St Kilda Mangroves Alliance has analysed compliance reports and PEPR documents hosted on the DEM website, relating to the management of the northern ponds of Dry Creek saltfields. A pumping regime (the Holding Pattern) was supposed to maintain feeding resources for migratory shorebirds, until a closure plan for the saltfield could be developed. The pumping regime depended on flows of treated wastewater in the SA Water Channel to dilute the strong brine that formed in the Holding Pattern ponds, to make the brines safe to discharge to sea. Flows in the channel are insufficient to dilute the brine produced from the area of ponds, causing unstable, extreme salinities to develop across the whole complex of ponds. It is likely the invertebrate populations used as food by the shorebirds have been significantly impacted.
The report can be accessed here: MngHoldPattNthStKIlda_final
The St Kilda Mangrove Die-off
Our beautiful tidal wetlands (mangroves and Commonwealth EPBC Act protected saltmarshes) surrounding the St Kilda Mangrove Boardwalk have been sickening and dying since mid 2020.
The nearby decommissioned gypsum ponds were filled with hyper-saline brines. Gypsum, lining the old ponds, had rotted after sitting empty for seven years and now the ponds are leaking and mobilising acidic materials from underneath the gypsum crust.
The SA Department of Energy & Mines regulate all the ponds as part of the Dry Creek Saltfields and the SA Department for the Environment manage the National Park next to the gypsum ponds.
Both departments have allowed this catastrophic impact to continue unchecked, merely measuring the impact, rather than being proactive and starting efforts to halt the ongoing leakage occurring from underneath the irreparably damaged gypsum crust.
Please sign, and share the petition for the South Australian Government to act immediately to minimise the damage done to the St Kilda Mangrove Forest through the continuing leaking of hyper-saline liquid from the adjoining gypsum ponds.
Aerial observations of the ponds have been continuing, extending from Dry Creek through to Middle Beach at the very top of the pond chain. Here first are just a small number of these images from around the St Kilda Ponds.
The lowering of the hyper-saline brine at the ponds here has slowed to an agonisingly slow rate after the initially rapid evaporation witnessed. This is primarily due to the alarmingly high content of sodium chloride within the ponds here. Any continued lowering appears to be occurring due to the ongoing leakage from the ponds into the neighbouring natural environments.
The pumping at St Kilda stopped a long time ago and is suspected to have never been an ongoing process due to the inability of running the pumps for longer than a few minutes at a time because of the excessive sodium chloride levels (hyper-salinity) in that brine. When pumping was able to happen it was shifting small amounts of the offending liquid from one leaking pond to another, it never was able to make its continued journey to the Dry Creek holding ponds as was instructed to the mining company by the Department of Energy and Mining.
The scenario at the Little Para River Estuary is not looking so good with the flow of water movement there having been drastically altered in such a manner as to impede the free movement of the Little Para River into the estuary region for the apparent benefit of a slightly raised crossing point for vehicles, when there used to be a perfectly good bridge which had no such negative impact there prior to works on the Northern Connector being started.
So far the impact continues, no one is admitting it is an ongoing disaster, no one is taking responsibility and the environment is losing ground (and ability to repair itself) daily. [28-12-2020]