Gwydir catchment
Legend
Ramsar site
DIWA site
| Security | Registered entitlements (ML) | Long Term Average Annual Yield (ML) |
|---|---|---|
| High | 375 | 375 |
| General | 89,525 | 32,229 |
| Supplementary | 19,100 | 3,629 |
| Total | 109,000 | 36,233 |
For more information regarding the characteristics of entitlements and the water resource plan held in the Gwydir catchment please refer to New South Wales Department of Primary Industries Office of Water
Planning for 2013-14
Commonwealth environmental water use options 2013-14: Gwydir River Valley identifies potential Commonwealth environmental watering actions for 2013-14. Decisions on using Commonwealth environmental water will be made throughout the year based on seasonal, operational and management considerations. If you wish to provide suggestions for Commonwealth environmental water use please contact us at ewater@environment.gov.au or send us your suggestion by visiting: Your suggestions for potential water use options.
Environmental watering in the catchment in 2012-13
| Watering action | Status of Commonwealth action |
|---|---|
| Environmental watering in the Mallowa Wetlands, Gwydir catchment | Completed |
| Environmental watering in the Gwydir Wetlands | Completed |
A summary of Commonwealth environmental watering from previous years in the Gwydir is included below. For further information about Commonwealth environmental watering in the Gwydir and the outcomes achieved, please refer to the Commonwealth environmental water Outcomes Reports and Annual Reports.
Water availability and portfolio management
Portfolio management statements for the Gwydir catchment provide information on the Commonwealth Environmental Water Office's approach to the management of Commonwealth environmental water holdings in the catchment. The portfolio management statement identifies the type and amount of entitlements held, the forecast of water available and the proposed approach to trading, carryover and use of the water.
Environmental watering in the catchment in previous years
| Watering action | Amount of water delivered (ML) | Status of action |
|---|---|---|
| Lower Gwydir and Gingham watercourses | 1 206 | Completed |
| Total in 2011-12 | 1 206 |
| Watering action | Amount of water delivered (ML) | Status of action |
|---|---|---|
| Gwydir wetlands | 3 056 | Completed |
| Gwydir wetlands | 10 000 | Completed |
| Total in 2010-11 | 13 056 |
Catchment profile
Where is it?
The Gwydir catchment is in north-eastern New South Wales and is based around the Gwydir River. The catchment is bordered to the north by the Border Rivers, to the south by the Namoi River, to the east by the Great Dividing Range, and to the west by the Barwon River (a tributary of the Darling).
Semi-permanent wetlands develop as floodwaters flow through natural channels and swamps in the Gwydir
Photo: D Albertson DECC
The Gwydir catchment covers 28,998 km2, which represents 2.78 per cent of the total area of the MDB. The river flows in a westerly direction from its headwaters in the Great Dividing Range near Armidale. The region's topography spans from tablelands in the east, through the central slopes to the western plains where the Ramsar-listed Gwydir Wetlands are located. The main tributary of the Gwydir is the Horton River. Downstream of the catchment's largest town, Moree, the Gwydir River breaks into two major streams: the Gingham Watercourse (northern arm) and the Lower Gwydir or Big Leather Watercourse (southern arm). The Gwydir River is regulated by the Copeton Dam which stores water for towns, stock, domestic use and irrigation. There are also many farm dams and ring tanks in the region.
Semi-permanent wetlands in the Gwydir include natural channels and swamps. Widespread inundation of the catchment's wetlands occurs primarily from floods originating in the upper catchment.
What makes this place so special?
The Gwydir River catchment is an ecologically significant area because it includes:
- systems or subcatchments considered to have high conservation value, such as the Georges Creek Subcatchment
- wetlands of national significance, including the New England Wetlands
- a diverse range and large areas of flora, include approximately 60,000 ha of wetland vegetation (particularly coolabah woodlands) and one of the largest expanses of water couch in NSW
- an appreciable assemblage of rare, endangered and vulnerable species including the Australian bittern, the silver perch and the painted snipe.
The Gwydir Wetlands, which feature on the floodplain of the lower Gwydir River, cover an area of 102,120 hectares. These are among the most extensive and significant semi-permanent wetlands in north-west New South Wales. Portions of these DIWA-listed wetlands are also listed under the Ramsar Convention: the Lower Gwydir Watercourse and the Gingham Watercourse. The Gwydir Wetlands Ramsar site has four components, covering 823 ha in total. These wetlands provide a typical example of an inland terminal wetland delta system. The Gingham Watercourse is also host to the largest stand of marsh club-rush in NSW (listed as a critically endangered ecological community), which covers some 1300 ha. Other significant assets in the catchment include the Gwydir River channel and the distributaries including Mallowa Wetlands on Mallowa Creek.
What does the latest science say about the ecological health of the catchment?
The Sustainable Rivers Audit (SRA), coordinated by the Murray-Darling Basin Authority, provides scientifically robust assessments of the ecological health of the Basin's river valleys. The overall ecosystem health of the Gwydir Valley catchment as reported by the SRA is summarised below.
| SRA Report | Overall ecosystem health of catchment |
|---|---|
| SRA 1 (based on data collected from 2004 to 2007) | Poor |
| SRA 2 (based on data collected from 2008 to 2010) | Poor |
The CSIRO Sustainable Yields Report on the Gwydir Valley Catchment report was developed for the Gwydir area and it found that the current level of surface water extraction is very high, with 41 per cent of average available water being diverted away from the waterways. This report indicated that the average period between flood events that inundate at least 20 per cent of the Gwydir Wetlands has increased by more than 75 per cent. Ecosystems in the Gwydir Wetlands are adapted to floods, and many species require inundation to trigger breeding events.
Under the best estimate 2030 climate the report found the average surface water availability would be reduced by 10 per cent and flows at the downstream end of the waterway would be reduced by 6 per cent.
Note that the boundaries of this catchment as defined by the Sustainable Rivers Audit and the Sustainable Yields report differ slightly to the boundaries used here.