2014022_71_SeaviewTce_SWMP-revC_full · OPW16/0021

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urban! stormwater! management! systems! at! the! conceptual! level.! ! MUSIC! Version!
6.1.0,!released!in!2015,!was!used!in!this!assessment.!
Climate!data!for!the!catchment!was!sourced!from!the!MUSIC!model!database.!!The!
rainfall! and! evaporation! data! template! for! this! site! has! been! based! on! data! from!
Cooroy!from!1/1/1973T!31/12/1983!with!six!(6)!minute!rainfall!duration.!
The!“MUSIC!Modeling!Guidelines”!(Water!By!Design,!2010)!was!used!as!the!basis!for!
constructing! the! MUSIC! model.! ! The! default! parameters! of! the! MUSIC! model! were!
used!in!representing!the!treatment!nodes!(where!applicable).!!
Source! node! parameters! for! urban! residential! (roof,! road! and! ground! level)! and!
forest!from!the!“MUSIC!Modeling!Guidelines”!(Water!By!Design,!2010)!were!used!in!
the!MUSIC!model.!
The! following! scenarios! were! modelled! in! order! to! assess! the! performance! of! the!
proposed!development!and!treatment!devices:!

    1. Base! Case! –! developed! case! with! the! inclusion! of! the! building! with! a!
       conventional!impervious!roof;!
    2. Green! Roof! –! the! inclusion! of! the! roofed! areas! as! forest! source! nodes,! no!
       additional!treatment;!and!
    3. Mitigated! –! the! inclusion! of! the! green! roof! and! additional! water! quality!
       treatment!devices,!namely!bioretention!gardens.!

The!fraction!impervious!value!applied!for!each!of!the!source!nodes!in!the!scenarios!
outlined!above!are!detailed!in!Table!2.!
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Table!2:!Impervious!Percentage!

Source!Node!                            Base!Case!         Green!Roof!          Mitigated!
Driveway!                                 100%!               100%!               100%!
Deck!areas!(excluding!pool!
                                          100%!               100%!               100%!
surface)!
Roof!                                     100%!                 0%!                 0%!
Garden/lawn!                                0%!                 0%!                 0%!
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2.3.3 Catchment!Areas!
For!the!purposes!of!water!quality!modelling!the!development!site!has!been!split!into!
catchments! that! report! to! the! various! water! quality! treatment! devices.! Each!
catchment! is! then! divided! into! roofed,! paved,! road! and! grassed! areas.! ! Significant!
areas!of!the!site!remain!undeveloped!and!have!been!included!in!the!MUSIC!model!as!
forested,! however,! results! are! reported! upstream! of! these! areas.! Table! 3! outlines!
the!catchment!areas!represented!within!the!MUSIC!model.!The!stormwater!quality!
catchments!are!provided!in!Figure! 5.!External!catchments!have!not!been!modelled!
as!they!do!not!contribute!to!the!water!quality!improvement!devices.!
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