Wellington Weir
Wellington Weir is a proposed weir on the River Murray at or near the town of Wellington, South Australia, not far upstream from where the river flows into Lake Alexandrina.
Announced in 2006 by the state government of South Australia, the proposed Wellington Weir is suggested as an attempt to secure drinking water supplies for the city of Adelaide. The weir would perform two roles: first, it would maintain a pool of water up-river, sufficiently deep enough to allow continued use of the pumping station at Mannum during prolonged drought conditions; and second, the weir would reduce the flow of fresh water into Lake Alexandrina and Lake Albert which lose over 1,000 gigalitres of water a year to evaporation.
Much of the river is already controlled by a system of locks and weirs, including the barrages near the mouth, and Lock 1 upstream at Blanchetown, 274 km from the Murray Mouth. The lowering of water levels in the lake system would severely impact on all who rely on the Lakes and River for their livelihood. This would include irrigators, such as the Langhorne Creek wine region, farmers on the Narrung Peninsula and Point Sturt and fisher people at Meningie and Clayton, to name a few.
Opponents of the weir contend that the planned weir could kill the Coorong, and that already endangered species in the Lakes and Coorong could become extinct. Sim and Muller (2004) trace the complex history of the area. Lloyd (2007) argues the weir diverts attention from the real issue: the sustainability of the Murray-Darling system. There has been no Environmental Impact Assessment regarding the proposed weir. The area impacted is subject to a Ramsar Agreement (Australian Government 2006), as part of an international convention that aims to halt the loss of wetlands and conserve those that remain through wise use and management.
Questions of over-allocation loom large in the debate regarding the cost of a weir (Australian Conservation Commission). For instance, why not spend money on buying water licences from irrigators that use water from the Murray River system to grow cotton in Queensland instead of a weir? (The Australian 2007).
Local Actions Groups formed to oppose the weir point out that the water held back by the proposed weir would be stagnant because "winds from the northwest to the south circulate oxygenated waters from the lakes up the river for many kilometres and winds from the north and northeast bring back freshened water benefiting both areas and precisely fitting in with our anti-clockwise wind rotation" (Jones 2007; see also Webster et al. 1997).
Notes
References
- Australian Conservation Commission (2007) Water crisis - govts must buy back water from irrigators. Jan 12.
- Australian Government - Department of Environment and Water Resources. (2006) The Convention of Wetlands.
- Jones, Henry (2007) Address to the Alexandrina Council, 15 January 2007.
- Lloyd, Tim (2007) Weir plan recipe for disaster. Adelaide Advertiser, Jan.6.
- Sim, Terry and Kerri Muller (2004) A Fresh History of the Lakes: Wellington to the Murray Mouth 1800s to 1935 River Murray Catchment Water Management Board.
- The Australian (2007) Why are cotton farmer being offered yet more water? Letters, Jan 11.
- Webster IT, Maier H, Baker P & Burch M (1997) ‘Influence of wind on water levels and lagoon levels and lagoon river exchange in the River Murray, Australia’, Australian Journal of Freshwater Research vol. 48, pp. 541–550.