124-003 Engineering Report

         STORMWATER DRAINAGE

It is expected that stormwater drainage management will be required as part of the development. This would
include quality control measures with treated stormwater runoff directed to the existing stormwater system
in the rear of the property and ultimately into the stormwater network in Gumdale Court to the south.

             Flooding

Flood mapping courtesy of the Noosa Council and provided in Appendix B indicates the site is not subject to
flooding from any sources.
The mapping demonstrates all defined major and extreme flood extents are limited to the Lake Entrance
Boulevarde in the south.

             Quantity

The objective of the stormwater management will be to limit the post-development, peak discharge to the
pre-development peaks in order to control flooding and erosion and to limit nuisance. It is expected that due
to the impervious site area being reduced from 100% to 85% and that major overland flows would be diverted
to the north, the post-developed conditions will be slightly lessened and detention will not be required. This
will be subject to a detailed analysis during the operational works design.

             Quality

The stormwater quality treatment measures will be designed to mitigate stormwater pollutants in accordance
with WSUD load reduction targets in Council’s Planning Scheme Policy for Development Works.
The stormwater quality management objectives during the construction phase will be addressed in separate
Erosion and Sediment Control Plans (ESCP) prior to the commencement of works. The efficiency of the
Stormwater Quality Improvement Devices (SQIDs) will be modelled for efficiency and will consist of baskets
(SPEL Stormbaskets or similar) in the carpark gully inlets and bioretention systems in the landscaping design



         SEWER RETICULATION

An existing sewer main is located along the northern boundary. A 150mm diameter (AC) pipe traverses the
property from the west to the east and flows towards the east. Being a proposed commercial development,
the sanitary drainage from the property will connect into a proposed manhole in the north east corner of the
site.


The existing sewer infrastructure is shown on the Assets map provided in Appendix C.


                                              Page 9 of 12
   2261 david low way, peregian beach, qld 4573      acn: 626 671 092          [email protected]