Attachment 7 - Flood Impact Assessment - Covey · 132005.638.06

                                       Figure 3-1 – Model Extent with 1 meter Contours



         3.3     Temporal Patterns and Rainfall Intensity

         Temporal patterns are based on Australian Rainfall and Runoff (ARR) 2019 Ensemble Storm Temporal
         Patterns and have been sourced directly from ARR data hub. Rainfall intensities are typical for this area
         and have been sourced directly from the Bureau of Meteorology (BOM).

         3.4     Rainfall Durations

         Initially, flood modelling was undertaken for all rainfall durations ranging from 10 minutes to 720 minutes.
         This range of durations was simulated to ensure the critical durations for the catchment were captured.
         From reviewing the results, it was determined that the critical durations experienced at the proposed
         development site and immediately surrounding the site ranged from 20 minutes up to 360 minutes and
         therefore these were the durations adopted for this analysis.

         3.5     Rainfall Losses

         Adopted rainfall losses were sourced from ARR Data Hub. Rainfall losses for this region are as follows:
         •        Initial Losses – 27.2 mm; and
         •        Continuing Losses – 2.8 mm/hr.
         The losses were scaled up to consider 1.0 degree of warming.




Flood Impact Assessment                                                                                       Page 8 of 25
Project No 244035 | Ref No M25-0479Rpt – Issue A – January 2026