10 July 2025
Green Adelaide's latest monitoring data is available online to download from ResearchGate. Click on the link below to go to the pdf. The summary of the report reads, "Mangrove recovery continues, slowly and unevenly, across the hypersalinity impacted area at St Kilda. Numbers of juveniles are increasing in all the embankment and transition zone quadrats. In the three dead zone quadrats (Q50, Q100 and Q150) numbers of juveniles remain very low. When reviewing the average propagule numbers recorded in each mangrove quadrat across the entire monitoring period, the dead zone quadrats are receiving fewer propagules than quadrats in the embankment, transition, and healthy zones. Growth rates of individuals, as distinct from numbers of individuals establishing, are improving in all dead zone quadrats, but average leaf counts in the dead zone are slow to match other quadrats, even though average heights are similar to the other quadrats. Average heights of juvenile mangroves across the entire site have not yet reached half a metre, giving some indication of the long times frames that may be required for site recovery. Adult trees continue to show signs of stress in the transition zone immediately surrounding the dead zone and small numbers of adult trees may continue to succumb when stressors exceed their adaptation capacity. Significant heterogeneity in recovery is visible in the saltmarshes, where recovery is progressing on higher land and creek edges but is remarkably slow on lower lying areas that have formed scalds. While soil amendments (slightly raised mounds of seagrass) conducted in the scald near the site entry are showing inconclusive results so far, the program is not yet a full year old and there are some indications that benefits are occurring."
http://dx.doi.org/10.13140/RG.2.2.31781.61928
4 December 2024
Some months back (22 August 2024) the EPA and the miner settled upon a civil remedy for the harm done to the mangroves, through mediation at the ERD Court. They finally updated the Alliance on the 19th November 2024 about the outcomes. The EPA agreed that the miner was at "no fault" and the miner agreed they would provide a "civil remedy" of $100,000 over three years ($33k per year) for monitoring at the mangroves.
To say the Alliance is disaapointed at this outcome is to put things very mildly. We don’t think that this is enough for a thorough monitoring program, especially in the light of excellent survey work and monitoring already conducted by DEW, Green Adelaide, Adelaide University, Flinders University and indeed DEM/EPA's own monitoring.
But worse, after five years since the pollution was started, we dont think monitoring is an appropriate response. What would be great would be some amelioration of the risk posed by the residual salt in the salt dams south of St Kilda, and some actual work to remediate the impacted area of mangroves and saltmarsh. Your thoughts?
Read about it at the ABC news report below:
30 June 2024
Green Adelaide's latest monitoring data is available online to download from ResearchGate. Click on the link below to go to the pdf. The summary of the report reads, "Mangrove recovery continues, at a very slow rate, in the hypersalinity impacted area at St Kilda. The ongoing occasional loss of mature trees leads to some concerns about how the many thousands of tonnes of salts crystallised in the adjacent ponds will be managed to prevent further impacts. The patchy recovery of the saltmarsh appears to be related to soil conditions. The saltmarsh soils, including soils on the lower cheniers, are very much saltier, wetter, and have lower pH, than in 2005. Of particular concern is the fact that chloride concentrations remain above the 2005 baseline, in all three zones of the marsh, more than four years after the hypersalinity impact occurred. This is most obvious in the now-unvegetated low marsh, where the mean chloride concentration currently exceeds the chloride concentrations of all but one of 240 saltmarsh soils sampled right around Barker Inlet as far north as Middle Beach, over winter and summer in 2004 and 2005. It has not been established whether this is a result of poor rinsing of accumulated salts from the saltmarsh soils by the daily tides, or whether it is a signal of ongoing leaching from the deposited salt in the adjacent pond system."
(PDF) Monitoring recovery at St Kilda 2023-2024
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.
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]
Peri Coleman (CONSULTANT, DELTA ENVIRONMENTAL CONSULTING)