Information Response

Item 21

It appears that a detention basin was provided within the downstream drainage
reserve as part of the original development of the industrial estate. Consider
whether the detention tank proposed is necessary given this downstream
infrastructure.

Response: Please refer to the Engineering RFI Response Letter and amended Engineering
Plans prepared by Barlow Shelley Consulting Engineers.

Item 22

If the detention tank is retained, address the following:
    ● Sizing appears to be small given the land use change. This may be due to the
       low initial loss values adopted for pervious surfaces in the model. Provide
       further information of how rational method flows were calculated, including
       tc estimates. Provide, as a comparison, detention sizing based on QUDM
       recommended initial pervious loss rate of 20mm.
    ● Provide survey for the existing drainage system that the detention tank will
       connect into (i.e. existing pit IL and pipe diameter and outfall IL).
    ● The outlet structure from the detention tank is unclear. Is the final outlet an
       upstand 225 dia pipe as seems to be shown? If this is the case won’t the
       upstream orifices all be drowned?
    ● Regardless of the above, for whatever outlet pipe is selected for the detention
       tank, demonstrate that the final outlet won’t drown the orifices and that the
       assumptions in the model will be met (eg. The outlet pipe from the tank
       should be set down lower than the lowest orifice so that it does not become
       drowned)
    ● An access chamber to the detention basin outlet structure is shown and is
       supported. However why is the lid on this chamber shown as a grate rather
       than a sealed lid? Won’t the grate allow flows to bypass the detention tank?

Response: Please refer to the Engineering RFI Response Letter and amended Engineering
Plans prepared by Barlow Shelley Consulting Engineers.

Item 23

Provide amended plans that detail compliance with the Driveways and Parking Code
removing the tandem spaces.

Response: An additional 11 car parks have been proposed in addition to the 32 required by
the code. The tandems have been maintained, however, these are in addition to minimum code
requirements and will be maintained for use by staff. Being located west of the Bruce Highway
this surplus of parking is a crucial feature of this site. It is further noted that there is nothing in
the planning scheme that expressly limits that tandem parking.




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