2014022_71_SeaviewTce_SWMP-revC_full · OPW16/0021

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7 Conclusions!
It! can! be! seen! from! the! results! presented! in! Table! 6! that! the! treatment! train!
proposed! for! the! development! achieves! the! performance! criteria! set! by! the! NSC.!!
Annual! Load! Reductions! of! Total! Suspended! Solids! (TSS),! Total! Nitrogen! (TN)! and!
Gross!Pollutants!(GP)!have!been!met.!!
A! detention! system! consisting! of! a! Stormwater! Tank! and! a! detention! basin! is!
proposed!on!the!site!in!order!to!achieve!Council’s!nonTworsening!criteria.!Table!15!
and!Table!16!provides!a!comparison!of!the!peak!existing,!developed!and!mitigated!
flows.!!It!can!be!seen!that!whilst!peaks!flows!increase!under!the!developed!scenario!
in! Catchment! 2,! the! modelled! detention! tank! ensures! nonTworsening! is! achieved.!!
Similarly! the! inclusion! of! the! small! detention! basin! at! the! northern! end! of! the!
driveway! ensures! that! the! peak! flows! within! Catchment! 1! are! mitigated! to! preT
development!condtions.!
This! plan! demonstrates! that! effective! treatment! of! stormwater! generated! by! the!
proposed!development!can!be!achieved!through!the!integration!of!Water!Sensitive!
Urban! Design! (WSUD)! principles.! ! Through! the! incorporation! of! bioretention!
gardens,!reuse!and!detention!system,!the!plan!successfully!demonstrates:!
    •   Compliance!with!the!requirements!of!NSC’s!Water!Quality!Objectives;!
    •   Ecological!sustainability!in!terms!of!the!development’s!impact!upon!receiving!
        waters;!!
    •   Compliance!with!NSC!nonTworsening!of!peak!flows!in!the!2,!5,!10,!20,!50!and!
        100!year!ARI!storm!events!(Development!Condition!28a);!and!!
    •   Addresses!concerns!raised!in!the!NSC!RFI!(dated!5!April!2016).!

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