Attachment 5A - Noosa Landfill RRA Flood Assessment

Noosa Landfill RRA Flood Assessment



6 RESULTS
Base Case and Proposed Case peak flood depth maps are provided in Appendix B and C
respectively. Modelling predicts that the area of proposed filling is subject to peak depths of up to
approximately 700mm in the base case modelling of the DFE event. Peak DFE flood levels are
predicted to increase by up to approximately 600mm around the fill pad in the proposed case.

Peak flood level impact mapping is provided in Appendix D. For ease of reference an extract of
the DFE peak flood level impact map is provided on Image 6-1. The impact mapping shows that
the proposed fill pad is predicted to cause a re-distribution of floodwaters across the northern site
boundary. There are increased flood levels on the western side of the floodplain and reduced
levels on the eastern side downstream of the fill pad. These impacts occur in bushland areas only
so are likely to be of no consequence. If necessary, it would be possible to significantly mitigate
this effect by including a flow spreading channel along the norther edge of the fill.

The predicted flood level increases do not affect any infrastructure on the site or the surrounding
area.

Proposed case peak flood levels in the drains surrounding the RRA fill pad are shown on Image 6-
2.

Proposed case peak flood velocities in the area are less than approximately 1.2m/s.




Image 6-1 Extract of the 1% AEP Year 2100 Peak Flood Level Impact Map (DFE)


J00352R1V2                                                                                        10