|Security||Registered entitlements (ML)||Long Term Average Annual Yield (ML)|
* Total holdings for upper and lower Namoi catchments
Commonwealth environmental water in the Namoi River catchment
Water availability and portfolio management
Portfolio management statements for the Namoi 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.
Options for Commonwealth environmental water use
Annual water use options 2012-13: Namoi catchment identifies potential Commonwealth environmental watering actions for 2012-13.
Annual water use options 2012-13: Namoi catchment - Fact sheet summarises the approach and some of the options for using Commonwealth environmental water, as well as identifies how anyone may provide suggestions for use of environmental water.
Environmental water delivery
Environmental Water Delivery: Namoi River collates current knowledge of the operational and administrative arrangements for the delivery of environmental water to the Namoi River. The document provides an overview of the environmental assets and potential environmental water use options. This work has been undertaken to support the efficient and effective use of environmental water and to engage communities on how this may best be achieved. This aims to encourage community discussion and feedback on the use of environmental water, to identify future opportunities and recognise operational risks and constraints. Comments on the document are encouraged and can be provided to: firstname.lastname@example.org.
Environmental watering in the catchment in 2012-13
Environmental watering in the catchment in previous years
No Commonwealth environmental watering has occurred in the Namoi catchment prior to 2012-13.
Where is it?
The Namoi River catchment is in north-eastern New South Wales, and is based around the Namoi, Manilla and Peel rivers. It is bounded to the east by the Great Dividing Range, the north by the Gwydir, the south by the Macquarie-Castlereagh region and the west by the Barwon-Darling region. The Namoi River and its main tributary, the Peel River, rise in the Great Dividing Range at elevations over 1000 m, falling to 250 m where the two rivers meet near Gunnedah. The river then flows through sedimentary slopes to the open floodplains in the west. Nearly two-thirds of the region is comparatively flat.
This catchment covers an area of 41,856km2 or 4 per cent of the MDB. Other major tributaries of the Namoi River include the Manilla and McDonald rivers, Coxs Creek and the Mooki and Cockburn rivers, all of which join the Namoi upstream of Boggabri. The Namoi River then flows westerly across the western plains and joins the Barwon River near Walgett. Regulation in the catchment includes Keepit Dam (capacity 426 GL), Chaffey Dam (capacity around 63 GL), Split Rock Dam (capacity 397 GL) and a number of weirs.
What makes this place so special?
The Namoi catchment is an ecologically significant area because it includes:
- a wide range of aquatic habitats of ecological importance, including large areas of anabranch and billabong wetlands downstream of Narrabri
- endangered ecological communities
- species protected under state legislation, including silver perch, Australasian bittern, Australian bustard, black-tailed godwit, Bell's turtle and brolga
- a variety of flora including coolabah, river red gum and river cooba, and six vegetation communities including Carbeen Open Forest and bimble box woodland
The only wetland of national importance in the Namoi region is Lake Goran, adjacent to the Liverpool Plains. This lake is situated at the end of an internal drainage basin that does not connect to the Namoi River. Due to this lack of connection it cannot be watered using Commonwealth environmental water.
Another important ecological site is Gulligal Lagoon, near Gunnedah – a semi permanent wetland that is connected to the Namoi River, filling during flood events and from surface flows. The lagoon provides important habitat for native fish species including olive perchlet. This lagoon acts as a drought refuge in the mid-Namoi region and was restocked with breeding pairs of purple spotted gudgeon in late 2009 as part of the Namoi Demonstration Reach project.
What does the latest science say about the ecological health of the catchment?
The Murray-Darling Basin Commission Sustainable Rivers Audit (SRA) rated the overall health of river ecosystems in the Murray-Darling Basin. The SRA reports the overall ecosystem health of the Namoi catchment as poor.
The CSIRO Sustainable Yields Report on the Namoi River catchment identified that the region uses 2.6 per cent of the surface water diverted for irrigation in the MDB. Under the best estimate 2030 climate there would be a 5 per cent reduction in water availability, an 8 per cent reduction in end-of-system flows and a 1 per cent reduction in diversions overall. The region has one of the highest levels of groundwater extraction within the MDB and groundwater use is 15.2 per cent of the MDB total.
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.