17155 - Stormwater Quantity Assessment Letter - Rev 0 · OPW17/0612

                                                                       MORGAN CONSULTING
                                                                      E NGINEERS P TY LTD
                                                                                    16003/CG
                                                                                        Page 2




drainage infrastructure within Resort Drive and connections to the development have been
designed for the 10 year ARI (minor storm) event while the drainage flow paths through
Noosa Springs Resort, which includes overland flow paths and underground drainage, have
been designed for the 100 year ARI (major storm) event.




Figure 1: Drawing SW 1 from Noosa Spring Master Drainage Report (June 1995) by Ralph Grierson

Based on this report, the Resort Drive road pipe drainage and property connections to the
development have been designed for the minor storm event with the site developed to an
imperviousness of 50%.

2.0 Stormwater Quantity Analysis

XP-RAFTS was used to model the peak discharges from the development under both existing
(pre development) and proposed (post development) conditions.

       2.1 Pre Development

Refer to the enclosed Pre Development Catchment Plan for the catchment details.