We are considerably encouraged by decisions not to dump dredged materials in the Caley Valley wetlands, the primary focus of our previous submission for the Abbot Point Growth Gateway Project. We are also concerned about dredging in the Great Barrier Reef Marine Park but support no dumping of dredging in this area. We are also less critical about the level of information provided into this project, particularly in relation to modelling of hydrology.
However, we retain concerns about the potential impact of the development on the nationally important wetland , the Caley wetlands (listed on the Directory of Important Wetlands in Australia), a significant community of migratory shorebirds, the endangered Australian painted snipe and the Great Barrier Reef World Heritage Area. Since the last assessment of the environmental impact of this project, two further migratory species found in the Cayley wetlands are now listed as critically endangered: the curlew sandpiper (Calidris ferruginea) and the eastern curlew (Numenius madagascariensis). The importance of the Caley Valley wetlands and the potential impacts of this project include:
- The Caley wetlands are nationally important for their complex mixture of wetland vegetation, extensive area, support of up to nearly 50,000 waterbirds, up to an estimated 1709 migratory individual shorebirds, a significant population of the endangered painted snipe and 36 species of fish supported by a complex catchment system. They would qualify as a wetland of international importance under the Ramsar Convention.
- The proposal will impact on the hydrology and water quality of the wetlands through the interactions between groundwater and stormwater into the wetland, affecting the wetland ecosystem, its functioning and its waterbirds, including migratory shorebirds and other organisms (fish, frog species, turtles, invertebrates, native vegetation).
- There remains concern about the potential pollution of the wetland with leakage from the levees of dredge material.
- The diversion of stormwater directly into the wetland poses a considerable long-term risk given the potential mobilisation of acidity from acid sulfate soils and heavy metals, driven by extreme rainfall and wave action events.
- Dredging of the port in the Great Barrier Reef World Heritage Area will mobilise fine sediment which will affect marine ecosystems and their fauna and flora, including coral reefs.
- Operation of the port will increase accidents with marine fauna, including whales and turtles, as well as increasing pollution.
The UNSW Centre for Ecosystem Science offers four key recommendations to reduce the impact of the project on the nationally important wetlands, the migratory shorebirds or the Great Barrier Reef World Heritage Area:
- Establish a suitable drainage network around the development and build a storage on site which diverts leakage and stormwater, allowing for the capture of potential pollutants. The water should be regularly tested to ensure that no pollutants which might affect the viability of the wetlands and its shorebirds are discharged into the natural environment. Discharge of this water could then occur at a time when it is least likely to impact on shorebird populations;
- Given the importance of the area for migratory shorebirds and the likely impact of initial development works in the area, which will include disturbance and dust mobilisation, the timing of construction works should occur when migratory shorebirds are predominantly in the northern hemisphere (i.e. May –August).
- The Queensland Government must implement best practice rehabilitation works when removing the western bund and causeway to improve flushing of the wetlands.
- It is vital that rigorous data is collected on shorebird populations wetland function, water quality and also potential pollutants (i.e. heavy metals, acidity), for a significant period (c. 1-2 years) prior to, during and after construction works. A long-term environmental monitoring project should also be initiated, and all data collected should be made publically available for the duration of the monitoring period.
