Amended Stormwater Plan

SC5551 - 28 Elkhorn Dr, Tewantin                                                                     7


During the construction phase of the development, silt fences should be erected downstream of all
disturbed areas. In addition erosion and sediment control devices should be regularly inspected and
maintained following storm events. An Erosion and Sediment Control Plan will be provided as part of the
operational works application.



3.3      Operational Phase
During the operational stage of the development, the following impacts have been identified in relation to
stormwater runoff and water quality of the receiving waterways:
         Gross pollutants which include human derived litter, course sediment and vegetation
         Sediment and suspended solids
         Nutrients such as phosphorous and nitrogen
To target these potential pollutants stormwater quality improvement devices (SQID’s) are proposed to be
incorporated within the design.


3.3.1    Water Quality Objectives
The water quality objectives (WQO’s) for this site were determined in accordance with Appendix 2 of the
State Planning Policy (SPP) Dec 2013.


Table 3.2 indicates the minimum load reduction targets required to be met:


                                   Pollutant               Minimum Reduction Targets

                     Total Suspended Sediments (TSS)                   80%

                            Total Phosphorus (TP)                      60%

                              Total Nitrogen (TN)                      45%

                           Gross Pollutants (>5mm)                     90%

                                         Table 3.2 - Water Quality Objectives



3.3.2    Pollutant Export Modelling
The Model for Urban Stormwater Improvement Conceptualisation (MUSIC) has been utilised to calculate
pollutant loads from the proposed development and to predict performance characteristics of the proposed
treatment train. The pollutants have been generated stochastically and modelling parameters used were
adopted from the Water by Design “Music Modelling Guidelines for South-East Queensland”, and the
updated MUSIC Version 5 recommended parameters for Bio-retention basin nodes. MUSIC modelling
setup and results are attached within Appendix B.