Appendix C - Stormwater Management Plan

31 October 2018


The runoff from the basement subsurface drainage pump out sump will be treated to neutralise any pH
increases due to the acid sulfate soils prior to discharge from site. This system will be separate to the
treatment of the stormwater runoff from the exposed surfaces of the site which will be treated by the
filtration cartridges.




                                                   Figure 3 – Treatment Plan

5.3.3.7 MUSIC Results
The resulting percentage based load reductions at the outlet are shown in Table 5 below together with
the Water Quality Objectives for the receiving waters.


                                                      Sources           Residual Load   % Reduction   Target %


Total Suspended Solids (kg/yr)                         1,840                   168         90.9         80

Total Phosporous (kg/yr)                                3.97                   1.25        68.5         60

Total Nitrogen (kg/yr)                                  29.9                   16.4        45.3         45

Gross Pollutants (kg/yr)                                208                      0         100          90


5.3.3.8 POD Pollutant Reduction

5.3.3.8.1          Litter
Rubbish bins will be located within the building and car park for use by staff and visitors. The carparks
will be cleaned regularly. As a result of this and with the installation of the treatment devices, levels of
litter exiting the site via stormwater are expected to be negligible.

5.3.3.8.2       Sediment
The TSS outflow is identified in Table 5 above. As can be seen from the above table the pollutant load
reduction achieves the Water Quality Objectives. The TSS level is therefore considered acceptable.




Excellence with Economy in Engineering                                                                           13
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