20220089 Jirrima Cr SWMP

                                           Figure 3.1 – Adopted Surface Material for Each Area




          3.3.4 Boundary Conditions
Downstream of the site, the waterway that passes through the site discharged into the unnamed tributary of Ringtail
Creek downstream of the property, which has a larger catchment area. To account for tailwater impacts arising from
the flooded condition of the downstream environment, the TUFLOW grid area has been extended to incorporate
the larger upstream and downstream catchment of the downstream waterway to model it under peak flow
conditions. Tailwater assumptions influencing the hydraulic performance of the culverts are therefore allowed for in
the proposed design.

The downstream Boundary conditions were generated for outflow channels having a depth greater than 0.3m
along the downstream boundary, with the boundary energy slope as measured from the lidar data for the
downstream drainage feature channel. A cut-off depth of 1cm was used for the modelling results to minimise
superfluous output.


          3.3.5 Drainage Culverts & Pipes
Within the catchment area, major culverts and crossings have been identified, and their dimensions and levels have
been obtained from Noosa Council Intramaps. Where levels were not available for a crossing, the invert levels
assume the height of the LiDAR topography at the inlet and outlet locations.



Project number 20220089                                                                                        Page 11 of 23
File 20220089 Jirrima Cr SWMP.docx, 2023-05-09 Revision 0


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