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

59.

59.

Reference is made to the Bayview Noosa Hydrology and Stormwater Management Plan
prepared by WBM Oceanics Australia and that the strategies contained in this report,
regarding water quality and quantity of the runoff leaving the site, will still be adopted for the
proposed development. There is concem that the percentage of impervious area on the site
has been increased since the CAS and it is requested that this be investigated to ensure the
proposed strategies are sufficient to handle any increases in quantity of runoff and any
deterioration in quality of runoff.

in this regard, please submit a copy of the Bayview Noosa Hydrology and Stormwater
Management Plan prepared by WBM Oceanics Australia for this application with any relevant
amendments to ensure the current proposal will have no detrimental impacts from the
quantity or quality of runoff leaving the site.

The previously prepared report, titled Bayview Noosa Hydrology and Stormwater
Management Plan, has been entirely revised to ensure that it specific to the proposed
development.

In relation to water quality, there have been some changes in the proposed stormwater
treatment train for the site. The revised treatment train is shown in Figure 2-1 of the updated
report, titled Viridian Noosa Hydrology and Stormwater Management Plan. The current
proposed stormwater treatment train is described below:

« Upslope runoff (i.e. above the gabion walls) will be either diverted around the
development, or captured and piped under the development directly to the creek,
where it will be released via appropriately designed outlets (includes energy
dissipation devices);

+ All areas external to the site have been extensively revegetated, the revegetation
works will be monitored and managed to ensure the program is successful;

+ Within the site, rainwater tanks will be attached to the Resort Villas, water from
the tanks will be reused for toilet flushing and landscaping;

+ Roof drainage (not going to the tank) and tank overflows will be piped directly to
the ephemeral creek;

: There will be some use of swales on site; and

+ The majority of road and open space areas within the resort will be captured in a
piped stormwater system and treated via gross pollutant traps prior to discharge
to the ephemeral creek.

Pollutant export from the site was assessed using MUSIC Version 3. The results of the
pollutant export modelling indicate that pollutant loads exported from the site (including the
already constructed Stages 1 and 2 and the current proposal) do not worsen when going from
the undeveloped site scenario to the fully developed site scenario. This was the result
demonstrated in the previous, Bayview Noosa Hydrology and Stormwater Management Plan
prepared in 2003. These results are however, reliant on the success of the revegetation
strategies in the undeveloped portions of the site.

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