RFI - Black & More - Stormwater Management Plan

 Stormwater Assessment
 The following design criteria have been adopted after consultation with the Noosa Planning Scheme (PSP05). Please note the
 below are only highlighted for relevance to this project, the entire Noosa Plan must be complied with, to the satisfaction of Noosa
 Council.
 -   For each allotment, two PVC kerb and channel adaptors to be installed in the kerb 1m away from both side boundaries
     (section 4.15)
 -   Design Recurrence Interval of 1 in 10 year for Commercial Development (Section 4.6a). Although a higher immunity will be
     provided.
 -   Allotments shall have a minimum grade of 1% (Section 4.9)
 -   Maximum of 25L/s out of each kerb adaptor (as advised by Client/Council’s Officer)
 It is proposed to discharge all roof water flows via downpipes to the kerb.
 The carparking area should be repaved and re-surfaced. It is proposed to install a surface drainage pit in this carpark, which will
 connect to the kerb adaptor also.
 It is unlikely any stormwater will enter the carpark area. However, this pit will provide a means to drain water from other sources
 (i.e. from cleaning with hose).
 It is also possible, in a major event, that stormwater may enter the car parking area from flooding of the adjacent ground. For
 this reason, we have considered the exterior catchment of the property adjacent the carpark which may contribute to stormwater
 flows as impervious, this is a conservative approach.
 The pre-development impervious area is approximately 375m2. The development increases this impervious area by
 approximately 50m2 (or 13%). The increase in runoff due to this increase is not appreciable and by splitting flows between kerb
 outlets will result in an overall improvement of stormwater drainage.




                                                Figure 7 - Existing Roof Catchments




                                     Figure 8 – Roof Catchments for Post Development Scenario



195 Weyba Road SMP
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