Assessmentof the Long Term Reliability of a Water Quality Monitoring System, 1993-1996

ReportNo WSAA 152

April 1999




The aims of thisproject were to continue the R & D which commenced in 1990 with the crucialsupport of the UWRAA for producing an Automatic Water Quality Analyser (AWQA)suitable for unattended use in rivers and streams.


The followingwere some of the main outcomes and recommendations of this UWRAA project:


1.       More R & D is required to expand theflexibility of this unique water quality monitoring system.

2.       Further trials over long periods duringthe rainy season would consolidate reliability and expose the instrumentationto a wider set of water quality changes and environmental conditions.

3.       Measurements could be improved by usingtwo point calibrations for all chemical sensors.

4.       Turbidity and conductivity probes neededdesign improvements.

5.       Event triggering to be improved to sensethe rate of water level change at the Weir.

6.       Telephone two-way link to provide theusers with direct communication with the AWQA.


The currentUWRAA study was awarded to further develop the AWQA for reliable long termdeployment, taking into account the outcomes and recommendations of theprevious UWRAA study (UWRAA No 55). The specific objective of the currentproject was to direct the R & D towards very long term deployment withon-site, two point calibration where possible.


All of the R&  D objectives, concerned withimproving the software and hardware, providing calibration regimes for chemicalanalyses, improving the economy of operation and the sensitivities of thesensors, developing a highly interactive communication and data presentationsystem, were achieved. Quite long term deployment of 30 to 60 days weresuccessful in testing and evaluating new regimes and procedures. However, dueto a number of unforeseen circumstances, the main objective of very long termdeployments was not achieved.


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