Att8 - SWMP

to connecting the run in the existing dam to ensure water levels and quality is maintained to protect the existing
ecosystem around the dam. Once completed, the existing overflows and dam levels will be maintained at existing
levels, so downstream flows and run-off will not be impacted by the additional area.

The internal stormwater systems shall be designed to comply with:

     1. Noosa Plan 2020 Schedule 6 – PSP6 Engineering Design Standards;

     2. The Queensland Urban Drainage Manual (QUDM); and

     3. AS/NZS 3500.3:2015 - Plumbing and Drainage Part 3: Stormwater Drainage.

Refer to Appendix A - Proposed Concept Plans for the proposed development concept plans plan illustrating the
stormwater layout described above. Other elements of the proposed stormwater system are described in the
following sections.


          2.3.2 Lawful Point of Discharge
The site naturally drains towards the existing flow paths within the site, which continue downstream to the east
towards Lake Cootharaba and serve to discharge the sites run-off from the development across the site boundaries
towards the adjacent properties. The upstream catchments are also conveyed through these drainage flow paths.
The lawful point of discharge test, as described in Section 3.9.1 of QUDM, requires:

      •    The development does not change the flow characteristics leaving the site; or
      •    The proposed development will not alter the sites stormwater discharge in a way that may substantially
           damage a third-party property; or
      •    The location of the discharge from the site is under lawful control of the government or other statutory
           authority from whom permission to discharge has been received; or
      •    An authority to discharge has been obtained.

The relatively minor increase in impervious surfaces relative to the size of the lot means that the overall impacts to
run-off discharging from the development are insignificant as demonstrated in Section 5.1. The major flow
characteristics leaving the site are unchanged, and stormwater is not altered in a way that would substantially
damage third party property, therefore the existing drainage features continue to be the lawful point of discharge
from the site.



          2.3.3 Canoe Run Works
The lower dam within the site is proposed to be extended upstream to create a length of ‘at grade’ canoe run for
water activities at the camp. The proposal involves cutting a channel along the 8.5m AHD contour lines, to provide
a length of approximately 260m. The works will extend the existing water body by an area of approximately 7,200m²,
requiring earthworks cutting totalling 3,200m³ to achieve the proposed profile. As the run will be at-grade the
existing overflow locations and dam levels will remain as per their existing state and the extension will not result in
worsening for any upstream or downstream properties along the existing flow path.

The earthworks are to be sequenced such that the proposed canoe run and the existing dam will not be joined until
the canoe run has been filled to maintain the water levels and prevent sediment loss into the dam, avoiding impacts
to the existing ecosystem. Additionally, the canoe run will provide an overflow channel along its existing alignment
through a vegetation area designated VC1a which has been identified as reliant upon the creek water to maintain
its biodiversity and health.




Project number 20220146                                                                                    Page 8 of 20
File RECOR Stormwater Management Plan- 20220146.docx, 2022-09-06 Revision 0

P +61 7 5211 1003                         A 37 Mary St, Noosaville Qld 4566   E [email protected]    recorconsulting.com