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

4 Table 2 - How to interpret bands from AUSRIVAS. 3.1 Rapid Creek 2014 Two macroinvertebrate sites were sampled in the 2014 reporting year. These sites are in the upper reaches of the Rapid Creek system which is a small seasonally flowing coastal stream in the Darwin urban area. Results of the AUSRIVAS scores are described below in Table 3. These results are similar to previous years. The creek has an impoverished macroinvertebrate fauna which is to be expected for a stream with an urbanised catchment. Table 3 - Rapid Creek AUSRIVAS Scores for 2014. Band Description What it represents X More biologically diverse than reference More types found than expected. Potential biodiversity hot-spot or mild organic enrichment. A Similar to reference O/E scores range found at 80% of the reference sites, or equivalent to reference condition. B Significantly impaired Potential impact either on water and/or habitat quality resulting in a loss of types. C Severely impaired Many fewer types than expected. Loss of water and/or habitat quality. D Extremely impaired Few of the expected types and only the hardy, pollution tolerant families remain. Rapid Creek, Darwin. 3. Biological Indicators for freshwater systems. Organisms living in streams and rivers can tell us about the condition or health of waterways. Diverse communities of macroinvertebrates (or water-bugs) indicate a stream in good condition, while simple communities of few water-bug types indicate a damaged or degraded stream. Regular monitoring of stream health is currently undertaken in Rapid Creek and uses an assessment system known as AUSRIVAS. This stands for Australian River Assessment System, and works by comparing water-bugs present in a stream with those expected to be present in reference streams of a similar type. AUSRIVAS produces a score based on the number of types found in a sample relative to the number of types expected. To simplify interpretation of these scores a banding system has been developed (Table 2). Band A means streams are equivalent to high quality reference steams; bands B, C, or D indicate that the stream is below reference condition and is degraded to varying degrees. Site number 2013 O/E Score 2014 O/E Score RC182 B 0.61 C 0.43 RC142 B 0.42 B 0.72