Response to Info Request - Attachment 4a - Engineering Report Part 1 MCU18-0015 & RAL18-0001 · MCU18/0015

7.3     Stormwater Quality Management


The site currently consists of 95% pervious surfaces. The proposed development will
result in an increase to impervious surfaces, typically roadways, roof areas, driveways and
hardstand areas. This increase to impervious areas would result in additional nutrient and
suspended solids discharging into downstream waterways if a water quality treatment
system was not implemented.


The impact of the development on water quality discharge has been assessed by the Co-
operative Research Centre for Catchment Hydrology’s Model for Urban Stormwater
Improvement Conceptualisation (MUSIC).



7.3.1       Assessment Criteria


The Water Sensitive Urban Design Technical Design Guidelines for South East Queensland
and Noosa Council Guidelines recommends the following minimum reductions in mean
annual pollutant loads leaving a development site compared to the developed
unmitigated case:


                80% reduction in Total Suspended Solid Load;
                60% reduction in Total Phosphorous Load;
                45% reduction in Total Nitrogen Load;
                90% reduction in Gross Pollutant Load.




7.3.1   Proposed MUSIC Model Concept


The efficiency of the proposed treatment train has been identified by the Model for Urban
Stormwater Improvement Conceptualisation (MUSIC) developed by Monash University.




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