20210153 - Maple Street SWMP

     2.3. Proposed Development Drainage Pattern

          2.3.1 Stormwater Concept
Stormwater run-off from the site will be managed through a combination of pit inserts, stormwater
detention tanks and an end of line bioretention swale to treat run-off from the development prior to
discharge from the site into the legal point of discharge for the development, being the Myall Street
drainage system downstream of the site.

Stormwater drainage lines will be installed to captured surface run-off from the driveway and
hardstand areas throughout the proposed development area. Pit inserts will be provided in the
driveway pits to reduce gross pollutants and sediment loading in the run-off.

Roof water from the new buildings is to be drained via downpipes into a large stormwater detention
area with 50kL of attenuation storage that is used to reduce the overall developed site flows to pre-
development levels.

Run-off from the drainage network and the attenuated outflows from the detention area will be
discharged through a bioretention swale along the south-eastern boundary of the development,
allowing for treatment of minor flows, while providing an overflow path towards Myall Street for larger
storm events. The treated run-off will be collected by subsurface drains and an inlet pit at the end of
the swale allowing for the run-off to be discharged into the drainage system in Myall Street.

The run-off from the reconfigured lot which retains the existing dwelling will be directed towards a
drainage pit at the rear of the dwelling to be conveyed through the stormwater network and
discharged into Myall Street. As the proposed attenuation measures restrict stormwater quantity
peak flows from the development to existing levels, there is considered to be no worsening to the
downstream network to which the site will discharge and therefore sufficient capacity is available to
service the development.

The roof and allotment drainage system for the proposed site shall be designed to comply with:

     1. Noosa Shire Council Planning Scheme Policy (PSP) - Engineering Design Standards – Roads,
        drainage and earthworks;

     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 Plan for the proposed stormwater drainage layout plan
illustrating the concept described above.



          2.3.2 Stormwater Catchments
A schematic layout plan of the proposed development and its drainage catchments as described in
the previous sections is shown below in Figure 2.3 – Proposed Catchments Plan.




Project number 20210153
File RECOR Preliminary Stormwater Management Report - 20210153.docx, 2022-03-31                                 Page 7 of 26
Revision 0

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