F - Traffic Response and Revised Traffic Impact Assessment (17.09.19)

41.   Demonstrate the modelling has considered the external catchments to the north and
      west of the site.
      To the north
            Eenie Creek Road formation and Easement T on SP182880.
            Eenie Creek service road adjacent to the northern property boundary.
      To the west.
            Commerce Court – through No 3 Commerce Court and Easement G on
            RP230888.
Issue – Flood Modelling
Further details of the flood modelling are required before an assessment of the suitability of
the model can be made.
Information Required
42.   Provide further details of the hydraulic model assumptions and a revised assessment as
      necessary to address the following:
      a.    Clarify model grid size and provide a plan showing location of 1-D elements in
            existing and proposed scenarios
      b.    Provide a plan showing the locations of the proposed drainage upgrades/features
            described in the post-development scenario (Section 6.4.3). Is the detention tank
            proposed to detain only the local site catchment flows?
      c.    Provide plans of existing and proposed roughness values
      d.    Provide a plan showing topographic differences between existing and proposed
            scenarios
      e.    Provide further information on what blockage assumptions have been applied in
            the model consistent with ARR2016 and QUDM. Particularly since it seems pipe
            upgrades are a significant component of the impact-mitigation strategy being
            employed.
      f.    Provide a severe blockage/severe storm assessment in addition to the design
            blockages requested above. It should be clarified whether the proposed 750mm
            RCP is completely replacing the existing overland flowpath and if so, what the
            consequences are during a severe blockage or severe storm scenario. For clarity,
            complete removal of overland flowpaths is not supported and there should be
            provision made for severe blockage such that floor levels are not inundated in such
            an occurrence.
Issue – Local Flood Impacts
The local flood impact maps provided with the IWMP demonstrate that flood depths external
to the site are predicted to increase as a result of the proposal. This is in conflict with Specific
Outcome O17 of the Noosaville Locality Code and Specific Outcome O33 of the Business
Uses Code.
Information Required
43.   Provide revised proposed plans and flood impact mapping which demonstrates
      compliance with Specific Outcome O17 of the Noosaville Locality Code and Specific
      Outcome O33 of the Business Uses Code and specifically demonstrates no flood
      impacts external to the development site boundary.




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