Attachment 7B - Site Based Stormwater Manamgment Plan by ADG

                                                                   RACV Noosa Resort: 94-142 Noosa Drive, Noosa Heads

                                                                             ADG Ref: 22366 C R10 Rev04 14.12.22.docx

                                                                                                      December 2022

          Table 19 of the Bioretention Technical Design Guidelines (Water by Design, 2014). These plants
          provide additional treatment and will prevent clogging of the basin. Runoff within the bioretention
          area gradually infiltrates the soil layers, assuming the in-situ soil of the area is sand. This assumption
          is based on the neighbouring Geotechnical Report (Refer Appendix I) undertaken by Coffey
          Geotechnics for the Noosa Sanctuary Project, which states that the site location has sandy soil
          texture up to a minimum depth of 10m. It is recommended that a hydraulic conductivity test be
          performed by an experienced geotechnical engineer at the detailed design phase to confirm the soils
          permeability and infiltration capability.

 6.5      Rainwater Harvesting – Reuse Minimum Sizing of Rainwater Tank
          To satisfy Council’s code performance outcomes by reducing the need for mains water, the roof area
          is to be connected to a rainwater tank with a minimum capacity of 5,000L in accordance with
          Department of Housing and Public Works MP4.2 – Rainwater Tanks and Other Supplementary Water
          Supply Systems. For the eight proposed cabins this equates to a total rainwater tank volume of 40
          kL. Each rainwater tank is to be plumbed to be available for outdoor cleaning, washing machines
          and toilet flushing in accordance with Council’s WSUD Planning Scheme Policies.

 6.5.1    Internal Demand

          To calculate expected internal demand, the following assumptions were made:

             Toilet requires 25 L/day (per person) in accordance with Table 4.4 of the MUSIC Modelling
             Guidelines 2010;

             Laundry requires 21 L/day (per person) in accordance with Table 4.4 of the MUSIC Modelling
             Guidelines 2010;

             Peak occupancy of two (2) people per dwelling for the proposed 16x 2-bedroom units for the
             holiday accommodation in accordance with Table 4.3 of the MUSIC Modelling Guidelines 2010.

          Based on these assumptions the required volume for the internal demand component of the
          rainwater tank is calculated as;

              25 L/day (per person) + 21 L/day (per person) x 2 people per dwelling (peak) = 92 L/day

              Daily demand (representing indoor use) = 92 L/d * 16 units = 1,472 L / day = 1.472 kL / day

 6.6      MUSIC Model
          The sites stormwater run-off for both the pre and post development were modelled using MUSIC
          (version 6.3.0) and the water quality objectives for South East Queensland specified in the SPP 2017
          of 80% TSS reduction, 60% TP reduction, 45% TN reduction, and 90% Gross Pollutants reduction.
          Since the site slopes toward Weyba Creek which is a High Ecological Value waters, the post-
          development pollutant discharge cannot be more than that of the pre-development discharge
          according to The Noosa Plan 2020 Water Quality and Drainage Code.




BRISBANE / DARWIN / GOLD COAST / HOBART / MELBOURNE / PERTH / SUNSHINE COAST / SYDNEY / TOOWOOMBA            Page 16