What is a water allocation plan?

    Water allocation planning is a legislative requirement under the Landscape South Australia Act 2019. On Eyre Peninsula, we have the Water Allocation Plan for the Southern Basins and Musgrave Prescribed Wells Areas, which is maintained by the Eyre Peninsula Landscape Board.

    The plan manages how groundwater is taken (e.g. from wells) and how much of it can be used, so that there is a fair balance between groundwater for environmental, social and economic needs and so that the taking and use is sustainable.

    The plan estimates how much groundwater there is, allocates water for environmental needs, ensures locals have access to groundwater for stock, domestic, roadmaking and fire-fighting purposes, and regulates the amount that water licence holders can extract for mains water, industry (e.g. irrigated agriculture, mining) and recreational use (e.g. golf course irrigation).

    Why is the plan being revised?

    These plans must be reviewed every 10 years, as per the legislation. This review and amendment have been combined and brought forward in time, due to science advice that groundwater resources in the Prescribed Wells Areas will no longer be able to sustainably meet the water supply demands of the Eyre Peninsula region.

    Why can't groundwater still meet water supply demand?

    Long-term measurements show that there is a decline in rainfall, which is needed to refill (“recharge”) these local groundwater resources.

    Before the drought, water levels in some of the groundwater basins have fallen to very much below average, or lowest on record levels. In some bores, water levels are close to sea level.

    These low water levels increase the risk of seawater, or underlying salty groundwater, being drawn up into the fresh groundwater supply by pumping.

    If groundwater extraction continues at its current rate, groundwater may not be able to be extracted from some bores, or it may become polluted with salty water.

    Will the revision of the plan reduce groundwater use?

    It is expected that the revised plan will reduce the amount of groundwater that can be extracted from some parts of the Prescribed Wells Areas.

    If this is not done, falling groundwater levels may mean that groundwater cannot be extracted from some bores.

    In other bores, if groundwater levels drop too far, continued pumping may cause seawater, or saline groundwater that sits underneath the fresh groundwater in places, to be drawn up into the fresh groundwater supplies.

    This will pollute the fresh water, reduce or prevent groundwater use for mains water and other uses, and affect environmental and cultural values that rely on this fresh groundwater.

    Will the revision consider climate change, the environment, and Aboriginal water interests?

    The revision will consider these issues, as required by the Landscape South Australia Act 2019, which recognises that climate change is a significant factor in our environment and aims to protect biodiversity and support the interests of Aboriginal peoples.

    Climate change is a major issue driving this revision, as rainfall monitoring has shown a long-term decline in local rainfall, which means there is less refilling (“recharge”) of these groundwater resources, which rely on local rainfall. Dating of the water in these local groundwater resources has shown it to be less than 30 years old, compared to nearly 2 million years old, for water in northern SA, which flows through the Great Artesian Basin all the way from Queensland.

    Before the drought, some wet years did not result in the expected recovery of groundwater levels, suggesting that climate change (e.g. hotter and drier conditions) may have affected the relationship between rainfall and recharge.

    Groundwater allocations for the environment (e.g. soaks, wetlands, coastal springs, redgums that use groundwater) are in the current plan and will be incorporated into the revised plan.

    The revised plan aims to incorporate the interests of Aboriginal peoples, by recognising the cultural importance of groundwater, by acknowledging the water rights that arise from Native Title determinations that have been made since the last plan, and by exploring future economic opportunities from groundwater that will support the national Closing the Gap program.

    Will my mains water supply be affected?

    The revised plan will reduce the amount of groundwater that is allowed to be extracted by SA Water, which will reduce the amount of water available for mains water supply.

    The proposed Port Lincoln desalination plant will offset reduced groundwater availability from the Southern Basins, which currently supply 75% of Eyre Peninsula’s mains water.

    Elliston relies solely on groundwater from the Bramfield basin in the Musgrave area for mains water. If these groundwater supplies were compromised due to falling water levels or increasing salinity, alternatives would need to be reconsidered, such as water carting, a mains water connection to the regional pipeline system at Polda, or a small-scale coastal desalination plant.

    Will water licence holders be affected?

    The revised plan will reduce the amount of groundwater that can be extracted from some parts of the Prescribed Wells Areas and close some public water supply basins.

    Most of the licensed water extraction is by SA Water for mains water supply, so the reductions in groundwater extraction in the revised plan will mostly affect SA Water. SA Water is constructing a desalination plant at Port Lincoln to offset this reduced groundwater availability.

    The revision has identified a small number of private water licence holders in the Southern Basins who will have reduced access to groundwater.

    What about stock and domestic groundwater use in these areas?

    The Landscape South Australia Act 2019 requires that water allocation plans take into account the needs of the occupiers of the land.

    In the case of these Prescribed Wells Areas, stock and domestic water is needed by the occupiers of the land to meet their livestock water requirements and their household water needs.

    The revision of the plan will make provision for adequate stock and domestic water needs.