24-7-19 Attachment E - MPN consulting Response

18 July 2019 (7 10 M consulting

Response

The concept bulk earthworks layout and section on MPN Plan DA.03 demonstrates the bulk
excavation for the proposed basement will be less than 4m in depth from existing surface level. As
no groundwater was observed during the geotechnical investigation, no permanent dewatering
measures are anticipated to be required as part of the development. On this basis, the application
of lime to the acidic soils as recommended in the Acid Sulfate Soils Investigation will not result in
impact to the wallum frogs through dewatering measures.

Item 31 & 32
There is inadequate information to assess and verify the validity of the input nodes to the MUSIC model to
achieve the stated water quality outcomes.

No information was provided to verify what the input parameters to the treatment nodes of the MUSIC
model should be and whether they were correct as tested under the SQUIDEP protocol.

The extensive information provided does not address:

e howthe proposed proprietary devices have been tested against the SQIDEP protocol,
e whether the pollutant reduction claims of the proposed proprietary devices relate to sites of
comparable size or rainfall patterns to the subject site.

Further, the information provided does not demonstrate that the suitably qualified and experienced
professional offering verification has a minimum of 10 years urban stormwater testing and modelling
experience with examples to demonstrate appropriate reputation and track record within the stormwater
industry to provide such independent advice confirming that the devices are tested and verified as per the
SQIDEP protocol.

Fi formation Required

Please provide the information requested within previous information request 31 & 32.

Where this information is provided - the person verifying the pollutant reduction capability of the
proprietary device must also include the input parameters to be included within the MUSIC treatment
nodes.

Where this information is unable to be provided - review the stormwater design to instead include a
traditional bioretention basin with filter media area sized to 2.2% of the contributing catchment (to meet
the Water by Design Deemed to Comply solutions), or provide a music model to verify filter media surface
areas that are smaller than the 2.2% catchment size.

Response

The stormwater design has been updated to include a bioretention basin for stormwater treatment
instead of proprietary treatment devices. The updated stormwater design is detailed in the
attached Stormwater Management Plan along with the accompanying MUSIC Model.

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