Ltr-20190925-IR Response-Noosa Marketplace_FINAL (1)

a) The TUFLOW model grid size was performed with a cell size of 2 metres. This size was deemed
   to provide enough resolution while ensuring reasonable run times. An updated plan for the existing
   and proposed scenarios, including showing the location of 2D elements, is included in Section 7 of
   Appendix H;

b) Please refer to Section 7.4.3 of the revised IWMP report (Appendix H) for a full response to this
   item. In the report, Figure 7-3 of shows the drainage proposed upgrades. Section 5 details that the
   detention tank will only mitigate local site flows.

      Figure 47 shows the intended stormwater drainage network overlaid on the levels plan.


Figure 47 – Level plans with stormwater infrastructures




    Source: Cardno

The post-development drainage map shows existing and proposed drainage features including the
proposed upgrades. Based on the revised flood modelling the proposed drainage includes:

•     In connection with aesthetic concerns and proposed landscaping within the car parking areas, as
      noted in Issue 8 sub-item 38 & Issue 9 sub-item 39b, the detention systems on site have been
      reviewed;
•     The proposal stormwater quality treatment now includes litter baskets on all inlets and a series of
      appropriately sized bio-retention gardens on the margins and central areas of the car park. These
      are appropriately sized to filter stormwater run-off, whilst including a variety of vegetation including
      perennial native plants and shrubs;




    Ltr-20190925-IR Response-Noosa Marketplace_FINAL                                                       78