RFI - Engineering Response · MCU26/0001

         rainwater collection and reuse measures for non-potable purposes such as
         irrigation".

         To demonstrate that the proposed 3,000L tank maximises water efficiency on
         site, a Water Balance Model has been prepared for the development. The model
         assesses the capture of rainwater from a 242m² roof catchment and its reuse
         for irrigation of 158m² of landscaped area at an irrigation rate of 548 mm/year,
         using historical daily rainfall data for the Noosa locality (Bureau of Meteorology
         Station 040908).




     The Water Balance Model demonstrates that the single 3000L tank meets 93% of
     the irrigation demand in the 2023 design year (based on historical data) and 80%
     of the irrigation demand across the assessed 10-year rainfall record. In accordance
     with SC6.7 PSP6 This confirms that the tank is appropriately sized to the available
     roof catchment and the intended non-potable reuse, and that it is highly effective
     in capturing and reusing rainwater on site. Given the limited roof catchment area
     available, a larger combined storage volume would yield only marginal additional
     reuse relative to the increase in tank size.

     On this basis, the proposed 3,000L rainwater tank is considered to maximise water
     efficiency on site and to satisfy Performance Outcome PO2 of the Sustainable
     Building Design Code and has been implemented into the architectural design.


2613 – 17 Bottlebrush Ave, Noosa Heads – RFI Response Letter –15.05.2026                  3
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