H - Revised Integrated Water Management Plan by Cardno (inc MUSIC file) (13.09.19)

                                                                                 Integrated Water Management Plan
                                                                         Noosa Marketplace : 2-20 HOFMANN DRIVE




Figure 7-6    Flow Capture Line L16

To the south at the legal point of discharge, (environmental reserve) there are minor increases in flood levels
during the 39% and 20% AEP events. These increases are caused by improvements to the drainage system
removing water that currently flows along Hofmann Drive and passing it under Hofmann Drive into these areas.
This change to the flow patterns is also seen in the larger events with flows at L16 (Figure 7-6) decreasing by
300 L/s in the 1% AEP, post development event.
Flows at culvert C26 (Figure 7-7), increase from 281 L/s to 733 L/s respectively for the existing and developed
cases during the 39% AEP event. This increase in flows is due to the extension of the existing non-compliant
750mm RCP that currently discharges onto the development area conveying stormwater more effectively
through the site, increasing C26 culvert capacity and the removal of the current flow path around the end of
the site access road. At C1, flows increase from 491 L/s to 610 L/s during the 39% AEP event due to the
improvements in drainage efficiency.
The insignificance of minor flood level increases is demonstrated in Figure 7-8, with the developed flood level
still 1.5 m below the Noosa Civic Carpark. The profile location is shown in Figure 7-9 while Figure 7-8 clearly
shows that there is no additional risk to persons, property, environment or infrastructure at this location.




V190428 | 10 September 2019 | Commercial in Confidence                                                        30