Lock 3, located near Overland Corner, controls 85 kms of the River Murray and connects many significant water bodies, including Lake Bonney, the Ramsar listed Banrock Station and Wachtels Lagoon. It is also at the heart of the Riverland townships of Loxton and Barmera and is the traditional home of the First Peoples of the River Murray and Mallee region.
The Lock 3 Reach contains the most diverse range of flow conditions of all the weir pools in the South Australian River Murray and contains a number of sites of significant ecological, social and cultural importance.
Currently, there are a range of threats causing ecological decline in the Lock 3 Reach, including:
- reduced size, frequency and duration of floodplain inundation
- loss of variability in water levels, salinity risks
- obstructions to fish passage.
There has already been significant infrastructure investment in Weir Pool 3, namely at Pyap, Yatco Lagoon and Beldora wetlands, as well as the South Australian Riverland Floodplains Integrated Infrastructure Program (SARFIIP) investment on the Katarapko Floodplain. However, the extent of environmental benefit that could be achieved in this reach has been constrained due to salinity risks associated with Lake Bonney, operational constraints of infrastructure and legacy social issues from past river management (that is, Loveday Wetlands).
Building on from the recent success of SARFIIP, the Sustaining Riverland Environments Program of activities associated with Lock 3 Reach aims to deliver:
- infrastructure upgrades at crucial floodplain and wetland sites to improve their function and integrate their operations with weir pool manipulation and future higher flows
- increased flexibility in the operation of Lock 3 and the consequential management of lakes and wetlands
- improved understanding of the salinity risks associated with Lake Bonney and the best way to manage them
- removal of infrastructure that is no longer fit-for-purpose and restricts the movement of water or biota between the river and floodplains
- infrastructure upgrades, on and off farm, to enable business continuity during increased variability in water levels.
This investment will enhance and improve:
- environmental outcomes as a result of increased hydraulic diversity, inundation extent and connectivity in the Lock 3 reach
- recruitment of river red gums and other woody-vegetation in riparian areas through the introduction of a more variable water regime
- the return of valuable nutrients and water to the river from pool connected wetlands.
The Sustaining Riverland Environments Program is a $37.6 million program funded by the Australian Government through the Murray-Darling Basin Authority and delivered by the Government of South Australia through the Department for Environment and Water.