Stormwater Management Plan

The zone between RL 5.0m and the inlet was recognised as having
particularly high ecological values, supporting numerous stands of swamp
mahogany and various species of fauna. Critically it was recognised that
these ecological values were dependant on maintenance of the natural
hydrogeological regime and no nett reduction in rainwater infiltration post-
development.

Consequently, and in order to counteract the effect of significant impervious
areas being constructed, the design approach will see stormwater runoff from
roofs and hardstand areas, up to 100-year ARI infiltrated into the natural
sands via a series of Rapid Infiltration Pits (RIPs) in order to achieve no net
reduction in rainwater infiltration.


       4.1 EXTERNAL CATCHMENTS                  RAPID INFILTRATION
       SWALE A

       The eastern end of the Serenity Close roadway and the existing
       residential building at the north-eastern corner of the site; Macquarie
       Lodge and Petrie Mansions were all constructed by RF Thompson
       Developments                                                    Settlers
       Cove Noosa Residential High Density Environmental Management Plan
       (EMP 1) produced by WBM Oceanics Australia.

       As mentioned above that approved document recognised the
       importance of rainwater infiltration for the ecology of the site and
       surrounding wetland areas and provided the ground rules for
       stormwater management on all subsequent Settlers Cove development.

       As such the current best practice of rainwater infiltration was not
       adopted for those early developments and instead stormwater was
       collected and conveyed to Noosa Inlet via traditional methods
       including the existing stormwater line mentioned in section 2.0 above.

       In or around 2005 the stormwater line was partially realigned with two
       (2) Rapid Infiltration Pits (RIPs) retrofitted in a nominal effort to
       promote rainwater infiltration (Refer Historical Engineering Drawings
       at Appendix F).

       The current proposal seeks to rectify the outdated approach of those
       earlier developments by constructing Rapid Infiltration Swale A at the
       existing low point in Serenity Close to intercept piped and overland
       flows from earlier upstream developments mentioned above. The
       swale will                                             rate all flows up
       to 100 year ARI.

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A6769/22/SWMP/RevA      October 2022                                         Page 3 of 6
SH/PL
                         Brah101 Pty Ltd t/as ALTA PROJECTS