06/0823 - Applicant's Response to Information Request including Attachments [As Published] · 132006.823

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In relation to the site's hydrology, the already constructed Stages 1 and 2 and proposed
development were modelled using the RAFTS-XP hydrologic package. The results of this
modelling indicate that the peak flows from the site (for a range of critical storms ranging from
a 1 year through to a 100yr event) do not increase the peak flows at the main site outlet. The
reason for this is that despite there being an increase in the total flows from the catchment,
the flows from the developed portions of the catchment are discharged faster than flows that
come from the upslope areas (e.g. the National Park). As such the larger flow volume is
better distributed and does not result in a lumping effect which would have seen increases in
the peak flow rates.

The revised report Viridian Noosa Hydrology and Stormwater Management Plan can be
provided to Council Officers upon request.

Please provide a plan showing locations of rainwater tanks for each dwelling unit. Schedule 8
of The Noosa Plan shows the site as being located in a Rainwater Tank Area and as such
needs to comply with the requirements of this schedule.

The amended plans detail the provision of 3000 litre rainwater tanks for all Villa
accommodation units. The tanks are proposed to be located within the building undercroft
areas, and will be supported by the Villa structure. It is noted that these tanks will be
plumbed into service the surrounding landscaping and toilets of each Villa.

Please provide site details as to how stormwater outlets will be designed to ensure flows are
not concentrated and will not cause erosion.

Stormwater outlets will be designed similar to the existing construction outlets using both pipe
work, gabions or ‘rip rap’ basins to prevent scouring. Plans detailing these stormwater outlets
are included in Attachment 20.

It is proposed to review each outlet on site with Council and amend construction techniques
to suit individual outlet issues that may arise.

As detailed in Item 57 of this Response, The applicant’s on-site representative will hold a
weekly review meeting with Council Officers, and will then instruct the Head Contractor to the
reviewed design (ie. if any changes are required).

Please provide details on the Stormwater Treatment Train proposed for the site when in
operation.

The revised treatment train is shown in Figure 2-1 of the updated report, titled Viridian Noosa
Hydrology and Stormwater Management Plan. This revised report can be provided upon
request.

Council requires all basement carparks to be gravity drained. Please provide details of the
drainage plan for the site.

It is acknowledged that all basement carparks are to be gravity drained. Detailed drainage
plans will be submitted as part of the Operational Works application to Council.

Stormwater outlets are shown on plans included in Attachment 20. These plans show the
drainage outlet levels, drainage line levels and lowest building floor levels. All outlet levels
are well below the level of adjacent building basements. Ail buildings will be connected to the
proposed new drainage systems except Building | (N). The basement of Building | (N) will be
connected to the existing drainage system that runs to the north. Invert level of the existing
drain is RL 24.71 and the basement level is RL 27.00.

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