RFI Response Letter

Response
The site is subject to an approved plan of development which includes water quality treatment criteria.
The proposed water quality treatment measures to be incorporated into the development are
understood to comply with the requirements of the plan of development.

Covey Associates provide the following response:

The resulting daily pollutant loads estimated by MUSIC modelling have been reduced significantly
from the previous submission to best meet the water quality objectives for the surrounding waterways.
The levels of reduction and estimated daily pollutants leaving the site have been provided to Seqwater
during discussions. Refer to updated Stormwater Management Plan SMP for details of proposed
treatment details.

21. Demonstrate the development is consistent with the SEQ Water Development Guidelines:
    Development Guidelines for Water Quality Management in Drinking Water Catchments 2012.

Response
Covey Associates provide the following response:

The third party advice from Seqwater dated 23rd August 2016 (CE:DB F16/3997) identified that they
had reviewed the submitted SWMP against the development guidelines identified in Item 21 above.
The only further information requested was the annual rainfall data used for modelling and a
comparison of the daily pollutants loads leaving the site against the water quality objectives. The
response to the third party advice from Seqwater is detailed separately within this letter.

…….

In response to the Stormwater Management items requested by Seqwater we have included the
following information within the Stormwater Management Plan. The MUSIC modelling rainfall data
used to model pollutant reduction targets is from Cooroy Composite Station 1973 to 1983 as this is
the most continuous dataset available. The annual rainfall for each year has been included within the
SWMP as requested. Refer to Table 3: Annual Rainfall in the report.

The report demonstrates that the measures proposed to reach the WQOs identified in the
Environmental Protection (Water) Policy 2009. The proposed measures significantly exceeded the
required pollutant reduction targets by State Planning Policy and Noosa Shire Council to ensure the
best possible change of meeting the WQOs and prevent any potential adverse impacts on Lake
Macdonald. The daily loads estimated in MUSIC for TSS and TN are mean values and only marginally
over the WQOs due to the low concentration of the remnant pollutants. There is no practical or
reasonable way to address the remaining concentrations. The report has been signed off by an RPEQ.

22. Provide a preliminary drainage plan to demonstrate there is adequate grade between
    underdrainage of the bioretention basin and receiving stormwater network.

Response
Covey Associates provide the following response:

A stormwater management (plan) has been updated to demonstrate there is adequate grade between
the underdrainage of the bioretention basin and receiving stormwater network. Refer to Plan SWMP01.

23. Demonstrate that the footprint allocated for the bio retention basin includes sufficient area for
    inclusion of batters from the surrounding area to the surface of the filter media consistent with the
    Water By Design Bioretention Basin Technical Design Guidelines (in particular Table 9).

Response
Covey Associates provide the following response:

The inclusion of a rainwater tank to the site has enabled the bioretention basin to be made smaller and
thus a batter can be constructed on the northern side of the basin to prevent a high drop from the