220508.2 - Response to Information Request OPW

DME Projects Pty Ltd
P.O. Box 7481
Sippy Downs, QLD, 4556
Tel 0438 157 612
ABN 79 224 274 637

                        Response to Information Request (OPW23/0179) – 128 Gympie Tce Noosaville
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The proposed design achieves a continuous flood bund/barrier above the 1%AEP Defined Flood
Event as per the Planning Scheme Flood Hazard Overlay Code Table 8.2.6.3 AO6.5 editors note that
states “ Editor's note—Basements should have flood immunity above the 1%AEP defined flood event
with alternative means to mechanical pumping used to achieve such immunity”

Compliance with the AO does not require the basement flood immunity design to achieve the
1%AEP plus freeboard and freeboard has not been incorporated into the design accordingly. This
was investigated during the MCU application phase and in our opinion was confirmed by email from
Mark Lewis to Dale Martin on 16th February 2023 with the following:
    In regard to the specific site I would suggest that the driveway would need to achieve the 1%AEP
    level as a minimum before entering the basement. If that requires works on the driveway of the
    neighbouring property to achieves grades the adjoining property would need to be in agreement
    and I would suggest that you would need to ensure that your new works do not adversely impact
    on the adjoining development.

It is not possible to ramp the driveway to a higher level without introducing grades that are in excess
of the limits of AS2890.1, this was thoroughly tested during earlier design development. The site is
narrow and the requirement to access via the existing easement arrangement (not directly to
Gympie Tce) is a constraint that does not allow for any additional height to the driveway bund.

We also offer to Council that the basement is not a habitable space, will be constructed using
concrete and other flood resistant products and as such achieves compliance with all parts of QDC
MP 3.5. – Construction of Buildings in Flood Hazard Areas.

Issue
     The submitted dewatering management plan requires amendment.
     Information Required
          4. Provide an updated dewatering management plan that includes the following:
                   i. The DMP states that the shoring design is provided in Appendix C – however only
                   the civil engineering plans are provided. Include plans which show the location and
                   type of temporary shoring, groundwater spears, treatment and monitoring equipment
                   location and space requirements. Why do the structural engineering plans (provided
                   separately) only show shoring on 3 sides of the excavation? The type of CFA piling
                   (contiguous or secant) should also be stated on plan
                   ii. Remove references to ‘steel sheet piling’ on page 10 and refer to CFA secant piling.
                   Please note that the references should reflect the proposed method or the alternate method
                   chosen by the civil engineer.
                   iii. Update section 6.5.2 and 6.5.3 (Water Quality Monitoring) to include continuous
                   monitoring of pH and dissolved oxygen at the release point from the treatment
                   system. Total iron and aluminum are to be sampled where identified in the document
                   as ‘if required’.
                   iv. Update the figure in Appendix A to also show the stormwater network and specifically the
                   stormwater pit which the dewatering system will discharge into and the outlet headwall.
                   v. Update section 6.4.3 to identify that discharge is to the stormwater network prior to
                   entering the canal system.
                   vi. There seems to be plenty of room in the frontage of the site for establishing a
                   groundwater monitoring bore outside of the excavation and shoring system in which