8. Volume 5 - Stormwater Management Plan

                                          LAMBERT & REHBEIN
                                             ENGINEERS • MANAGERS • SCIENTISTS


The MUSIC modelling program is able to simulate the quantity and quality of stormwater runoff
from catchment sizes which range from a single house lot up to 100 km2. The program is able to
report on the pollution uptake efficiencies of a wide range of treatment measures.

The model can be used to generate both pollutant concentrations and long term pollutant loads
and is recognised as the most appropriate modelling software for the planning of stormwater
treatment measures for commercial catchments.

4.3.1   GENERAL MUSIC MODELLING APPROACH

MUSIC modelling was conducted generally in accordance with the Healthy Waterways Water by
Design “MUSIC Modelling Guidelines, Version 1.0, 2010”. The MUSIC guidelines suggest that
the timestep of each model should match the time of concentration of the smallest source node
and the smallest detention time of any treatment devices. As WSUD principles are to be applied,
a six (6) minute timestep should be adopted to match the range of treatments incorporated and
the low time of concentrations expected from the catchment.

Table 11 below, details the MUSIC parameters utilised in running the model.
                         Table 11 MUSIC Model Hydrological Parameters

                     Parameter                                      Description
                                                    Cooroy Composite -SCRC North (Stn. Number:
               Meteorological Data
                                                         40059) from 1973 to 1983 inclusive
                    Source Node                          Commercial – Road, Roof, Ground
              Modelling Time Step                                    6 minute
                    Drainage Link                                   No Routing
             Pollutant Concentration                     Commercial – Roof, Ground, Roads
           Rainfall-Runoff Properties                               Commercial


The MUSIC model defaults of k and C* assist in the definition of treatment performance and are
based on research and judgement by academics and industry leaders assisting the eWater
Cooperative Research Centre (CRC). The k constant is used in a first order kinetic model to
simulate the removal of pollutants within the treatment system. C* values represent the
background concentrations of pollutants for end of line treatment measures. All modelling for this
study has used the default values for k and C*.




 Ref: B16239CR002                                       - 12 -                       Stormwater Management Plan
                                                                                  Noosa Energy Centre - Noosaville