ENVIRONMENTAL
RESULTS
ABOUT THE ZONE
The Western Basin is located near the north-western end of Gladstone Harbour. Three large-scale Liquid Natural Gas (LNG) plants have been constructed on the south-western shore of Curtis Island. The first of these commenced operation in late 2014. Large industrial plants located on the western shore of this zone include Queensland Energy Resources, Rio Tinto Yarwun, Orica, Transpacific Waste and Cement Australia. Areas of mangroves and mudflats remain between Fisherman’s Landing and the Wiggins Island Coal Export Terminal (WICET) and on the southern tip of Curtis Island.
WATER & SEDIMENT
The Western Basin received an overall water quality score of 0.80 (B).
Sediment quality of The Western Basin was very good with an overall score of 0.98 (A).
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The following graphs compare the Water and Sediment scores reported for 2024 (top line) to those from 2023.
WATER
SEDIMENT
Very good (0.85-1.00)
Poor (0.25-0.49)
Good (0.65-0.84)
Satisfactory (0.5-0.64)
Very Poor (0.00-0.24)
No data available
Overall, Water quality in the Western Basin scored 0.80 and received a good grade (B), similar to the 2023 report card. This score was calculated by aggregating the three sub-indicator and associated measure scores (Physicochemical – pH and turbidity, Nutrients – total nitrogen, total phosphorus and dissolved metals, and dissolved metals – aluminium, copper, lead, manganese, nickel and zinc).
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Within the Physicochemical sub-indicator, Western Basin received a score of 1.00 and a very good grade (A) for pH, indicating that the average pH was well within the guideline value range. This zone received a score of 0.67 and a good grade (B) for turbidity, indicating that average turbidity was within the guideline value range – an improvement from a satisfactory grade (C) in 2023.
Within the Nutrient sub-indicator group, total nitrogen (0.45) and chlorophyll-a (0.46) both received poor grades (D), indicating that average concentrations for these measures were above the guideline values for this zone. Total nitrogen and chlorophyll-a at the Western Basin zone declined in grade from satisfactory (C) in 2023 to poor (D) in 2024. Total phosphorus improved from a satisfactory grade (C) in 2023 to a good (B) in 2024 in this zone.
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All six Dissolved metals received high scores and very good grades (A) indicating that concentrations were well below the water quality guideline values.
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For Sediment quality, the Western Basin zone received an overall score of 0.98 and a very good grade (A), a similar result to the previous year. This score was calculated by aggregating measure scores (Metal and metalloids – arsenic, cadmium, copper, lead, mercury, nickel and zinc).
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In 2023, all seven of the Metal and metalloids sub-indicator measures received very high scores (0.92–1.00) and very good grades (A), indicating that average concentrations were below the guideline values for this zone.
HABITATS
SEAGRASS RESULTS
Meadow 4
Meadow 6
Meadow 8
Meadow 5
Meadow 7
Meadow 52-57
The Western Basin includes six monitored seagrass meadows, five of which are intertidal and one subtidal (Meadow 7).
In 2024, this zone scored an overall score of 0.70 and received a good grade (B) for the fifth consecutive year. Biomass and area scores for Meadows 4, 5 and 6 were similar to the 2023 report card. A decline to a poor grade (D) was seen in species composition for Meadow 6, while improvements were seen for this sub-indicator in Meadows 4 and 5 (2023: satisfactory (C), 2024: very good (A)). In Meadow 7, the biomass score improved to a very good grade (A) from a satisfactory (C) the previous year, while the area score remained similar. However, the area scores for Meadows 7 and 8 decreased and resulted in a lower grade (satisfactory, (C)). Meadow 52–57 declined in grade from a very good (A) in 2023 to a good (B) in 2024 due to a reduction in biomass, while Meadow 4 improved a grade to very good (A) in 2024 after improvements in species composition scores.
MANGROVE RESULTS
Overall, the Mangroves grade improved from a satisfactory (C) in 2019 to a good (B) at the Western Basin zone. Mangrove extent declined in grade to a satisfactory (C) at Western Basin in 2024. The grade for canopy condition at Western Basin improved from a poor (D) in 2019 to a good (B) in 2024. Shoreline condition of mangroves at Western Basin monitoring zones remained poor (D) in 2024.
FISH & CRABS
FISH RECRUITMENT RESULTS
Fish recruitment was assessed for two species: Yellowfin bream Acanthopagrus australis and Pikey bream Acanthopagrus pacificus. The fish recruitment sub-indicator for Western Basin remained a good grade (B) in 2024.