Environmental watering in the Lower Murray River (South Australia)
14 March 2012 – Update to watering action
The delivery of enhanced flows to South Australia ceased on 3 February 2012 due to natural high river flows. Commonwealth environmental water continues to be provided as part of Entitlement Flow to South Australia, and is enabling additional flows over the barrages at the Lower Lakes from February to June 2012.
12 January 2012 – Lower Murray River
Commonwealth environmental water has been made available to enhance flows to South Australia until mid 2012. This environmental water will help to manage the recession from high flows during late December/early January, and ensure that river levels decrease gradually from the recent peak. This will provide for a more natural flow pattern and supports the environment by assisting, for example, the return of native fish to the main river channel from the floodplain.
The enhanced flows to South Australia to meet environmental demands in the Lower Murray River, Lower Lakes and the Coorong for the remainder of 2011-12 complements existing environmental water releases. Commonwealth environmental water released to meet environmental objectives in the Goulburn River and current releases in lower Broken Creek will help sustain flows in the Lower Murray River, Lower Lakes and the Coorong over the coming months.
The delivery of Commonwealth environmental water will be adaptively managed to take account of river conditions and rainfall. River flows will be carefully monitored and environmental water delivery will be adjusted in relation to flow targets. Up to an additional 380 gigalitres of Commonwealth environmental water has been made available, however river and rainfall conditions will influence how much of this total additional volume may be required.
Commonwealth environmental water will contribute to a flow target at or below 16.5 gigalitres per day at the South Australian border until late January to manage the recession from recent high flows. Water will then be used to provide elevated baseflows to South Australia over the coming months at or below 15 gigalitres per day at the South Australian border. This will ensure that there is no inconvenience or inundation at the construction worksite for the Chowilla Regulator, in the Riverland area, from delivery of the water.
Providing enhanced flows to South Australia aims to support the management and improvement of aquatic habitat in the Murray River channel, Lower Lakes and Coorong, with increased flows provided through the Murray Mouth. In particular, the environmental water will help protect and restore the flora and fauna in the Lower Lakes and Coorong by supporting the management of variable water levels. This will help to prevent a rise in salinity due to evaporation.
The enhanced flows to South Australia will also:
- support aquatic and semi-aquatic vegetation along the Murray River, and promote the ongoing recovery of native aquatic vegetation including water-milfoil (myriophyllum spp) in the Lower Lakes
- enhance spawning and recruitment opportunities for large bodied native fish species in the Murray River channel, such as golden perch (Macquaria ambigua)
- increase connectivity between Lake Alexandrina and the Murray estuary so native fish species such as congolli (Pseudaphritis urvillii) and common galaxias (Galaxias maculatus) can move between habitats to complete breeding cycles
- allow more water to flow over the barrages to flush salt and nutrients from the Murray-Darling river system and to help manage salinity levels in the Lower Lakes and Coorong. This will support the recovery of aquatic species such as ruppia (ruppia tuberosa), which provides an important food source for waterbirds and habitat for fish.
The use of Commonwealth environmental water involves detailed planning. Consideration is given to the individual environmental water requirements of each catchment, risks, and how watering actions can complement each other for multiple environmental outcomes across the southern connected basin. Planning for the use of environmental water is an on-going process.
Commonwealth Environmental Water draws on scientific advice and local knowledge in planning the management of environmental water in South Australia. The watering will be managed in cooperation with the South Australian Department for Water, South Australian Department of Environment and Natural Resources, SA Water and the Murray-Darling Basin Authority.