For the last couple of decades there has been great interest in the Darling River and the Menindee Lakes. The Menindee Lakes are old ephemeral lakes, which under natural conditions, would have filled during high river flows and then drained back into the Darling River.
In 1938, an agreement was reached between the-then Broken Hill Water Board and the NSW State Government to build a storage at Menindee and pump water to Broken Hill, providing an unfailing water supply. Before construction began, war broke out and no work commenced. At the end of the war, a decision was made to start the Snowy Mountains Scheme. Premier of South Australia, Tom Playford, challenged the building of the Snowy Scheme, believing it would at times deprive South Australia of water. A compromise was reached whereby the early version of the Menindee storage was modified and enlarged with South Australia receiving an allocation secured by the Menindee Storage and the Murrumbidgee River.
Work started and the lakes were modified in the 1950s and early-1960s to form the largest water storage on the Darling River. The interest in the Menindee Storages is largely because they are shallow with a large surface area of 463km. They are subject to large evaporation losses which accounts on average for some 425,000 megalitres per year.
The storages are owned by the NSW Government and jointly managed by the Department of Natural Resources, Murray-Darling Basin Authority and State Water Corporation.
The natural environment of the lakes is unique. They are amongst the most important breeding sites along the Darling River and include a number of rare, endangered species and migratory species. The lakes and surrounding areas are also significant for Aboriginal heritage and provide a focus for recreation, regional tourism and significant irrigation development. The lakes are vital to the local and regional economies and an invaluable social resource.
In 1995, the Minister for Land and Water Conservation announced a review of the operations of the Menindee Lakes, promising that the review would include broad community involvement. This led to the formation of the Menindee Lakes Advisory Committee, a draft management plan, an issues paper, an ecologically sustainable development project, an EIS report, the State of the Darling report, and more recently, the Darling River Water Savings Project Report. This report is scheduled to be handed to the appropriate state and federal ministers before the end of 2009.
The NSW and Federal Governments are jointly funding the feasibility study to identify substantial water savings in the Darling River, including the Menindee Lakes. The outcome of the study is to be a 20-year strategic plan for water savings based on an integrated approach of structural works, river and storage operating strategies, and water market activities.
The fundamental objective of the study is to develop a strategic plan to secure substantial water savings within the Darling River and secure Broken Hill’s water supply. The plan also recognises the importance of improving operational flexibility of river and water storage; management to better meet the needs of water users and the environment; protecting the environment and riverine ecology; protecting water quality and water security for water users; and to contribute to economic development in the region.
The study has identified that operation rules have a large impact on water savings (in the range of 10 – 250 gigalitres), while structures alone have a lesser impact on water savings. Options that create ‘cells’ within Lake Menindee are least favoured. Structures for operational flexibility and environmental outcomes for the lakes are to be further assessed. The anticipated capital costs range from $30 to $200 million.
Modeling will continue to assess better environmental filling strategies for the lakes; and how changes to state sharing of lakes might impact on stakeholders. Modeling will continue to examine options to cancel potential negative impacts on irrigation, social, heritage and economic factors.
Modeling will also continue to assess best options for independent and secure supply for City of Broken Hill and surrounds (which will include both in-storage and external storage sites).
Lower Murray Darling Catchment Management Authority