33522 Stormwater report018-01 SWQA issued 180704 · MCU18/0001

                                                                                   CIVIL ENGINEERING PROJECT MANAGEMENT
                                                                                          SEDIMENT AND EROSION CONTROL




           RESOLUTIONS

                   Increase in Infiltration Volume

With an increase in runoff volume, the infiltration system would need to be increased to provide adequate
capacity. Additional Atlantis Matrix modules could be added to the site and linked to the existing infiltration
to achieve the additional capacity required. This additional volume of 0.35m3 could be achieved by installing
an additional module of 0.366m3 capacity. While the Atlantis Matrix systems are easily retrofitted, the location
of the existing system underneath the shared concrete driveway would need to be cut, removed and replaced
in order to make the change.

                   Diversion of Stormwater

The design of the proposed development provides the opportunity to divert some of the captured stormwater
to the street frontage. The reduction in catchment of 83m2 is shown in Appendix B.
By diverting this runoff via roof water pipes and kerb adaptors to the Stevens Street frontage, the catchment
being diverted to the infiltration system would be dramatically reduced from 433m2 to 350m2. This would
mean that the impervious area would reduce to under 70% (i.e. 350m2/506m2) and sufficient storage capacity
made available within the existing system.

                   Removal of Drainage Swale

With the proposed development reshaping the fall of the lot to numerous localised areas, it is expected that
the existing cut-off drain along the rear of the property is no longer needed. A roof water pipe system could
direct flows from the property to the infiltration system (and Stevens Street). It is expected minor adjustments
would be made to the existing 900x600 field inlet pit to suit the proposed driveway design.




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   2261 david low way, peregian beach, qld 4573       acn: 626671092            [email protected]