations from the former RMC and includes environmental water provisions. Under the Water Management Act, the WSP will be reviewed before its 10 year term expires. The review will consider the River Flow Objectives framework, along with other requirements of the State Water Management Outcomes Plan and the Act.
The Paterson River will be the subject of a separate WSP.
Supporting Information
- This category includes the Hunter River below Glenbawn Dam, Glennies Creek below the Glennies Creek Dam, and the Paterson River below Lostock Dam.
- Drinking water offtakes along the major regulated section of the Hunter River include Singleton, Denham and Muswellbrook. Several towns, such as Denham and Singleton, also take groundwater from alluvium near the river.
- Industrial water use is also a major value of this river category and requires good quality water-in particular, low salinity and turbidity.
- Potential industry-induced salt levels in the regulated sections of the Hunter River are managed through the Hunter River Salinity Trading Scheme.
- Boating (secondary contact recreation) 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 streams with increased flows
In these rivers, the flow is supplemented for large portions of time by water
diverted from an adjoining catchment for town water, hydro-electric power or
water supply augmentation purposes. These releases alter the river flow patterns and may
affect water quality.
Map: These streams are shown as brown lines on
the map.
Water Quality Objectives for Black Creek
Protection of:
River Flow Objectives for Black Creek
Supporting information
- The stream sections in this category include Black Creek. Cessnock's town water supply
originates in Chichester Dam in the Williams River catchment. Black Creek receives a
relatively constant, medium volume flow from Cessnock Sewage Treatment Plant (STP). Cessnock STP is being upgraded to tertiary treatment (expected completion 2007).
- Black Creek has high nutrient levels from the sewage effluent and high salt levels from
the underlying geology. Water quality will need to be improved to be suitable for
non-potable homestead uses.
- Black Creek is much wetter and has a more constant flow than natural. Reinstating some
drying and natural variability are priorities.
Water Quality Objectives for Oaky Creek and
the Hunter above Glenbawn
Protection of:
River Flow Objectives for Oaky Creek and
the Hunter above Glenbawn
Supporting Information
- The stream sections in this category include Oaky Creek and the Hunter River from
Glenbawn to the junction with Oaky Creek. The Barnard Scheme, which can potentially divert
water from the upper Manning River (in the Manning River catchment) to augment water
supply for the power industry in the Hunter catchment, could increase flows in Oaky Creek
and the Hunter above Glenbawn.
- The Barnard Scheme has been rarely used in recent years and is partly decommissioned.
Estuary
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: The estuary is coloured purple on the map.
Water Quality Objectives
Protection of:
River Flow Objectives
Supporting Information
- The limited data available indicate that the Hunter River does not have good enough
water quality to protect aquatic ecosystems, or for fish and shellfish to be eaten raw.
This is mainly due to high levels of pathogens (disease-causing organisms). Swimming is
possible for some of the time, especially near the entrance of the estuary. Boating is
usually safe.
- All commercially harvested shellfish and mussels in NSW are harvested in accordance with the NSW Shellfish Program. Achievement of water quality sufficient to meet
protection of aquatic ecosystems and commercial shellfish production would help protect
environmental features such as wetlands, seagrass beds and aquatic reserves.
- Freshwater inputs to the estuarine sections are affected by upstream extraction to an
extent, usually resulting in more freshwater than natural at lower flows, and less than
natural in higher flows.
- Nationally and internationally recognised wetlands in the lower Hunter need to have
their inundation regime restored to some extent.
- The quality of groundwater needs to be protected in the Kooragang and Fullerton Cove
areas (see 'Town water supply subcatchments', above); alternatively groundwater levels
should not be depleted in areas of acid sulfate soils, which underlie most of the estuary.
- Levees and floodgates cause major disruption to fish access to nursery and breeding
areas in the lower Hunter, although there are currently two major rehabilitation projects
underway, at Kooragang Island and Hexham Swamp (Ironbark Creek). RFO Maintain wetland and floodplain
inundation is a high priority, but should be done with consideration for both the
needs of the environment and affected landholders.
- 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 for the same reason.
This page was published 1 May 2006
About the Objectives
