Attachment 7 - Civil engineering report and plans

                                                                                                        STP CONSULTANTS



3.       Stormwater Management Plan
3.1      FLOOD STUDIES
         According to the Noosa Shire Council Flood Study, the site is not subject to flood inundation at the AEP 1% level.

3.2      STORMWATER DETENTION
         Comparison of the impervious areas between the existing layout and the ultimate layout following Stage 3B, shows
         no increase. As there is no change to the impervious area, there is no change to the overall site runoff. As this is
         the case, there will be no requirement for on-site detention.

3.3      STORMWATER QUALITY
         Although the site area is greater than 2,500m2, the proposed development does not result in a change to the net
         developed area. Also, the area of disturbance will be less than 2,500m2. In accordance with the requirements of
         the State Planning Policy, stormwater quality treatment will not be required.

3.4      SITE STORMWATER DRAINAGE
         A preliminary stormwater drainage layout is illustrated in Figure 3.3. The roofs and paved areas are to discharge
         or connect directly to the existing internal stormwater infrastructure via roof water and grated inlet pits then
         connect to the open drainage structures that currently discharge to the eastern boundary.

         The existing access track that is positioned downstream of the stormwater outlet is in disrepair and subject to
         washouts during severe rain events. A rock-lined causeway is proposed to ensure trafficability during rain events.
         Detailed design drawings are included in Appendix B to this report.

3.5      EXISTING STORMWATER INFRASTRUCTURE
         The site currently drains to the wetlands to the north-east, which is the Lawful Point of Discharge as illustrated in
         Figures 3.1 and 3.2 below.




Civil Engineering Report | STP21-1452                                                                                    5