RFI - SWMP.pdf

6.2      Proposed Drainage


The proposed site drainage is detailed in drawings SCG 31131- SW1.1 thru SW1.5 (Appendix D) and
is discussed below.



6.2.1    Catchments



Roof Catchment



         1.     Runoff from catchment A, consisting of the roof area of buildings containing units 17-22
                and unit 1 will flow via downpipes to an internal drainage network where it will be
                directed to an underground rainwater tank for re-use. The tank will then overflow to the
                Eumundi Noosa Road kerb and channel (lawful point of discharge).
         2.     Runoff from catchment B, consisting of the remaining roof areas of the site, will flow via
                downpipes to an internal drainage network where it will be directed to the on-site bio
                retention/detention basin prior to discharging to the existing inter-allotment drainage
                network located in Lot 99–101 on SP106085 (lawful point of discharge).



Ground Catchment



Surface runoff from the hardstand and landscaping areas will be directed to a series of entry pits and an
underground pipe network to the on-site bio retention/detention basin. The treated/detained runoff is
then discharged to the existing inter-allotment drainage network located in Lot 99–101 on SP106085
(lawful point of discharge).



6.2.2    Peak Flow Mitigation



As shown in Table 6.3 Stormwater peak discharge will increase as a result of the proposed development.
Therefore, it is proposed to utilise an OSD system to mitigate the peak stormwater discharge rates from

SCG Consulting Engineers                   Page 18                                 SCG Ref: 31131(SWMP)