Scg 30086(L3) · OPW20/0227

8 December 2020
SCG Ref: 30086(L3)

By email: [email protected]

The Chief Executive Officer
Noosa Council
PO Box 141
Tewantin Qld 4565


Dear Sirs

       Re: Proposed Stormwater Reconstruction - Lot 110 N21846 #43 Witta Circle, Noosa Heads

Please find attached our proposed stormwater drain relocation design for the existing Council drain passing
through the above allotment.

For our design we are proposing to replace the existing 300∅ RCP with a 375∅ pipe on a new, slightly adjusted
alignment within the site but at the same levels of the existing pipe. The design also includes the construction
of a new side entry pit in Witta Circle and a new headwall at the opposing end of the pipe which drains into the
canal. A clear overland flow path is to be established through the site to the canal, which will cater for a 1% AEP
Storm Event overland flow. We have modelled the proposed stormwater drainage system using the program
DRAINS, using the existing pipe levels recorded via a site survey. A copy of the design can be provided if
required.

During the basement construction for the proposed dwelling the existing stormwater pipe will be undermined.
To counter this, a temporary 300∅ uPVC diversion pipe will be installed and suspended from the proposed piled
retention wall. Once basement backfilling has commenced the new 375∅ pipe can be installed

We are proposing a 1.5m wide easement be established over the proposed stormwater pipe. With this
considered and coupled with our provision of a clear overland flow path which currently doesn’t exist, we seek
Councils relaxation on the requirement for the easement to be centered over the new pipe. We envisage this
final offset between the pipe and easement centre lines will be less than 200mm. We don’t believe this will
present any access issues to the pipe as it will be reasonably shallow and small in size.

We look forward to Councils approval for the attached design. Should Council have any queries on this matter
please do not hesitate to contact the undersigned.

Yours faithfully


SEAN RICHARDSON - RPEQ 5835
For and on behalf of
SCG CONSULTING ENGINEERS

Enc SCG Drawings - 30086-CS, C1.1, C2.1, C2.2