Australian River Assessment System: AusRivAS Protocols Development and Testing Report (Final Report)
Monitoring River Health Initiative Technical Report Number 29
Environment Australia, 2002
ISBN 0 642 54890 0 ISSN 1447-1280
- Australian River Assessment System: AusRivAS Protocols Development and Testing Report (Final Report) (PDF - 822 KB)
About the report
The National River Health Program (NRHP) aims to the deliver standardised methods for the assessment of river health throughout Australia. One of the main components of the NRHP is the Australia-wide Assessment of River Health (AWARH) which consists of a nation-wide evaluation of the ecological condition of rivers using a set of rapid, standardised and integrated methods, the Australian River Assessment Scheme (AusRivAS), and a series of Toolbox projects aimed at developing and refining the set of existing assessment techniques.
This report evaluates a number of suggested improvements to the existing river health assessment protocols. The objectives of this project are to:
- formally test the effects of the recent and proposed improvements to the sampling protocol for AusRivAS on sampling quality, reliability and representativeness;
- select optimal modifications to the current sampling protocols and the final form of the sampling protocol; and
- evaluate implications of the modifications to the sampling protocol for model development and performance.
Four changes to the standard AusRivAS were evaluated:
- using visual aids during sorting;
- sorting fine and coarse fractions separately;
- using a minimum time/number of animals; and
- selecting a minimum number of chironomids.
The measures used in this study to evaluate the proposed changes to the AusRivAS protocols included:
- The ratio of the number of live-picked taxa (LS) to the number of taxa remaining in the sample residue (WSE)
- The differences in the O/E scores produced from the AusRivAS predictive models.
The study found that there was no significant difference in the LS/WSE ratio or the O/E scores between the different protocols trialed.
The AusRivAS Protocol Development Project has established that none of the proposed alterations to the sampling and sorting procedures improves the current standard methods. This suggests that no modification in the sampling and sorting protocols of AusRivAS is necessary at this stage and therefore the final version of the AusRivAS should remain the same as its current form. Continuation of current AusRivAS protocols provides many benefits and precludes the need for expensive retraining of staff or adjustment to the current predictive models.
However, prior to any final recommendation regarding the efficacy or necessity of changes to AusRivAS protocols it is strongly recommended that the proposed protocol revisions be further assessed using a similarity measure to investigate differences in taxa between live-picked and residue samples.