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The Environmental, Social and Human Health Importance of the Aquifers and Wetlands of the Lower South East of South Australia An

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The Environmental, Social and Human Health Importance of the Aquifers and Wetlands of the Lower South East of South Australia An The environmental, social and human health importance of the aquifers and wetlands of the Lower South East of South Australia and SW Victoria and the increasing threats to their existence. My submission to the Senate Select Committee on Unconventional Gas Mining March 2016 I am Marcia Lorenz B.A. Grad. Dip. Ed. Admin., a retired school teacher. I only discovered the attractions of the South East when I came to Beachport 12 years ago. I am a volunteer at the Millicent High School where I support the Aboriginal children in their work with their culture and the environment. I am also a volunteer with other environmental groups in the region. My submission concerns the likely detrimental effect of unconventional gas extraction (“fracking”) on the aquifers and wetlands of the South East of South Australia and therefore on the myriad of species, both flora and fauna that constitute wetland habitats. 1 HISTORY Historically, post white settlement, wetlands were viewed as wastelands with no thought being given to the natural environment and the diversity of species they contained. Economics was the driving force. It would be wonderful if we could say that times have changed and politically there is the realisation that in order for humans to exist, the natural environment must be taken into consideration. After all we now have knowledge that wasn’t available to the ordinary person in the early days of settlement. Post European settlement change in land use has significantly altered the landscape of the South East resulting in the loss of many areas of wetland habitat with <6% of the original wetland extent now remaining.1 An estimated 2,515 km. of drains were installed to remove surface water and shallow groundwater from the landscape.1 Most ground water is now directed out to sea in some cases destroying seagrass meadows. Yarra Pygmy Perch 2 UNDERGROUND AND SURFACE WATER FEATURES OF THE SOUTH EAST OF SOUTH AUSTRALIA 2.1 Aquifers The water used in the South East is generally extracted from either the confined or the unconfined aquifer but there are also many localised sub-aquifers.2 2.1.1 The Tertiary Confined Sand Aquifer (TCSA) The tertiary confined sand aquifer is used as the primary water supply for 8 towns in the region: Beachport, Kalangadoo, Kingston, Lucindale, Naracoorte, Port MacDonnell, Robe and Tarpeena. The following information from PIRSA appears to describe it well. 2 The TCSA is a deep and relatively unpolluted aquifer at a depth of 35-300 metres. The water quality is very good because it is protected from contamination not only by its depth but also by the presence of the confining layer that separates the two aquifers. The confined aquifer contains ‘ancient water’, more than 25,000 years old and is not replenished by local rainfall or surface water. For management purposes the confined aquifer is treated regionally as one aquifer but it is actually a multi-aquifer underground system.3 The NRM Board has more information: In recognition that much of the water in the confined aquifer is over 25,000 years old and has minimal modern day recharge, new water allocations from the confined aquifer will be limited to the following uses: public water supply bridging volumes co-produced water from petroleum and CO2 production (temporary allocation) mining (temporary allocation) A risk assessment to determine the level of risk to the confined aquifer groundwater and its users from current levels of demand and allocation,(my emphasis) indicated that no management areas were at a high or very high level of risk. Some policies in the Water Allocation Plan (WAP) require new allocations or transfers to be the subject of a hydrogeological assessment. For the confined aquifer the assessment will seek to confirm that the allocation of water shall not cause or have the potential to cause an increase in groundwater salinity or have a detrimental impact on the structural integrity of the aquifer as well as not resulting in excessive seasonal variations or long-term declines in water levels.2 2.1.2 The Unconfined Aquifer The unconfined aquifer underlies much of the South East of SA. More than 90% of the water e xt racte d from this aquifer is used for irrigation. As for the confined aquifer, the unconfined aquifer is treated as one aquifer for 2 management purposes but there are actually multiple sub-aquifers. It is important for the maintenance of water-dependent ecosystems, including important coastal springs; drinking water supplies for Mount Gambier, Millicent and 2 Penola and other private domestic water supplies; recreation and tourism. Salinity of the unconfined aquifer is one of the major factors that limits water use in the South East…..The unconfined aquifer has been subjected to pollution, both point source and diffuse source and shows increasing nitrate levels.4 The combined thickness of the aquitard between the confined and unconfined aquifers is about 20 metres…..Some flow between the confined and unconfined aquifers has been identified where fractures, faults and sinkholes occur however this is considered to be minimal.5 (my emphasis) 3 2.2 Surface Water 2.2.1 Natural Creeks Natural creeks are not widespread in the Lower South East due to the topography of parallel sand dune systems and the sandy soil. 8 Mile Creek is the only one of significance in the lower South East with Salt and Maria Creeks further north. While these creeks have all been highly modified from their original condition, they are, given the rarity of these types of habitats in the region, still significant, supporting 5 values that are not otherwise well-represented in the region. The Regional NRM Plan states that action is needed to conserve and manage refuge pools along the creeks to conserve threatened species populations. 2.2.2 Coastal Dune Lakes These lakes are a major feature of the South East. Some are saline and some fresh. They receive water from underground water discharge, rain water and surface water drainage systems. Banded Stilts on Lake George, Beachport, Lower SE, SA These lakes, like Lake George, near Beachport, are very important for shorebirds, migratory and non- migratory, and other waterbirds such as swans and ducks that can be seen in thousands around the fresh water springs rising into Lake George. The South East is also an internationally significant site for migratory waterbirds including a large number that are listed under the following international agreements: Japan-Australia Migratory Bird Agreement (JAMBA), China-Australia Migratory Bird Agreement (CAMBA) and the Republic of Korea-Australia Migratory Bird Agreement 5 (ROKAMBA). Migratory water birds….make round trip migrations of up to 26,000 km. each year between their breeding grounds in the Northern Hemisphere and their non-breeding areas in the south. The wetlands of the South East and the marine environment are 5 significant staging points for large numbers of these birds. 4 Shorebirds on Lake Eliza Coastal wetlands and lakes are important for shoreline stability, storm protection, ecological productivity and sediment and nutrient retention/discharge. They provide nursery, breeding and feeding areas for many species of fish, crustaceans and waterbirds.5 2.2.3 Swamps and Marshes The majority of the wetlands of the South East are either swamps or marshes and many are of an ephemeral nature. They occur across the region from the samphire scrublands of the upper South East coastline to the freshwater meadows that occur inland to the Victorian border down to the peat fens associated with rising springs in the far South East of the region…..Wetlands in the region are primarily under threat from competing high demand for underground water and surface water resources.5 (my emphasis) 5 Swamps and marshes have a complex interaction with the regional hydrology and incorporate processes that combine to produce a mosaic of underground water- dependent ecosystems.6 2.2.4 Karst Rising Springs and Peat Fens Karst rising springs and peat fens are distinctive and fascinating elements of Lower South East hydrology. Prior to European settlement 30,526 hectares of rising springs associated with wetland 5 habitat existed in the South East. Only 1040 hectares (3.4%) remain today. Piccaninnie Ponds are one of Australia’s best examples of rising limestone springs and are surface expressions of a much larger cave system of great beauty and interest, which has made the site one of Australia’s premier cave diving destinations, Paul Caica said, when Minister for Sustainability Environment and Conservation. Karst Landscapes are characterised by features created through solution, the most obvious being caves and sinkholes. The South East has over 600 numbered cave 5 entrances that lead to subterranean features. The original wetland covered 1,100 hectares, most of which was drained post the Second World War. It supported large areas of open water, reed beds, coastal peat fens, a mobile coastal dune system, grassy open woodlands and dense thickets of Tree Everlasting (Ozothamnus ferrugineous), Tall Saw Sedge (Gahnia clarkei) and Silky Teatree (Leptospermum lanigerum)… However, despite the loss of habitat this wetland system remains one of the most extensive examples of Karst Wetlands in Australia.6 (my emphasis) It is situated in one of the 15 national biodiversity ‘hotspots’ listed by the Australian 5 Government in October 2003. A number of nationally-threatened orchid species are exclusively associated with terrestrial rising springs habitats… Rising spring habitat is also important for a number of reptile species considered threatened in South Australia… Dense scrublands associated with rising springs are the preferred habitat of the State endangered 5 Swamp Antichinus (Antichinus minimus maritimus). Peat fens occur where there is continuous upwelling of groundwater which is their primary water source.
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