Appendix C - Stormwater Management Plan

31 October 2018



5.3.3.8.3        Nitrogen and Phosphorous
The TN and TP loads are identified in the above Table 5. As can be seen the TN and TP loads leaving the
site achieve the Water Quality Objectives. The Nitrogen and Phosphorous residual loads are therefore
considered acceptable.

5.3.3.8.4     Hydrocarbons
Hydrocarbons will become trapped within the filter cartridges.

The hydrocarbons will be removed during the maintenance of the filter cartridges.

5.3.3.9 Surfactants
Washing of cars is not expected on site for the proposed development, as a result surfactants should not
be an issue for the drainage system.

5.3.3.9.1       Heavy Metals
Heavy metals in stormwater runoff generally become attached to fine sediment. The filter cartridges
will remove the majority of this fine sediment. The removal of the fine sediment should effectively
remove most of the heavy metals in the runoff.

5.3.3.9.2       Pathogens/Faecal Coliforms
Domestic animals within the development will be under the control of their owners at all times and the
owners will be expected to clean up after them.

5.4       Proposed Stormwater Quality Treatment Devices

5.4.1 Locations

The location of the proposed stormwater quality treatment device is shown on MPN Plan 7700-DA.01
attached in Appendix 3.

5.4.2 Device and Size

The device type and size are depicted on MPN Plan 7700-DA.01 attached in Appendix 3.

5.4.3 Operation

The Stormwater 360 stormfilters will treat stormwater runoff from all surfaces within the proposed
development.

The Stormwater 360 stormfilters operate by filtering stormwater through media-filled filter cartridges.
As the stormwater percolates through the cartridges, pollutants, particulates, surface scums and
floating oil and greases are captured within the filter media. Once filtered through the media, the
treated stormwater is directed to a collection pipe.

Enviropods will be fitted to each field inlet.

The Enviropods consist of a screening bag supported by a filter box and structural cage. Modular plastic
deflector panels attach to the filter box and guide the flow of water to the screening bag. The screening
bag captures pollutants and allows water to pass through to the outlet pipe. Absorbent material inside
the screening bag captures oil and grease. Openings in the filter box allow water to bypass the screening
bag during high flow conditions.




Excellence with Economy in Engineering                                                                      14
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