Attachment I - Updated Engineering Report & SWMP

Table 6.2a compares pre and post development flows with the implementation of
the detention tank, with a range of frequent and infrequent storm events for the
ARR19 IFD.

                           Table 6.2.a: Pre v Post Developed Flows




       Refer to Appendix D for full Detention Tank modelling results and data
       provided by the Australian Government, Bureau of Meteorology.

       6.3    Stormwater Quality Management

              In accordance with Noosa Council planning scheme requirements
              water quality treatment will be required to be provided. Stormwater
              Quality Treatment is proposed to be undertaken via the
              implementation of a bioretention basin and swales.

              The Healthy Waterways Water Sensitive Urban Design Guidelines
              for South East Queensland recommends that stormwater quality
              treatment trains are designed to achieve the following reductions in
              mean annual pollutant loads, compared to the traditional untreated
              case.


                     80% reduction in Suspended Solids and Gross Pollutants
                     60% reduction in Total Phosphorous
                     45% reduction in Total Nitrogen
                     90% reduction in Gross Pollutants

              6.3.1 Proposed MUSIC Model Concept

              The concrete roadway and parking and roof water runoff will drain
              directly to stormwater pits which will connect into the bioretention
              basin, via the detention tank.



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A6035/21/Engineering Report/30-32 Doonella Street, Tewantin                  Page 5 of 9
May 2021    WM/tk
                                    Alta Projects P/L