The future aim of LLCMM icon site managers will be to achieve as many of the above-listed flow targets as possible for the Lower Lakes and Coorong, in any given year. As more environmental water is incrementally available to the icon site, more targets can be met, and a greater ecological outcome achieved.
The following is based on the above discussion, and is a summary of targets to be achieved in priority order on an annual basis, as more water becomes available to the icon site:
• Lake levels are maintained above 0 m AHD to prevent exposure of acid sulfate soils.
• Lake levels are maintained within the seasonal operating levels.
• Fishways are operated year-round.
• Attractant flows are provided adjacent to fishways, and a limited estuary achieved in Boundary Creek.
• Minimum annual flow from the barrages required to achieve salinity target of <1,000 EC in Lake Alexandrina (650 GL+).
• Minimum annual flow required to keep the Murray Mouth open (730 - 1,090 GL).
• Flows of at least 2,500 GL over two years to prevent the Coorong existing in a degraded ecosystem state.
• Flows of 6,000 – 10,000 GL in a year to achieve a healthy Coorong ecosystem state.
Note that more specific information about barrage operation is provided in Chapter 4 - Water Delivery.
Table : Environmental water requirements of the Murray Mouth and Coorong to achieve icon site ecological targets
TLM Objective (M/F/B)
Optimum salinity (ppt)*
Preferred Annual Volume (GL)
Duration & Timing
Maintain or improve bird populations in the Coorong