Attachment C - Stormwater Management Plan - 30-32 Doonella Street_SMP-revA_full (00016826)

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2.4 Treatment!Measures!
Runoff!from!the!development!will!be!treated!via!roof!water!to!a!15kL!rainwater!tank!
with!site!flows!then!directed!to!a!bioretention!system.!!The!locality!of!the!treatment!
devices!are!detailed!in!Appendix!1.!

2.4.1 Rainwater!Tanks!
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Through! appropriate! design! of! rainwater! tanks! it! has! been! found! that! significant!
reductions!in!run"off!can!be!achieved.!!Rainwater!tanks!not!only!provide!temporary!
detention!of!stormwater!run"off,!but!also!provide!a!significant!alternative!for!water!
supply!uses.!!Collected!roof!water!is!suitable!for!garden!irrigation!or!toilet!flushing!
with!no!additional!treatment.!!!
Sizing!of!the!tank!volume!has!been!modeled!in!MUSIC!using!estimated!demands!for!
each!use!to!achieve!a!minimum!70%!reliability.!!It!is!proposed!that!the!water!stored!
in! the! tank! be! used! for! irrigation! of! the! proposed! landscape! areas.! ! Applying! an!
irrigation! rate! of! 548mm/yr,! the! annual! irrigation! demand! scaled! by! daily! PET! was!
calculated! as! 342kL/yr.! ! Based! on! the! roof! catchment! areas! and! the! demands!
estimated! for! each! use,! the! rainwater! tank! modeling! parameters! are! detailed! in!
Table!5.!
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Table!5:!MUSIC!Rainwater!Tank!Parameters!

                                   Parameter!            Value!
                              Total!Tank!Volume!
                                                          15!
                                      (KL)!
                               Surface!Area!(m2)!          6!
                              Overflow!Pipe!(mm)!         90!
                                Annual!Demand!
                              Scaled!by!Daily!PET!        342!
                                     (kL/yr)!
                              Daily!Demand!(kL/d)!         0!
                              PET!Demand!(kL/yr)!          0!
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