MCU25 0079 - Negotiated Reference Documents (As Published)

                 2. 2       Law fu l P oint of D is ch ar ge

                 Under existing site conditions, roofwater runoff from the existing dwelling appears to discharge to
                 Clipper Street via kerb outlets. Ground level runoff will also discharge to Clipper Street via overland
                 flow.

                 The lawful point of discharge for the development is proposed to be the existing kerb and channel in
                 Clipper Street as per existing conditions. New on site stormwater infrastructure shall be constructed to
                 direct runoff from the development to the lawful point of discharge in accordance with NC requirements
                 at the build phase. Refer to Appendix B for further information regarding the proposed stormwater works
                 for the development.

                 2. 3       Ups tr e am D r ain ag e C onne ct ion

                 An upstream stormwater drainage connection through the lower half of Lot 183 has been proposed to
                 convey stormwater flows from the proposed house on the upper portion of the site.

                 2. 4       Flood ing

                 Noosa Council’s Flood Hazard Overlay mapping indicates that the site is not impacted by any flood
                 planning overlay. The site can therefore be considered flood free.

                 3      STO R M WAT E R Q UA N TIT Y M AN AG E ME NT


                 The stormwater quantity analysis of the existing and developed site conditions has been undertaken
                 with reference to the requirements and procedure outlined by:

                        •    Queensland Urban Drainage Manual (QUDM)
                        •    Australian Rainfall and Runoff 2019 (ARR2019)

                 The following section of the report discusses the proposed development’s impact on peak stormwater
                 runoff from the site and compares the existing site condition to ensure no adverse impacts to
                 downstream properties.

                 The DRAINS software package has been used for modelling the peak flows off site. ARR2019 rainfall
                 patterns have been adopted in drains utilising an Initial Loss – Continuing Loss (IL-CL) hydrological
                 model with loss parameter input as specified by the ARR2019 data hub for Noosa.

                 The following losses have been adopted in the DRAINS hydrological model:

                        •    Effective impervious area initial loss   1 mm
                        •    Effective impervious area continuing loss 0 mm/hr

                        •    Remaining area initial loss              20 mm

                        •    Remaining area continuing loss           3.4 mm/hr

                 Design ARR2019 storms for Noosa have been added into DRAINS utilising a rainfall pattern file
                 downloaded from the ARR2019 data hub along with IFD rainfall depth files downloaded from the Bureau
                 of Meteorology (BOM) website.

                 3. 1       E xi st i ng C at c hm ent
                 Catchment Area

                 The existing site currently consists of a detached dwelling. The existing surface generally falls to the
                 east towards Clipper Street.

                 The existing site area is currently approximately 921m2.


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Document Set ID: 23959990
Version: 1, Version Date: 23/07/2025