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music incorporates musicincorporates the ability to display the predicted probabilistic water probabilisticwater quality conditions at source nodes (e.g. urban subcatchment),treatment nodes (e.g. wetland) or receiving nodes, against local or regional orregional water quality concentration standards. Example concentration Exampleconcentration standards for TSS, TP and TN are provided, however these howeverthese should only be taken as a guide and do not constitute adopted standards adoptedstandards for any particular location. You can add any relevant values relevantvalues that they wish and these are then reflected in the charts when chartswhen the model is run and the charts are displayed.

The most appropriate mostappropriate water quality concentration standards for the catchment you catchmentyou are investigating are likely to be those that have been derived for derivedfor that specific catchment, or at least the local region. Use of the ofthe example concentration standards is only to demonstrate how the standards thestandards may be displayed in the graphs and do not represent any particular anyparticular locality.

Selected water quality standards can be displayed on either the Time theTime Series Graph or Cumulative Frequency Graphs (more detail on these onthese is provided in Chapter 4).

Water quality concentration standards are usually specified in the inthe form of a threshold water quality concentration value, and a required arequired compliance frequency for that value. The use of the cumulative thecumulative frequency curves is the best means of assessing the performance theperformance of a stormwater quality treatment strategy against the water thewater quality standards. For example, the TSS standard for Brisbane specifies Brisbanespecifies a median daily value of 15mg/L. This means that TSS concentration TSSconcentration in Brisbane should not exceed 15mg/L more than 50% of the ofthe time.

Irrespective of the time-step used in model simulation, the model themodel compiles predicted water quality concentrations for cumulative forcumulative probability analysis in several forms:

1.Daily mean
'
– the flow-
weighted mean
weightedmean concentration for each day,
2.Daily maxima
'
– the
maximum concentration
maximumconcentration in any time-step for each day,
3.Daily sample
'
– the
concentration in
concentrationin a randomly selected time-step each day,
4.All data
'
– the concentration
in all
inall time-steps (any time-step in which there is no flow will
be recorded
berecorded as zero concentration).
5.Flow-based sub-sample
' the concentration
– theconcentration in all time-steps for which the flow falls within
a user
auser-specified range.

You can choose the time-step of analysis for the production of statisticsofstatistics. For example, even if the model is run at a 6 minute timeminutetime-step, statistics can be produced at an hourly or daily timedailytime-step, if required.

 

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