RFI - Stormwater Management Plan

5.0    EXTERNAL CATCHMENTS

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 during the 1990’s and early 2000’s
predating the Settlers Cove Noosa Residential High Density Environmental Management
Plan (EMP 1) produced by WBM Oceanics Australia.

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.

Following on from discussions with Council officers it is now proposed that flows
from external catchments be re-routed through the development site on a revised
alignment but in a traditional fashion consisting of minor event flows conveyed
underground via piped drainage with a landscaped major event overland flow path
above.

Architectural changes made in response to planning matters now provide a viable
alignment for a relocated stormwater line and emergency overland flow path
westward along the northern face of the proposed building and discharging to the
Serenity Close cul-de-sac head.


       5.1 External Catchment Drainage Route

       The proposed route for minor event pipework and major event overland flow
       will follow the northern face of the building/southern extent of landscaped
       area in order to minimise impacts on large mature trees which may need to be
       preserved. A pipework alignment just 2m from the building would see
       shallow excavation works limited to a width of 4m for the landscaped channel
       base with a further maximum 5m for gentle landscaped batters.

       Whilst it is anticipated that safety concerns would generally preclude large
       trees from being preserved any closer than 10m or so from buildings discrete
       retaining walls could be utilised outside the 4m channel base should this prove
       not to be the case.

       Whilst an easement in favour of Council is proposed over the external
       catchment system, inspection and maintenance of the swale, pits and pipes
       would fall to the hotel operator.




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A6769/22/SWMP/RevB – June 2023                                              Page 7 of 9
SH/PL
                       Brah101 Pty Ltd t/as ALTA PROJECTS