Territory Stories

Darwin Harbour in good health



Darwin Harbour in good health


Westra Van Holthe, Willem

Political affiliation

Country Liberals


Media Releases for 12th Assembly 2012 - 2016; Media Releases; ParliamentNT






Made available by via the Publications (Legal Deposit) Act 2004 (NT)




Oceans; Marine life

Publisher name

Northern Territory Government

File type



Issued as a Media Release

Copyright owner

Northern Territory Government

Parent handle


Citation address


Related items

https://hdl.handle.net/10070/528211; https://hdl.handle.net/10070/528213

Page content

13 5.1.7. Nitrogen Oxides Median NOx values ranged between 3 mg/L (Myrmidon Creek) and 16.5 mg/L (Middle Harbour) with highly variable minimum and maxima values across reporting zones of Darwin Harbour. High nitrate values were episodically observed in Myrmidon and Buffalo Creeks. All other reporting zones had medians within water quality objectives. 5.1.8. Ammonia Median values for ammonia ranged between 2.5 mg/L (Elizabeth River) and 9 mg/L (Buffalo Creek). Significant extremes were observed in Myrmidon Creek, Buffalo Creek and the Outer Harbour region around the East Point outfall servicing the Ludmilla treatment plant. 5.1.9. Total Nitrogen Median total nitrogen values ranged from 130 mg/L (Middle Harbour) to 1420 mg/L (Buffalo Creek). Although most sites in the outer harbour zone met WQOs, sites adjacent to the East Point outfall failed to meet benchmarks for total nitrogen. Results for this region of the reporting zone skewed data with the outer harbour zone not meeting WQOs for total nitrogen. Total nitrogen was typically observed to be higher in the upper reaches of main systems and within tidal creeks. 5.1.10. Total Phosphorus Total phosphorus for all reporting zones with the exception of Buffalo Creek met WQOs with medians ranging between 5-24 mg/L. The median for Buffalo Creek was 106 mg/L. However elevated concentrations were recorded in Blessers Creek (East Arm reporting zone), Myrmidon Creek and Outer Harbour at East point. 5.1.11. Filterable Reactive Phosphorus Filterable reactive phosphorus, the soluble fraction of phosphorus was low across Darwin Harbour. Median values ranged from 2 mg/L - 6 mg/L for all reporting zones with the exception of Buffalo Creek (15 mg/L) exceeding locally derived WQOs. Extremes for FRP were observed in systems associated with licensed wastewater discharge such as Buffalo Creek, Myrmidon Creek and Blessers Creek, a tidal creek in the East Arm reporting zone. For chlorophyll a, nitrogen oxides, ammonia, total nitrogen, total phosphorus and filterable reactive phosphorus data needed to be log10 transformed. This transformation was necessary to make results clear on the graphs, due to the wide variability of results between reporting zones and sites.