Attachment 4 - Engineering Report · MCU18/0015

               Flows up to and including the major Q100 storm event will be conveyed
               to and attenuated by the proposed attenuation tanks. Inspection of Excel
               screenshots (Appendix E) demonstrates that attenuation of stormwater
               runoff to pre-developed levels is achievable for all proposed sub-
               catchments.

               A total attenuation volume of 5kL will be required under covenant for
               each proposed townhouse/residential dwelling with a further 3kL of
               storage to be made available for indoor non-potable and outdoor
               irrigation reuse (8kL total) with low flow pipes sized to provide non-
               worsening of peak discharge volumes for a range of storm events.

               Please refer to the attached engineering drawings in Appendix C for
               locations and details of proposed attenuation measures.

       6.4     Stormwater Quality Management

       The site currently consists of 100% pervious land with significant tree/shrub
       cover. The proposed development will result in ≤ 25% of the site area becoming
       impervious, typically made up of roof and hardstand/road areas.

       For the purposes of stormwater quality management, the following design
       standards have been considered;

                      Table 3.4 – Desired Standard of Service – Stormwater Management
                       – Noosa Priority Infrastructure Plan
                      Table 14-61 – Water Sensitive Design Code – The Noosa Plan
                      Table 2 – Implementation Guideline No. 7 - South East Queensland
                       Regional Plan.

       The proposed development will result in ≤ 25% of the site being covered by
       impervious surfaces. In accordance with Item 3 – Table 2 – Design Objectives for
       Urban Stormwater Management – Implementation Guideline No. 7 - SEQ Regional
       Plan the development is exempt from pollutant load reduction targets provided;

              Stormwater from all impervious areas is captured and managed prior to
                discharge
              Management of captured stormwater includes reuse of stormwater and
                /or infiltration of stormwater to native soils.




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C5756/17/Engineering Report - 27 Attunga Heights, Noosa Heads          5
January 2017   JW/jl