Gwydir River
Water Quality and River Flow Objectives
| Contents | Background | Consultation | Objectives | WQOs | RFOs | Glossary | Bibliography| Map |
At a Glance |
This section gives the Water Quality Objectives (WQOs) and the River Flow Objectives (RFOs) for the Gwydir River catchment, 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.
Town water supply subcatchments
Streams within these subcatchments typically feed into a town water supply storage. In some cases the subcatchment may be declared specially protected to minimise the effects of land use on water quality.
Map: This category applies to streams running through areas coloured light blue on the map.
Water Quality Objectives
Protection of:
River Flow Objectives
Supporting information
- This category includes Kentucky Creek Dam catchment.
- Raw water sourced from Kentucky Creek or future designated drinking water catchments will need to be of high enough quality in the long term for available treatment to be effective. Existing land management programs aimed at maintaining or improving drinking water catchments should continue and be reviewed. These land management programs include efforts to reduce erosion in the catchments, the frequency of algal blooms in the dams, and other pollutant sources that limit drinking water quality.
- 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 drinking water offtakes.
- Local factors to be considered include maintaining natural flows from springs (groundwater); effects of land management on volumes and times of runoff, particularly in droughts; flow needs of ecosystems and people within the area and downstream; and reliability of town supplies.
- Protecting freshes and high flows does not currently require action but is essential for town water reliability and ecosystems. Minimising any adverse effects of weirs should continue.
Mainly forested areas
Streams in mainly forested areas are often valued for their conservation or recreational values. They usually have relatively natural flows and water quality. Many are in national parks or state forests. Other forests are generally in the upper areas of catchments.
Map: This category applies to streams running through areas coloured green on the map (state forests, national parks and nature reserves). It also applies to other forested areas if any are defined locally.
Water Quality Objectives
Protection of:
River Flow Objectives
Supporting information
- Where the whole catchment of a stream is naturally vegetated, WQOs and RFOs are generally, though not always, achieved. High-level protection should be given to flows and water quality in these least affected streams and in other streams with high conservation values. Existing management practices in national parks or other reserves may already aim to achieve this. In some streams, local circumstances restrict achievement of objectives; for example, the use of streams in state forests by cattle may conflict with the achievement of water quality suitable for swimming and can degrade aquatic ecosystems.
- Some of the state forests and other reserves marked on the map include streams that start in largely cleared land. The water quality and flow patterns through vegetated areas generally reflect any upstream effects. The public accessibility of these areas, particularly for recreation, leads to a high public expectation for good water quality.
- Some streams flowing from disturbed vegetation, plantations or regrowth may meet most WQO and RFOs, but streams below and within recently disturbed sites may have increased turbidity and downstream sedimentation. Extensive areas of rapidly growing trees may reduce low flows in adjoining streams. Thick groundcover may absorb storm peaks and increase the duration of some flows.
- Vegetation on streambanks and floodplains can provide good habitats for native fish, other animals and plants. The effective value of these habitats is likely to be limited if the water quality is poor or if flow patterns are not sufficiently close to natural to provide correct cues for breeding and survival of the young. Returning water quality and flow patterns as close as possible to natural is therefore desirable.
- Waters flowing out of naturally vegetated areas, including private forests, can provide clean waters for downstream uses such as homesteads or livestock. These downstream benefits may be defined locally for specific protection.
- Aboriginal people have identified the consumption of raw aquatic foods as an existing use within the catchment. NSW Health recommends against the consumption of raw shellfish harvested on a non-commercial basis and local communities should be made aware of the risks involved.
- A high level of protection should apply to streams with high conservation value outside reserves.
Waterways affected by urban development
Waterways within urban areas are often substantially modified and generally 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.
Water Quality Objectives
Protection of:
River Flow Objectives
Supporting information
- This category includes creeks and minor waterways within Uralla, Warialda, Bingara and Moree.
- In some urban waterways, aquatic ecosystems are considerably modified. A return to pristine aquatic ecosystems in these areas is unlikely and impractical, but 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 ecosystems.
- Action is needed to reduce the effects of surface and groundwater quality from stormwater and sewerage discharges and unsewered villages.
- The tendency for urban developments to cause rapid rises in storm runoff should be minimised.
- See supporting information under 'Uncontrolled streams', below.
Uncontrolled streams
This category includes all uncontrolled streams and waters that are not in the other categories. Their flow patterns are largely natural. Flows can occur in these streams from local runoff. They are typically ephemeral (flowing only during floods and freshes). Frequently, they open into or flow through wetlands and billabongs.
Map: Uncontrolled streams are shown as blue lines on the map.
Water Quality Objectives
Protection of:
River Flow Objectives
Supporting information
- This category includes unregulated effluent creeks (e.g. the effluent streams west of Moree, such as Thalaba Creek), which are common on the Western Plains, where high flows in the main rivers flow away from the river in natural channels.
- Water taken at point of supply must be kept at a high enough quality in the long term for the available level of treatment to be effective. Towns on uncontrolled streams that extract water for drinking include Bundarra (river), Warialda (bores), Horton (bores) and Bellata (bore).
- Tingha and Inverell (in the Border Rivers catchment) draw drinking water supplies from Copeton Dam. Water levels can often be low owing to irrigation demand from downstream; blue-green algal blooms are common.
- In some areas where there are more intensive industries and rural residential developments (for example, around Moree), the water quality in streams is often poor. Primary contact recreation objectives are currently not being achieved at some locations. High bacterial levels have been found downstream of major urban centres.
- Local factors to be considered in sharing river flows in dry seasons and protecting inundation patterns of flood-dependent ecosystems include:
- strong demand for low flows from some streams; for example, Horton and Rocky rivers and Myall and Laura creeks
- occasional reduction of higher flows in some streams; for example, effluent streams west of Moree
- identified conservation values; for example, native fish
- environmental worth and natural inundation patterns of small wetlands, river red gums, and other riparian or floodplain vegetation; for example, effluent creeks.
- Managing land-use practices to limit groundwater recharge above areas with existing or potential dryland salinity problems is important in the upper catchment. Management would continue to be on a case-by-case basis, aiming to avoid a rise in the watertable or threats to agricultural production, streamwater quality or terrestrial or aquatic ecosystems.
- Minimising the adverse effects of weirs is an important issue. Local factors include the wish to restore native fish populations; and to reduce the filling of natural waterholes by sediment, which causes increased dependence on weirs to secure stock and domestic supplies.
Major regulated rivers
These rivers have large dams supplying irrigation water (and some town and industrial water) for substantial distances downstream. Flows are typically supplemented by releases from dams during the irrigation season resulting in fairly stable and unnaturally high water levels. River flow is substantially reduced during the 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.
Water Quality Objectives
Protection of:
River Flow Objectives
No RFOs were recommended in 1999 as flow rules were in place. A Water Sharing Plan has been in place since July 2004.
Supporting information
- These rivers extend from Copeton Dam to the Barwon River near Collarenebri and include the Mehi River, Carole Creek, Moomin Creek and parts of the Gwydir River.
- Towns that extract water for drinking include Bingara (river) and Gravesend (bores).
- Where there are more intensive agricultural industries and rural residential developments, the water quality in streams is often poor.
- Monitoring data suggest that the Gwydir River at and downstream of Bingara would usually fail the criteria for primary contact recreation. The monitoring identified human sources of bacteria, such as sewerage and septic systems, and animal sources, pointing to problems throughout the catchment.
- Pesticides have been commonly detected in these rivers, particularly downstream of irrigation areas. Pesticide levels in river water and sediments are frequently above guidelines for the ecosystem.
- The quality of water released from Copeton Dam (for example, its temperature) has been identified as a problem. Opportunities to modify the outlet works should be taken.
- DNR's Integrated Monitoring of Environmental Flows Project incorporates important indicators of water quality and river health that can be improved with flow management.
- All RFOs and WQOs should be considered when the WSP is reviewed by the NRC and if a new WSP is developed.
- In particular, there needs to be a focus on how the WSP could address any RFOs not addressed by the existing WSP, whilst protecting licence holders security consistent with the National Water Initiative.
- The RFOs Protect pools in dry times and Mimic natural drying in temporary waterways will not normally be applicable. Plans, however, may identify some locations where specific actions related to these objectives are appropriate.
- Alluvial aquifers adjoining these rivers will need to be managed in association with the rivers. Groundwater levels may affect ecosystems. Action is needed to maintain groundwater within levels critical to ecosystems and streamflows and to deal with other local concerns such as the reliability of bore water supplies for stock.
Controlled rivers with reduced flows
This category covers two situations:
1. River reaches downstream of the major regulated sections where the water is extracted or diverted. Flow is generally reduced throughout the year. Water is delivered from the main stream for stock, domestic, some irrigation, and town water supplies several times a year.
2. Sections of rivers immediately below town water supply dams, where water is diverted directly from the dam. Flows can be substantially reduced throughout the year, though special environmental releases may be possible.
Map: These rivers are shown as red lines on the map.
Water Quality Objectives
Protection of:
River Flow Objectives
Supporting information
- These rivers include the Lower Gwydir River and the Gingham Watercourse (situation 1) and river sections below Kentucky Creek Dam (situation 2).
- Where flows have been reduced, water quality can be affected by the loss of diluting or flushing flows.
- Water quality problems, usually associated with pesticides, are common in the lower Gwydir River.
- Flows in much of the river downstream of Kentucky Creek Dam are often substantially reduced by diversion of water to meet urban and industrial needs. Landholders downstream depend on the remaining flow and may contribute to further reductions. Augmentation of town water supplies will not be required, but the management of the storages should be reviewed, along with the conditions on water licences along the streams. Local factors include support for protection of native fish and landholders' needs.
- Flows in the Lower Gwydir River and Gingham Watercourse have been substantially altered by regulating works upstream and large-scale irrigation extraction. Developments on the floodplain have also significantly altered the natural patterns of flow. There are numerous weirs along these streams.
- A Water Sharing Plan (WSP) has been developed for the regulated Gwydir River, which supplies stock and replenishment flows to effluent watercourses, such as the Gingham and Lower Gwydir.
- Water Sharing Plans for remaining areas are being developed (2006) and will be exhibited for community comment. (www.dnr.nsw.gov.au)
- All RFOs and WQOs should be considered when the WSPs are reviewed by the NRC and when new WSP are developed.
- In particular, there needs to be a focus on how the WSP could address any RFOs not addressed by the existing WSP, whilst protecting licence holders security consistent with the National Water Initiative.
- Landholders in the lower Gwydir River and Gingham Watercourse areas have developed a wetland management plan that integrates water distribution, water quality, vegetation management and land use.
This page was published 1 May 2006